As i recall the 55 BT has a boatail? I can't stabilize them in a 14T Swift but I can get good groups with a 55 VMax (flat base). There must be just enough extra length with the BT to give the 14T trouble or if just doesn't like that bullet.
I wouldn't think they'd come apart from a 12T at 3600...
on the brass-- I full length resize when they start getting pretty snug,otherwise neck size and anneal with each firing. I don't know that the brass wear out in the web area unless the pockets get loose.
I went with a 9 twist and was going to shoot 75 amax until I tried to get them in the...
Welcome,
Been shooting the Swift a long time (20+) and am really fond of the chambering.As long as you have brass and dies I'd recommend a set back or another tube with same clambering- perhaps considering a 9/12 twist for heavier slugs. There is plenty of powder capacity and case strength...