Making comfortable minor with 9mm N320 and 124 gn

[lordpaxman]

I need professional help.
I've got several other minor loads, but, I'm having trouble making a comfortable minor with N320 and a 124gn RMR FMJ TC FP match winner. A comfortable minor for me is a 10 round average of 132 or about 1064fps for this weight bullet.

The gun is a P226 with a 4.4" barrel. Max COL on this barrel is 1.175, max reload COL for me is 1.160.

The VV data I've been using is for a FMJ/FP Hornady 3.9-4.3gn, COl 1.142.
I've worked up to the max load data and still only see about 1009 fps, which is about 125.

I understand it's best not to exceed the published load data, but... I've read quite a few other entries in this forum and others where some will exceed the max powder weight while others will decrease COL to make minor, both of which to me exceed the published load data. I'm pretty happy with all my digits so I'd like to keep it that way, but this gun loves N320 and I'd like to pass the chrono stage with flying colors.

I did venture a bit and 4.4gn leads to an average of 1032 or about 128. It's close, but, not quite.

So the questions are, if one was intent on making this combination work, is it safer to add powder or decrease COL, given there are no obvious pressure signs or excessive velocities? And yes, by the time you see pressure signs, you're already in dangerous territory.

I'm hoping I don't get slammed too hard!

 

[Kaldor]

Are you really hung up on using 124gr bullets? If you arent, I suggest trying 147gr bullets. Generally the old stand by load of 3.2gr of TiteGroup and a 147gr bullet is set for minor, and shoots like a baby. N320 generally gives about the same results with 147s. If are dead set on using 124s, then I suggest using a little slower burning powder, so you can pick up velocity, without getting into danger zone. I also suggest trying some HiTek coated bullets as they are cheaper than plated or jacketed, but generally can go a little faster with less powder. Lastly, run the COL that matches your pistol for best accuracy, IE dont shorten it trying to increase velocity.

 

[lordpaxman]

Are you really hung up on using 124gr bullets? If you arent, I suggest trying 147gr bullets. Generally the old stand by load of 3.2gr of TiteGroup and a 147gr bullet is set for minor, and shoots like a baby. N320 generally gives about the same results with 147s. If are dead set on using 124s, then I suggest using a little slower burning powder, so you can pick up velocity, without getting into danger zone. I also suggest trying some HiTek coated bullets as they are cheaper than plated or jacketed, but generally can go a little faster with less powder. Lastly, run the COL that matches your pistol for best accuracy, IE dont shorten it trying to increase velocity.

I was hoping to keep this thread specific to the bullet powder combination. I do have other minor loads I use. Your points are definitely valid and in line with some of my other loads. I suspect reducing the COL will lead to an increase velocity (and pressure), but don't know what affect that will have on accuracy as I've not tried it yet. Who knows, it may tighten the groups?

 

[Kaldor]

N320 is a pretty fast burning powder, comparable to TiteGroup from what Ive read, thats why I suggested 147s. I would not change the COL as it could result in a pressure issue alot faster than just bumping a tenth or two in charge weight. Did you see pressure signs, and was the gun really snappy at 4.4gr? If the recoil is manageable and pressure signs were fine, Id try 4.5, but at proper COL based on your pistol. Best accuracy will always come from proper COL based on a "plunk" test, not what the book says.

I can understand trying to use what you have. My standby loads for 9mm havent changed in a few years now. I stack TiteGroup and CFE Pistol deep in my cabinet for 9 and 45, tailor my loads around those powders with just a couple bullet weights. The fact of the matter is that faster burning powders always create more felt recoil than a slower burning powder when using lighter bullets. The opposite is true with heavy bullets.

 

[ray15]

So the questions are, if one was intent on making this combination work, is it safer to add powder or decrease COL, given there are no obvious pressure signs or excessive velocities? And yes, by the time you see pressure signs, you're already in dangerous territory.

If your measured velocities are accurate and the barrel length used in developing the VV load data comparable, the overwhelming likely cause is that you're not very close to max pressure. I would increase charge.

Surely not all 124gr. bullets demonstrate the same pressure/velocity relationship. But the slowest 124gr. bullet VV has load data for is still in excess of your velocity goals. I would feel safe in increasing charge until I got to the max velocity listed for their slowest 124gr. load. In truth you are not exceeding the published load data - there isn't any for your combination. It's always a bit of a guessing game in re-purposing load data, but I believe you're well safe until you exceed 1,050fps.

 

[Walkalong]

3.9 Grs N320 - X-Treme 124 Gr HP at 1.060 OAL - 87 Degrees 77% RH

3" S&W Shield 5" Colt Series 80 5" S&W Pro
HI 905 HI 1066 HI 1104
LO 869 LO 1025 LO 1030
AVG 885 AVG 1048 AVG 1061
ES 36 ES 41 ES 74
SD 14 SD 13 SD 27


3.9 Grs N320 - RMR Hardcore Match HP at 1.080 OAL - 83 Degrees 35% RH

EMP 5" S&W Pro 16" RRA AR
HI 977 HI 1073 HI 1091
LO 937 LO 1038 LO 1037
AVG 957 AVG 1055 AVG 1066
ES 40 ES 35 ES 54
SD 14 SD 13 SD 18


3.9 Grs N320 - Powerbond 124 Gr HP at 1.060 OAL - 73 Degrees 83% RH

3" EMP 4.5" XDm 5" Colt Series 80 5" S&W Pro 16" RRA AR
HI 947 HI 1057 HI 1082 HI 1058 HI 1079
LO 934 LO 1039 LO 1056 LO 1044 LO 1040
AVG 939 AVG 1050 AVG 1068 AVG 1051 AVG 1055
ES 13 ES 18 ES 26 ES 14 ES 39
SD 5 SD 6 SD 8 SD 4 SD 14

Welcome to THR

 

[LiveLife]

having trouble making a comfortable minor with N320 and a 124gn RMR FMJ TC FP match winner. [want] 132 or about 1064 fps.

P226 with a 4.4" barrel ... 3.9-4.3gn, COl 1.142 ... I've worked up to the max load data and still only see about 1009 fps, which is about 125.

Basics first.

Are you sure you are using 4.3 grains of N320? Have you verified your scale with a set of check weights around 4.0-4.5 gr?

Because many are making minor PF on BE forum with less than 4.3 gr of N320 and 124 gr bullets - http://forums.brianenos.com/topic/133796-n320-minor-loads-9mm/?do=findComment&comment=1507570

I like member CocoBolo's posts. Here's his take on making minor PF with 124 gr bullet and N320:

"Locally 3 of us shoot MTG's (Montana Gold) in CZ Shadows at 135 pf with 4.0 gr of N320. We all bought our N320 from different places, Grafs, Powder Valley, and one local at different times of the year, consistent results across the board."


As to OAL, are you really getting max OAL of 1.175" with RMR 124 gr FP in your Sig barrel?

BTW, these are OALs I am using in my barrels (KKM and Lone Wolf) with RMR bullets. Notice I am loading 124 gr FN (TC FP Match Winner) to 1.080" OAL - https://www.rmrbullets.com/products...-gr-rmr-truncated-cone-flat-point-matchwinner

I think you should be making comfortable PF with 124 gr FN loaded to 1.080" and below 4.3 gr of N320. Try using shorter OAL after verifying scale.

 

[Walkalong]

4.0gr of N320

With S&B primers I have to use 4.0 vs 3.9 or the occasional case will get caught trying to leave the ejection port in the 5" 1911.

 

[rfwobbly]

But the slowest 124gr. bullet VV has load data for is still in excess of your velocity goals. I would feel safe in increasing charge until I got to the max velocity listed for their slowest 124gr. load. In truth you are not exceeding the published load data - there isn't any for your combination. It's always a bit of a guessing game in re-purposing load data, but I believe you're well safe until you exceed 1,050fps.

The reason your velocities are slower is that load testing is done in a much longer test barrel (shown below), not a pistol. So the extra length gives quite a lot of added velocity. Ray is correct. As long as you don't exceed the published Max Velocity you're going to be under the Max Load for your pistol.



You're relying on the tight relationship between chamber pressure and bullet velocity, which holds fairly close as long as you compare your load to data from similar bullet weights and constructions (e.g. 124gr JHP data to 124gr JHP results). That tight relationship is the entire basis for owning a chrono.

I regularly shoot the RMR 124gr JHP "Multi Purpose" at 4.2gr of N320 at 1.060" in a 4" CZ SP-01.

Hope this helps.

 

[lordpaxman]

Wow, thank you everyone for all the help! I'm a bit new at how to format replies, so adapologiesvance if this is not coherent.

N320 is a pretty fast burning powder, comparable to TiteGroup

N320 is fast, but I'm not sure it's comparable to TG - depending on what burn rate chart you're looking at, TG is 15, N320 is 25. Now, it's all relative, however, I've got minor loads for this bullet and IMR Target which is 14 on the chart and those are well within Hodgdon's published data. N320 is a single base powder though.

If your measured velocities are accurate

Always a good thing to check, I've got a CE chrono with the Bluetooth option which makes it easy to collect the data. I fire 5 rounds of CCI blazer 115 prior to any session and they repeatedly come in at 1113-1120. I'm working on another chrono to test the test loads with, but that hasn't happened yet. I found this post which indicates I'm probably in the ball park:
https://www.thehighroad.org/index.php?threads/standard-barrel-9mm-velocities-info-requested.116207/

Basics first.

I calibrate and check my scales regularly. My 1972 Ohaus 510's batteries are still good to go, so I check a test throw on it, then the Gempro 250, and then the Chargemaster 1500. Occasionally I'll weigh a couple of test brass washers, 3-2.00 grains, 1-1.98 grain, and 1-2.02 grain to make sure the scales are accurate at smaller weights.

I like member CocoBolo's posts

I did find those entries on the BE forum and the OP's was close to what I'm measuring - almost but not quite minor. I can make minor with an MG JHP/4.3 N320/1.140.

As to OAL, are you really getting max OAL of 1.175" with RMR 124 gr FP in your Sig barrel?

Yes, my max COL is 1.175 in the Sig. It's 1.200 in my DW PM, but, in my SA 1911 it's 1.114.
With the RMR JHP MP 124, the max COL in the Sig is 1.150. Are you loading N320 in those pictured rounds at those shorter COL's? ​

With S&B primers I have to use 4.0 vs 3.9 or the occasional case will get caught trying to leave the ejection port in the 5" 1911.

I'm loading CCI 500s, and was trying not to vary the primers in the long list of variable! I'll keep this in mind though. And thanks for the other load data as a datum point.

You're relying on the tight relationship between chamber pressure and bullet velocity, which holds fairly close as long as you compare your load to data from similar bullet weights and constructions (e.g. 124gr JHP data to 124gr JHP results).

If only we had the model of that relationship. It's non-linear, but close to linear throughout part of the range. I was hoping max velocity is really the limit, but, have never really confirmed that through any of the published data. I'm presuming the RMR TC FP is really close to the FMJ/FP Hornady data that VV has. I have checked case volume with 4.4gn of N320 and can go much shorter than 1.140 without running in to a compressed load. I'll keep my eye on the chrono numbers and if they slow or stop increasing linearly, then I will too.

Based on all of this I'll try both a 4.5gn increase at current COL, and decrease the COL in .005 decrements with a 4.3gn load. Thanks so much for all your help!

 

[LiveLife]

I have checked case volume with 4.4gn of N320 and can go much shorter than 1.140 without running in to a compressed load. I'll keep my eye on the chrono numbers ... and decrease the COL in .005 decrements with a 4.3gn load.

Sounds like a plan.

Are you loading N320 in those pictured rounds at those shorter COL's?

No, initially with W231/HP-38 so far with plans for Sport Pistol next.

BTW, did you get the memo that Sport Pistol is the next N320 that burns cleaner at lower cost?

I can post chrono numbers with Sport Pistol and RMR 124 gr Match Winner as soon as I can go shooting.

 

[Walkalong]

Sounds like a plan

It does indeed.

 

[ray15]

Always a good thing to check, I've got a CE chrono with the Bluetooth option which makes it easy to collect the data. I fire 5 rounds of CCI blazer 115 prior to any session and they repeatedly come in at 1113-1120. I'm working on another chrono to test the test loads with, but that hasn't happened yet.

I don't distrust your figures - I was just qualifying my statements in that the things we are comparing have to actually be comparable before any of this has merit. I also use the CE unit and use Blazer Brass 115 as my control round. Your gun is a bit faster than mine (or your lot of BB is). I get about 1090 from my P10-C (4" land-and-groove barrel) where I saw ~1,110 with a 4" PPQ (polygonal). Your 4.4" barrel is producing the expected velocities.

If only we had the model of that relationship. It's non-linear, but close to linear throughout part of the range. I was hoping max velocity is really the limit, but, have never really confirmed that through any of the published data. I'm presuming the RMR TC FP is really close to the FMJ/FP Hornady data that VV has.

You may wish to invest in the Quickload software at some point. It's a pretty good tinker's sandbox and you can develop and validate models pretty easily with your chronograph.

Regarding how close the RMR bullet is to the Hornady - generally we see RMR bullets making a bit more pressure and velocity than standard 0.3550" jacketed bullets because the RMR ones are typically sized to 0.3555". But the fact that your velocities are low at a given charge trumps this sort of rule of thumb. Within reason velocity = pressure, so as I previously posted there's essentially no chance you are approaching 35,000psi until you exceed 1,050fps.

 

[vaalpens]

The gun is a P226 with a 4.4" barrel. Max COL on this barrel is 1.175, max reload COL for me is 1.160.

I can't help you with an N320 load, but I load the RMR 124gr FMJFP match winner with a COL of 1.065" in my SP2022. As a reference point, even though I only have a 3.9" barrel, 4.5gr HP-38 gives me 1057fps and 5.4gr BE-86 gives me 1090fps. Sorry I don't have more 9mm data to share with this bullet since I mostly use it for 357sig.

 

[lordpaxman]

BTW, did you get the memo that Sport Pistol is the next N320 that burns cleaner at lower cost?

I did get that memo, darn. Someone please disconnect my PV membership. They had both SP and N330 in stock, and after I received a large order, they showed 244 in stock. Someone, I won't mention whom, is now dangling that carrot.

With the Sig, CCI500, .FC. cases, 1.130 COL, 4.4gn SP: AVG 1060, ES 48, SD 16. Cases were relatively clean, no failures, no smoke and group at the chrono was tight.
I did another load workup a bit longer to 1.140 but had to push to 4.5 but SP is a bit snappy. I'm just loaded a batch of 200 to run and gun and see how I like it. It does meter well in my LNL, but almost everything does except Target and Clays.

I do have minor loads for 231, but it's with the Rainier RN, and they do pretty well accuracy wise. I started some with the RMR TC/FP and MP/HPs but didn't get them into minor territory yet.
I was hoping to keep this thread specific to N320 and RMR TC/FP just to keep on point but there's just too many loads to talk about. My go to load is with WSF.

You may wish to invest in the Quickload software at some point.

You're the devil's helper. You're trying to tempt me, and, it'll probably work. I can feel you on my shoulder, you're saying get that neat Mantis X toy as well, you'll be much better off with both, better loads, better trigger.... I've been keeping tabs on Quickload and was waiting for it to mature a bit and it's probably time. The biggest reason I'm skittish about decreasing COL is the only time I ran into pressure problems was with 9mm and TG. I misread, yes, I'll admit it, the load data sheet and went 1.090 COL instead of 1.100 COL and had a case web separation. I traced it back to the reloading bench and pulled a few bullets that day. There were no other obvious pressure signs. I love hate TG.

the RMR ones are typically sized to 0.3555"

The last 3k batch I received, and are just about done, came in at 0.3554" for me. There's another 3k on the way, along with their new 147 FMJ/FNs. Oh joy, working up some more loads. I do plan to try the 147 N320 combo.

I can't help you with an N320 load, but I load the RMR 124gr FMJFP match winner with a COL of 1.065" in my SP2022.

Thanks for the input. I started some 231 work, but, it's anemic at this point. I used the Hodgdon 125gn SIE FMJ data, but they spec it short at 1.090 COL, and you're even shorter than that. There's some that say "load as long as possible", and I've typically tried to do that, but permutations of both COL and powder weight get unwieldy. My starters were at 1.120 COL with the RMR 124gn TC FP. Partly because I wanted at least one load for the Sig and that SA whose barrel I'm either going to throat or throw out.

Thanks again for all the input and I'll post the N320 numbers when I get them.

 

[LiveLife]

BTW, did you get the memo that Sport Pistol is the next N320 that burns cleaner at lower cost?

I did get that memo, darn. Someone please disconnect my PV membership. They had both SP and N330 in stock, and after I received a large order, they showed 244 in stock.

Yeah, I tried powder reduction twice (Walkalong, stop laughing ) ... now I have more than twice the powders I started out with, including Vectan, Lovex/Shooters World and IMR powders (Target, Red, Green) and I too am looking for W244.

With the Sig, CCI500, .FC. cases, 1.130 COL, 4.4gn SP: AVG 1060, ES 48, SD 16. Cases were relatively clean, no failures, no smoke and group at the chrono was tight.

Looking good. Loading even shorter at 1.125" may get you the velocity you are looking for from tighter neck tension for more consistent chamber pressure build. Keep in mind I am loading those 124 gr Match Winners at even shorter 1.080" OAL.

I used to think longer was better (but let the holes on target be the judge). It is for my 40S&W 180 gr loads with longer bullet base which I load to 1.142"-1.155" depending on TCFP or RNFP and many match shooters use 1.180" (I am limited by 1.145" magazine length for TCFP and 1.142" feed reliably) but for 9mm with shorter bullet base/bearing surface, I found shorter was better.

During my load development, after determining max OAL and working OAL, once I identify the most accurate powder charge, I will incrementally decrease the OAL to see if accuracy improves (They often do for 9mm). My guess is 4.0-4.1-4.2 gr of N320 with 124 gr Match Winners loaded at 1.080" may produce the velocity you are looking for with comparable or better accuracy than your current load. You could load some at 1.080" for your next range test to compare.

Here's a comparison test I did with 1.155" vs 1.130" using IMR Target and RMR 115 gr FMJ (FYI, I use 1.110"-1.115" with RMR 115 gr FMJ for my Lone Wolf barrel with short leade) - https://www.thehighroad.org/index.p...g-oal-col-long-vs-short.819257/#post-10511700

25 Yard 10 shot groups with 17" JR carbine
IMR Target 4.2-4.3 gr and RMR 115 gr FMJ at 1.155" (Left) and 1.130" (Right)

I do have minor loads for 231, but it's with the Rainier RN, and they do pretty well accuracy wise.

While I like W231/HP-38, but in 9mm, Bullseye/WST/Titegroup/BE-86 have shot more accurate and Target/Sport Pistol have shown promise for greater accuracy in recent range tests.

25 yard groups with 124 gr Berry's regular plated RN and Titegroup - https://www.thehighroad.org/index.p...e-pistol-reloaders.746062/page-2#post-9382933

25 Yard groups with 124 gr RMR Thick Plated RN and WST/BE-86 - https://www.thehighroad.org/index.p...ts-and-discussions.778197/page-6#post-9924922

I ran into pressure problems was with 9mm and TG. I misread, yes, I'll admit it, the load data sheet and went 1.090 COL instead of 1.100 COL and had a case web separation. I traced it back to the reloading bench and pulled a few bullets that day. There were no other obvious pressure signs. I love hate TG.

Titegroup burns hot and violent. When I can, I look for different powders (We now have many to choose from like Target, N320, Sport Pistol, etc.). But for 9mm, I do like Titegroup.

Thanks again for all the input and I'll post the N320 numbers when I get them.

Look forward to your range report.


FYI, you may want to check out this same/comparable powder thread - https://www.thehighroad.org/index.p...-different-labels.797388/page-6#post-10806193

 

[Doublehelix]

With the RMR JHP MP 124, the max COL in the Sig is 1.150.

I can load my SIG P226 Legion SAO at this COAL as well (1.150") with the RMR JHP MP 124, and I used to shoot at that length. I now load at 1.06" for a couple of reasons:

1. I can use the same round in multiple guns. This is a compromise I don't normally make if I am looking for the best cartridge for a given task (such as competition rounds), but see #2.
2. I found that the loads at 1.06" were more accurate! I am used to the philosophy that you should shoot for the longest COAL that your gun can accommodate (jump to lands), but as @bds found out, that is not always true.
3. I load these RMR JHP MP 124s at 1.06" with 4.1 gr of Titegroup, and hit about 132 PF if I remember correctly.

Without #2 above, I would never have done #1, and I have to admit, I was surprised by the results. I had some 1.06" cartridges that I was using for my H&K VP9 (my only striker-fired gun), and I tried some on the SIG when I was out of the 1.150" cartridges. Ouch. They were better.

I spent a lot of time chasing that longer COAL only to find out that the SIG liked the shorter cartridges better. Thanks @bds for keeping us honest and not just blindly following the Internet lore (his myth-busting threads are the best!!!).

 

[ray15]

I can load my SIG P226 Legion SAO at this COAL as well (1.150") with the RMR JHP MP 124, and I used to shoot at that length. I now load at 1.06" for a couple of reasons

I actually go one step further. At 1.03", the 124MPR will clear in a barrel with zero leade. I load there - it's the longest load I can expect to work in any and all SAAMI-compliant 9mm luger arms. This is the envelope that factory ammo is engineered to fit in - once you load the MPR in similar fashion you realize just how different the profile of the bullet is as well as how reliant on leade the OALs that many reloaders use are.

I use the Hornady cartridge gauge to establish what clears in a SAAMI-minimum chamber, and load that. I've not had any trouble producing accurate loads with this OAL strategy - 5.1-5.2gr. of CFE-P or 5.4-5.5gr. of BE86 set the MPR alight proper with great accuracy with at most +p pressures. I really like the MPR and intend to employ it in 357Sig soon, but one does need to understand its (unique) profile and seating depth characteristics when adapting load data developed around different projectiles.

 

[Walkalong]

124 Gr RMR MPR @ 1.070/1.075 OAL - 3.9 Grs N320 - CCI 500 primer

3" S&W Shield 5" Colt Series 80 16" RRA AR
HI 955 HI 1076 HI 1070
LO 918 LO 1042 LO 1006
AVG 932 AVG 1057 AVG 1033
ES 37 ES 34 ES 64
SD 12 SD 13 SD 23

Notice with the fairly fast N320 the FPS actually went down with that jacketed bullet in the 16" AR. With the various 124 Gr plated bullets and that load they usually gain just a tiny bit.

I found that the loads at 1.06" were more accurate!

I actually go one step further. At 1.03", the 124MPR will clear in a barrel with zero leade. I load there - it's the longest load I can expect to work in any and all SAAMI-compliant 9mm luger arms.

Hmm, maybe I should try it a bit shorter.

 

[lordpaxman]

During my load development, after determining max OAL and working OAL, once I identify the most accurate powder charge, I will incrementally decrease the OAL to see if accuracy improves (They often do for 9mm).

I, perhaps conservatively, kept within the published load data which for me meant >= COL AND <= max gn. I definitely explored the working OAL with many powders, but haven't done too much in the shorter OAL, at least yet. How do you know the most accurate powder charge will still be that with a decreasing COL? And/or, with a fixed powder charge, and decreasing COL, how do you know you're operating in a safe zone? And what incremental steps do you take? I'll post my range results in a separate post but they were surprising to me. With the various bullet/powder/length permutations, that's a significant number of rounds. I should run a query against my 9mm spreadsheet and I'll bet I've fired a lot of test rounds.
Thanks again for all the great info in your posts. Nice shooting! One thing I've switched to in my test targets is using quadrille ruled paper. I then have 4 lines per inch to gauge group size, and, I can print on it before I take it to the range.

Titegroup burns hot and violent.

It sure do. I've had very accurate loads with it in all calibers, in .38 I've had one hole groups at the chrono without trying hard. It meters excellent, is clean, but it is hot.

I can load my SIG P226 Legion SAO at this COAL as well (1.150") with the RMR JHP MP 124

It's nice to hear there's a similar gun spec to what I have! However, I found the RMR 124 JHP MP 124 max COL in my barrel was at 1.150, and have only loaded it at 1.140.

I spent a lot of time chasing that longer COAL only to find out that the SIG liked the shorter cartridges better.

I'll be decrementing COL for the same reason as there are several barrels to load for. Regarding the shorter COL for accuracy, well, now, if that turns out to be true then I lose one of my excuses.

I actually go one step further. At 1.03", the 124MPR will clear in a barrel with zero leade.

Thanks for that datum point - in my SA barrel this has a max COL of 1.085 which I'd load max at 1.070. I pretty much discounted using this round across all guns, until now.
For me the MP measures .557 and the TCFP is .555 so very similar. With the N320 4.4gn, I see about .270 from the powder level to the top of the case. That put my min COL to 1.035.

I use the Hornady cartridge gauge

I use the Hundo/Shockbottle 100 round gauge, which is to SAAMI spec as well. Always good to verify the rounds, but you lose that excuse when the gun jams on the COF.

Notice with the fairly fast N320 the FPS actually went down with that jacketed bullet in the 16" AR.

That is interesting, but perhaps points to the variations in chamber and barrel? I'm sold on the "can load shorter COL within reason" and will be trying this as well.

 

[Walkalong]

That is interesting, but perhaps points to the variations in chamber and barrel?

Pressure dying down/powder expended and drag/friction. Slower powders get more velocity from the 16" tube.

RMR 124 Gr MPR - 5.7 Grs BE-86 - CCI-500 primer - 87 Degrees 77% RH - 1.070/1.075 OAL

3" S&W Shield 5" Colt Series 80 16" RRA AR
HI 1107 HI 1253 HI 1326
LO 1058 LO 1204 LO 1261
AVG 1080 AVG 1237 AVG 1289
ES 49 ES 49 ES 65
SD 16 SD 16 SD 21


Master Match 125 Gr JSP - 5.7 Grs N340 - Fed 100 primer - 87 Degrees 77% RH - 1.125 OAL

3" S&W Shield 5" Colt Series 80 5" S&W Pro
HI 1106 HI 1261 HI 1321
LO 1091 LO 1243 LO 1295
AVG 1099 AVG 1248 AVG 1307
ES 15 ES 13 ES 26
SD 5 SD 8 SD 11


Federal 90 Gr JHP - 7.2 Grs 3N37 - Fed 100 primer - 83 Degrees 35% RH - 1.090/1.095 OAL

EMP 5" S&W Pro 16" RRA AR
HI 1283 HI 1426 HI 1628
LO 1240 LO 1409 LO 1604
AVG 1260 AVG 1415 AVG 1618
ES 43 ES 17 ES 24
SD 15 SD 5 SD 9

Work up to any of these if you try them. Use data at your own risk.

 

[lordpaxman]

N320 and 9mm 124gn RMR FMJ TC FP match winner test results.
This includes two trips to the range since the first trip's results were not what I expected.

First trip: 3 loads - 4.4gn N320 1.135 COL; 4.4gn N320 1.130 COL; 4.4gn N320 1.125 COL , All RP HS, All CCI500, Sig P226

Name: 9n31
4.4gn N320 1.135 COL
Shots: 9
Average: 1029 FPS
SD: 15 FPS
Min: 1003 FPS
Max: 1046 FPS
Spread: 43 FPS
Power Factor Average: 128

Name: 9n32
4.4gn N320 1.130 COL
Shots: 9
Average: 1026 FPS
SD: 11 FPS
Min: 1015 FPS
Max: 1044 FPS
Spread: 29 FPS
Power Factor Average: 127

Name: 9n37
4.4gn N320 1.125 COL
Shots: 9
Average: 1019 FPS
SD: 14 FPS
Min: 1001 FPS
Max: 1050 FPS
Spread: 49 FPS
Power Factor Average: 126

So I almost didn't post these, as the actual didn't align with my expectations. I did verify the loads were what was chrono'd and the strings from the chrono matched the loads. I also keep records of every round's powder throw and COL and can match every round to it's velocity. After reviewing the raw data, I think the 9 shots per were not statistically significant. I also load my test runs on my production machine, which can be controversial, but that's why I record every round. The raw data showed the 9n31 string was to the plus side of 4.4gn overall (avg was 4.45), and the last string 9n37 was right at an avg of 4.40.

I tend to be cautious and decreasing COL isn't my thing, so I wanted to rerun at least part of this to verify the numbers, but I wanted to broaden the experiment a bit. I was thinking either A - I'm in a non-liner part of decreasing COL and there's a KB waiting, or it's still linear but .005 per step isn't changing much.
I decided to re-run the 1.130 COL test, and add a 1.120 COL test. In addition, I added two loads with incremental powder increase.

Second trip: 4 loads - 4.4gn N320 1.130 COL; 4.4gn N320 1.120 COL; 4.5gn N320 1.130 COL; 4.6gn N320 1.130 COL , All RP HS, All CCI500, Sig P226

4.4gn N320 1.130 COL
Name: 9n39
Shots: 8
Average: 1032 FPS
SD: 13 FPS
Min: 1010 FPS
Max: 1057 FPS
Spread: 47 FPS
Power Factor Average: 128

4.4gn N320 1.120 COL
Name: 9n38
Shots: 9
Average: 1036 FPS
SD: 13 FPS
Min: 1017 FPS
Max: 1063 FPS
Spread: 46 FPS
Power Factor Average: 129

4.5gn N320 1.130 COL
Name: 9n40
Shots: 9
Average: 1050 FPS
SD: 10 FPS
Min: 1035 FPS
Max: 1066 FPS
Spread: 31 FPS
Power Factor Average: 130

4.6gn N320 1.130 COL
Name: 9n41
Shots: 9
Average: 1058 FPS
SD: 15 FPS
Min: 1031 FPS
Max: 1075 FPS
Spread: 44 FPS
Power Factor Average: 131

Well now, this is encouraging, at least it's trending the way I expected, and, the raw data looked reasonable as well. I may generate some additional loads at 1.120 as that would run in my SA as well.
At any rate, have at it!

 

[ray15]

Thanks for that datum point - in my SA barrel this has a max COL of 1.085 which I'd load max at 1.070. I pretty much discounted using this round across all guns, until now. For me the MP measures .557 and the TCFP is .555 so very similar. With the N320 4.4gn, I see about .270 from the powder level to the top of the case. That put my min COL to 1.035.

I was expecting to have to back way off the published load data at this short of an OAL, but chrono results showed I needed approximately as much CFE Pistol (5.1gr) to match the velocity of published max loads. Surely need to start low and work up. With BE-86 I stopped a tenth or two short of what others here are running with longer OALs. Mine are loaded to defense load speeds though, I've not tried the MPR HP with faster powders. I'm sure it would be awesome with Titegroup, Sport Pistol or VV powder in that speed range for minor loads

I use the Hundo/Shockbottle 100 round gauge, which is to SAAMI spec as well. Always good to verify the rounds, but you lose that excuse when the gun jams on the COF.

I apologize if you're familiar with these points, but things weren't very obvious to me when I started using cartridge gauges and others may not realize that gauges from different manufacturers employ different strategies and don't necessarily check the same things.

The Hornady is SAAMI-minimum, in that it reduces in diameter instantly to 0.347" at 0.755" down - to land diameter. This simulates a bore with no leade. Other types, like the Wilson or Dillon I have, reduce to 0.358" +. With the latter you aren't getting feedback on the implications of your OAL on chambering - it's just a case check. I find the SAAMI-minimum type more useful because I can quickly determine the no-leade number. I know approximately how much additional OAL the barrels of my guns will accomodate if I wish to load longer, but if I'm at the no-leade number I don't need to plunk anything and all guns feed from the same bag.

 

[lordpaxman]

The Hornady is SAAMI-minimum, in that it reduces in diameter instantly to 0.347" at 0.755" down - to land diameter.

I appreciate the information and distinction between these gauges. I knew the Hundo was primarily a case check with perhaps a slight check on the bullet. Mine is about .356 through holes after the case. If it did minimum, it wouldn't be much use for us uber-length junkies. I didn't know the Hornady was a minimum, I'm glad I didn't order one or I'd be sending it back! You indicated a .347 at case mouth, however, I'm not trying to nitpick but I thought the spec allowed for a very short leade. Most of my factory SD rounds, while very short (1.1 or so), don't have the ogive starting at the case mouth. At any rate, the only ones of mine that would fit through the Hornday are some ancient LRN with TG.

Thanks again for all the valuable information and assistance!