223 twist
- Thread starter GMHVAC
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Ar180shooter
CGN Ultra frequent flyer
- Location
- Ottawa, ON
1 in 7 is quite fast for 55gr bullets, too fast in some cases. If you want to shoot cheap bulk, stick with the 1 in 9. If you want to work up some handloads with heavier bullets, then a 1 in 7 or 8 twist is preferable.
Steve Janes
CGN frequent flyer
- Location
- Calgary/Ontario
A 1 in 7" Twsit barrel will stabilize most 55gr bullets.
However the norinco 55gr ammo is all over the place out of my 1in7 barrel. Also another guy I know had the same issues in his 1in7 with norinco.
I was approached at the range this weekend by another guy who had the norinco ammo yaw up to 90 degrees at close range, in his 1in8.5 twist.
I think the problem with the norinco ammo is the inconsistent bullet diameter. some have been measured as small as .222, which would explain the extreme yaw at close range. Some have suggestted this could be causing damage to the barrel, others disagree. I shoot enough that I want to finish the norinco I have a go back to AE
Example
This target was shot at 5-10M using a 14.5" stag with a 1 in 7" Twist. The guy I spoke with at the range said he was getting this kind of key holing out of a 1in8.5 twist as well
However the norinco 55gr ammo is all over the place out of my 1in7 barrel. Also another guy I know had the same issues in his 1in7 with norinco.
I was approached at the range this weekend by another guy who had the norinco ammo yaw up to 90 degrees at close range, in his 1in8.5 twist.
I think the problem with the norinco ammo is the inconsistent bullet diameter. some have been measured as small as .222, which would explain the extreme yaw at close range. Some have suggestted this could be causing damage to the barrel, others disagree. I shoot enough that I want to finish the norinco I have a go back to AE
Example
This target was shot at 5-10M using a 14.5" stag with a 1 in 7" Twist. The guy I spoke with at the range said he was getting this kind of key holing out of a 1in8.5 twist as well
Last edited:
boss351cleveland
CGN frequent flyer
- Location
- Down by the river
My 1/7 Swiss Arms shoots 55gr ammo at 100m just as good as 62gr even the norinco stuff , but if your shooting out to 200m plus ,the heavier bullets will group a bit better.
boss351cleveland
CGN frequent flyer
- Location
- Down by the river
A 1 in 7" Twsit barrel will stabilize most 55gr bullets.
However the norinco 55gr ammo is all over the place out of my 1in7 barrel. Also another guy I know had the same issues in his 1in7 with norinco.
I was approached at the range this weekend by another guy who had the norinco ammo yaw up to 90 degrees at close range, in his 1in8.5 twist.
I think the problem with the norinco ammo is the inconsistent bullet diameter. some have been measured as small as .222, which would explain the extreme yaw at close range. Some have suggestted this could be causing damage to the barrel, others disagree. I shoot enough that I want to finish the norinco I have a go back to AE
Example
This target was shot at 5-10M using a 14.5" stag with a 1 in 7" Twist. The guy I spoke with at the range said he was getting this kind of key holing out of a 1in8.5 twist as well
I have a 12 inch steel plate set up at 300m , i can hit it shooting Norinco 55gr with great regularity , the ammo i got is in white boxes , most other stuff i seen for sale was in yellow boxes ?
Steve Janes
CGN frequent flyer
- Location
- Calgary/Ontario
yes all of the undersized projectiles have been found in the yellow box norinco, I should have specified
And keep in mind, shooting it out to even 300m is no problem, except for the odd round the goes lord knows where
A 1 in 7" Twsit barrel will stabilize most 55gr bullets.
However the norinco 55gr ammo is all over the place out of my 1in7 barrel. Also another guy I know had the same issues in his 1in7 with norinco.
I was approached at the range this weekend by another guy who had the norinco ammo yaw up to 90 degrees at close range, in his 1in8.5 twist.
I think the problem with the norinco ammo is the inconsistent bullet diameter. some have been measured as small as .222, which would explain the extreme yaw at close range. Some have suggestted this could be causing damage to the barrel, others disagree. I shoot enough that I want to finish the norinco I have a go back to AE
Example
This target was shot at 5-10M using a 14.5" stag with a 1 in 7" Twist. The guy I spoke with at the range said he was getting this kind of key holing out of a 1in8.5 twist as well
Wow talk about a keyhole. You se I am leaning away from a 1:7 twist as most ammo I see is around 55 grain and it has Norinco. Let me ask you would you stay wit the 1:7 and get better ammo or go with 1:9 and shoot everything?
Steve Janes
CGN frequent flyer
- Location
- Calgary/Ontario
I'll stick with the 1 in 7" for now, I just won't shoot cheap chinese ammo with undersized projectiles. 1 in 7" Twists will stabilize the 55gr ammo consistently.
20.79" barrel.
Paladin308
CGN frequent flyer
- Location
- The Man Cave
A 1 in 7" Twsit barrel will stabilize most 55gr bullets.
However the norinco 55gr ammo is all over the place out of my 1in7 barrel. Also another guy I know had the same issues in his 1in7 with norinco.
I was approached at the range this weekend by another guy who had the norinco ammo yaw up to 90 degrees at close range, in his 1in8.5 twist.
I think the problem with the norinco ammo is the inconsistent bullet diameter. some have been measured as small as .222, which would explain the extreme yaw at close range. Some have suggestted this could be causing damage to the barrel, others disagree. I shoot enough that I want to finish the norinco I have a go back to AE
Example
This target was shot at 5-10M using a 14.5" stag with a 1 in 7" Twist. The guy I spoke with at the range said he was getting this kind of key holing out of a 1in8.5 twist as well
that is most definitely not overstabilization, as other's have said, undersized projectiles is the most likely culprit. Quite frankly I wouldn't take anything other than a 1 in 7" unless I planned on shooting super light varmint loads.
Ar180shooter
CGN Ultra frequent flyer
- Location
- Ottawa, ON
Unless you're shooting really heavy vld's, you don't need the 1 in 7. 1 in 9 is good for 95% of the .223 ammo that's out there.
Paladin308
CGN frequent flyer
- Location
- The Man Cave
Need? No. Nice to have? most certainly. A 1 in 7" won't degrade performance with 55gr M193 ball, and it's always good to have upwards mobility if you want to shoot something like M855 or heavier.
boss351cleveland
CGN frequent flyer
- Location
- Down by the river
The most accurate AR i own is a Colt SP1 with a 1/12 twist , it shoots 55gr ammo like no other , by far the best twist for light bullets under 60 grains but wont shoot anything heavier .. 1/7 twist is only really needed if your shooting bullets over 62gr beyond 300m .. In my opinion 1/7 is pointless in a rifle with a carbine length barrel , who really shoots 70 grain bullets beyond 300m with their 16 or 11 inch ARs ?? In a 18 or 20 inch barrel go with a 1/7 twist, anything shorter go with a 1/9
Paladin308
CGN frequent flyer
- Location
- The Man Cave
Why? it's not like 1 in 7" really costs any more, the whole overstabilization thing is a myth if not blown completely out of proportion. So what if you never really use the rifle at long range, why limit yourself? I'd have to see a lot more than anecdotal data before I'm convinced that a slower twist rate improves accuracy by any meaningful amount.
1/7 was a "solution" for 2 things, for one, to allow the rifle in question to work well with all variety of ammo, and for two, to speed up the stabilization of a shorter barrel.
It may not be ideal in a longer barrel shooting lighter bullets, but that barrel probably cost you less cause the company has tooled themselves to give the same twist to all their barrels to save themselves and you money.
Once upon a time, rifle barrels were long, generating high enough a velocity to stabilize a light bullet with a slow twist like 1/12.
Then they made the bullets heavier to reach farther and shoot a bit tighter, so they have to speed up the twist to say 1/9.
Then one day, some guy had the bright idea to make the barrels shorter for a lighter gun, the loss in velocity meant a loss in the RPM needed to stabilize the bullet adequately, so an even faster twist was developed. Now that we have 7" and 11" barrels on our AR, that 1/7 twist comes in handy.
Fussing over twist rate is something you do if you're planning on building a rifle to shoot groups with match grade or hand loaded ammo.
If you're plan is to run the rifle with cheap ammo for the fun of shooting, then it's nothing to worry about.
IMO, overstabalization isn't something you need to consider unless you're running a rifle length barrel with a fast twist.
Observations I've made are that 1/9 is a go to twist in 14.5" - 20" AR barrels that are designed for serivce rifles.
1/7 is a go to twist for 7 to 12" SBR barrels to compensate for the RPM/FPS reasons mentioned about, and it spills over to that same companies barrels up to 16" for the tooling reasons mentioned above.
And 1/8 is a go to twist in longer barrels designed for accuracy in which will likely be shooting heavier bullets.
I had a 223 bolt gun, it was 22" with a 1/8. It indeed could not groups lighter bullets as tight as heavier bullets, unless I down loaded light bullets rounds with really cold loads to bring the FPS down, so I believe that overstabalization is a true phenomenon. In the case we are talking about the difference between fractions of an MOA tho'. I admit, I'm not exactly sure how overstabalization works, but from what I understand I think it might have something to do with the excessive RPM causing centrifugal force to warp the bullet while in flights. There are cases where a particularly light bullet shot at a high FPS out a fast twist barrel would actually explode from the force of the RPM's after having left the barrel.
It may not be ideal in a longer barrel shooting lighter bullets, but that barrel probably cost you less cause the company has tooled themselves to give the same twist to all their barrels to save themselves and you money.
Once upon a time, rifle barrels were long, generating high enough a velocity to stabilize a light bullet with a slow twist like 1/12.
Then they made the bullets heavier to reach farther and shoot a bit tighter, so they have to speed up the twist to say 1/9.
Then one day, some guy had the bright idea to make the barrels shorter for a lighter gun, the loss in velocity meant a loss in the RPM needed to stabilize the bullet adequately, so an even faster twist was developed. Now that we have 7" and 11" barrels on our AR, that 1/7 twist comes in handy.
Fussing over twist rate is something you do if you're planning on building a rifle to shoot groups with match grade or hand loaded ammo.
If you're plan is to run the rifle with cheap ammo for the fun of shooting, then it's nothing to worry about.
IMO, overstabalization isn't something you need to consider unless you're running a rifle length barrel with a fast twist.
Observations I've made are that 1/9 is a go to twist in 14.5" - 20" AR barrels that are designed for serivce rifles.
1/7 is a go to twist for 7 to 12" SBR barrels to compensate for the RPM/FPS reasons mentioned about, and it spills over to that same companies barrels up to 16" for the tooling reasons mentioned above.
And 1/8 is a go to twist in longer barrels designed for accuracy in which will likely be shooting heavier bullets.
I had a 223 bolt gun, it was 22" with a 1/8. It indeed could not groups lighter bullets as tight as heavier bullets, unless I down loaded light bullets rounds with really cold loads to bring the FPS down, so I believe that overstabalization is a true phenomenon. In the case we are talking about the difference between fractions of an MOA tho'. I admit, I'm not exactly sure how overstabalization works, but from what I understand I think it might have something to do with the excessive RPM causing centrifugal force to warp the bullet while in flights. There are cases where a particularly light bullet shot at a high FPS out a fast twist barrel would actually explode from the force of the RPM's after having left the barrel.
Steve Janes
CGN frequent flyer
- Location
- Calgary/Ontario
1 in 9 is good for 95% of the .223 out there, but so is a 1 in 7, it just may not be bench rest accurate
I shoot 55 WW white box out of 1-7" barrel all day and the groups is a consistent 1.5-2 " however shooting Norinco 223 that's another matter all together I found it shot like a shotgun and at 200m I was lucky to hit a 2 ft square target 50% of the time . The only ammunition that performs badly is the 45 gr 223
Ar180shooter
CGN Ultra frequent flyer
- Location
- Ottawa, ON
I disagree. Out of a 20" bbl, a 1 in 9 can often still stabilize 75gr bullets, yet lighter varmint loads (45-50gr) are also usually good to go. With the 1 in 7 twist, I have personal experience with them sometimes over-stabilizing up to 55gr bullets. The gains in being able to shoot slightly heavier bullets than the 1 in 9 is IMHO over shadowed by not being able to shoot lighter bullets (you see many more 45 gr varmint loads than 80gr match loads). As Cote so eloquently described, a 1 in 7 twist is useful in shorter barrels, but in rifle length (20") barrels, you don't really gain anything. Now this doesn't mean you shouldn't get a rifle because it's a 1 in 7 twist, my point is you shouldn't get hung up on the twist rate when most people run and gun with cheap bulk ammo.
Ar180shooter
CGN Ultra frequent flyer
- Location
- Ottawa, ON
14.5" or 16" carbine, right?
