GeoDudeFlorida
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- Dec 1, 2020
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Remember this? I was trying to help.
Seating Depth
- Thread starter tws3b2
- Start date
OP
OP
tws3b2
Member
Yes I do. And I appreciate your help. But, right now I'm loading up several hundred 38spl. As I was taking a break I saw this 9mm case and bullet setting over there. Well, I picked them up and stuck the bullet in the case. Next thing I knew I had set it to the col I had in my data notes. That's when I got to thinking it just didn't look right. So, here I am asking another dumb question. I like asking dumb question. I figure when I ask enough dumb questions they will start sounding like smart questions. That's when I will know I'm ready to start loading 9mm. That one round in the photo is just a dummy, no primer, no powder.
I am planning to take your advice and load some 124 fmj first.
Thanks again.
Bazoo
Member
That's some darn good information.Welcome ! OAL is set by how your bullet fits into your barrel.... NOT the OAL listed in the loading manual.
► You did not tell us your gun, so no one here can suggest an OAL.
► The OAL in the manual is the OAL they used in their gun. Their "handgun" looks like this....
• Hornady and Hodgdon are REPORTING the OAL they used during their testing. They are not making a recommendation.
• You'll need to measure how that bullet interfaces with YOUR barrel and then make reasonable adjustments and plans based on your experience with the cartridge and pistol. Each bullet-to-barrel interplay is different/ unique/ individual.
• Understand that ALL auto pistol cartridges allow a RANGE of OAL to be used. There are PHYSICAL limits used by the shooting industry, and then typically further restricting those are the LOAD limits set by Your gun and Your load recipe.
The following cartoon shows/ explains this better....
► On the outside we have the SAAMI Physical limits for 9x19 Luger. Longer than ~1.169" won't fit inside the mag; shorter than 1.000" won't feed well.
► Typically, further restricting those are the additional limits of reality. You don't want to go shorter than the Reported OAL in the recipe, to prevent chamber pressure spikes. You do not want to go longer than what the barrel will accept, due to fears of creating a cartridge that has the physical ability to create an Out Of Battery accident. Every bullet is different; every barrel is different. No one here can advise you on this number... you have to measure it for yourself.
► ► Between those 4 Limits is a "zone" or range of OALs that is safe to use. This part is the Science of Reloading. Then, based on your past experience with your handgun (and the notes in your reloading notebook), within that range is an OAL that will allow your handgun to feed well and deliver the desired accuracy. This part is the Art of Reloading. Welcome to Reloading !
Hope this helps.
lordpaxman
Member
- Joined
- Jun 4, 2011
- Messages
- 2,446
And yet another poster to add to the ”please do a plunk test in all your 9mm barrels and write it down!”. Even loading at the book value COL, it may not plunk or fit your mag. For a known bullet like the XTP it most likely will fit but if you’re loading Brand X that looks like an XTP, there might be a different bullet profile that ruins your day at the range if you don’t first check.
You can load longer or shorter to some extent but you need to account for that with the powder charge.
While this was a curve denoting Unique, an uber fast powder like Titegroup will have a steeper curve that can disassemble a gun quickly.
Charlie98
Member
In reality, your question.... and the answer... is quite simple. Maintain the valid (Published) load data for that bullet, check that it feeds in your weapon(s) and you are good to go after a proper workup. No matter the cartridge, seating the bullet deeper into the case will raise pressure... all else being equal. You can seat the bullet deeper... but you would have to reduce to start, and work up, again, with the new COL.
That's why I asked what powder he was using. W231/HP-38 is fast, but relatively subdued, just like Unique, but where TiteGroup would not be so kind.... and the more bullet weight you add, the worse it gets. You deep-seat a 147grn 9mm bullet with a max load of TiteGroup... and unhappy things are likely to occur.
Welcome ! OAL is set by how your bullet fits into your barrel.... NOT the OAL listed in the loading manual.
► You did not tell us your gun, so no one here can suggest an OAL.
► The OAL in the manual is the OAL they used in their gun. Their "handgun" looks like this....
• Hornady and Hodgdon are REPORTING the OAL they used during their testing. They are not making a recommendation.
• You'll need to measure how that bullet interfaces with YOUR barrel and then make reasonable adjustments and plans based on your experience with the cartridge and pistol. Each bullet-to-barrel interplay is different/ unique/ individual.
• Understand that ALL auto pistol cartridges allow a RANGE of OAL to be used. There are PHYSICAL limits used by the shooting industry, and then typically further restricting those are the LOAD limits set by Your gun and Your load recipe.
The following cartoon shows/ explains this better....
► On the outside we have the SAAMI Physical limits for 9x19 Luger. Longer than ~1.169" won't fit inside the mag; shorter than 1.000" won't feed well.
► Typically, further restricting those are the additional limits of reality. You don't want to go shorter than the Reported OAL in the recipe, to prevent chamber pressure spikes. You do not want to go longer than what the barrel will accept, due to fears of creating a cartridge that has the physical ability to create an Out Of Battery accident. Every bullet is different; every barrel is different. No one here can advise you on this number... you have to measure it for yourself.
► ► Between those 4 Limits is a "zone" or range of OALs that is safe to use. This part is the Science of Reloading. Then, based on your past experience with your handgun (and the notes in your reloading notebook), within that range is an OAL that will allow your handgun to feed well and deliver the desired accuracy. This part is the Art of Reloading. Welcome to Reloading !
Hope this helps.
For benefit of OP, I asked a similar question a few months back as to COAL and seating depth for RMR nukes, which are excellent bullets, but which have limited to no reloading data to follow. Was given link below, authored by same guy as quote above (my current hero).
How to Determine Max OAL for a CZ/Dan Wesson Pistol
How to Determine Max OAL for a CZ/Dan Wesson Pistol
czfirearms.us
Both may be saying the same thing, but to elaborate on my takeaway, the plunk test is essential, but only tells half the story. What is needed is to find out the MAX OAL that can be used for any barrel / bullet combination. And you do that by fitting the bullet into a snug fitting case.....and pushing it into the chamber until it comes to a stop. At that point, two things have happened. Bullet is seated to the lands and case is head spacing on the chamber. If the measured OAL of that is equal to or greater than the published load data, you can use the load data. What you can't do is go less (shorter) than the published load data. The published load data is your minimum that you don't go below.
I now have 6 different 124 gr JHP bullets for 9mm and each of them have a different OAL in my barrel. Way different. And just as important, I also know where the base of each bullet stops relative to all the others. For me, that has become the critical factor for evaluating load data for these various bullets.
LiveLife
Member
This is what I do for new bullet load development, especially for barrels with shorter leade that forces me to use shorter OAL/bullet seating depth that increases pressure. For high pressure small internal case volume 9mm, reduction in several thousandths can increase pressure by several thousand PSI (See OAL reduction/pressure chart at bottom of linked post) - https://www.thehighroad.org/index.p...-and-discussions.778197/page-11#post-12503881
I first determine the Max OAL using the barrel (Dummy round drops in the chamber with a "plonk" and spin freely without hitting the rifling) then determine the Working OAL by feeding the round from the magazine until it feeds/chambers reliably using the "Plunk Test" mentioned in post #14 - https://www.thehighroad.org/index.php?threads/seating-depth.925253/#post-12765917
Here's more on "Plunk Test" using @Walkalong graphic illustration - https://www.thehighroad.org/index.p...-and-discussions.778197/page-11#post-12685871
If I can't find exact bullet brand/type with specific powder load data, I will check all available load data and reference more conservative load data for my initial powder work up as you can always go higher. (You can also reference load data for slightly heavier bullet weight)
And if my Max/Working OAL is shorter (deeper bullet seating depth) than published, I consider reducing my start/max charges by 0.2 - 0.3 gr as I can always go higher after INITIAL powder work up. During my initial powder work up using larger .2-.3 gr increments or low-to-mid charges, I am essentially looking for powder charge that will start to reliably cycle the slide and extract/eject spent cases. Then I monitor accuracy trend by watching group size reduction to identify lighter target load.
NOTE: Since you are new to reloading, you may not be aware/concerned about effects of neck tension/bullet setback. Consistent finished OAL/COL doesn't matter if insufficient neck tension produces bullet setback after bullet nose bumps the feed ramp during chambering from the magazine. So I do QC check by feeding dummy rounds from magazine and measure OAL before/after for bullet setback. And if you experience significant bullet setback that's greater than .005"+, consider using thicker case wall brass or larger sized bullets as illustrated in this myth busting thread - https://www.thehighroad.org/index.php?threads/myth-busting-9mm-r-p-thin-case-wall-notion.921546/
Then on subsequent range trips, I narrow my powder charge increments to .1-.2 gr or high-to-max charge to determine the powder charge that produces smallest groups (Most accurate load). And if you want to squeeze out a bit more accuracy (Do this only if you are not at max charge using shorter than published OAL), I incrementally reduce OAL by .005" to see if accuracy improves. If so, I use shorter OAL. If not, I use longer OAL.
FYI, consider going over this step-by-step load development guide - https://www.thehighroad.org/index.p...-and-discussions.778197/page-10#post-11419509
Very good point.
Not only is determining Max/Working OAL and powder charge that produces smallest groups, if you are loading for multiple pistols/barrels, you may need to identify a single OAL and powder charge combo that will work for all the pistols/barrels or develop different OAL/powder charge loads for different pistols/barrels to optimize accuracy and reliable function (Especially when working with lighter target loads).
Consider how same bullet will require different Max/Working OAL due to leade length of barrels in different pistols as listed in this reference thread (And this is if you are not experiencing any bullet setback
) - https://www.thehighroad.org/index.p...col-for-reference.848462/page-2#post-12249361- Glock 22, KKM 40-9 conversion barrel - RMR 124 gr FP: 1.150"
- M&P Shield 9mm - RMR 124 gr FP: 1.140"
- Glock 22, Tactical Kinetics 40-9 conversion barrel - RMR 124 gr FP: 1.095"
- M&P Shield 9mm EZ - RMR 124 gr FP: 1.090"
- Glock 23, Lone Wolf 40-9 conversion barrel - RMR 124 gr FP: 1.085"
- Taurus PT-809 - RMR 124 gr FP: 1.080"
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rfwobbly
Member
Gosh, I sincerely hope BOTH are saying the same thing, because..... I wrote both articles !!
.
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LiveLife
Member
Nice.Gosh, I sincerely hope BOTH are saying the same thing, because..... I wrote both articles !!
The one on the CZ site was what turned on the lights for me, which is why I linked to it. If it were up to me that would be mandatory to be included in every loading manual and a copy included with each set of 9mm dies sold. Author deserving a royalty for all of it.Gosh, I sincerely hope BOTH are saying the same thing, because..... I wrote both articles !!
.
Did I mention I found it helpful?
rfwobbly
Member
People have told me before that it should be in a book. But you know, first of all only about 30% of reloaders need that depth of information because most handguns simply have generous chambers. I only know this stuff because when I bought a CZ in 2001, I was totally stumped! I had been loading 9x19 since 1979 for a BHP without any issues, and all of a sudden my ammo didn't work !!
The second reason is, as Isaac Newton once said, "If I have seen further it is by standing on the shoulders of Giants." Older, wiser reloaders like RC Model and Walkalong have freely and generously donated their time to help me over the hard parts. I'm a degreed mechanical engineer with patents and awards, but I'm here to tell you, some of these solutions are simply not self evident. So all the glory belongs to the mentors.
Darth Vader once said to Obi Wan, "Once you were the teacher and I was the student. Now, I am the master !" However, 1) I'm a good bit more altruistic than Darth ever was, and 2) I hope even at age 73 I'm still a student ! No sir, I'd rather follow the greatest mentor who said, "Freely you have received; freely give."
Sometimes, those words are the greatest reward of all. Thank you.
GeoDudeFlorida
Member
- Joined
- Dec 1, 2020
- Messages
- 11,263
When I experimented with 147gr 9mm it was in a Star M30 pistol and I made the calculated decision to use Blue Dot based on three factors: I found loading data in a trusted source; it’s almost impossible to exceed the maximum charge in a 9mm; and it is a powder well known to behave more reliably in tight spaces, at higher pressures.
It was a success, eventually but it was a lot of work finding the sweet spot and I would never try it again in a weaker pistol. Those old Stars were built for hard use in wartime. It’s no wonder the IDF bought so many.
The name of the game with heavy for caliber loads is caution, research and patience.
What you think the load looks like has nothing to do with how it should be loaded. Hodgdon uses the COL as that is what HORNADY tested it at.
So if it plunk tests in your barrel then that's what should be used. Sometimes the COL has to be adjusted a hair but it it is not this complex!
So if it plunk tests in your barrel then that's what should be used. Sometimes the COL has to be adjusted a hair but it it is not this complex!
P Flados
Member
Many of the responses in this thread are absolutely great. However, one of the early responses just hit me wrong.
. "May need a shorter COL to chamber. Like to here? Use starting load"
Your picture shows what look like up to a 0.040" length reduction. With the book length, a new loader should use the start load and work up. For this kind of length reduction, the "start" load needs to be reduced even further. How much becomes the question. An experienced loader might have a feel for this based on past experiences or based on things he has read.
The right answer to "how much" for a new loader is probably something along the lines of "figure it out" before loading that first round. If you can do some more looking and find some published data closer to you desire end state, great. If not, then asking for help is not such a bad thing. On line forums can be great, but you will need to weed through answers until you get information that looks trustworthy.
For this exact example, I took the Hodgdon data loaded it into Quickload and adjusted the default case capacity just a little to get a predicted pressure very close to the published test result. I then shortened the length to 1.060". I found that expected pressure increases to right at the SAAMI limit at the published starting charge of 3.0 gr. So for this length reduction, the right starting point is probably closer to 2.6 gr to 2.8 gr depending on how you look at the results.
Code:
Cartridge : 9 mm Luger (SAAMI)
Bullet : .355, 147, Hornady HPBT XTP 35580
Useable Case Capaci: 4.647 grain H2O = 0.302 cm³
Cartridge O.A.L. L6: 1.060 inch = 26.92 mm
Barrel Length : 4.0 inch = 101.6 mm
Powder : Hodgdon HP38
Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms
-23.5 72 2.60 792 205 25149 2149 99.5 0.581
-17.6 78 2.80 837 229 29691 2270 100.0 0.540
-11.8 84 3.00 881 253 34862 2372 100.0 0.505 !DANGEROUS LOAD-DO NOT USE!
-05.9 89 3.20 923 278 40746 2471 100.0 0.474 !DANGEROUS LOAD-DO NOT USE!
+00.0 95 3.40 964 303 47447 2567 100.0 0.446 !DANGEROUS LOAD-DO NOT USE!
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243winxb
Member
Wrong powder. Burn rate to fast. See Hornady data i posted (photo) Run your "QUACKLOAD" on those powders, starting loads.
Plus, the Hornady 147 has a Boatail Base. Doesnt take up the same area as a flat base, when loaded in the case.
Do you even own a 9mm Luger?
243winxb
Member
A slower burn rate may be better when adjusting the COL shorter.
https://www.nosler.com/9mm-luger-parabellum#LNLINT4
Note Load density, volume.
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ballman6711
Member
I'm not quite understanding this, maybe you can explain it to me.
My understanding is that if I'm putting 75gr (bullet weight) into the case, it will take up a specific amount of space (in volume) no matter if it's a flat base or a boat tail. 75gr of lead will still be 75gr of lead no matter how it's shaped.
I hope somebody can explain it to me, because I feel like I'm missing something, and learning in this hobby is important to me. Thanks.
chris
OP
OP
tws3b2
Member
Well, I noticed when oal is 1.10 the round wants to lightly stick in the chamber. "Fully drops into the chamber but needs a tap to drop out"
At 1.09 it freely drops in and out.
With oal ar 1.10 a round wants to lightly stick in the chamber. "Fully drops in but needs a light tap to drop out".Welcome ! OAL is set by how your bullet fits into your barrel.... NOT the OAL listed in the loading manual.
► You did not tell us your gun, so no one here can suggest an OAL.
► The OAL in the manual is the OAL they used in their gun. Their "handgun" looks like this....
• Hornady and Hodgdon are REPORTING the OAL they used during their testing. They are not making a recommendation.
• You'll need to measure how that bullet interfaces with YOUR barrel and then make reasonable adjustments and plans based on your experience with the cartridge and pistol. Each bullet-to-barrel interplay is different/ unique/ individual.
• Understand that ALL auto pistol cartridges allow a RANGE of OAL to be used. There are PHYSICAL limits used by the shooting industry, and then typically further restricting those are the LOAD limits set by Your gun and Your load recipe.
The following cartoon shows/ explains this better....
► On the outside we have the SAAMI Physical limits for 9x19 Luger. Longer than ~1.169" won't fit inside the mag; shorter than 1.000" won't feed well.
► Typically, further restricting those are the additional limits of reality. You don't want to go shorter than the Reported OAL in the recipe, to prevent chamber pressure spikes. You do not want to go longer than what the barrel will accept, due to fears of creating a cartridge that has the physical ability to create an Out Of Battery accident. Every bullet is different; every barrel is different. No one here can advise you on this number... you have to measure it for yourself.
► ► Between those 4 Limits is a "zone" or range of OALs that is safe to use. This part is the Science of Reloading. Then, based on your past experience with your handgun (and the notes in your reloading notebook), within that range is an OAL that will allow your handgun to feed well and deliver the desired accuracy. This part is the Art of Reloading. Welcome to Reloading !
Hope this helps.
At 1.09 oal the round fully drops in and freely drops out. No tap needed.
rfwobbly
Member
In my humble opinion...
Optimally, a finished round (handloaded or store bought) should: 1) fall all the way into the chamber using only its own weight, 2) head space on the end of the chamber, 3) spin freely without the bullet catching in the rifling, and then 4) finally fall back out using only its own weight. No tapping or hammering, simply rotating the barrel to point the chamber downward.
Optimally, a finished round (handloaded or store bought) should: 1) fall all the way into the chamber using only its own weight, 2) head space on the end of the chamber, 3) spin freely without the bullet catching in the rifling, and then 4) finally fall back out using only its own weight. No tapping or hammering, simply rotating the barrel to point the chamber downward.
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fxvr5
Member
- Joined
- May 26, 2017
- Messages
- 3,298
You're not missing anything. As you've put it, 75 gr of lead is 75 gr of lead no matter the shape. It takes up the same volume of space no matter it's shape.
rfwobbly
Member
Certainly...
► Different bullets (even of the same weight) MAY interact with the freebore or rifling in completely different ways. This interaction will then require 2 different OALs... even though the bullets weigh the same. This is demonstrated in this cartoon...
Here we have 3 bullets of the same weight. The conical on the Left collides with the end of the freebore due to its "shoulder". The FMJ in the Center fits just fine. The FPRN on the Right has a chunky ogive which collides with the rifling. 1 barrel with 3 different bullets, and each has a different bullet-to-barrel interplay.
► Now, as to the 147gr "boat tail". The second cartoon shows the longer/heavier bullet interfering with the taper inside the case at its base. But, if there is a "boat tail" on that "longer, heavier bullet", then the base of the bullet ALSO has a taper that works to prevent this type collision.
All these conditions are on an very individual basis. No two brands of bullets have the same ogive shape; no two bullets have the same base. No two brands of brass have the same internal shape. No two brands of barrels have their chamber cut the same way. So broad generalizations rarely ever work for all reloaders. You must measure the pieces you are working with.
Hope this helps.
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Bazoo
Member
What's the verdict at 1.095? if that chambers freely, start there.
