1:7" vs 1:9" twist
- Thread starter jobbass
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dangertree
Business Rep
- Location
- NL/ON/FL/PL
If you're not a reloader, the 1/9 will likely shoot tighter groups than the 1/7 with most of the ammo you can buy off the shelf. This is the reason that most manufacturers choose to offer 1/9 by default. They both cost the same to make.
I shoot 1/7 and 1/9 rifles, (my 1/9s measure out to 1/8.5"), and both of them will stabilize whatever I can feed with a magazine. The 1/9 generally shoots 50gn/55gn ammo to tighter groups than the 1/7, I find 62 to be a wash.
I haven't done a head to head test with 75-77gn between the 1/9 and the 1/7 but mine both stabilize them. I'd reckon with the 77 it might be hit or miss with different 1/9 barrels though, so if you know you're setting up to shoot a lot of these bullets, go with the 1/7 to be sure.
One exception to my 'will shoot anything mag length' is the Federal 50gn frangible, 1/9 won't stabilize it, 1/7 required.
The reason for military use of 1/7 (long tracers) doesn't mean it's always the best choice for a particular persons uses, it really depends on what you're shooting.
If you know you'll be mostly be shooting 55/62, I'd say get a 1/9. If you're a handloader and/or know why you want a 1/7, then it might be a worthwhile option, but it's rarely a must have. If I knew I was building a gun to shoot 77gn ammo, I'd look for a 1/7 or 1/8. But, I shoot 55/62 99% of the time, so I prefer my 1/9. With 55/62, 1/7 offers no advantage, and possibly a reduction in accuracy (for me, with some barrels, YMMV). Most DMR/Precision type SS ARs are coming in 1/8. Colt uses 1/9 on their accurized rifles.
For 'action' shooting at 50m, none of this makes a bit of difference.
My $.02 only, usual disclaimers apply, we sell both, so.
I shoot 1/7 and 1/9 rifles, (my 1/9s measure out to 1/8.5"), and both of them will stabilize whatever I can feed with a magazine. The 1/9 generally shoots 50gn/55gn ammo to tighter groups than the 1/7, I find 62 to be a wash.
I haven't done a head to head test with 75-77gn between the 1/9 and the 1/7 but mine both stabilize them. I'd reckon with the 77 it might be hit or miss with different 1/9 barrels though, so if you know you're setting up to shoot a lot of these bullets, go with the 1/7 to be sure.
One exception to my 'will shoot anything mag length' is the Federal 50gn frangible, 1/9 won't stabilize it, 1/7 required.
The reason for military use of 1/7 (long tracers) doesn't mean it's always the best choice for a particular persons uses, it really depends on what you're shooting.
If you know you'll be mostly be shooting 55/62, I'd say get a 1/9. If you're a handloader and/or know why you want a 1/7, then it might be a worthwhile option, but it's rarely a must have. If I knew I was building a gun to shoot 77gn ammo, I'd look for a 1/7 or 1/8. But, I shoot 55/62 99% of the time, so I prefer my 1/9. With 55/62, 1/7 offers no advantage, and possibly a reduction in accuracy (for me, with some barrels, YMMV). Most DMR/Precision type SS ARs are coming in 1/8. Colt uses 1/9 on their accurized rifles.
For 'action' shooting at 50m, none of this makes a bit of difference.
My $.02 only, usual disclaimers apply, we sell both, so.
I Prefer 1:7 and wouldn't buy a 1:9 for much of the reasons 'Dangertree' spoke of.
If you are shooting at distance (400-500m) the difference between a 55gr. fmj and a 77gr. hpbt can be very significant.
If it floats your boat and suits your long range game, there is 75amax and 80gr. (and up) bullets that can be loaded to beyond mag length and shot single fire.
I'm not sure I'd agree that a 1:9 can throw the lighter stuff more accurately than a 1:7 as a general rule, as the tighter twist barrels I own do fine with 50ish grain stuff.
imho, if you plan on shooting 200+m you can benefit from 1:7 (or even 1:8) and match bullets.
If none of what I've typed applies, then 1:9 is likely a good fit.
If you are shooting at distance (400-500m) the difference between a 55gr. fmj and a 77gr. hpbt can be very significant.
If it floats your boat and suits your long range game, there is 75amax and 80gr. (and up) bullets that can be loaded to beyond mag length and shot single fire.
I'm not sure I'd agree that a 1:9 can throw the lighter stuff more accurately than a 1:7 as a general rule, as the tighter twist barrels I own do fine with 50ish grain stuff.
imho, if you plan on shooting 200+m you can benefit from 1:7 (or even 1:8) and match bullets.
If none of what I've typed applies, then 1:9 is likely a good fit.
dangertree
Business Rep
- Location
- NL/ON/FL/PL
^ My range is 200m. 
And I agree with your post.
And I agree with your post.
