I thought we had resolved this problem 15 years ago but increasingly I’m seeing factory guns and mid grade barrels coming in 1/8. What’s the advantage in not being able to stabilize heavy mono metals or even having questionable stability with 77gr in cold weather?
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Why is the 1/8 AR barrel coming back?
- Thread starter RyanScott
- Start date
Lots of people want a Jack of All trades.
Lots of peeps - meaning me - shoot 77s for reloads or when "it matters" - but find that if it holds an 8 inch circle at 100 yards through a red dot and Im going to be shooting a lot, M193 will do just fine.
My ARs are 1/7 basically because thats what they came with.
Weird thing is I spec'd my bolt .223 - every shot matters - with 1/7.7 just because I hedged a bet.
None of the 3 have let me down.
Lots of peeps - meaning me - shoot 77s for reloads or when "it matters" - but find that if it holds an 8 inch circle at 100 yards through a red dot and Im going to be shooting a lot, M193 will do just fine.
My ARs are 1/7 basically because thats what they came with.
Weird thing is I spec'd my bolt .223 - every shot matters - with 1/7.7 just because I hedged a bet.
None of the 3 have let me down.
Wasn't the 1:7 twist specifically to stabilize long 5.56 tracer bullets?
A 1:8 twist shooting a 77gr SMK at sea level, 0F, 2200fps has a stability factor of 1.62. Where's the problem?
A 1:8 twist shooting a 77gr SMK at sea level, 0F, 2200fps has a stability factor of 1.62. Where's the problem?
Its not a problem lol...
In the 14 years I've owned AR's of varying degrees, I've always seen 1:7, 1:8, and 1:9 as popular choices... 1:7 and 1:8 being used the most, especially for anything heavy.
My 1:8 Lothar Walther stabilizes 77TMK's just fine, and also stabilizes 50gr Varmint Grenades and Nosler B-tip's ... whats not to like.
The 223AI I just put together is also 1:8. The previous owner of the barrel ran all the way up to 85gr without any issues, although 80's performed the best as I assume 85's started to touch on that stabilization issue.
I'm a moron who wasn't using AB properly...77gr SMK @ 2200fps, sea level, 0F from a 1:8 barrel shows 1.44 which is plenty stable.
It does look like a 70gr GMX @ 2200fps, sea level, 0F from a 1:8 twist is very marginal at 1.12 as copper bullets tend to be long for weight...but how many people are using those particular bullets through a factory 1:8 barreled AR? The 55gr GMX at 2200fps and same environmentals is 1.74, a better non-lead solution for a factory barreled rifle with 1:8 twist.
I could see that for sure... I was listening to a podcast with Josh from PVA and his 308 is a 1:8.5 twist for long 220ish grain solids
Midsouth has 77 SMKs for $0.31 per. Barnes 77 grain LR-X is $0.63 per... Regardless of caliber, all copper bullets tend to be around 2x more expensive than their lead core counterparts...
And beyond that, if the barrel is proprietary, or the rifle has a proprietary barrel in 1-8 twist, them- perhaps- it was developed with a specific purpose in mind.
Kind of like that girl in 5th period that you can't get over, but doesn't know you exist. You may really like the barrel/rifle, but it's just not that in to you...
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Then if you want the newer Warner Flatlines or the PVA solids, you're looking more like $1-$1.25
We have been using 1:8 twist barrels since the early 90s and they will shoot everything up to the 80ELD and 80 Berger. Most 7 twist barrels were cheap military configured rifles with 6 groove enfield rifling. Most people use bullets lighter than that except those shooting the Valkyrie or 22 Grendel which are made with faster twist barrels.
Custom barrel makers can use or offer a fast twist since they know the barrel is sold before they spend money on it. I don't do it because I don't want to see 100 barrels sitting on the shelf for a year.
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I have personally built a few 5.56 rifles now, and shot dozens of others. Many off of a bench. I have never found 55 grain fmj to suffer from a 1:7 twist barrel. I have no interest in bullets below 55 grains for an AR. Heavies are my favorites, but I like them all to be able to pick up big box 55's and shoot them in around the 1.5"-2.5" groups I usually see from them. Better 55 grain ammo shoots around an inch with most of them. If I was building a varmint specific rig 1:9 stainless would be the way to go. For anything else I have never seen an accuracy difference that would lead me to go with a 1:8. I also tend towards go chrome or go home with AR's ( admit - sometimes nitride). It is odd to me, and reeks of the old Colt style efforts to keep military issue tech out of civilian hands. Remember large pin triggers for example...
I’m not on either and I’m not ScottRyan.
Use prices for loaded ammunition. Barnes VorTx 70gr is cheaper than BH 77 SMK.
I want to shoot a 70gr TSX or GMX what twist would you use for that?
Then shoot 7 twist lol.....the overwhelming majority of shooters aren't using solids.
Either way, 1:8 isn't a trend or fad, it's not new, and it works for almost every application. Guys like 1:8's because they want to shoot heavies and lights and not have two different rigs or barrels. Would a 1:7 work for it? prolly ... would a 1:7.7 be perfect? maybe
I have yet to see any data points to support 1/7 being disadvantaged for anything except specialized varmint bullets, and I had a class and meals with literally the guy at what is now PEO Soldier who did the test to confirm 1/7 was fine.
The one that’s frustrating me currently is that Proof only makes a 16 intermediate in 1/8. To get a 1/7 you have to get a mid gas system and that’s too short.
The one that’s frustrating me currently is that Proof only makes a 16 intermediate in 1/8. To get a 1/7 you have to get a mid gas system and that’s too short.
Varmint bullets in 223 are not specialized. They are the norm. Heavy bullets for long range on the other hand.....
WTF is a specialized varmint bullet? lol
Why is a mid gas system too short?
Why do you NEED a proof barrel?
Why don't you just get a brand name match barrel in the twist rate YOU need for your applications... Look at White Oak or Compass Lake
Why is a mid gas system too short?
Why do you NEED a proof barrel?
Why don't you just get a brand name match barrel in the twist rate YOU need for your applications... Look at White Oak or Compass Lake
Anything under 50gr is specialized.
Anything super light for shooting prairie dogs and groundhogs is specialized. Of course, so are the 69gr plus bullets and any mono metal.
Need? Need is a big word. But a proof intermediate barrel weighs the same as a 16” carbine M4 barrel. It slightly lighter than a lightweight stainless barrel like Noveske offers. It could be done, but I’d like another CF barrel.
I know, and I have some blanks I talked to them about finishing.
Its advantage is that it sufficiently stabilizes the largest spectrum of common projectile options, from 40gr varmint bullets up to 80-82gr match bullets, in a sea level/zero degrees atmosphere.
This is especially true in an AR platform where mag length is the biggest limitation.
If you desire to run 90s, tracers or evidently 70gr monometals you'll need a faster twist...and those "specialized applications" don't negate the broad advantages of a 1:8, especially from a manufacturing perspective and/or on factory rifles.
Because a 7 twist can over rev light bullets, and you aren't fitting flatlines, solids, or 90s in an AR-15 magazine.
I could never get 77's to shoot as well as 69's in the half a dozen barrels I've owned. Maybe it's a fluke, but I don't have any issue with 1/8 at all.
Apparently you have me confused with someone else. I’ve never used this name or a derivative anywhere else.
If I could still buy 40gr here I’d shoot some through a 7 twist to show that it works.
You’d think manufacturers would pause to wonder if people would be shooting more M856/brown tip/77gr through this particular .625” 11.5” barrel than 35gr varmint bullets...
If I could still buy 40gr here I’d shoot some through a 7 twist to show that it works.
You’d think manufacturers would pause to wonder if people would be shooting more M856/brown tip/77gr through this particular .625” 11.5” barrel than 35gr varmint bullets...
They probably did....and then they realized that 1:8 stabilizes all of those sooooooo
Believe what you want man....
That’s demonstrably not true though. And in any case in the situations where an 8 twist will stabilize well enough to not keyhole you still have degraded BC.
Worst shooting conditions I can expect are -20, 800’ASL and 60% humidity.At 0F? In Death Valley? With 100% humidity?
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