9mm refresher course

[Bartojc]

I have loaded thousands of 9mm over the past 4 or 5 years. All of them have been Berry's 115 gr plated RN. I've used these for 3 different autoloaders all loaded to 1.140 COAL with 4.5ish gr W231. I have not had any issues with bullet set back, tension, anything.
When I started with this load all I wanted was to reliably cycle the autoloaders and get range ammo. I wanted reasonable accuracy but that was not my main goal. Using mixed brass and 3 pistols there are a lot of variables but this load met my criteria.

I've just got my first shipment of RMR 125gr FMJ RN and I'm looking for a similar load. Its been a while since I've messed with 9mm, and when I developed the above load my notes were lacking
What I've decided to do is start with 4.4 gr W231, this seems to be reasonable based on Hodgedons site, Lee, Sierra, etc manuals. My COAL is at 1.130. Taper crimp measures roughly .377ish. Should my crimp be more or less with the RMR FMJ vs Berry's Plated ? I measured some of the Berrys and its the same which has been working. Am I over thinking it ? Should it be more? Less ?

Why do published loads seem so short for COAL ? Doing my plunk test on all 3 pistols seems like I can use longer, which I've been doing. I originally did it ass it provided insurance of less pressure than the published starting loads with published COAL. I figured if my COAL was longer I would have less pressure. It was my first try at mm and I like my fingers.

Re: plunk test. I have one barrel where no matter how short I make the round they do not 100% fall freely out on their own. Some do but some require a shake. All rounds pass case gauge. The rounds sit properly in all barrels. Why would that be ?

-Jeff

 

[Dan Wesson]

The RMR 9mm FMJ has a rather blunt ogive compared to Berry’s. While they may work at 1.130 I would try seating shorter (up to 1.100) and see how they work. I have a p938 that does not like them long but will run @ 1.1 COAL. W231 4.4gr.

Also, measure your crimp/case mouth to see how they compare to your Berry’s reloads or commercial loads that function well in your pistol. You might need to make a small adjustment.

 

[Axis II]

Shaking the bullet out of the barrel seems like you failed the plunk test. Seeing how 124gr data on Hodgdon is for Berrys plated and you can push the FMJ a little harder i don't see a reason why you cant use 125gr FMJ 4.4gr as a start. Just follow published data, make sure the dummy rounds fall freely out of the barrel and G2G.

 

[Gottcha]

I just tested RMR 124 GR RN plated with w231 yesterday.

4.0gr , col 1.150 shots soft and cycles
4.2gr, col 1.150 shot better and cycles
4.4gr, col 1.150 shot really good and cycles.

I'm going to try 4.5 and 4.6 loads next week

This is just what worked for me your results might vary always start low and work up. That said I had a hard time finding load data.... Well not a hard time but the min and max load data from different sources were kinda far apart and it seemed the vast majority of loaders were between 4.2 and 4.8gr with a 124gr bullet.

COL shorter that 1.150 with my loads I would drop down the charge weight. Decreasing from 1.150 to 1.130 would cause pressure to increase and going down to 1.100 would greatly increase pressure. So food for thought.

 

[Dan Wesson]

I just tested RMR 124 GR RN plated with w231 yesterday.

4.0gr , col 1.150 shots soft and cycles
4.2gr, col 1.150 shot better and cycles
4.4gr, col 1.150 shot really good and cycles.

I'm going to try 4.5 and 4.6 loads next week

This is just what worked for me your results might vary always start low and work up. That said I had a hard time finding load data.... Well not a hard time but the min and max load data from different sources were kinda far apart and it seemed the vast majority of loaders were between 4.2 and 4.8gr with a 124gr bullet.

COL shorter that 1.150 with my loads I would drop down the charge weight. Decreasing from 1.150 to 1.130 would cause pressure to increase and going down to 1.100 would greatly increase pressure. So food for thought.

The 124gr PLATED do work well at that length.

The FMJs however do not for me unless shorter COAL.

 

[Axis II]

The 124gr PLATED do work well at that length.

The FMJs however do not for me unless shorter COAL.

I have to run a different COAL for RMR compared to Berry and Extreme 124gr.

 

[Bartojc]

Multiple sources suggest 4.4gr W231 with 124/5 gr FMJ RN as a starting load, OAL on these are roughly 1.10. With my lowest COAL at 1.120 I think I'm ok as a start. Seem reasonable ?

Re: plunk test. Maybe I have too much oil in the chamber when testing. ? I dunno, but this one barrel is always a little different. Rounds never fall completely free 100%. I just made a couple dummy rounds with the RMR at 1.10 and they seemed the same as the 1.12, the 1.125 and the 1.30. They sit properly (headspace), but do not all fall out 100% of the time. Empty sized brass falls free 100% of the time.

-Jeff

 

[Dan Wesson]

Multiple sources suggest 4.4gr W231 with 124/5 gr FMJ RN as a starting load, OAL on these are roughly 1.10. With my lowest COAL at 1.120 I think I'm ok as a start. Seem reasonable ?

Re: plunk test. Maybe I have too much oil in the chamber when testing. ? I dunno, but this one barrel is always a little different. Rounds never fall completely free 100%. I just made a couple dummy rounds with the RMR at 1.10 and they seemed the same as the 1.12, the 1.125 and the 1.30. They sit properly (headspace), but do not all fall out 100% of the time. Empty sized brass falls free 100% of the time.

-Jeff

Check crimp OR you may be using brass that is a bit thicker than average.

 

[ArchAngelCD]

With a 124/125gr FMJ bullet I load 4.6gr W231 and a CCI-500 primer with an OAL of 1.115". Good load in my guns.

 

[Bartojc]

My crimp is .377 on both old loads with Berry's and all new loads with RMR. I think it is brass specific as some falls freely. Other 2 barrels don't seem to care. Everything passes cartridge gage.

Like I said it doesn't seem to matter what I shorten it too I do not get 100% fall free from this one barrel.

The more I learn the more I worry. Sometimes when you think you know what you are doing your not smart you are ignorant Some of you (BDS. Walkalong, etc) have forgotten more than I'll ever know.

-Jeff

 

[LiveLife]

RMR 125gr FMJ RN ... Taper crimp measures roughly .377ish. Should my crimp be more or less with the RMR FMJ vs Berry's Plated?

Am I over thinking it? Should it be more? Less?

I keep things simple and add .022" to the diameter of bullet for taper crimp.

So for .356" sized Berry's bullets, .378" taper crimp.

For .355" sized FMJ, .377" taper crimp.

Why do published loads seem so short for COAL?

For pressure testing, they do not use actual pistols rather universal test barrel fixtures and if test barrel has shorter or no leade, you have to load shorter to fully chamber.

My factory Glock, KKM and Lone Wolf barrels with longer leade will fully chamber 115/124 gr FMJ loaded to 1.169"+ but for my Lone Wolf barrel with shorter leade, I need to load shorter (depending on the bullet profile, as short as 1.110" to fully chamber).

I've decided to do is start with 4.4 gr W231 ... COAL is at 1.130. Taper crimp measures roughly .377ish.

Looking good as Hodgdon lists 4.4 to 4.8 gr as start/max charges for 125 gr FMJ - http://www.hodgdonreloading.com/data/pistol

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

124 GR. Berry's HBRN-TP W231/HP-38 Dia .356" COL 1.150" Start 3.9 gr (920 fps) 27,400 PSI - Max 4.4 gr (1,037 fps) 31,900 PSI


As to OAL/COL, if you are looking for accuracy, conduct your load development with longest working OAL. Once you identify the powder charge that produce smallest group size, then incrementally decrease the OAL by .005" (without compressing powder charge) to see if accuracy improves.

For 124 gr FMJ/RN bullets, I typically use 4.3 gr W231/HP-38 and shorter 1.120"-1.135" OAL produce smaller groups than 1.150"-1.160" (4.5 gr for longer OAL).

 

[sbwaters]

Once you identify the powder charge that produce smallest group size, then incrementally decrease the OAL by .005"

Good advice. It ended up that my CZ75B likes a shorter OAL. With TiteGroup, mine ended up liking even shorter than yours.

 

[Bartojc]

Working from home has it's advantages. My plunk test was bothering me and it got in my head so bad I had to do something. At lunch I went down to the bench, pulled the barrel in question and tested my test rounds of 3 sizes. Like I said some passed and some failed. Previous measurements had no real answers.

I decided to start from scratch. I reset my seating die, and crimp die from scratch. Running the rounds through the reset seating and FCD produced rounds that would plunk no issue in said barrel. Not sure what I am fixing but something was ever so slightly off. I believe that my issue stemmed from mixed brass. I was able to run all the questionable rounds through the FCD to "fix" them as well. I feel better that all test rounds plunk like they should, and new test rounds will as well. My OAL of 1.130 and less all plunk.

The lesson leaned here is if something seems off it probably is. I can now proceed and feel more confident in my testing.

-Jeff

 

[gifbohane]

Tested reloads in December. Berry's 124 Grain, with 4.4 grains of W231 at 1.15. They chronoed at an average of 1130. To me that was a little hot. No?

 

[LiveLife]

FCD produced rounds that would plunk no issue in said barrel. Not sure what I am fixing but something was ever so slightly off.

I believe that my issue stemmed from mixed brass.

Perhaps difference in case wall thickness?

https://www.thehighroad.org/index.p...nt-case-wall-thickness-and-plunk-test.834078/

Berry's 124 Grain, with 4.4 grains of W231 at 1.15. They chronoed at an average of 1130. To me that was a little hot. No?

Seems warm. They should be more around mid to high 1000 fps, definitely below 1100 fps.

Maybe you were shooting too close to the chrono?

 

[Bartojc]

Perhaps difference in case wall thickness?

https://www.thehighroad.org/index.p...nt-case-wall-thickness-and-plunk-test.834078/

I believe so. I suspected this. I reread your referenced thread. Now I need to go down and measure differences in brass below the case mouth as you did Thanks a lot....

-jeff b.

 

[santacruzdave]

I've had the FCD work on rounds that would not plunk when I put them thru the die the first time. They plunked fine after the second run thru.

 

[gifbohane]

Linux

No the Chrono was a good 10 feet in front of me. In between I fired some factory rounds, Blazers, and they chronoed at an average of 1150

 

[Dan Wesson]

Linux

No the Chrono was a good 10 feet in front of me. In between I fired some factory rounds, Blazers, and they chronoed at an average of 1150

If factory chrono’d at 1150 I would say you’re ok. Blazers are not known to be particularly hot loads.
Question: were the factory loads 124gr? Or 115gr?

 

[gifbohane]

drband

The blazers were/are 115 gr. I was curious and looked at the boxes just now. I thought that the box would show expected velocity.. it did not. Interesting the box clearly stated "Not for use by law enforcement."

 

[ArchAngelCD]

drband

The blazers were/are 115 gr. I was curious and looked at the boxes just now. I thought that the box would show expected velocity.. it did not. Interesting the box clearly stated "Not for use by law enforcement."

I'm fairly sure law enforcement dies not authorize the use of aluminum case ammo.

 

[gifbohane]

Arch

The blazer brass is not aluminum cased... it is brass

 

[Dan Wesson]

drband

The blazers were/are 115 gr. I was curious and looked at the boxes just now. I thought that the box would show expected velocity.. it did not. Interesting the box clearly stated "Not for use by law enforcement."

I just wondered if they were 115s if they were higher velocity than 124s. Just curious.

 

[GTS Dean]

As to OAL/COL, if you are looking for accuracy, conduct your load development with longest working OAL. Once you identify the powder charge that produce smallest group size, then incrementally decrease the OAL by .005" (without compressing powder charge) to see if accuracy improves.

For 124 gr FMJ/RN bullets, I typically use 4.3 gr W231/HP-38 and shorter 1.120"-1.135" OAL produce smaller groups than 1.150"-1.160" (4.5 gr for longer OAL).

This is what I do for rifle rounds as well. One of my rifles is EXTREMELY sensitive to bullet jump. .004" can mean 1" of spread, with only 10-15 fps of velocity difference.