Sierra 107 TMK Load Data

[Tanner]

you're working up some nice loads Taniel

All of my loads are compressed and ready to shoot !

 

[philcox]

Want to load 10 of that brass I sent back with you with my 116 load and see how it does the second time around? Hard to argue with the 107s so far though, that's for sure.

107s in Lapua brass over 40.5 gr H4350, 2950 fps avg, 2.82" COAL. Quick 6 shot group while rezeroing with the OG6S, didn't get a pic after 10 shots but it was ~.9MOA.

What length barrel? I am 42.5 H4350 2.82 (GM210M, Starline) and I am getting 2815 out of a 18"

 

[waspocrew]

My 6 arc is kinda giving me fits. 107s I can’t seem to get to shoot. Tried staball match, 8208, and cfe 223 and all shot 2+ inch 10 shot groups. Figured maybe just doesnt like tmks. Shot 10 round groups today with 108 eldm and 100gr interlocks both around 1.5” for 10 shots. My biggest hindrance is mag length in my Howa mini. Limited to about 2.325” coal for reliable feeding clearance. This jumps the 107s about .095”. Don’t want to single feed but tempted to seat closer to lands and see if it tightens them up. This gun also seems to pressure out early with cratered and flat primers and ejector swipes above about 29 grains of Staball. Hornady max is 31gr. This with federal 205s for primers and once fired and shoulder bumped starline brass. Thoughts? Should I try other primers as well?

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I had a Howa Mini and it seemed to like the 105s (Berger Hybrids, Hornady BTHP, and black tips from Midsouth). Generally, TMKs have shot well for me in other cartridges, so I'll give them another go with different powder.

In my AR, I've used CCI 450s with 87 Vmax and Lever, so I might go with 450s in my bolt gun to see if that has any effect. If I can't get them to shoot, I'll go with the 95s and leave the 107s to my 6 CM.

As for seating depth, you could seat a little closer to the lands to see if that helps, but I wouldn't want to single feed either.

 

[RancherJohn]

What length barrel? I am 42.5 H4350 2.82 (GM210M, Starline) and I am getting 2815 out of a 18"

18", CCI 450 primer.

 

[WhoGarrDen]

18", CCI 450 primer.

2 grains less powder and 135fps more velocity in the same length barrel? @philcox @RancherJohn who are these barrels from? same TW?

 

[2Stamp]

Want to load 10 of that brass I sent back with you with my 116 load and see how it does the second time around? Hard to argue with the 107s so far though, that's for sure.

107s in Lapua brass over 40.5 gr H4350, 2950 fps avg, 2.82" COAL. Quick 6 shot group while rezeroing with the OG6S, didn't get a pic after 10 shots but it was ~.9MOA.

View attachment 1074430

Is that with your Marshall?

 

[RancherJohn]

2 grains less powder and 135fps more velocity in the same length barrel? @philcox @RancherJohn who are these barrels from? same TW?

Not sure who made the barrel, it is an MRC Marshall and they had/have various barrel manufacturers in the last year. 1:7.5 TW. I should recheck velocity since I switched suppressors, but I doubt it’s much different now.

Is that with your Marshall?

Yes.

Edit - I went back and looked at my notes and have both 2905 and 2950 written down, I’ll send a few over the chrono tonight and get a correct velocity.

 

[RancherJohn]

Not sure who made the barrel, it is an MRC Marshall and they had/have various barrel manufacturers in the last year. 1:7.5 TW. I should recheck velocity since I switched suppressors, but I doubt it’s much different now.



Yes.

Edit - I went back and looked at my notes and have both 2905 and 2950 written down, I’ll send a few over the chrono tonight and get a correct velocity.

Shot 5 over the chrono. 2890 avg, 2905 highest of the 5. 2950 was what my corrected velocity shows in Shooter based off truing at ~800 yards. I'll edit my original post to remove confusion going forward.

@2Stamp @WhoGarrDen @philcox