The original Springfield Trapdoor rifle in .45-70 was designed for a 405-grain bullet. In Mike Venturino's book, and a couple of other references, some have said that at longer distances they only had good accuracy using a 500-grain bullet. So I loaded a few with a round-nose 500-grain to try out.
Apparently that only works with some Trapdoors. On the one I was shooting those bullets were starting to keyhole at 30 yards(indoor range). Switched to some 405-grain loads, and nice round holes. So either the rifling pitch in this(1 in 22" according to what I've read) is not enough to stabilize this bullet in this rifle, or there's something else that causes it to not like that one.
Apparently that only works with some Trapdoors. On the one I was shooting those bullets were starting to keyhole at 30 yards(indoor range). Switched to some 405-grain loads, and nice round holes. So either the rifling pitch in this(1 in 22" according to what I've read) is not enough to stabilize this bullet in this rifle, or there's something else that causes it to not like that one.
3 comments:
A little math for your weekend consideration. https://en.wikipedia.org/wiki/Miller_twist_rule
You measure the OD of the heavier bullets?
I'll check out the Wiki link when have time and somewhat rested brain cells.
And no, I didn't measure, that will be done.
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