Project SIG P365X, RMR 115gr, MPRJHP

[vaalpens]

I have started a new reloading project using the above combination. The plan is to find accurate loads out of the P365X using the 115gr RMR MPR bullet. The plan also is to find an accurate and reliable load, meeting the magical 1,150fps. This is the velocity RMR tested these bullets for expansion. This is a quote from their website: "It is recommended that you shoot them at 1150 FPS or more to get reliable expansion for self defense or hunting purposes."

This is obviously a long term project since it involves researching/deciding on loads, testing these load, and documenting everything. Before I can start with the loading, testing and documenting, a couple of things will be required outside the normal primers, cases and reloading equipment.

I will need the RMR 115gr MPRJHP bullets. Well these beauties were picked up today:


I measured 10 of the bullets with the following results:


The P365X I will be using to test these bullets. That is a Concealment Solutions OWB holster:


The P365X has a 3.1" barrel, so it will take a good solid load to reach 1150fps.

I will probably also need some advise regarding the type of testing that makes sense for a 3.1" conceal carry pistol. I normally test accuracy at 15 yards, but I'm not sure if that makes sense for this barrel length. With the little bit of testing I have done at 15 yards, a 1" grouping is doable, so it is probably not too far. Your comments regarding distance will be appreciated.

Also if you have a load that works well in the P365X, let me know. It could help me narrow down the powders I'll be testing.

I will be posting all my results to this thread, so hopefully I'll be able to get some results posted sooner than later.

Regarding the load data:
I mostly load 9mm with Federal No 100 primers, so I will stick to the No 100 primers for all the loads.
I will try and use the same headstamp where possible, so it will probably be WIN.
The COL I will use have not been decided yet, but I load the 124gr MPR's with a COL of 1.075". The COL I used for the 115gr bullet will probably be the same or less, not more. This will be finalized after my cycle and setback testing.

As always, any comments or suggestions will be appreciated.

 

[lordpaxman]

I only have the P365, and no red dot old person aiming system, but I’m interested.
I think the 15 yards is fine, and you can slow fire and try to get 1”, but a better criteria would be 3-5 shots rapid fire in a 6” group.
I haven’t loaded 115s in a long time, but when I did it was possible to make comfortable minor with just about any powder. Having said that I haven’t chrono’d the 365 with any 115 loads, but I did use a G43 and 938, and saw a difference of 50fps/inch of barrel length.
I’ve used Titegroup, N320, W231, WSF, N340 and CFEP with 115’s, and of those I’d prefer the VVs or WSF, if I was going for this project. But then again, I’d have probably chosen the 124 MPR. Any reason for the 115 choice? And, good luck.

 

[vaalpens]

I only have the P365, and no red dot old person aiming system, but I’m interested.
I think the 15 yards is fine, and you can slow fire and try to get 1”, but a better criteria would be 3-5 shots rapid fire in a 6” group.
I haven’t loaded 115s in a long time, but when I did it was possible to make comfortable minor with just about any powder. Having said that I haven’t chrono’d the 365 with any 115 loads, but I did use a G43 and 938, and saw a difference of 50fps/inch of barrel length.
I’ve used Titegroup, N320, W231, WSF, N340 and CFEP with 115’s, and of those I’d prefer the VVs or WSF, if I was going for this project. But then again, I’d have probably chosen the 124 MPR. Any reason for the 115 choice? And, good luck.

Thanks for the comments.

I think the rapid response criteria relies a lot on the skill level of the shooter, but it is maybe a test I can add once I found a load per powder. That will allow me to compare the different selected loads.

All those powders except the VV's will be tested, since I have them. The reasons for going/trying the 115's are that I have never used them before, should be easier to reach the 1,150fps with the 115gr, and I want to see how they perform in 357sig. My current carry round for my P365X is a 115gr bullet, so it is also a contributing factor.

 

[LiveLife]

plan is to find accurate loads ... using the 115gr RMR MPR bullet.

I measured 10 of the bullets with the following results:

Weight range from 115.1 gr to 115.4 gr with 0.3 gr spread is remarkable. (Some 115 gr bullet weight can vary up to 0.5 - 1.0 gr)

Looking forward to your load development and range tests.

 

[vaalpens]

Weight range from 115.1 gr to 115.4 gr with 0.3 gr spread is remarkable. (Some 115 gr bullet weight can vary up to 0.5 - 1.0 gr)

Looking forward to your load development and range tests.

Thanks!

The weight and diameter were perfect, but the length had some variance. Hopefully it is just the tip and won't impact the seating depth much.

 

[LiveLife]

length had some variance. Hopefully it is just the tip and won't impact the seating depth much.

At the seating depth you will likely be using these bullets for your testing shooting off hand, not sure if we will be able to shoot/see the difference.

 

[vaalpens]

At the seating depth you will likely be using these bullets for your testing shooting off hand, not sure if we will be able to shoot/see the difference.

Thanks. You are correct, with my shooting I'll probably not see the difference. My concern is more a spike in pressure, but with my conservative loading, there is probably no need to worry about it.

 

[lordpaxman]

I think the rapid response criteria relies a lot on the skill level of the shooter, but it is maybe a test I can add once I found a load per powder.

It certainly does, but I am always concerned with recoil management especially with my EDC that’s already a very small firearm. TG, to me, always has a very sharp felt recoil and takes me more time to get back on target, so I wouldn’t even try that powder. While your 1” at 15 yards is admirable, presumably slow fire, for a self defense scenario, I’d rather use a Bill drill to test accuracy.
I would also try Sport Pistol, it’s what I’ve been shooting for a while now with heavy bullets and it’s felt recoil is very similar to 320.

 

[vaalpens]

It certainly does, but I am always concerned with recoil management especially with my EDC that’s already a very small firearm. TG, to me, always has a very sharp felt recoil and takes me more time to get back on target, so I wouldn’t even try that powder. While your 1” at 15 yards is admirable, presumably slow fire, for a self defense scenario, I’d rather use a Bill drill to test accuracy.
I would also try Sport Pistol, it’s what I’ve been shooting for a while now with heavy bullets and it’s felt recoil is very similar to 320.

Thanks again for the comments.

I haven't done any drills with the P365X yet, but I think the Bill drill is an excellent suggestion. I actually recorded some times when I ran the Bill drill with my other guns, so it should be interesting to see how it compares. I did not record the groupings, but only the times.

I still need to record velocities, and normally I record velocities when I do the accuracy testing. So accurate testing will still be done, I just need to decide on the distance.

The red dot adds another challenge to the accuracy test since it takes up probably more than 1" at 15 yards.

 

[dh1633pm]

I am loading 115 XTP’s with No 7 at 7.6 grains with good results in my P365. COL is set per the manual 1.075. Remington primers.

 

[vaalpens]

I am loading 115 XTP’s with No 7 at 7.6 grains with good results in my P365. COL is set per the manual 1.075. Remington primers.

Thanks for sharing.

That seems like a good middle range load based on the Hornady load data. What velocity do you see out of the P365?

 

[dh1633pm]

I have used the Chrono on it yet. Too cold. What I do know is that it feeds well from my Camp 9, my Mossberg MC1, my Sig 365, and my friends Canik. It is accurate enough. My friend hit the gong at 100 yards with his Canik after a few tries to figure out where they were hitting. Will determine speed sometime. Happy with the loading thus far.

 

[vaalpens]

I have used the Chrono on it yet. Too cold. What I do know is that it feeds well from my Camp 9, my Mossberg MC1, my Sig 365, and my friends Canik. It is accurate enough. My friend hit the gong at 100 yards with his Canik after a few tries to figure out where they were hitting. Will determine speed sometime. Happy with the loading thus far.

Thanks again for the comments. For now I think I'll go for a 15yard accuracy test. I don't have a gong at 100 yards, so it is not something I'll be attempting. I don't have No 7, only No 5. I am probably start with CFE Pistol since it should reach the 1150fps, without going to max.

 

[vaalpens]

I made some progress today by creating 4 dummy rounds. This was just to get to the planned COL of 1.075", and also do the plunk and cycle tests.

All 4 dummy rounds passed the plunk test as expected.

The cycle test I had to cut short though. Dummy round 1 measured 1.075", and still measured 1.075" after 4 cycles through the P365X. The second round also measured 1.075", and still measured 1.075" after 4 cycles through the P365X. No setback at all. This is when I realized I was wasting my time and didn't do a cycle test on the last two dummy rounds.

Normally there is some sort of movement during cycling, but I did not detect anything. Maybe the combination of WIN cases, shape and COL of the bullet, and my load process resulted in no setback.

Next I will be deciding on a load or two. So far I am leaning towards starting with CFE Pistol based on the velocities I have seen with the 115gr FMJRN bullets.

 

[dh1633pm]

You have to load sometimes with what you got. CFE should work well. I got a lot of 5, 7 and 9 from my dad. Might as well use it up. 1.075 length works well on my two Pistols as far as cycling goes.

 

[vaalpens]

You have to load sometimes with what you got. CFE should work well. I got a lot of 5, 7 and 9 from my dad. Might as well use it up. 1.075 length works well on my two Pistols as far as cycling goes.

Thanks again for the comments. No 5 and CFE Pistol are reasonably close on the burn rate chart, so maybe I'll do both at the same time, or try an outlier like Longshot. Longshot is the slowest powder I have loaded in 9mm.

 

[dh1633pm]

We went to the range today. Wife and I enjoyed ourselves.



Let me know how your loads work out.

 

[vaalpens]

We went to the range today. Wife and I enjoyed ourselves.

View attachment 1042071

Let me know how your loads work out.

Nice family you have there. Glad to hear you enjoyed yourself.

I will definitely post my test results. Now I just need to make a final decision on the first two powders to use, decide on the loads, load them and go test them.

 

[dh1633pm]

You know, you could always load a few of each and see how it goes. Or use a quarter. I went with No 7, because I have a lot of it. No 7, No 9, Win 231, Bullseye, and H110 are what I have in stock. Sometimes that the best you can do when you can't find the exact one you want to try. Just finished cleaning the four. Going with a friend to an indoor range in Syracuse tomorrow after work. Never been there before. It will be better than shooting at 31 degrees at the shooting range. My wife likes the P365 and the 1911. On my side, I have the Mossberg MC1 (fixed with a Glock guide rod) (no failures again today) and my new Colt.

Can't wait to hear your choice.

 

[dh1633pm]

Any updates?

 

[vaalpens]

Any updates?

My apologies for not posting anything earlier, but it seems I ran out of testing time. We had a cold winter with my normal shooting places not available to me due to the snow. It seems our temperatures are improving, so hopefully within a week or so I'll be able to do some load evaluation.

The only loads I have created so far are using CFE Pistol. I decided to go with the 1.075" COL, with loads from 5.4gr to 5.9gr, a total of 6 loads.

 

[dh1633pm]

We have had a lot of snow and cold as well. Plus work travel for the year has already begun. I did load up some 124 grain plated with 6.2 grains of No 5. Haven't tested them yet. For the same reasons.

 

[Dudedog]

Looking forward to your results.
I always enjoy the results of your tests, thanks for taking the time to post them for everybody.

 

[vaalpens]

This has been a while since I posted any test results. On Monday I decided to go and find a spot and do some testing. Everything went well, except the weather did not cooperate again. I just completed testing the first loads for the P365X, when it started to rain. It seems this time of the year we can get rain at any time in the National Forest. My truck definitely needs a wash now.

I have another set of loads to test, but these are the CFE Pistol loads, I think they were accurate enough, especially with the 3.1" barrel, and using a red dot. The actual target wasn't that well defined for me at 15yards, so there are no guarantees that I was aiming at the exact spot every time. The P365X performed flawlessly, with no failures at all. Hopefully the chrono numbers are correct, since I had to remove the diffusers because in another test, the results became erratic with the diffusers on. It was getting dark and cloudy.

Part of the test was to reach the 1150fps, and the see how accurate it would be. Based on the results below, I think I found a good combination of velocity and accuracy.

9mm, P365X, 3.1"
Case: WIN
COL: 1.075"
RMR, 115gr, MPRJHP, CFEpistol, 5.4gr, FED100
Average: 1093
ES: 27
SD: 11.2
Force: 305
PF: 125
Velocities: 1101, 1090, 1108, 1081, 1085
Grouping @ 15yd: 1.4"
Test Date: 07/04/2022

9mm, P365X, 3.1"
Case: WIN
COL: 1.075"
RMR, 115gr, MPRJHP, CFEpistol, 5.5gr, FED100
Average: 1116
ES: 50
SD: 19.3
Force: 318
PF: 128
Velocities: 1121, 1103, 1096, 1146, 1117
Grouping @ 15yd: 2.72"
Test Date: 07/04/2022


9mm, P365X, 3.1"
Case: WIN
COL: 1.075"
RMR, 115gr, MPRJHP, CFEpistol, 5.6gr, FED100
Average: 1143
ES: 28
SD: 11.5
Force: 334
PF: 131
Velocities: 1152, 1147, 1141, 1124, 1151
Grouping @ 15yd: 0.92"
Test Date: 07/04/2022


9mm, P365X, 3.1"
Case: WIN
COL: 1.075"
RMR, 115gr, MPRJHP, CFEpistol, 5.7gr, FED100
Average: 1154
ES: 42
SD: 17.1
Force: 340
PF: 132
Velocities: 1167, 1158, 1170, 1147, 1128
Grouping @ 15yd: 0.73"
Test Date: 07/04/2022

9mm, P365X, 3.1"
Case: WIN
COL: 1.075"
RMR, 115gr, MPRJHP, CFEpistol, 5.8gr, FED100
Average: 1186
ES: 12
SD: 4.6
Force: 359
PF: 136
Velocities: 1188, 1179, 1189, 1191, 1187
Grouping @ 15yd: 1.68"
Test Date: 07/04/2022

9mm, P365X, 3.1"
Case: WIN
COL: 1.075"
RMR, 115gr, MPRJHP, CFEpistol, 5.9gr, FED100
Average: 1197
ES: 33
SD: 12.2
Force: 366
PF: 137
Velocities: 1178, 1201, 1195, 1211, 1201
Grouping @ 15yd: 1.66"
Test Date: 07/04/2022

 

[RashQuestion]

Thanks for posting your test results!!! Very generous with your time!!!

Thanks Again and God Bless!!!