My end question is what kind of mould to buy,..... but before I ask it let me explain.
For background I am an experienced reloader, caster, gun nut and shootist. I have worked with standard cartidges wildcats, rifles, revolvers, auto loaders, the gammit. I have succesfully loaded and used cast bullets from several manufacturers and have had good results with everthing, except the example below.
The problem is with a 6.5x55 Ackley improved rifle built on a Montana 1999 action and barrel. The problem I describe has been consistent before and after the AI chambering. The rifle was I ordered it with a 1 in 7.5 twist and a throat to fit a dummy 6.5x55 dummy round with a Hornady 160 RN bullet in it. The AI change was done because the rifle had a problem with round popping out of the magazine. The AI fixed the problem and increased performance a full 10% (which is fun but irrelevant). The file shoots 140 grain and 160 Hornbady bullets to 3/4 " @ 100 yards, with a preference for the 160 grain round nose. The bore measure .2635. The chamber .2645.
BTW if you have not tried this wildcast, it is amazing. The 140 grain HOR bullets easily achieves 3000 FPS in this 24" barrel.
I had LBT make me a 160 grain mould to mirror the HOR 160 from the same dummy round the gun was made from. The goal being to shoot the same kind of load as jacketed, a lot, cheaply. It is gas checked bullet design. Lube is LBT Blue. They cast from the mould @ .267. They are very difficult to cast, perfectly, unless the mold is "HOT". At temps where anything else casts find, these .267 are apt to wrinkle unless the mould is heated in the melt briefly before each cast. The alloy is 7 parts monotype and 3 parts pure lead. I casts to about 17-18 BHN when dropped from the mould into water.
I heat the melt in a big on a burner then transfer into a Lee bottom pour pot for casting. Sprues and such go back into the bulk pot. I I have a Star lubrisizer and resize the bullets to .264. The lube is LBT blue, Hornady .264gas checks.
I have tried loads from about 1300 FPS to 2100 FPS, using IMR 7625 powders to 4198, 3031, 4895, 4350. The best I have been able to shoot is about 2" @ 50 yards. Most of the tests are more of a pattern than a group. Very disappointing. The bests speed range where the 2" group occured appears about 1750 FPS ( I use a chrony). Loads too much either side become patterns, instead of groups.
I am very bamboozled.
I really do want to find a mould which will meet my goal, but I don't know where to look for the problem. Aside from adjusting powder, filler materials, slugging the bore, fire lapping the bore, cleaning the bore, weighing and sorting bullets, how else might I proceed to solve this dilemma and what mould should I buy?
BTW, I realize one of your goals is to shoot more, so I'd be hpy to help you with that by sending this thing to you to try
Thanks a bunch.