Bullets, cases etc.
I have an M44 that I have been working up loads for. It is a newer post war production gun, with very few miles on the bore. It slugged at .312/.301 (groove/bore) and will use Sierra, Speers etc. .311 x 150 gr spitzers okay, but pressures up and shoots all over the place with the Hornady .312 x 174 gr rn as that bullet has a very long bearing surface on the .301 bore.
From what I have been able to find out the Russians never used larger than a .310 bullet and all long ogive spitzer types. ( try 7.62x54r.net for info) That is not to say that the guns will not use and be accurate with the larger diameter bullets, they can and do, but the shape of the bullet plays a part and so does the condition of the barrel. For instance I have found that in my M44 with the tight bore a Sierra 180 RN in .308 works quite well, accurate too, but that again has a long bearing surface.
I just want to mention one other thing that I have found as it might cause someone some nasty problems. I have two types of brass. One is Yugo made and was purchased loaded with 148 gr spitzers in .308 ( Bell is the brand name) This is good brass, and measures .0095 wall thickness. With the .308 bullet seated it is .327 od at the neck and with .311 bullet seated it is .330 od. This is important as the chamber neck of my rifle is only .336". I found that some of the Hornady bullets are a nominal .312 (range from .311 to .312) and gave me intermitent pressure problems no matter what the load and I suspect it is due to the tight chamber neck and the varying bullet diameter.
The other brass that I have is Winchester, also good brass but THICKER, it is .0105" unfired. Any .311 bullet in this brass causes release problems and .312 may be the straw that breaks the camels back.
It may be wise to carefully test the gun that you are loading for. Start with some .308 spitzer bullets, measure how far the brass expands at the neck of the fired case to get an idea of the chamber neck of the rifle, then work up from there. Shoot safe and happy, Cman.
