I'm looking for a new load for my 16" 1:10 twist M&P 10 that will run well to 800 yards. . The rifle has shot a 1.25 MOA 10-shot group off a bipod with 155 AMAX and 43.2 grains Vhitavuori N140 at 2500 fps muzzle velocity. I haven't tried heavier bullets. I still have enough N140 powder to load up a fair amount.

The 155 AMAX is discontinued. Right now, I can find Sierra 155g and 168 g in both SMK and TMK. How would a 155 TMK load with N140 perform in this? I'd prefer the recoil of a 150ish range bullet but would I see huge improvement with 168s?

800ft ASL, 60*F, 50% humidity, 30.0in Hg; to 800yds with 10 mph full value wind.

155gr SMK (#2156) at 2600fps: 1300fps, 26.5 MOA up and 8 MOA drift.

155gr TMK at 2600fps: 1340fps, 26.0 MOA up and 7.6 MOA drift.

168gr SMK at 2500fps: 1180fps, 30.5 MOA up and 9 MOA drift.

168gr TMK at 2500fps: 1370fps, 27 MOA up and 7 MOA drift.


If you can actually feel the difference between 150gr and 170gr class, I vote 155gr TMK.

You'll have to test it for yourself, but I can't get 175gr TMK, and I'd wager the other weights, to group all that well at magazine length.

I got excellent results with single feeding, but that's not for me at this point. At mag length they were still better than factory match, but lacking compared to what I can do with a regular SMK at mag length.

In this market, get what you can find at reasonable pricing, you ought to be able to tune a load with most any bullet.

I read up on it after your comments. The TMKs are indeed long and seem to be jump sensitive. I need it to run reliably from mags so I should probably stick with SMKs.

If you can afford the loss, get a box and try. Maybe they'll work well for you. You might also be able to get the lighter ones out far enough to work.

IIRC, the 175TMK has a similar seating depth to ogive as a 185gr VLDH. Which I also could not get groups worth a damn from at mag length. Getting well over and single feeding yielded acceptable results for the fairly generic loading (worked up a nice, warm, safe charge and called it good enough to test seating)

I gotta tell you my DPMS LR 308 loves the Sierra MK 175 gr with a moderate dose of Varget and Federal GMM lg rifle primers  !!

This load supposedly is used by Designated marksman M118 LR or something .. 24 inch free floated barrel .

Shoots 1/2 inch depending on conditions of the wind and shooter

Later-

John

That will get it done.