Quote:
Originally Posted by cyphertext
Ok, nice sample of one... some 1:9 barrels will, and some won't. Generally speaking, the odds of getting a 1:9 barrel that won't stabilize a longer projectile are higher than getting one that will.
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Generally when you go over 72 gr in 1:9 twist 16" barrel there are a lot of variables which will come into play which will result in a stabilized or not stabilized bullet.
I am not an expert on the subject but my understanding is that weight, load, bullet profile, OAL and their interactions with an individual barrel all come into play at around 72 grs in a 1:9 barrel. Some will stabilize up to 75 gr some will not. Some will stabilize some 75 gr rounds and not others.
This is why people suggest if you are going to be shooting 72gr to 75gr and above on a regular basis you should get a 1:7 twist.
The 1:9 is a great twist if you like to shoot in the 45gr to 69gr window. This is why it is often recommended for recreational shooters. Most people blasting away at your local range are shooting 55gr ammo.
The other thing to consider is that the 1:7 16" barrel will shoot the 55gr range fodder with the same level of accuracy that the 1:9 will but will go up to the 90gr. So there is more of a spread but if you are shooting a lot of light 40gr to 45gr the 1:8 or 1:9 might shoot better for you.
In the end I agree that if you are shooting a lot of heavy bullets 75gr and above it makes sense to hedge your bets and get a 1:7 twist. There is no way to know until you shoot it if a 19 twist will stabilize your 75gr round of choice so why risk getting something not up to the designated task when there are barrels like 1:7 that will work.