My extremely lucky 15 year old son drew an apprentice elk tag, he has a .270 that he was taken several deer with. He has been shooting 130 grain Barnes TTSX BT.
We would like to load up some heavier bullets for the elk hunt, according to the Barnes load data the 150 gr TSX FB require a 1:9.5" barrel twist rate, and the 155 gr LRX BT require a 1:8" twist rate.
"require" seems like a strong word... what will happen if we load some test loads for his rifle with its 1:10" twist rate?
Thanks,
worst case keyhole and not fly well.
provide poor groups
if you want to push heavy bullets in a slower twist barrel , then speed is your friend look for a powder that gets you the most velocity you can get of course using safe load data
think about this in a 223 vs 22-250 senario
a 1:12 twist with a 60gr bullet in a 223 is conditionally stable , but a 1:12 twist in a 22-250 is fine with the same bullet
you are looking for a sweet spot a range of RPMs for the bullet that keep it spin stabilized without spinning it too fast so that a tiny imperfection in a bullet would make it unstable from being off round or unballanced.
thinking of it like a spiral with a football that keeps it spinning on a strait trajectoryfor your minimum rpm
while
thinking of it like a slightly unbalanced tire , you don't feel the vibration till you get to a certain rpm for your max rpm
you might be able to hit that window of works with speed in a 1:10 rather than needing a 1:8 barrel.
the target will tell you if your doing it through consistent groups
if you get way off int he too slow rpm range the bullet will keyhole on targets.
