Chargar, I got to dinkin' around with an idea. I had a Lee 312-185-1R SC on the shelf for I don't know how long. So, I lee-mented it and cast a bean can full just for grins. I ran the first one through a .312 as they were .312 by .314 and it came out .312 all the way around. It would not start in a fired case. Hmmm, says I. So, I changed dies to a .311, and it did not change the diameter. I loaded one anyway with a little flare to start it and kept trying to chamber it to find the right length. The load is 25.5/5744 and dacron. Okay, chambers good, nose lightly engraves. I went ahead and shot a few like this at 50 yds and they did just fine. Very clean necks and primers just barely starting to flatten. I went back to the loading bench and inspected the cases. Now, a .312 boolit is a slip fit in the just fired cases. So the same cases previously fired with either 165 Sil or 311299 the 312-185 sized to .312 would not fit. But, after firing the 312-185 another is a slip fit.
So, the question begs, just how big is the throat in these rifles? Have you checked yours?
I suspect that next weekend I will dig out the Fat 30, that I haven't yet used, and cast some of them for a trial.
btw, the 312-185 just isn't anywhere close enough for me to use in my No 4 Mk I. I can stick is nose first in the muzzle and it just rattles around. The Fatter 30 is and I use it in the Brit, but is probably to big for a 'normal' .308 bore. Also, I have had good success in a scoped 03 sporter with a full sized 314299 (sized .314) and IMR 4064. Fill the throat.
I guess the gist of all this is that I was a little suprised by the results of the fired neck in the 700 - I would have thought it might be a little tighter. Maybe it's just my copy. Perhaps a chamber cast. Just trying to find a way now to fill the throat. sundog