RMR in-house 9mm 124gr FMJ FN bullet - 357sig fit

As you all know, RMR is now making a 9mm 124gr FMJ FN bullet. Late on Wednesday they became available and I put in a order for 500 for evaluation in 357sig.

On Saturday I received the package after very quick processing from RMR. Thanks RMR! This is what they look like.


As always when I receive a bullet I haven't loaded before in 357sig, these are the steps I follow:
-Take some measurements
-Calculate to see if they will fit in 357sig
-Based on the calculation decide on a COL
-Load some dummy rounds
-Verify the fit to ensure start of ogive is outside the mouth of the case
-Do a plunk test
-Do a setback test by cycling the dummy rounds through the gun
-Do a bathroom scale test
-Decide on the first set of loads
-Create the first loads
-Evaluate the loads

Let's start with the measurements:
Length of 10 bullets were .5525" (4), .5510" (1), .5535" (3), .5550 (2)
Diameter of all 10 were .3555" with a few floating to .3560" when I removed my hand from the caliper (excellent for 357sig)
Weight: Most of them were just below 124gr, with one over 124gr

Based on my calculation and the shape of the bullet, it seems that I could maybe load it with a COL of 1.135", but a 1.140" COL will probably be better with a sliver of breathing room. Based on this calculation I will classify this bullet as a 9mm bulle, that will also fit in 357sig. For me a 357sig bullet is one I have the flexibility to load it with a COL of 1.125" to 1.135" with ease.

I then created my dummy rounds with a COL of 1.140":


The next step was to verify that my COL/ogive calculation was correct. From this photo you can see that there is a visible gap, which means the ogive starts outside the case mouth:


My next steps will be the plunk and battery of setback tests and I will post an update as soon as I have performed the tests.

So far I am impressed with the bullets, especially the consistent diameter. When I seated the dummy rounds, I could feel this was not something that just slipped in, but there were some tension. The neck tension on these seemed to be very good, but the setback test will provide the final answer.

FROGO207 said:

The only problem I find is the short neck and neck tension problems. Then the extra step of making sure each round will not set back when pushed on the scale. Yes I do it for each and every 357 SIG round I make. I have randomly found several over the years that failed that test so I keep doing it. I feel it is never too much trouble to stay safe.

Click to expand...

I only do the setback and scale test when I load a bullet for the first time. Since all my 357sig loads are done on a single stage, by now I know hoe it should feel when I seat these bullets. If they go in too easy, then I would normally do a quick check since it could be a bullet or case issue. Even with crimping I set the die up a specific way, but then adjust it based on feel. Experience is important when loading 357sig.

Just a quick update with the plunk and setback tests.

Both dummy rounds seated at 1.140" passed the plunk test.

Both dummy rounds were cycled manually through the gun 4 times.
Dummy round #1 started at 1.1405" and ended at 1.1405"
Dummy round #2 started at 1.1400" and ended at 1.1395"

After the setback test I did the bathroom scale test. I use a digital scale where I push the bullet down on the scale and then hold it for 5 second for the weight to register.
Dummy round #1 registered 22lbs with no setback
Dummy round #2 registered 21lbs with no setback

My conclusion so far are that these bullets are a very good fit for 357sig, with the only steps now remaining, decide on the first loads and evaluate the loads.

So far based o the depth these bullets will be seated, it seems my loads will be the same as the MG bullet loads, and maybe a little higher or the same as my RMR JHP loads. It should be very easy to decide on my starting loads.

longdayjake said:

Vaalpens,

I am curious about the ones that you measured that were .555" I stood by that machine for 8 hours measuring bullets and the longest one I ever measured was .5535" And I measured thousands. I'm wondering if they were a little light or a little heavy. But getting two of them seems odd to me. The biggest spread I found on them was .550-.5535." Are you sure you didn't mean to write .550"? I never once measured one at .555". The vast majority of the ones I measured were .5525"

I personally had my hand in the design of this bullet. Yes, it was designed with 9mm in mind, but I made sure when I came up with the length of the ogive that it would work in the .357 sig. I personally cannot figure out why the 9mm is allowed a max OAL of 1.160" and the sig only gets 1.140." Especially when they can be loaded in the same size magazine as 9mm. I think that the SAAMI specs are dumb. Maybe it has to do with feeding of a flat nose projectile. But it probably wouldn't need to be flat nose if 1.160" was the max.

Click to expand...

longdayjake, When I do my measurements I normally would just place the bullet inside the jaws one time and take down the measurement. I also use the start of the wider area of the jaws since it makes it easier to place the bullet in the same spot every time. When I rotate the bullet while it is in the jaws, it could change by .0005". Any little speck of dust or something on the jaws can also impact the measurements.

I did some more measurements, but this time I made sure I wiped both the bullets and the jaws. I measured 25 bullets with the following results:
.5510" (1)
.5520" (3)
.5525" (3)
.5530" (8)
.5535" (9)
.5545" (1)

I went back and measured the .5545" bullet a few times and got the same result. My scale is not that precise, but the .5545" bullet was the only one over 124gr (124.3gr).

It could be that my calipers read different. I should probably invest in one of those micrometer standard bars. Have a great 4th of July!

I bought a "Fowler 52-227-001-1 Inch Individual Micrometer Standard" to verify that my caliper returns accurate readings. Hopefully this not so expensive 1" standard is a standard 1 inches. Here are the results:

Walkalong said:

If it is dead on at 1.000, it isn't likely to be off .0015 in the neighborhood of .555.

I bought these gauge blocks. It lets you check you caliper or micrometer in different areas. Grade B blocks have tighter tolerances than I can measure consistently and are good enough for my purposes.

Click to expand...

Those are a nice set of gauge blocks. I would have thought that Walkalong would have a more expensive set like the Mitutoyo set for $918.

Being off by .0015" is a lot. I can see it drift by .0005" depending on how tight you hold the jaws when measuring a bullet.

It is getting closer to the time in the season where the fire restriction will be lifted from the national forest close to me. This will allow me to test and chrono some of my loads.

So finally this week I decided on my first loads in 357sig with the new in-house 9mm 124gr FMJ FN bullets. At the end I decided to go with loads in the lower and middle velocities, to first see how they perform. After evaluation I will decide on the direction regarding velocity and powder.

The first load I picked was my bracketed standard BE-86 load that produces around 1300fps. This load has worked with different bullets, so it should be close to where I will probably end up with BE-86. The loads are 7.5gr, 7.6gr, 7.7gr and 7.8gr of BE-86 loaded to a COL of 1.140".

The second load I picked is on the lower end around 1250fps using Unique. The reason for going with this load is that I had very good results with the only other FMJ FP I tested so far using this loads. With limited testing previously, I thought it would be a good idea to explore this load again. This is a good practice load with less stress/wear on the gun. The loads are 7.0gr, 7.1gr, 7.2gr and 7.3gr of Unique loaded to a COL of 1.140".

Following is a picture after I completed the loads:

longdayjake said:

The suspense is killing me. Of all the people who have reviewed this bullet for me, you're the one I'm most interested in.
Small bit of info, I actually got my first match win in a 3 gun competition when I switched to these bullets. I've been shooting them out to 100 yards trying my best to hit an 8" plate. Sure helped with the bonus stage at 25 yards. Took a stage win on the bonus stage and it jumped me from like 8th place to first place.

Click to expand...

Thanks for the encouragement and kind words. I am getting edgy not being able to really test my loads, but hopefully it will happen soon.

Congratulations with your competition placement. Once in a while I will test my load out to 50 yards, but then it will be purely shooting at a full size silhouette just to get some idea how the gun/ammo combination performs. This is normally where the flat shooting 357sig shines for me.

Have a great weekend!

The results are in, well sort of.

Yesterday I made some time to test the new bullet in 357sig, but probably should have stayed at home. My eyes did not feel that great, plus it was not a normal clear sunny day. When your eyes get older you need more light not less. During the testing I had to remove the diffusers when one round did not register. This gives you some idea of how bright it was. During the shoot (@ 15yards) I realized that I had a difficult time focusing on where to place my sights, especially on the vertical since my focus was so bad. The results for all my reloads were mostly showing the impacts were stretched out on the vertical. One or two loads came out good, but I would think it was more luck than anything else.

So the bottom line for me is that I need to revisit the size of the target I use at 15 yards and come up with something that has enough focus so that I have a consistent aim point. I am not doing any bulls-eye shooting, but I am trying to get a true representation of each load's grouping potential.

Having gotten all the excuses out of the way, following are the results:

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, Unique, 7.0gr, WSP
No chrono numbers due to operator error
Grouping @15 yards: .96" (the best of the day)


357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, Unique, 7.1gr, WSP
Average: 1217
ES: 54
SD: 21.9
Force: 408
PF: 150
Velocities: 1204, 1253, 1199, 1208, 1224
Grouping @15 yards: 2.24" (1.71" horizontal grouping)

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, Unique, 7.2gr, WSP
Average: 1233
ES: 35
SD: 16
Force: 419
PF: 152
Velocities: 1213, 1248, 1244, 1228, (* removed diffusers)
Grouping @15 yards: 2.43" (1.54" horizontal grouping)

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, Unique, 7.3gr, WSP
Average: 1249
ES: 31
SD: 12
Force: 429
PF: 154
Velocities: 1242, 1246, 1238, 1269, 1250
Grouping @15 yards: 2.08" (1.02" horizontal grouping)

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, BE86, 7.5gr, WSP
Average: 1264
ES: 11
SD: 4.4
Force: 440
PF: 156
Velocities: 1257, 1268, 1266, 1266, 1267
Grouping @15 yards: 2.04" (.45" horizontal grouping)


357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, BE86, 7.6gr, WSP
Average: 1270
ES: 27
SD: 11.2
Force: 444
PF: 157
Velocities: 1269, 1263, 1263, 1268, 1290
Grouping @15 yards: 2.1" (.86" horizontal grouping)

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, BE86, 7.7gr, WSP
Average: 1280
ES: 31
SD: 11.5
Force: 451
PF: 158
Velocities: 1285, 1280, 1283, 1262, 1293
Grouping @15 yards: 1.68" (.89" horizontal grouping)


357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, BE86, 7.8gr, WSP
Average: 1306
ES: 26
SD: 11
Force: 470
PF: 161
Velocities: 1316, 1308, 1300, 1291, 1317
Grouping @15 yards: 2.08" (1.82" horizontal grouping)

My conclusion so far is that these bullets works very well in 357sig. These bullets load and shoot well. I haven't seen any advantages using any other jacketed bullets in 357sig, so at the current price point this is definitely my preferred jacketed bullet in 357sig.

sellersm said:

Thanks vaalpens! This load here seems to have lots of promise:
357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, BE86, 7.5gr, WSP
Average: 1264
ES: 11
SD: 4.4
Force: 440
PF: 156
Velocities: 1257, 1268, 1266, 1266, 1267
Grouping @15 yards: 2.04" (.45" horizontal grouping)

Click to expand...

BE86 really works well in 357sig for me and I load most of my bullets in the 7.5gr-7.7gr range. It would be nice if I can resolve my eyes/aiming issue to produce better accuracy reports. Thanks for the comments.

fxvr5 said:

I've done some accuracy tests in 9mm and 38 Super Kart barrels, at 25 yards from a Ransom Rest with this new bullet. Accuracy is excellent with several gunpowders. By excellent I mean 15 shot groups under 1.5".

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That is some great accuracy. I am happy if I can go sub 1.5" at 15 yards.

After my disastrous testing last time where I could not find a spot to focus, I decided to purchase a 2x20 pistol scope to help with the load evaluation. The pistol scope was mounted an IMI pistol scope mount. None of these component were expensive since I just wanted something to help with the load evaluation.

Following is an accuracy update to my BE-86 7.5gr load. I did not chrono the load again since I was more concerned about the accuracy. Following is the previous chrono data and the updated target:

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, BE86, 7.5gr, WSP
Average: 1264
ES: 11
SD: 4.4
Force: 440
PF: 156
Velocities: 1257, 1268, 1266, 1266, 1267
Grouping @15 yards: .74"


I don't know what is good for 15yards, but I am very happy with a .74" grouping at 15yards. Excellent accuracy from the RMR 124gr JHP FN bullet.

Edit: Adding grouping results for rest of the BE-86 loads:

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, BE86, 7.6gr, WSP
Average: 1270
ES: 27
SD: 11.2
Force: 444
PF: 157
Velocities: 1269, 1263, 1263, 1268, 1290
Grouping @15 yards: .88"

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, BE86, 7.7gr, WSP
Average: 1280
ES: 31
SD: 11.5
Force: 451
PF: 158
Velocities: 1285, 1280, 1283, 1262, 1293
Grouping @15 yards: 1.06"

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, BE86, 7.8gr, WSP
Average: 1306
ES: 26
SD: 11
Force: 470
PF: 161
Velocities: 1316, 1308, 1300, 1291, 1317
Grouping @15 yards: 1.39"

I have also tested my CFE Pistol loads for the first time with the RMR FN bullets capturing chrono and grouping data. Following are the results:

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, CFEpistol, 7.4gr, CCI500
Average: 1288
ES: 28
SD: 10.1
Force: 457
PF: 159
Velocities: 1288, 1292, 1287, 1274, 1302
Grouping @15 yards: 1.27"

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, CFEpistol, 7.5gr, CCI500
Average: 1305
ES: 12
SD: 4.8
Force: 469
PF: 161
Velocities: 1300, 1312, 1302, 1307, 1308
Grouping @15 yards: 1.12"

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, CFEpistol, 7.6gr, CCI500
Average: 1308
ES: 20
SD: 9.5
Force: 471
PF: 162
Velocities: 1298, 1299, 1318, 1312, 1316
Grouping @15 yards: .85"


357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, CFEpistol, 7.7gr, CCI500
Average: 1327
ES: 30
SD: 12.6
Force: 485
PF: 164
Velocities: 1314, 1320, 1337, 1322, 1344
Grouping @15 yards: 1.27"

Another powder I tested with the RMR 124gr FMJ FM bullet was using PowderPistol. For some reason I though I had chrono data for it, so I only tested for accuracy. After getting home I realized I never captured any chrono data. Following was the most accurate load:

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, PowerPistol, 7.7gr, CCI500
Average: Estimated average of 1300fps
Grouping @15 yards: .87"



357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, PowerPistol, 7.8gr, CCI500
Average:
Grouping @15 yards: 1.07"

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, PowerPistol, 7.9gr, CCI500
Average:
Grouping @15 yards: 1.45"

357sig, P229, 3.9"
COL: 1.140"
RMR, 124gr, FMJFN, PowerPistol, 8gr, CCI500
Average:
Grouping @15 yards: 1.06"