69 and 77 TMK's Data? .223 or 223AI

[LitLBoy]

Anybody have any load data for the new TMK's in .223 or .223AI? Snert has a line going in 30 cal on the TMK's. Wanted to know if anyone has anything on the 223 Cal. Seems as if seating length is critical.
LitLBoy

 

[sscoyote]

I'm running the 69TMK at 3075 out of a 26" barreled 223 Ack. IMP. AR15 26 gr. Varget...but I'm seating mine to 2.416 VLD magazine OAL.

 

[unclenick]

I haven't tried these yet, but I suspect the secant ogive will mean they need to be treated like Berger secant ogive VLD's. Berger's Tech Talk page includes an article on getting VLD's to shoot that indicates jump to the lands is a significant tuning factor. If I'm right that this turns out to be a factor with the TMK's, then many of us can look forward to them being for single-loading only. It just depends on where the individual gun wants them seated.

 

[johnfred1965]

I duplicated my 69 gr MK load with the with the 69 TMK.(25.5gr Varget loaded mag length) I've only tested them at 100 yards, but they shot to same point of impact that close. the tipped ones shot a little tighter from my rifle. (3/4 in vs 1/2 in groups) I've been wanting to take them out to 300 to see how the better BC works out, but hunting season has inturupted my testing.

 

[Mozella]

Anybody have any load data for the new TMK's in .223 or .223AI? Snert has a line going in 30 cal on the TMK's. Wanted to know if anyone has anything on the 223 Cal. Seems as if seating length is critical.
LitLBoy

I don't usually publish my load data, but I can tell you my experience when testing the Sierra TMKs.

Sierra SMK 69grs shoot best in my 1:9 twist, .223 bolt gun. Best 5 shot group at 100 yards is .155 MOA and the average of the best 150 rounds (all five shot groups) is .310 MOA with the SMKs, which I moly coat myself. I shoot them at 93% of max published charge weight; i.e. pretty slow.

I had hopes that the similar TMK would shoot as well if not better. But, for me at least, such is not the case. Best 5 shot group is .328 MOA and the average of the best 150 rounds is .477 MOA. The best TMK charge weight, for me, is 98% of max published data.

I've done a lot of testing with various charge weights, seating depths, primer and powder brands, etc. For example I've carefully tested and measured the performance of 1100 rounds of the 69gr SMKs in this rifle since May of this year. I'm not some guy shooting at paper plates and judging performance using a coin or a carpenter's tape.

For some reason, the TMKs don't work as well as the SMKs in my rifle.

Of course, YMMV.