RMR bullet users and Sport Pistol/N320 data collection

[ColoradoNick]

For those of you who use RMR match winners or MPR's what's your load data vs power factor? 

 

I've done some testing lately comparing powder charges of RMR's (both 124 and 115 MW's and MPR's) to another brand of fully plated RN's and the power factor variance is extreme.

 

For example out of a shadow 2:

RMR 124 Matchwinnners with 4.3 grains of Sport Pistol loaded to 1.09OAL produced a 5 shot average of 127 power factor with a SD in the teens.

Fully Plated 124 RN's with with 4.0 grains of Sport Pistol loaded to 1.11OAL produced a 5 shot average of 128.5

 

In a 14.5" PCC barrel:

RMR 115gr MPR's (nukes) with 4.7 grains of Sport Pistol loaded to 1.08OAL produced a 5 shot average of 127. 

Fully Plated 115gr RN's with 4.5 grains of Sport Pistol loaded to 1.11OAL produced a 5 shot average of 136

Fully Plated 115gr RN's with 4.7 grains of Sport Pistol loaded to 1.11OAL produced a 5 shot average of 142. 

 

I did this testing because locally a lot of people have told me I am using a lot more powder than I should have to to achieve minimum power factor. I have shot and loaded thousands of rounds of RMR and chronographed on multiple occasions. Even done temperature extreme testing- mid 30's to HOT. I don't know anyone else locally shooting RMR's so I would like to compare. The only understanding I can come up with as to why the RMR's are slower is possibly the bullet not expanding in the chamber as much as a plated round? Both bullet manufacturers tested measured a true .3545 diameter.

 

The next testing I'm going to do is a deeper comparison of OAL. 

 

So far through my Shadow 2:

124gr fully plated with 4.0gr of Sport Pistol @ 1.13OAL = 121 Power Factor

124gr fully plated with 4.0gr of Sport Pistol @ 1.11OAL = 128 Power Factor

 

There is a variance of indoor vs outdoor with a lab radar chronograph that might be causing some issues but I'm starting to doubt it. Otherwise SD's in all groups were acceptable. More outdoor testing to follow. 

 

Edited December 16, 2023 by ColoradoNick

[ColoradoNick]

Edited.

Edited December 16, 2023 by ColoradoNick

[bowenbuilt]

Plated bullets of the same weight will always be faster than the copper jacketed RMR Match Winners. Plated bullets offer much less resistance to the rifling than the much tougher copper jacket. 

Deeper seating produces more pressure therefore a higher power factor.

I use 124 RMR Match Winners exclusively in my CZ's and get the same results as you do with N320 or SP.

[ColoradoNick]

34 minutes ago, bowenbuilt said:

Plated bullets of the same weight will always be faster than the copper jacketed RMR Match Winners. Plated bullets offer much less resistance to the rifling than the much tougher copper jacket. 

Deeper seating produces more pressure therefore a higher power factor.

I use 124 RMR Match Winners exclusively in my CZ's and get the same results as you do with N320 or SP.

Interesting, I'm glad to hear someone has the same results and it's kind of what my assumptions were. I still need to do some accuracy testing but with the volume I am shooting (2500/mo) it might make sense for me to switch to plated. I figure I can get an extra round worth of powder every 10-13 rounds loaded. Next week I'm going to try an OAL of 1.09 but with the plated rounds to see if I can get an acceptable power factor and accuracy at 3.9 and 4.0 grains in my CZ. Why do you stick with RMR? The match winners have been extremely accurate for me- grouping around 1" at 25 yards in my CZ but they don't run in my PCC. 

Edited December 16, 2023 by ColoradoNick

[bowenbuilt]

Plated bullets of the same weight will always be faster than the copper jacketed RMR Match Winners. Plated bullets offer much less resistance to the rifling than the much tougher copper jacket. 

Deeper seating produces more pressure therefore a higher power factor.

I use 124 RMR Match Winners exclusively in my CZ's and get the same results as you do with N320 or SP.

[bowenbuilt]

I use them because they are THE most accurate bullets I have tried in the last 45 years in all of my CZ competition guns. They are reasonably priced, quickly shipped, make a clear round hole and provide match grade accuracy. They are also available when most others are in back order and the customer service is A-1.

[ColoradoNick]

So far with my own use I definitely can't argue that! 

[Farmer]

It’ll be interesting what you come up with by changing the seating depth. I did some testing years ago and the results were not what I expected. I tested same loads with different seating depths starting with .010 from the lands and seating deeper in .010” increments up to .050”. What I found was that the .010 didn’t necessarily give the best accuracy or velocity and the ES was erratic. At .020 the ES settled down and accuracy increased as did velocity, psi looked good. At .030 ES was pretty much the same, velocity dropped and accuracy fell off some, psi similar. At .040” it was similar to .030” but velocity was starting to increase and ES was worse with accuracy slightly worse. At .050 velocity jumped similar to the .020” loading but ES was erratic and accuracy fell off,  higher psi indications showed up too. I’ve done this test with rifle rounds and pistol too and the results are very similar. There’s that drop in velocity which I contribute to the extra free bore but not enough decrease in case volume to increase psi. Just some stuff I’ve run across over the years. YMMV. 

[ColoradoNick]

35 minutes ago, Farmer said:

It’ll be interesting what you come up with by changing the seating depth. I did some testing years ago and the results were not what I expected. I tested same loads with different seating depths starting with .010 from the lands and seating deeper in .010” increments up to .050”. What I found was that the .010 didn’t necessarily give the best accuracy or velocity and the ES was erratic. At .020 the ES settled down and accuracy increased as did velocity, psi looked good. At .030 ES was pretty much the same, velocity dropped and accuracy fell off some, psi similar. At .040” it was similar to .030” but velocity was starting to increase and ES was worse with accuracy slightly worse. At .050 velocity jumped similar to the .020” loading but ES was erratic and accuracy fell off,  higher psi indications showed up too. I’ve done this test with rifle rounds and pistol too and the results are very similar. There’s that drop in velocity which I contribute to the extra free bore but not enough decrease in case volume to increase psi. Just some stuff I’ve run across over the years. YMMV. 

There’s an article in the latest USPSA magazine where someone did OAL testing and if I remember correctly velocity increased to a certain point and plateaued. I should be able to do my own testing on Monday and Wednesday and I can hopefully report back. What I can say is RMR’s at 1.09 are extremely accurate. Hopefully the plated version I am trying will be as well. At 1.11 the results were promising. 

[Farmer]

58 minutes ago, ColoradoNick said:

There’s an article in the latest USPSA magazine where someone did OAL testing and if I remember correctly velocity increased to a certain point and plateaued. I should be able to do my own testing on Monday and Wednesday and I can hopefully report back. What I can say is RMR’s at 1.09 are extremely accurate. Hopefully the plated version I am trying will be as well. At 1.11 the results were promising. 

  I also get good accuracy from the match winners in my pistols, and actually the plated are good too. What’s funny is that the 135 MW shoots great out of my XDM but the 135 RN doesn’t. Jake at RMR said they are the same bullet and they just run the RN through another stamping process to make the flat nose MW. If I seat the RN .015” deeper off the lands than the MW’s then they shoot better but still not as good. 

[nkresho]

I still shoot mainly 147 MWs but have done some load testing with the 124s.

 

Here's mine to throw in the hat:

shadow 2 factory barrel

ran this test in July so upper 70s, all ran over shooting chrony with sky shields on, 10' muzzle to chronograph,

all 10 shot groups, and using mixed brass.  I've found that the increased thickness of CBC brass by the base causes an increase in pressure enough to bump the speed up.  These tests include some of that brass which accounts of a lot of the variation in velocity.  I'd guess maybe 10-20% of my brass is CBC lately.

 

4.1 grains n320 and FED SPP under 124 MW  1.085" OAL: 994.9-1039  (123-127 power factor) 

4.2 grains n320 and FED SPP under 124 MW  1.085" OAL: 1002-1068 (124.248-128.96 power factor) 

4.3 grains n320 and FED SPP under 124 MW 1.085" OAL: 1013-1089 (125.6-130.2 power factor) 

4.4 grains n320 and FED SPP under 124 MW 1.085" OAL: 1050-1073 (130.2-131.44 power factor)

 

After being chronoed at a sectional last season, I can say that my chrony does read conservatively compared to the labradar they used.  The labradar gave me 888, 895, and 913 from a load that consistently gave me an average of about 870 (128pf) with my chrony.

Edited December 17, 2023 by nkresho

[RangerTrace]

My current load is a RMR 124 TC Match Winner over 4.8 grains of N330 to 1.125" = 137 PF out of an XC.

[Rich406]

The load I’ve settled on for RMR 124gr mpr is 4.75 grains of sport pistol loaded to 1.15. This gives me about 1060 fps out of a 4.6” barrel. 
 

This seems to me to be a larger charge normal for the 131ish PF. 

 

For comparison a blue bullets 124 gr .356 bullet at 1.15 only needs 4.1 grains of sport pistol to achieve the same 1060ish fps.

 

ive messed around with OAL a bit and every .01 reduction adds approximately 10 fps from 1.15 down to 1.12.  I’d load a bit shorted but then I get feeding problems.  
 

 

[ColoradoNick]

22 minutes ago, Rich406 said:

The load I’ve settled on for RMR 124gr mpr is 4.75 grains of sport pistol loaded to 1.15. This gives me about 1060 fps out of a 4.6” barrel. 
 

This seems to me to be a larger charge normal for the 131ish PF. 

 

For comparison a blue bullets 124 gr .356 bullet at 1.15 only needs 4.1 grains of sport pistol to achieve the same 1060ish fps.

 

ive messed around with OAL a bit and every .01 reduction adds approximately 10 fps from 1.15 down to 1.12.  I’d load a bit shorted but then I get feeding problems.  
 

 

Thats way over max? I seem to remember the Lyman book I have says 4.4 is max?! Also odd I currently load RMR’s to 1.09 (about 10k worth) and even with 24+1 don’t have any feeding issues!

[Rich406]

6 minutes ago, ColoradoNick said:

Thats way over max? I seem to remember the Lyman book I have says 4.4 is max?! Also odd I currently load RMR’s to 1.09 (about 10k worth) and even with 24+1 don’t have any feeding issues!

That may be so, but I don’t see any signs of overpressure. It’s pretty much the  minimum load to make that bullet work for me. 

[ES13Raven]

On 12/16/2023 at 10:52 AM, bowenbuilt said:

I use them because they are THE most accurate bullets I have tried in the last 45 years in all of my CZ competition guns.

Curious, have you tried Precision Delta 124gr JHP?  I had great results with those.

[ohsevenflhx]

I use 124gr RMR Match Winners with 3.9gr of American Select at 1.125 Oal. Avg 1074 fps for 133 PF, 30 ES.  Very accurate, low smoke and clean. 

Edited February 9 by ohsevenflhx

[bowenbuilt]

On 2/6/2024 at 2:49 PM, ES13Raven said:

Curious, have you tried Precision Delta 124gr JHP?  I had great results with those.

Yes, I used to buy them in bulk until I tried the RMR bullet. They are excellent.

[ysrracer]

Name: 9mm: 124gr RMR FP: Sport Pistol 3.15gr: OAL 1.090: Glock 19
Notes: Glock 19

 

Shots: 4
Average: 838 ft/s
SD: 11 ft/s
Min: 823 ft/s
Max: 855 ft/s
Spread: 32 ft/s
Power Factor Average: 103
Power Factor Low: 102
Power Factor High: 106

 

Barometric Pressure: 29 in Hg
Temperature: 71F

 

Bullet Weight: 124

 

Powder/Wt: Sport Pistol 3.15gr
Bullet/Wt: RMR 124 FP
C.O.A.L.: 1.090
Primer: Fed SPP
Case: Federal
Gun: Glock 19

[ES13Raven]

13 hours ago, ysrracer said:

Name: 9mm: 124gr RMR FP: Sport Pistol 3.15gr: OAL 1.090: Glock 19
Notes: Glock 19

Are you working up a CCP load?

[Blue Jacket]

So with 124gr RMR Match Winner bullets loaded at 1.095 I am getting a power factor of about 126-127 with 4.3 grs of N320.  Too close for me to take a chance at crono. That was from a 4.7 inch Grey Guns slide in a Sig 320.

 

I was planning on bumping it up to 4.4 Gr, but the VV lists the max as 4.3.  Has anyone had an issue going to 4.4.  I saw no pressure signs at 4.3, but figured I would ask here before actually doing it.  Thanks  

[bowenbuilt]

No issues. N320 is somewhat slower than it used to be out of all my guns.

[ysrracer]

7 hours ago, ES13Raven said:

Are you working up a CCP load?

 

I can't even spell CCP. What is it?

[ES13Raven]

15 minutes ago, ysrracer said:

 

I can't even spell CCP. What is it?

Compact Carry Pistol division, power factor = 105

[ysrracer]

Oh, no. My wife can't rack the slide on my glock 19, so I put in a light recoil spring, and loaded up some light ammo.