The oversized pins really help stabilizing the sights and getting group sizes down in the 3-4 MOA range. This with only replacing the rear pin too. The assembly pins on the newer stocks with the swinging latches are enough undersized to add some 2 MOA to the base accuracy of the gun using the iron sights, and 6 MOA if you're using some sort of optics which rely exclusively on the bolt shroud for support and stability. I'm using a 7/32" dowel pin in the rearmost hole, the front hole proving to be just a bit sticky. Next time.
I tried Power Pistol powder as it's a rather slow-burning type on the theory that it might favor the longer barrel on the carbine. Available bullets were 155 gr Barry's plated. Sure enough:
Power Bullet Source pistol Amount Velo 155 Me 8.1 8.3 8.7 8.9 1594 1617 2267 1669 1649 1656 2114 2231 1616 1672 1687 2158 1690 1694 1453 1695 1677 1656 2221 1698 1645.2 1659 1948.4 1890.2 Var+/- 44.8 35 318.6 340.8 Nice start at 1645 and 1652 fps for the lighter loads. Impressive numbers, 2267 and 2231 for the heavier loads although the variation in velocity over 5 rounds was appalling. I suspect that at the higher speeds the plating was disintegrating from the bullets. The gun is noticeably more accurate using 180 gr jacketed bullets anyway and the combination of thin plating and light weight isn't helping. I may need to get a pound of Power Pistol and some real jacketed bullets for the next go-round.