RMR 124gn 9mm FMJ with HP38

maddmaxx11 said:

But the Hodgdon site says to start at 4.4 with a max of 4.8. with a sierra 124gn.

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IIR the Hodgdon data was a Sierra 125gr FMJ. The 1 gr is not a big deal, it's just if you check the 124gr box, you'll never see the 125gr data. That data also includes a COL of 1.090". What's your COL?

I'm doing this same combination and using the Hodgdon 125gr data as my COL is 1.065. This is for my son's Taurus G2. My first ladder was 3.9, 4.1, 4.3 with 4.1 being the worst group and not much difference in the other 3. These were 5 round samples. Next ladder we're trying 3.7, 3.9 and 4.3 with 10 round samples.

Edit - Error on my part. I am using RMR 124gr JHP MPR. Although I would use this same recipe for FMJ.

With 124gr FMJ bullets I charge 4.4gr HP-38

maddmaxx11 said:

I am using a col of 1.13.

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I thought I had worked up the 124 RMR FMJ and 231 but only have data for the 124 RMR JHP and FPMW.
SA 1911 A1 5”
124gr RMR JHP, 3.9 W231, 1.120 COL, Vel Avg 969
124gr RMR FPMW, 4.1 W231, 1.120 COL, Vel Avg 997

Just as a side note, I also have data for W244.
124gr RMR FPMW, 4.1 W244, 1.120 COL, Vel Avg 1030

I shoot these quite a bit.

4 grains of hp38.

4.5 grs zip, 231, or HP-38 in 9mm with 124-5 gr. plated, fmj, or cast in glocks and 1911s. Same load with same weight bullets in .38 Spl.

Just FYI, I load RMR's 124 FMJRN with 4.8 Win 231 @ 1.100 COL for my G17-5 with no issues. Yesterday I loaded some with 4.5 Win 231 @ the same 1.100 COL to try.

I use 4.2 gr of W231 at a COL of 1.135. I shot about 4500 of these last year across 3 different 9MM handguns ranging in size from a 4.5" 1911 to a S&W Shield. They work well for general range use.

-Jeff

lordpaxman said:

I thought I had worked up the 124 RMR FMJ and 231 but only have data for the 124 RMR JHP and FPMW.
SA 1911 A1 5”
124gr RMR JHP, 3.9 W231, 1.120 COL, Vel Avg 969
124gr RMR FPMW, 4.1 W231, 1.120 COL, Vel Avg 997

Just as a side note, I also have data for W244.
124gr RMR FPMW, 4.1 W244, 1.120 COL, Vel Avg 1030

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How is your accuracy when comparing W231 and W244 in the same cartridge/bullet combination? I have been meaning to do some testing with W244 but haven't yet. Thanks...

ArchAngelCD said:

How is your accuracy when comparing W231 and W244 in the same cartridge/bullet combination?

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My accuracy didn't change. I sure wish it did though!
The group size on paper was virtually the same. For me that's a bench rest at 10 yards and these were roughly 3/4 to 1" for 9 shots. But it wasn't quite fair since the 4.1gr of 231 is a bit under minor PF and the 4.1 of 244 is a bit over. I didn't equalize the PF and re-run the testing, but my notes indicate the felt recoil, case cleanliness and smoke were also similar (all being very acceptable).

Thank you @lordpaxman

I load W231/HP38 at 4.3gr with a RMR 124gr RN @ 1.145. I get groups under 1.5" at 15 yards with my M&P CORE.

I just got some RMR 124 gr RN. I never used their bullet before, and just wondering where to start with a charge for a Beretta 92FS. I just got the pistol used, last month. I haven't shot it yet. I replaced the trigger with the steel trigger kit with the "D" hammer spring, and a few other parts.

maddmaxx11 said:

Thanks for the info. I made up 5 ea from 4.1 to 4.4 with a col of 1.135 to try. I was shooting 124gn plated at 4gns and they were fine in my P228 and 4.5" Xdm but would not eject on my new Canik Tp9sfx because of the stiff spring.

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Do a plunk test before you load all those rounds to be sure that OAL will work in your barrel/barrels. Load a dummy round and check each barrel the ammo will be fired in.

Like I said above, I load 4.4gr W231/HP-38 for general use with jacketed bullets but have gone to the 4.8gr limit on the Hodgdon site with 124/125gr JHP bullets.

glc24 said:

I just got some RMR 124 gr RN. I never used their bullet before, and just wondering where to start with a charge for a Beretta 92FS. I just got the pistol used, last month. I haven't shot it yet. I replaced the trigger with the steel trigger kit with the "D" hammer spring, and a few other parts.

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For my Beretta M9 and 92 FS I'll use 4.2-4.4 grains of ww231/HP38 for 125 grain cast. To more closely mimic a std velocity service type loading, I'll stoke them up a bit more... 4.8-5 grains with a jacketed bullet. FWIW, Zero Bullets used WW231/HP38 in their loading's, as shown in the attached load sheet.



Also thought I would add a bit about D-spring ignition concerns, it any exist. As what I considered a rigorous test of the ability of the D-spring to do its job reliably allowing 100% ignition, I loaded up test rounds using CCI small rifle primers. In limited testing there were absolutely no issues with ignition, and being these pistols are primary defense weapons, I wanted to have no worries using any primer.

Here are some chronograph numbers of the testing, and you might note I used .357" Hornady XTP bullets... Their .357" diameter very well suits my pistols (almost all Euro pistols) generous groove diameter specs, and feed perfectly. Both of mine gauge just a bit over a .357" groove diameter:

Beretta M9 - 6.6 grains Power Pistol - CCI 400 SMALL RIFLE PRIMER - Hornady 125 .357" XTP HP - COL 1.125”

1208, 1206, 1227, Av 1213 ES 21 SD 11

Here for comparison is the charge weight dropped by 4/10's a grain, using conventional SPP:

Beretta M9 - 6.2 grains Power Pistol - 125 gr .357” XTP - WW cases - CCI 500
1179, 1187, 1180, 1174, 1179, SD 4 ES 13 AV 1179 - * Very accurate @ 15 yards... Almost one hole.

PP and these bullets are magical stuff... I only wish expansion were a bit more positive. Good luck.

maddmaxx11 said:

I shoot rmr 124gn RN FMJ with 4.3 guns HP38 with COL of 1.13. I ran some through the chronograph yesterday and was surprised to see about 1180 fps from my 5.2" barrel with a PF of around 140-145. Hodgson says start at 4.4 gn with about 1000 fps and that 4.8gn gives about 1080 fps with a 4" barrel and shorter COL than I am using. I have not seen any signs of pressure at all. Why is the speed so much higher?

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Wow, I'm not seeing how 4.3 grains of HP38 is giving you that speed? Looking over my load notes, I'm seeing 4.2 grains of WW231 gave me a nice consistent 1065 FPS, from my 5" Beretta M9 with 125 grain cast; jacketed would be slower. I can say until I got rid of my second Shooting Chrony, I would suffer no way type of readouts at times. It was not an issue with setup, battery, usage, etc... It just sucked (as did Shooting Chronys CS)

Even when not going schizo, it avg about 6-8% fast compared to my other two chronographs. Best thing I ever did, was get a ProChrono Digital... Actually a pleasure now to do chronograph work.

Wow, I'm not seeing how 4.3 grains of HP38 is giving you that speed?

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This is the MPR JHP in my gun
S+B SP, mixed range brass, charges as thrown after setting the measure
String: 2
Date: 10/29/2017
Time: 9:42:14 AM
Grains: 124
Hi Vel: 1068
Low Vel: 1004
Ave Vel: 1034
Ext Spread: 64
Std Dev: 24
RMR 124 MPR JHP 4.3 HP38 1.055 5inch 1911 (short OAl test, normally load these about 1.08, going to 1.055 picked up say 20-30 fps over 1.08)
Velocity Power Factor Ft/Lbs
1046 129.704 301.222
1021 126.604 286.995
1004 124.496 277.518 (low, skewed the #s)
1068 132.432 314.026
1034 128.216 294.35
so 4.3 gr was giving me about 1035fps
Some guns are faster but to get to 1180??
Hodgdons numbers
125 GR. SIE FMJ Winchester 231 .355" 1.090" 4.4 1009 24,600 CUP 4.8 1088 28,800 CUP

1180 almost makes me think that maybe some how you might have loaded 5.3 (over max) not 4.3
Assuming a linear increase (which is not safe to assume but just guess from 4.4 to 4.8 picked up say 80 FPS so IF another .5gr added about 80-100fps (and pressure probably would go WAY up) that would put you
around 1160-1180.
If you have any left I would pull one and reweigh the charge, double check the scale with a check weight.

As Walkalong mentioned the chrono might not be telling the truth, just might not have been reading right that day.

Shot quite a few different 124-125 with 4-4.4gr of HP38 never got that high a vel in any of my 9s, in general 4-4.4gr HP38 gives me between say 1000 to 1060.

9mmepiphany said:

RMR [124 gr FMJ] to 1.135" ... 4.3 grs of HP-38 is giving me 1060 fps (131PF)

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Ruger 15151 said:

I load W231/HP38 at 4.3gr with a RMR 124gr RN @ 1.145. I get groups under 1.5" at 15 yards with my M&P CORE.

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Add me to the 4.3 gr club for RMR 124 gr FMJ ... I load to 1.130"-1.135", variance from using mixed range brass.

FWIW, I use 4.8 gr for RMR 115 gr FMJ loaded to 1.125"-1.130".