I am toying with getting another Swiss 550 but trying to figure the best twist rate. is the idea that the 1:7 stabilizes heaver bullets better but also shoots well with 55gr? what happens when you shoot heaver grain out of the 1:10 they key hole or just loss of accuracy?
Swiss Arms twist rate
- Thread starter stefofthenorth
- Start date
As you likely know, it isn't so much the weight of the bullet as it is the length in general, and specifically the bearing length of the bullet that really matters with twist. Couple those two factors with velocity of the round as well.
While the optimal bullet weight range seems to hover around 60 grains for the 10 twist, you can vary it a bit but not much heavier as it pretty much maxes out on a bullet such as the 69gr. Sierra Match King. In my experience, they may shoot pretty decently at short range (100-250m), but may fall apart the further you go (300+m). However, every barrel is different so you may see your's perform slightly better or worse.
If you do experiment with heavier bullets in the 10 twist barrel, you may want to give a VLD type bullet that has a short bearing surface a try.
The one thing the Swiss Arms has going for it is the ability to stretch the OAL on finished rounds considerably longer (relatively speaking) than the typical for ARs due to the magazine.
This can help you a bit if playing with seating depth on the longer bullets if you go with a 7 twist.
While the optimal bullet weight range seems to hover around 60 grains for the 10 twist, you can vary it a bit but not much heavier as it pretty much maxes out on a bullet such as the 69gr. Sierra Match King. In my experience, they may shoot pretty decently at short range (100-250m), but may fall apart the further you go (300+m). However, every barrel is different so you may see your's perform slightly better or worse.
If you do experiment with heavier bullets in the 10 twist barrel, you may want to give a VLD type bullet that has a short bearing surface a try.
The one thing the Swiss Arms has going for it is the ability to stretch the OAL on finished rounds considerably longer (relatively speaking) than the typical for ARs due to the magazine.
This can help you a bit if playing with seating depth on the longer bullets if you go with a 7 twist.
