-2" groups, now that's a shooter!
What about the relationship between bullet velocity and rate-of-twist?
Take for instance a .223 and .22/250. Most rifles in both cartridges will shoot 50-55 grain bullets the best. But I've noticed that most factory .223's are rifled 1-in-10 or 12", where most factory .22/250's are 1-in-14".
Using the reloading data on Hodgdon's website, and averaging the velocities produced by all of the powder combinations (max loads) I get the following velocities from each cartridge:
.223 Rem - 3,247fps
.22/250 Rem - 3,608fps
By doing some simple calculations it's found that the rotational speeds of both are:
.223 w/ 1-in-10" = 233,784 rpm
.223 w/ 1-in-12" = 194,820 rpm
.22/250 w/ 1-in-14" = 185,554 rpm
So we see that while the twist rates are significantly different, the rpms are fairly close. If the .22/250 had a twist rate of 1-in-10" it would be rotating at 259,776 rpm.
I'm thinking that maybe 1-in-10"/12" overstabilizes the 55 grain bullets in a .22/250 because of the increased velocity.
Please note that this is just MY theory based on the information I've read and interpreted. Please feel free to point out any errors in my evaluation.
Mike
Gun control means putting the second bullet through the same hole as the first- Ted Nugent
NRA Member
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -Ben Franklin