Sierra Heavy TMK 6MM Testing

[overlandozzy1]

Fits pretty nice. I’ll for sure be going 16” on the UM Corax build for the 6 CM. If the 112 MB’s were going 2940 from my last 18” bbl, I’d safely estimate the 115 TMK’s should be able to go 2850 from the 16”. At 5,000 DA that’s an 8 mph gun that reaches 1800 at 850 yards.

Carry on with the testing posts. Sorry for the detour.

View attachment 984995

Sent you a PM

 

[Formidilosus]

117gr today. 35.5gr IMR4166, but u changed seating depth in these- probably shouldn’t have. 2.795”. Averaged 2,820 fps MV.

First 8 in the main group, 9 and 10 are marked and are the two low ones- could be the load, could have been suppressor mirage.




Used .595 G1 BC to start at 1,025 yards. Trended high, .605 to .610 G1 BC was correct.

 

[ID_Matt]

117gr today. 35.5gr IMR4166, but u changed seating depth in these- probably shouldn’t have. 2.795”. Averaged 2,820 fps MV.

First 8 in the main group, 9 and 10 are marked and are the two low ones- could be the load, could have been suppressor mirage.

View attachment 985111


Used .595 G1 BC to start at 1,025 yards. Trended high, .605 to .610 G1 BC was correct.

View attachment 985171

2 questions…. How much have you seen mirage shift impacts in 10 round groups like that? Had some funky shifting the other day that made me question not having a suppressor cover.

Next - shooting over canyons like that do you worry that day to day could have different thermals/updrafts and maybe skew the results a bit if you aren’t shooting them at the same time?

 

[mxgsfmdpx]

2 questions…. How much have you seen mirage shift impacts in 10 round groups like that? Had some funky shifting the other day that made me question not having a suppressor cover.

When shot for 10 rounds back to back, with no vet wrap or suppressor cover, with a 6 creed, you’re going to have slight mirage by shot 5 or 6 (your eye can ignore this).

By shots 8-10 the mirage is normally enough that the eye can no longer filter it out and it will affect the shooters ability to resolve a small target like that.

It’s no issue on vital size gongs normally, but shooting for groups at small targets, if you shoot 10 in a row with no cover, it will nearly always cause stringing due to mirage.

 

[Carl Ross]

These bullets just don't seem to be picky.

Shot 4x 10 shot groups today with a Seekins 6 Creed PH2, with around 1400 rounds on it. All three bullets, plus one got a second group which was seated deeper.



Individual groups were between .6's and .8's (MOA). All 40 rounds laid overtop each other were right at one MOA.




Next I did 6 groups with my Dasher, all three bullets at two seating depths. This is the barrel from my No Clean Dasher Test, you can look up how it typically shoots Berger 109's.



The groups ranged from .4's to .7's (MOA). All 60 rounds together were right at .9 MOA.



Finally I did three more groups with the Tikka, jumping further this time.



These were fine, although the one impact to the right on the middle group did make it the worst of the whole test. .9's, 1.4's, and 1.0's for those three.

This aggregate is less impressive, but it's still ~ 1.6 for 60 rounds over three bullets, two charge weights, two seating depths, and two days.



Had a fantastic day for testing here, was in a t-shirt most of the time.

 

[Formidilosus]

2 questions…. How much have you seen mirage shift impacts in 10 round groups like that?

.1-.2 mil with medium to heavy mirage isn’t unusual.

Had some funky shifting the other day that made me question not having a suppressor cover.

It absolutely will affect POI if it is heavy.

Next - shooting over canyons like that do you worry that day to day could have different thermals/updrafts and maybe skew the results a bit if you aren’t shooting them at the same time?

In this specific one- not much. In the last 4-5 years I’ve shot over 20,000 rounds across it. I am also shooting known bullets to proof out the conditions as well. Point is, that while yes: for most, shooting at range to figure out BC is going to be full of issues. However because of known conditions, history, an understanding of what errors will present, chrono for each shot, and shooting known bullets to proof the environmental conditions- while I couldn’t say that the BC numbers I have stated are perfect- they are as solid as shooting will show.

 

[TradLife406]

.1-.2 mil with medium to heavy mirage isn’t unusual.




It absolutely will affect POI if it is heavy.





In this specific one- not much. In the last 4-5 years I’ve shot over 20,000 rounds across it. I am also shooting known bullets to proof out the conditions as well. Point is, that while yes: for most, shooting at range to figure out BC is going to be full of issues. However because of known conditions, history, an understanding of what errors will present, chrono for each shot, and shooting known bullets to proof the environmental conditions- while I couldn’t say that the BC numbers I have stated are perfect- they are as solid as shooting will show.

Got damn that's a lot of ammo! Wifey thought I was crazy buying 1500 rounds of 223. See honey, that's not even as much as I really need

 

[khuber84]

Got damn that's a lot of ammo! Wifey thought I was crazy buying 1500 rounds of 223. See honey, that's not even as much as I really need

Forms got loss off feeling and gator skin callouses on his trigger finger from so much action.