Help with 9mm loads and OAL

[TBL65]

Hello all,
Saturday I loaded up my first rounds ever in 9mm. Looking for some help on OAL.

Using 124gr RMR FP Matchwinner bullets
( https://www.rmrbullets.com/shop/rmr-in-house/9mm-124-gr-rmr-truncated-cone-flat-point-matchwinner/ )
CCI primers
W231 powder

My Nosler manual load data is 3.6-4.6gr with a OAL of 1.120”
Hodgdon site data is 3.9-4.4gr with a OAL of 1.150”

When I looked for info online I’ve seen people reporting using OAL between 1.080” and 1.135.”
A lot of people seem to report liking 4.3gr of W231 at either 1.125 or 1.135”

I did the plunk test in my Glock 19 barrel, and my loads from 3.6gr to 4.3gr all make the plunk noise, drop out under their own weight, and spin freely at 1.148-1.150”

I’m stuck on at what OAL to seat the bullets at and at what minimum or maximum length does it start to be a safety concern given the charge weights.

Being my first loads I want to be as safe and cautious as possible until I gain some experience. Any advice would be much appreciated!
Thanks

 

[Texas10mm]

Neither your Nosler manual or the Hodgdon site have data for RMR bullets.

In 9mm I load them as long as possible and still being able to plunk them.

Powder charge weight has no effect on whether or not a round will plunk. That's a function of OAL.

 

[sequins]

The OAL depends heavily on the shape of the projectile, which itself is based on bullet weight. 90-110gn projectiles have a relatively shorter COAL relative to 124-147gn bullets.

Your cone bullets are one of the longest styles and I'm not surprised it correspondingly has a longer COAL. If they plunk and cycle you're good to go- longer usually chokes on cycling if length is the issue, rather than the plunk though (unless it's too long for the chamber, and if you're plunking its surely not)

 

[TBL65]

Neither your Nosler manual or the Hodgdon site have data for RMR bullets.

In 9mm I load them as long as possible and still being able to plunk them.

Powder charge weight has no effect on whether or not a round will plunk. That's a function of OAL.

I did realize that, used the load data for 124gr to get myself close as I figure not many manuals have load data for the RMR billets.
1.150 seems about max for my G19. I’m thinking I will test them at the 1.148 I have them loaded to now and look for any pressure signs,Cycling issues and accuracy. Then try some a little shorter at 1.135 and just continue to test and look for any cycling issues, pressure signs, and accuracy.

The OAL depends heavily on the shape of the projectile, which itself is based on bullet weight. 90-110gn projectiles have a relatively shorter COAL relative to 124-147gn bullets.

Your cone bullets are one of the longest styles and I'm not surprised it correspondingly has a longer COAL. If they plunk and cycle you're good to go- longer usually chokes on cycling if length is the issue, rather than the plunk though (unless it's too long for the chamber, and if you're plunking its surely not)

Sounds like I’m being as safe as possible. They definitely plunk, so now I just need to see if they cycle okay and check accuracy. I imagine the 3.6gr at 1.148” may not lock the slide back. I bought this bullet style based on the reviews on being accurate and I always liked the flat point /hp style over round nose

I’ve also taken average OAL of some factory ammo, even though it’s 115gr, my freedoms munitions reloads had OAL from 1.155 to 1.160. Rem UMC as 1.106 to 1.111 and hornady critical defense 1.085 to 1.088. I understand these are different weights and profiles but are noted in for my 9mm data

Thanks for the reply’s so far!

 

[kcofohio]

You got the plunk pass and started low on you loads. I'd say you're on the right path.

 

[kcofohio]

On a new to me load, I start with the low load. Place just 1 round in the magazine, if after firing, the slide locks back, I feel I have a workable load. If the slide doesn't lock back, I repeat to the next higher load until the slide does lock back.

 

[ATLDave]

Going longer than the book data (up until you start jamming the lands - but that's no-plunk length) will reduce the pressure relative to the book. So if you're longer than book length and under the max, you should generally be safe.

 

[ray15]

Using 124gr RMR FP Matchwinner bullets
( https://www.rmrbullets.com/shop/rmr-in-house/9mm-124-gr-rmr-truncated-cone-flat-point-matchwinner/ )
CCI primers
W231 powder

My Nosler manual load data is 3.6-4.6gr with a OAL of 1.120”
Hodgdon site data is 3.9-4.4gr with a OAL of 1.150”

As pointed out above, your data is generated using different bullets and the characteristics of the bullet hugely affect pressure.

When I looked for info online I’ve seen people reporting using OAL between 1.080” and 1.135.”
A lot of people seem to report liking 4.3gr of W231 at either 1.125 or 1.135”

Again, with what bullet? There are a lot of threads on this specific RMR bullet here, I hope you are basing your survey on them.

I did the plunk test in my Glock 19 barrel, and my loads from 3.6gr to 4.3gr all make the plunk noise, drop out under their own weight, and spin freely at 1.148-1.150”

The charge weight isn't of concern here, only the geometry of the loaded cartridge.

I’m stuck on at what OAL to seat the bullets at and at what minimum or maximum length does it start to be a safety concern given the charge weights.

Guns vary a lot with respect to how much 'leade', or bevel they have on the edge of the chamber. The more leade, the longer OAL the gun will tolerate (within reason). If you use all the leade your gun has you can go longer sometimes to a surprising degree. Just ensure your stuff really is plunking correctly (color it up with a sharpie so you can see any contact marks) if you want to go as long as 1.15" with this bullet - I would see 1.08-1.12 as a more 'normal' longer OAL for it.

The SAAMI specification for chambers doesn't describe any leade, so I seat my stuff short enough to clear in those chambers, ensuring my 9mm Luger is really 9mm Luger and is safe to use in other guns regardless of how little leade they may have. With the RMR 124MW I use an OAL of 1.06", and with this OAL and BE86 I ended up needing ~0.2gr less than Alliant's published max charge for an unspecified 124gr. JHP to attain their velocity, which is where I stopped. A chrono is really helpful.

Being my first loads I want to be as safe and cautious as possible until I gain some experience. Any advice would be much appreciated!
Thanks

Although inconvenient and usually somewhat more expensive, it's a good idea to start with a bullet for which there is published data to directly guide you.

One of the first bullets I loaded was the RMR 115gr. FMJ RN, and it was difficult grasping how its unique characteristics affected OAL and pressure concerns whilst trying to learn everything else. Your situation with this W231 load is a good example. In the Hodgdon data there is the 125gr. jacketed bullet, the Hornady HAP, that hits max with 3.3gr. of 231. There is also the Sierra 125FMJ, which hits max at 4.8gr. Both are valid for the bullets used, but neither directly guides your choice for the RMR bullet.

The thing that makes the HAP hit max so early is its 0.356" diameter. The Sierra is a 0.355" bullet. There are (many) other factors involved but this is a big one. The RMR 9mm stuff is typically sized to 0.3555" and as such will likely fall between these two examples, meaning an unknown max charge in between 3.3 and 4.8gr. Typically in cases like this a starting charge of 3.6gr. is safe, but this one demonstrates how precarious the terrain can be once you are off the reservation of combos for which specific load data exists.

 

[mdi]

When I looked for info online I’ve seen people reporting using OAL between 1.080” and 1.135.”
A lot of people seem to report liking 4.3gr of W231 at either 1.125 or 1.135”

I pay very little attention to most data I see on line, and to no powder charges posted. ("They say", "I heard..", can lead to trouble.). I use my published reloading manuals for load data 98% of the time with a few time powder manufacturer's web sites. I determine my own OAL with the same methods mentioned above, starting long and shorten until the cartridge plunks. My first semi-auto was a 1911/45 ACP and I started with a classic load (right out of my manual, with a like/similar bullet for OAL). I started with minimum loads, right out of my manuals, and a bit long from book OAL. I shortened or lengthened the OAL as needed until I got a good plunking length then worked on the powder charges. Same process with my 9mms. Never a Kaboom, never a FTF...

 

[Walkalong]

Loaded to 1.073 to 1.075 OAL with 3.9 Grs of N320 and a CCI 500 primer they gave me 967 FPS from a 3" P-365, 1059 FPS from a 4.5" XDm, & 1075 FPS from a 5" Colt 1911.

Loaded to 1.073 to 1.075 OAL with 5.3 Grs of Silhouette and a CCI 500 primer they gave me 998 FPS from a 3" P-365, 1121 FPS from a 4.5" XDm, & 1150 FPS from a 5" Colt 1911.

Start low and work up, but this should give you some reference material to help you along with the data from PDFs etc at those OALs. It's how deep it is in the case that matters. I measured the RMR 124 Gr MW TrFPs at .555 long.

 

[LiveLife]

RMR 124 gr FP Match Winner ... W231 ... 1.150 seems about max for my G19. I’m thinking I will test them at the 1.148 I have them loaded to now and ... Then try some a little shorter at 1.135

Published load data COL/OAL vary because test barrels they used to measure chamber pressures have different leade (Space bullet jumps from case to start of rifling). And since most universal barrel fixtures used for testing are single shot that do not feed from the magazine, us reloaders must determine the OAL that will work in our pistols/barrels/magazines.


Load Development - First step in load development with a new bullet is determining OAL. There are two different OALs that we use, Max OAL and Working OAL. Max OAL is the longest length chambered round's nose will not touch the start of rifling. But the Max OAL may not reliably feed from the magazine. So we function test by feeding dummy rounds (no powder, no primer) at Max OAL from the magazine and see if they will reliably feed from the magazine (Pull slide back and release without riding the slide). If they don't, I will incrementally decrease the OAL (say by .005") until they do. Working OAL is the longest length that will reliably feed from the magazine. Often Max OAL can be the Working OAL but usually, Working OAL is shorter than Max OAL.


Determining Working OAL for Multiple Pistols - Just because a particular Working OAL works in your pistol doesn't mean it will work in another pistol as factory barrels can have different leade length, start angle of rifling, groove-to-groove diameter, different rifling type and chamber dimensions (SAAMI maximum or SAAMI mininum). Gen1 through Gen4 Glock barrels have leade length on the longer side and 9mm Glock barrels can allow longer than SAAMI max OAL of 1.169" depending on bullet nose type. In recent years (Including Glock with Gen5 "Marksman Barrel"), factory barrels have moved towards shorter and shorter leade length and thus require shorter Working OAL.

To address this new trend, this THR support thread lists max/working OALs of various factory/aftermarket barrels matched to particular brand/weight/nose type of bullets for reference - https://www.thehighroad.org/index.p...let-max-working-oal-col-for-reference.848462/

From the reference thread, following are listed as max/working OAL for RMR 9mm 124 gr FP Match Winner (Current production with larger .074" copper fold over at base - https://www.thehighroad.org/index.p...g-oal-col-for-reference.848462/#post-11077625):

• 1.150" / 1.150" - KKM aftermarket barrel
• 1.140" / 1.140" - M&P Shield factory barrel
• 1.095" / 1.095" - Tactical Kinetics aftermarket barrel
  
• 1.090" / 1.080" - Taurus PT-809
• 1.085" / 1.085" - Lone Wolf aftermarket barrel

So if you load for multiple pistols, use the Working OAL that will work with barrel with shortest leade. FYI, below is comparison picture of different RMR 124 gr jacketed bullets to show different max/working OAL depending on nose profile. OALs shown is Working OAL for my barrel with shortest leade.

Powder Work Up Consideration - Once a Working OAL is determined, then proceed to powder work up. One consideration I use when conducting powder work up is using significantly shorter OAL (deeper bullet seating depth) than published and I will reduce start/max charge by .2 - .3 gr depending on the amount of bullet seating depth.

If you look at comparison picture above with different nose type bullets, you will notice different bullet base lengths. Depending on the Working OAL and bullet type used, bullet seating depth will vary.

Start low and work up ... It's how deep it is in the case that matters. I measured the RMR 124 Gr MW TrFPs at .555 long.

Walkalong makes very good point. It's how deep the bullet base is seated inside the case neck that matters more than OAL. Usually, Truncated Cone/Flat Point bullets have longer base than FMJ/RN bullets and bottom of bullet base will get seated deeper in the case than FMJ/RN bullets.

So when referencing FMJ/RN load data that used 1.125"-1.150" OAL for FMJ/FP bullets at much shorter OAL which results in deeper bullet seating depth, I will consider reducing my start/max charges by .2 - .3 gr. As Walkalong suggested, it's good idea to start low as you can always go up.

Below are load data for 124/125 gr bullet from Hodgdon (Since 124 gr bullet weight can vary by 1.0 gr, I reference load data for 125 gr bullet interchangeably with 124 gr bullet) - http://www.hodgdonreloading.com/data/pistol

• 125 gr Hornady HAP W231/HP-38 Dia .355" COL 1.069" Start 2.8 gr (753 fps) 25,300 PSI - Max 3.3 gr (876 fps) 33,600 PSI
• 125 gr Lead Cone Nose W231/HP-38 Dia .356" COL 1.125" Start 3.9 gr (1,009 fps) 25,700 CUP - Max 4.4 gr (1,086 fps) 31,200 CUP
• 124 gr Berry's HBRN-TP W231 Dia .356" COL 1.150" Start 3.9 gr (920 fps) 27,400 PSI - Max 4.4 gr (1,037 fps) 31,900 PSI
• 125 gr Sierra FMJ W231/HP-38 Dia .355" COL 1.090" Start 4.4 gr (1,009 fps) 24,600 CUP - Max 4.8 gr (1,088 fps) 28,800 CUP

Note the different bullet types/nose profiles/diameters/COL/OAL and different start/max charges. IMO, RMR FP Match Winner comes closest to Lead Cone Nose as far as bullet nose/base and would feel comfortable referencing my initial/starting powder work up from. But as the Working OAL decreases below published 1.125", I would consider reducing my charges as I can always go higher.

And as ray15 posted, another consideration to factor is your barrel's groove-to-groove diameter and bullet diameter. Not all commercial 9mm jacketed bullets are sized the same and can vary from .354" to .356" (With .355" being typical) - https://www.thehighroad.org/index.p...re-sized-the-same.818806/page-2#post-10567453

Many factory barrels are oversized at .356"+ and accuracy benefit from using larger sized bullets (FYI Speer TMJ/Gold Dot are sized .3555" and Zero FMJ .356"). RMR 9mm jacketed bullet sizing run slightly larger at .3555" and this can increase chamber pressure a bit and may require slightly less powder charge to produce same muzzle velocity as published.


Determining Target Loads - For my powder work up, I look for two things:

1. Powder charge that will reliably cycle the slide and extract/eject spent cases
2. Powder charge that will produce smallest groups (most accurate)

As I conduct my powder work up and once achieve reliable slide cycling and spent case extraction/ejection, I will look for accuracy trend to determine possible light target loads. Depending on the powder used, this may not be the case as with slower burning powders, you may not achieve accuracy until high-to-near max load data.

And if I achieve reliable slide cycling and spent case extraction/ejection with start charge and good accuracy (especially with W231/HP-38/Sport Pistol and faster burning powders), I will "work down" from start charge to see if I can identify even lighter target loads. (Disclaimer: "Work down" below published start charges at your own risk)


Determining Most Accurate Loads - After my powder work up, once the most accurate powder charge(s) is identified, especially with light target loads, I will then incrementally decrease the OAL (say by .005") to see if accuracy improves without compressing the powder charge. You can calculate max case fill by following this post - https://www.thehighroad.org/index.php?threads/red-dot-9mm-and-case-fill.848934/#post-11078957

So even though your starting working OAL may have been 1.150", you may end up with 1.130" or even shorter at 1.080" as your most accurate load. (Of course, significant incremental reduction in OAL will also trigger incremental reduction in powder charge)

These are many reasons why members post different OALs for the same bullet.

I hope this helps with your load development.

 

[kmw1954]

bds, excellent post and I think you covered most everything clearly.
TBL65 so glad you started a new topic, I think it will help you and others tremendously. I believe you are on the right track with your loads and have a pretty good understanding of what is going on.

There is a topic on this site and a couple others that describe how to obtain MAX OAL using a fired case ,un-sized, and a bullet. The bullet should easily and freely start into the un-sized case and then slowly close the slide until it is in full battery. What this does is uses the barrel to seat the bullet and will give you the max length the barrel will accept. I use this method and find the shortest barrel in the bunch and then reduce length by.005 and that then becomes the COAL that I use for that bullet in my guns. I do that because I do not want to keep multiple loads of the same thing developed for just one gun.

BTW I have one 9mm pistol that I could load to 1.177" with the Berry's or Xtreme 124gr RN but they would never fit into the magazine.

 

[TBL65]

Wow some very good and lengthy information posted. I will reply to those who put the time to give lengthy reply this post.

Went to the range and shot my first loads which were 3.6gr to 4.3gr W231 with the RMR FP match winners. OAL was 1.148 (determined max for my Glock 19 and always fits in the magazine)

Charges 3.6-3.9gr either did not lock the slide back and/or had no/poor ejection. 4.0gr and above the ejection got slightly better.
I found my cases from 3.6-4.2gr, could not for the life of me find the one from 4.3gr. Inspected cases and saw no pressure signs. Although some cases (mainly the lower charges) were a bit dirty near the case mouth.

 

[kmw1954]

Charges 3.6-3.9gr either did not lock the slide back and/or had no/poor ejection. 4.0gr and above the ejection got slightly better..

That is pretty much what I expected to hear from those loads. 4.0gr of HP-38/W231 seemed to be the magic spot. Next you could try those same light loads at a shorter length. Though with were you are at with charge weight and length you should be well under Max pressures even up to the 4.6gr. load.

 

[TBL65]

As pointed out above, your data is generated using different bullets and the characteristics of the bullet hugely affect pressure.
Again, with what bullet? There are a lot of threads on this specific RMR bullet here, I hope you are basing your survey on them.
The charge weight isn't of concern here, only the geometry of the loaded cartridge.
Guns vary a lot with respect to how much 'leade', or bevel they have on the edge of the chamber. The more leade, the longer OAL the gun will tolerate (within reason). If you use all the leade your gun has you can go longer sometimes to a surprising degree. Just ensure your stuff really is plunking correctly (color it up with a sharpie so you can see any contact marks) if you want to go as long as 1.15" with this bullet - I would see 1.08-1.12 as a more 'normal' longer OAL for it.

The SAAMI specification for chambers doesn't describe any leade, so I seat my stuff short enough to clear in those chambers, ensuring my 9mm Luger is really 9mm Luger and is safe to use in other guns regardless of how little leade they may have. With the RMR 124MW I use an OAL of 1.06", and with this OAL and BE86 I ended up needing ~0.2gr less than Alliant's published max charge for an unspecified 124gr. JHP to attain their velocity, which is where I stopped. A chrono is really helpful.

Although inconvenient and usually somewhat more expensive, it's a good idea to start with a bullet for which there is published data to directly guide you.

One of the first bullets I loaded was the RMR 115gr. FMJ RN, and it was difficult grasping how its unique characteristics affected OAL and pressure concerns whilst trying to learn everything else. Your situation with this W231 load is a good example. In the Hodgdon data there is the 125gr. jacketed bullet, the Hornady HAP, that hits max with 3.3gr. of 231. There is also the Sierra 125FMJ, which hits max at 4.8gr. Both are valid for the bullets used, but neither directly guides your choice for the RMR bullet.

The thing that makes the HAP hit max so early is its 0.356" diameter. The Sierra is a 0.355" bullet. There are (many) other factors involved but this is a big one. The RMR 9mm stuff is typically sized to 0.3555" and as such will likely fall between these two examples, meaning an unknown max charge in between 3.3 and 4.8gr. Typically in cases like this a starting charge of 3.6gr. is safe, but this one demonstrates how precarious the terrain can be once you are off the reservation of combos for which specific load data exists.

A lot of good info ther and I much appreciate it insight. I apologize if my original post was confusing. When talking about the OAL not published by Nosler or Hodgdon, I was talking about ones specifically for the RMR 124gr FP MW people have said they use. Obviously this it taken with a grain of salt and used as reference once obtaining my own workup.

I mainly used the Nosler manual with the 3.6-4.6gr at 1.120” OAL loads as it was for a 124gr JHP which I thought resembled the RMR better than the 124gr data published by Hodgdon which was for Berry’s HBRN.

I Also thank you for your OAL data for this bullet using BE86. And seeing the 1.08-1.12” being more normal. Never hurts having a second opinion.

 

[LiveLife]

Went to the range and shot my first loads which were 3.6gr to 4.3gr W231

Charges 3.6-3.9gr either did not lock the slide back and/or had no/poor ejection. 4.0gr and above the ejection got slightly better.

Great, thanks for the range report.

4.0gr of HP-38/W231 seemed to be the magic spot. Next you could try those same light loads at a shorter length.

I agree, especially due to longer 1.150" OAL.

For your next range trip, could you also load up some 4.1 gr W231 at 1.100" OAL or 4.0 gr W231 at 1.080" OAL to see how they shoot in your Glock?

 

[TBL65]

bds, excellent post and I think you covered most everything clearly.
TBL65 so glad you started a new topic, I think it will help you and others tremendously. I believe you are on the right track with your loads and have a pretty good understanding of what is going on.

There is a topic on this site and a couple others that describe how to obtain MAX OAL using a fired case ,un-sized, and a bullet. The bullet should easily and freely start into the un-sized case and then slowly close the slide until it is in full battery. What this does is uses the barrel to seat the bullet and will give you the max length the barrel will accept. I use this method and find the shortest barrel in the bunch and then reduce length by.005 and that then becomes the COAL that I use for that bullet in my guns. I do that because I do not want to keep multiple loads of the same thing developed for just one gun.

BTW I have one 9mm pistol that I could load to 1.177" with the Berry's or Xtreme 124gr RN but they would never fit into the magazine.

Thanks for that tip, I will have to try that and see if it matching up with what I found using a loaded round for the plunk test. I am also glad I started this, it’s been super helpful and reassuring! I hope others can learn from this thread as well! bds didn’t a great job with his post!!

That is pretty much what I expected to hear from those loads. 4.0gr of HP-38/W231 seemed to be the magic spot. Next you could try those same light loads at a shorter length. Though with were you are at with charge weight and length you should be well under Max pressures even up to the 4.6gr. load.

4.0gr was definitely better than the lighter ones especially at that longer length. I do plan to try and shorten them up. Will probably stick with using the 3.6-4.3gr range and use the OAL’s of 1.135”, 1.130” and 1.125”.

 

[TBL65]

Published load data COL/OAL vary because test barrels they used to measure chamber pressures have different leade (Space bullet jumps from case to start of rifling). And since most universal barrel fixtures used for testing are single shot that do not feed from the magazine, us reloaders must determine the OAL that will work in our pistols/barrels/magazines.


Load Development - First step in load development with a new bullet is determining OAL. There are two different OALs that we use, Max OAL and Working OAL. Max OAL is the longest length chambered round's nose will not touch the start of rifling. But the Max OAL may not reliably feed from the magazine. So we function test by feeding dummy rounds (no powder, no primer) at Max OAL from the magazine and see if they will reliably feed from the magazine (Pull slide back and release without riding the slide). If they don't, I will incrementally decrease the OAL (say by .005") until they do. Working OAL is the longest length that will reliably feed from the magazine. Often Max OAL can be the Working OAL but usually, Working OAL is shorter than Max OAL.


Determining Working OAL for Multiple Pistols - Just because a particular Working OAL works in your pistol doesn't mean it will work in another pistol as factory barrels can have different leade length, start angle of rifling, groove-to-groove diameter, different rifling type and chamber dimensions (SAAMI maximum or SAAMI mininum). Gen1 through Gen4 Glock barrels have leade length on the longer side and 9mm Glock barrels can allow longer than SAAMI max OAL of 1.169" depending on bullet nose type. In recent years (Including Glock with Gen5 "Marksman Barrel"), factory barrels have moved towards shorter and shorter leade length and thus require shorter Working OAL.

To address this new trend, this THR support thread lists max/working OALs of various factory/aftermarket barrels matched to particular brand/weight/nose type of bullets for reference - https://www.thehighroad.org/index.p...let-max-working-oal-col-for-reference.848462/

From the reference thread, following are listed as max/working OAL for RMR 9mm 124 gr FP Match Winner (Current production with larger .074" copper fold over at base - https://www.thehighroad.org/index.p...g-oal-col-for-reference.848462/#post-11077625):

• 1.150" / 1.150" - KKM aftermarket barrel
• 1.140" / 1.140" - M&P Shield factory barrel
• 1.095" / 1.095" - Tactical Kinetics aftermarket barrel
  
• 1.090" / 1.080" - Taurus PT-809
• 1.085" / 1.085" - Lone Wolf aftermarket barrel

So if you load for multiple pistols, use the Working OAL that will work with barrel with shortest leade. FYI, below is comparison picture of different RMR 124 gr jacketed bullets to show different max/working OAL depending on nose profile. OALs shown is Working OAL for my barrel with shortest leade.

Powder Work Up Consideration - Once a Working OAL is determined, then proceed to powder work up. One consideration I use when conducting powder work up is using significantly shorter OAL (deeper bullet seating depth) than published and I will reduce start/max charge by .2 - .3 gr depending on the amount of bullet seating depth.

If you look at comparison picture above with different nose type bullets, you will notice different bullet base lengths. Depending on the Working OAL and bullet type used, bullet seating depth will vary.

Walkalong makes very good point. It's how deep the bullet base is seated inside the case neck that matters more than OAL. Usually, Truncated Cone/Flat Point bullets have longer base than FMJ/RN bullets and bottom of bullet base will get seated deeper in the case than FMJ/RN bullets.

So when referencing FMJ/RN load data that used 1.125"-1.150" OAL for FMJ/FP bullets at much shorter OAL which results in deeper bullet seating depth, I will consider reducing my start/max charges by .2 - .3 gr. As Walkalong suggested, it's good idea to start low as you can always go up.

Below are load data for 124/125 gr bullet from Hodgdon (Since 124 gr bullet weight can vary by 1.0 gr, I reference load data for 125 gr bullet interchangeably with 124 gr bullet) - http://www.hodgdonreloading.com/data/pistol

• 125 gr Hornady HAP W231/HP-38 Dia .355" COL 1.069" Start 2.8 gr (753 fps) 25,300 PSI - Max 3.3 gr (876 fps) 33,600 PSI
• 125 gr Lead Cone Nose W231/HP-38 Dia .356" COL 1.125" Start 3.9 gr (1,009 fps) 25,700 CUP - Max 4.4 gr (1,086 fps) 31,200 CUP
• 124 gr Berry's HBRN-TP W231 Dia .356" COL 1.150" Start 3.9 gr (920 fps) 27,400 PSI - Max 4.4 gr (1,037 fps) 31,900 PSI
• 125 gr Sierra FMJ W231/HP-38 Dia .355" COL 1.090" Start 4.4 gr (1,009 fps) 24,600 CUP - Max 4.8 gr (1,088 fps) 28,800 CUP

Note the different bullet types/nose profiles/diameters/COL/OAL and different start/max charges. IMO, RMR FP Match Winner comes closest to Lead Cone Nose as far as bullet nose/base and would feel comfortable referencing my initial/starting powder work up from. But as the Working OAL decreases below published 1.125", I would consider reducing my charges as I can always go higher.

And as ray15 posted, another consideration to factor is your barrel's groove-to-groove diameter and bullet diameter. Not all commercial 9mm jacketed bullets are sized the same and can vary from .354" to .356" (With .355" being typical) - https://www.thehighroad.org/index.p...re-sized-the-same.818806/page-2#post-10567453

Many factory barrels are oversized at .356"+ and accuracy benefit from using larger sized bullets (FYI Speer TMJ/Gold Dot are sized .3555" and Zero FMJ .356"). RMR 9mm jacketed bullet sizing run slightly larger at .3555" and this can increase chamber pressure a bit and may require slightly less powder charge to produce same muzzle velocity as published.


Determining Target Loads - For my powder work up, I look for two things:

1. Powder charge that will reliably cycle the slide and extract/eject spent cases
2. Powder charge that will produce smallest groups (most accurate)

As I conduct my powder work up and once achieve reliable slide cycling and spent case extraction/ejection, I will look for accuracy trend to determine possible light target loads. Depending on the powder used, this may not be the case as with slower burning powders, you may not achieve accuracy until high-to-near max load data.

And if I achieve reliable slide cycling and spent case extraction/ejection with start charge and good accuracy (especially with W231/HP-38/Sport Pistol and faster burning powders), I will "work down" from start charge to see if I can identify even lighter target loads. (Disclaimer: "Work down" below published start charges at your own risk)


Determining Most Accurate Loads - After my powder work up, once the most accurate powder charge(s) is identified, especially with light target loads, I will then incrementally decrease the OAL (say by .005") to see if accuracy improves without compressing the powder charge. You can calculate max case fill by following this post - https://www.thehighroad.org/index.php?threads/red-dot-9mm-and-case-fill.848934/#post-11078957

So even though your starting working OAL may have been 1.150", you may end up with 1.130" as your most accurate load.

These are many reasons why members post different OALs for the same bullet.

I hope this helps with your load development.

This! This is very helpful and well laid out. I’m going to have to read over it a few times to get that how to find the most accurate load! A lot of information there!

Great, thanks for the range report.


I agree, especially due to longer 1.150" OAL.

For your next range trip, could you also load up some 4.1 gr W231 at 1.100" OAL or 4.0 gr W231 at 1.080" OAL to see how they shoot in your Glock?

No problem on the range report! Was a perfect day for it. Light breeze and 75 degrees here in northern Ohio!

I will have to see about that OAL once I do my own load testing. I’m actually enjoying playing around with load workouts and bullet lengths. I’m going to start slowly shortening the OAL up while still using the 3.6-4.3gr test range. Going to try 1.135” then 1.130” and finally 1.125”.

If all goes well I may get down to 1.100 and 1.08. Don’t want any kabooms, I kind of like my hands and need them for work! Haha

Right now I am only loading for my Glock 19 but would like to get an accurate load for multiple 9mm’s as i see one or two more 9mm’s in my near future!

 

[LiveLife]

Producing accuracy is essentially producing high enough consistent chamber pressures for more efficient powder burn. Longer the OAL (less neck tension) and shallow bullet seating depth, more powder is needed. Shorter the OAL (more neck tension) and deeper bullet seating depth, less powder is needed.

For longer 1.150" OAL, you will need to keep increasing powder charge towards 4.3-4.4 gr to decrease group size.

At 1.130"-1.135", accuracy achieved with around 4.2-4.3 gr.

At shorter 1.080"-1.100", accuracy achieved with around 4.0-4.1 gr.

 

[kcofohio]

I found my cases from 3.6-4.2gr, could not for the life of me find the one from 4.3gr. Inspected cases and saw no pressure signs. Although some cases (mainly the lower charges) were a bit dirty near the case mouth.

Unless you have an unsupported chamber, the only pressure sign you will probably see in handgun is what you found with the case mouth, not sealing in the chamber and getting the sooty exterior of the case.

Your off to a good start. And you got good advice that it sounds like you're heeding.

 

[Dudedog]

Get a set of different color sharpies and mark the base of the cases. (easy to do if they are in a plastic ammo box just color the base does not affect the ammo even do the primer)
So 3.6 might be blue, 3.8 green, 4.0 orange, 4.2 Red etc.
(the wide tip ones work best)
Color comes off when you tumble and it makes it easier to find your brass on the range and tell which was which.
Some people draw designs but different colors work for me.
A side benefit is if somehow they get spilled and mixed up you can tell them apart.

All guns are different but for me at least I have gotten better accuracy seating shorter than what will plunk.
For me the 124gr match winners were happier around 1.08ish even though I could load them longer.

 

[lordpaxman]

Being my first loads I want to be as safe and cautious as possible until I gain some experience. Any advice would be much appreciated!

There's a lot of great advice on this forum as you've seen (and read). I also struggle with matching "published" load data vs the bullets I'm using and the COL. Since I can't measure pressure I do have a chrono to see what velocity is being produced by a specific load. I also try to shoot at competitions where you need to prove your reloads meet a specific criteria (power factor). The only way I know how to do this is to chrono before going to the match. For my guns and the 124gr RMR FPMW I settled on a COL of 1.120 and 4.1gr of 231. BTW check elsewhere on the forum and you'll find a coupon code for RMR bullets. If you like the 124s, you may try the 147s as well.

And if I achieve reliable slide cycling and spent case extraction/ejection with start charge and good accuracy (especially with W231/HP-38/Sport Pistol and faster burning powders), I will "work down" from start charge to see if I can identify even lighter target loads. (Disclaimer: "Work down" below published start charges at your own risk)

The OP didn't indicate what the loads were for, but when you do your "Work down", you're just looking for loads that function and don't meet a specific PF? The same question applies for when you start decreasing COL, I'm assuming from a constant powder grain weight. Your Vel is increasing, so again your not holding PF constant. I'm curious because felt recoil is a big factor and supposedly loading the heaviest bullet with the longest COL and the least amount of powder to make PF will result in the least felt recoil, or so they say.

Unless you have an unsupported chamber, the only pressure sign you will probably see in handgun is what you found with the case mouth, not sealing in the chamber and getting the sooty exterior of the case.

Can you clarify this? My understanding is a sooty exterior was an insufficient pressure to expand the case and seal the chamber. I also make notes of my loads and try to gauge the cleanliness of the outside of the case. Most of my match loads have some amount of soot on the exterior of the case. Some factory loads also have soot on the exterior.

 

[Dudedog]

I think he was talking about the sooty exterior as being a sign of lower pressure not excessive pressure.
If the load shoots well for me I don't worry about soot on the cases, they clean up.

 

[kcofohio]

I think he was talking about the sooty exterior as being a sign of lower pressure not excessive pressure.
If the load shoots well for me I don't worry about soot on the cases, they clean up.

Yes, that is what I meant. I should have been more clear of that.

 

[kcofohio]

Can you clarify this? My understanding is a sooty exterior was an insufficient pressure to expand the case and seal the chamber. I also make notes of my loads and try to gauge the cleanliness of the outside of the case. Most of my match loads have some amount of soot on the exterior of the case. Some factory loads also have soot on the exterior.

You're right and I should have more clear on that.