Subsonic 147gr

[pug]

Missed the question back awhile ago. My pistol ported 16" barrel would not cycle subsonic 150gr loads originally. In the end, to get it to cycle, that barrel had its gas port opened up to .101~.102" and had the standard gas block on it. I then switched to an adjustable gas tube but after forgetting to turn it down one day and blowing the ejector and ramp off the bolt/carrier I have since switched to a three position gas block.

[Colohunter]

Well, I am finally getting around to loading up some of the Hornady 150gr FMJs today. Tomorrow I will be shooting, so I will hopefully find something that works. I will be using the H110 loads from here, and trying some AA 1680 as well.

[Pitt300]

My 150g Sierras w/8.3g H110 on 66* day clock @ 1066.6 fps & group in 0.648".
Very accurate & cheap & cycle fine but low on the energy scale.

[Colohunter]

Here are some of the results from my trip to the range today, all groups were five round sets of each load:

11.7gr of AA #1680, 220gr Sierra HPBT, 1089fps
All rounds ejected, cycled and the bolt locked back after the last round.

10.5gr of AA #1680, 150gr Hornady FMJ, 1095fps
All rounds ejected and cycled, but the bolt did not lock back after last round.

8.3gr of H110, 150gr Hornady FMJ, 1113fps
All rounds ejected, none were cycled, and the bolt did not lock back.

These were fired from a M1S upper with less than 100 rounds through it, using Pmags. Accuracy is still around 3-4", so that will be the next step to work on.