There's something to this ball powder...
I have been messing with a 6.5 TC-U bolt rifle for a couple of years now. It shoots awesome with greasegroove boolits, but until today it never has worked with paper patched. So, what changed? Powder. I had been using IMR powders, mostly 3031. Reading here about good results with 760, I tried some loaded with 748 and some with 760. Boolit is the BRP 129 Kurtz, sized to .259" and patched back up to .2645. Seated to the base of the neck with the case completely full of powder, it put 20 rounds - 10 of 748 loads and 10 760 loads, into a 4 inch group at 200 yards. It has never done that, usually throwing PP boolits all over the landscape. The 748 loads were pretty snappy, the 760 noticably slower but all hit the same place. Looks like I'll have to be buying more ball powder to play with in the future.
Help me choose a ball powder
Well, I've been looking for a ball powder to replace my AR2208/Varget. So far I have identified three candidates. Those are H335, BL-C(2) which has the lowest pressure of any powder and H414. (H380 could be a possible but it seems to have too much empty space in the case).
What troubles me with highest velocity and lowest pressure is that it means the mean pressure is higher and that means a longer barrel is called for. I want this for my short barrelled pig gun so I'm leaning towards H335.
On the other hand, BL-C(2) would be more versatile in so far as I could attain near 308 velocities using it in my mint bore two-groove No.4.:roll: (Not a bad plan since I have other 303's working at normal 303 Brit velocities).
So, which should I select?
( BL-C(2) is very similar to Winchester 748 ).