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Posted: 8/9/2010 4:08:10 AM EDT
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So, went to the gun show today at the raceway to poke around and had a dude go on about how useless an upper with a 1/7 twist is in the "real world," and that a 1/9 is the best you can get because it can use "all ammo."
Did I miss something? As far as I knew, a 1/7 or 1/8 would be the best way I could go for my build, because a 1/9 limits the max bullet weights that you can use. I was under the impression that a 1/7 would work well with heavier bullets, and I'd only be limited by what would actually fit in the mag.... Am I the wrong one? |
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Very true. BUT I did manage to leave with a pair of PMags for $27. Granted, I STILL don't have an upper, I'm stocking up on everything else I need... He also claimed to have filled a "military contract" with 1/9 barrels. He's a bold faced liar. 1/7 is specified by the military's TDP as the only twist that qualifies. |
| I didn't feel like calling BS (all the M16's and M4's I've ever been issued clearly stated "5.56 NATO 1/7" on the barrel, and IIRC it was right behind the flash hider. He will not be getting an order from me when I have the spare dough for an upper, and I'll be buying a 1/7 so I can, in fact, use any bullet weigh I damn well please. Lol. |
| The closest you will get to what you had in the military (outside of a Colt 6921 upper) is BCM. |
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Quoted:
Very true. BUT I did manage to get a pair of PMags for a few bucks off the retail price. Granted, I STILL don't have an upper, I'm stocking up on everything else I need... He also claimed to have filled a "military contract" with 1/9 barrels... I'm going to take a guess and say you talked to Tony's Custom Uppers right? He will claim that whatever he has is the best. If he has extra chrome lined barrels he will go on about how they are the best. If he has a stock on non-chrome lined ones then the chrome is worthless. Most people I have seen seem to be happy with his product though. Quoted:
I didn't feel like calling BS (all the M16's and M4's I've ever been issued clearly stated "5.56 NATO 1/7" on the barrel, and IIRC it was right behind the flash hider. He will not be getting an order from me when I have the spare dough for an upper, and I'll be buying a 1/7 so I can, in fact, use any bullet weigh I damn well please. Lol. Depending on what you shoot and the application a 1/8 or a 1/9 might be better. Really comes down to use though. A 1/7 is fine though. FYI the older m16's had a slower twist rate. I'm sure someone with more experience can chime in but I believe the early m16's had a 1/12 twist. |
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Quoted:
Very true. BUT I did manage to get a pair of PMags for a few bucks off the retail price. Granted, I STILL don't have an upper, I'm stocking up on everything else I need... He also claimed to have filled a "military contract" with 1/9 barrels... Yea,....rrrright. FWIW, 1/7 is faster than req'd for all but the heaviest bullets (>90gr)...so some say it just raises pressure, >bbl wear, can "damage" lightly constructed bullets, etc. But it's not going to hurt anything....there's 1,000's of M4s out there with 1/7" doing just fine. |
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Mark Westrom of Armalite has stated some very convincing arguements in favor of the 1-9" twist rate for a general purpose rifle that include improved terminal ballistics, uniform stable flight of a wider range of bullet weights than any other twist rate factory offered, uniform bore fouling, reduction of wear and flame erosion of the bore which increases useful barrel life, this last one is most apparant in unchromed Chrome Moly and stainless steel barrels
All that said, the 1 in 9" twist has NEVER been used on a production 5.56 NATO caliber rifle destined for Military use. The biggest drawback for the 1-9" twist comes for what has already been stated, It does its best work with bullets ranging from 52 to 64 grains, anything heavier will not stabalize in the 1-9" Barrel and you will be spending money for less than satisfactory results by choosing ammunition with heavier bullet weights for use in rifles with this rate of twist. Lighter bullets can be fired in the faster 1-8" and 1-7" barrels and will do so with decent if not spectacular accuracy. Generally you will want to avoid thin jacket "Blitz" bullets and bullets designed for use in the .22 Hornets and other small centerfire .22 cartridges as these bullets can and will disintigrate when pushed at high speed through a fast twist barrel. These bullets normally weigh in around the 37-45 grain weight and are really best avoided for use in any 5.56/223 application. Bullets of 50-53 grain+ are generally acceptable for use in 5.56/.223 caliber rifles of any twist rate because the jackets of these bullets are heavy enough to resist disintigration at the speeds and pressures normally associated with this cartridge. The drawback is reduced terminal ballistics and lethality of bullets lighter than 62 grains, especially bullets of full metal jacket construction that rely on the bullets ability to yaw and tumble in soft to medium dense flesh. Soft point and special construction bullets of lighter weights fare much better in faster twists because the overstabalizing effect has little effect on the bullets ability to expand in soft to medium dense flesh and in some cases, such as when using bullets designed for use in higher velocity .22 centerfire rifles such as the .22/250, lighter 60 and 70 grain bullets designed for such an intended use actually perform quite well in the 5.56 NATO caliber rifle when pushed to near maximum speeds in the faster 1-7" and 1-8" twist barrels. If you chose your rifle for target shooting and do most of your shooting at 100 meters, as most shooters do, the difference between a 1-7" and a 1-9" barrel will not be noticed. Both will give adequate service with acceptable accuracy with the majority of factory loads offered on the commercial market. Where you will notice a difference is in a rifle chosen specifically for Defensive/Offensive roles or a rifle chosen for hunting most especially when the ranges exceed the average 100 meter maximum at which most shooters employ their rifle. The difference in the performance of, hunting, defense, and especially full metal jacketed, ammunition will be readily apparent. In this scenario, choose a twist rate that will perform adequately with the ammunition you intend to use as your life or your livelyhood as well as your recreational satisfaction and enjoyment will depend on it.HTH |
| I have a 1/7 wilson 14.5 barrel. It shoots 55 just fine. My buddy has a 14.5 bcm upper it shoots 55 just fine. we have both shot to about 300 yards, at that range the 55 loses a bit to to even 62 grain with shoots alot better at that distance but I can hit man sized steel at 300 with 55 so I'm happy:) |
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I think he's full of shit.
The only thing you *might* get into with 1/7 is that it may make lightweight varmint bullets come apart in flight from too much rotational velocity. But it may not, some 1/7 barrels won't do that, others will. I've never observed myself personally. I'm also not personally interested in shooting 40 to 50 gr bullets from an AR anyway, so it's a moot point for me. |
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Very true. BUT I did manage to get a pair of PMags for a few bucks off the retail price. Granted, I STILL don't have an upper, I'm stocking up on everything else I need... He also claimed to have filled a "military contract" with 1/9 barrels... Yea,....rrrright. FWIW, 1/7 is faster than req'd for all but the heaviest bullets (>90gr)...so some say it just raises pressure, >bbl wear, can "damage" lightly constructed bullets, etc. But it's not going to hurt anything....there's 1,000's of M4s out there with 1/7" doing just fine. Well, it actually does increase friction and barrel wear....but that's one reason why 1/7 barrels have hard chrome lining. The lining eliminates what would be accelerated wear in a regular barrel. A 1/7 twist chrome moly barrel probably wouldn't have a very high round count life. |
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Well, I think I'm just going to keep pinching my pennies for the BCM upper. Sucks, though, because it'll cost me over $600 total (BCG and handguards). There's always Hannukah coming up in 4 months. And I will neither confirm nor deny who it was I talked to. 
Called it. On the vaguntrader forum I seem to recall a thread on him. Their is one on here that is prob in archive by now as well. Might want to search for his name. Anyway I was going to tell you to look at spikes if you want to save some cash. Aimsurplus has them for around 500 bucks with bcg from time to time. Past that the bravo company uppers are good and I would say fair priced. |
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Quoted:
Very true. BUT I did manage to leave with a pair of PMags for $27. Granted, I STILL don't have an upper, I'm stocking up on everything else I need... He also claimed to have filled a "military contract" with 1/9 barrels. He's a bold faced liar. 1/7 is specified by the military's TDP as the only twist that qualifies. True...and for whatever reason...as 1/7 is overkill (faster than necessary) for anything the .mil (currently) or just about everybody else shoots. |
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Hey, not to start a twist-rate war...
But my 24" Bushy Varminter (stainless 1/9) shoots 75g's accurately out to 300m(1-2 MOA). It'll also sling 50 grainers all day long. The most accurate sub-MOA loads though are SMK 69g... So it really just depends on the rifle. |
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Quoted:
Well, I think I'm just going to keep pinching my pennies for the BCM upper. Sucks, though, because it'll cost me over $600 total (BCG and handguards). There's always Hannukah coming up in 4 months. And I will neither confirm nor deny who it was I talked to.
Let's see, Hannukah, 8 days, one part per day = YOU'RE THERE (WITH OPTICS)! |
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Hey, not to start a twist-rate war... But my 24" Bushy Varminter (stainless 1/9) shoots 75g's accurately out to 300m(1-2 MOA). It'll also sling 50 grainers all day long. The most accurate sub-MOA loads though are SMK 69g... So it really just depends on the rifle. 1/9 is theoretically the correct twist for a bullet weight of 75gr. Note also that we are talking about a continuum here...not discrete #s...in other words, it's not like 1/8 will stabilize and 1/9 won't...depending on bullet weight, one will stabilize better or worse than another...not will and won't. |
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Well, I think I'm just going to keep pinching my pennies for the BCM upper. Sucks, though, because it'll cost me over $600 total (BCG and handguards). There's always Hannukah coming up in 4 months. And I will neither confirm nor deny who it was I talked to.
Let's see, Hannukah, 8 days, one part per day = YOU'RE THERE (WITH OPTICS)! Now I just gotta see if I can get the wife to go for that. I also need to pay for a membership at an outdoor range (Richmond area seems to suck for that. Too urbanized, and I don't think the apartment complex would appreciate me using the "back yard," as it's less than 100 yards to the next property). I've been looking at the Spikes upper, and may end up going with that because of the price. But I'd still slap on a set of MOE handguards with accessory rail attachments. I must say, though, most of the other people at that show had some good prices and knew what they were talking about, especially the dude that almost exclusively had CZ products
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Not to redirect the thread (but hey, it's YOUR thread) I would think about the BCM upper/lower...they do have some of their basic models on sale plus $250 for a "blem" lower.
Just a "sample" build: 1. BCM blem lower:...............$250 2. 16" middy with CHF bbl:....$475 3. Bolt carrier group:.............$135 4. Handguards:.....................$20-30 = one a$$ kickin' little rifle for not a lotta cheese. |
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Quoted: The STG77/AUG A1 and AUG A2 and FAMAS G2 have a 1/9 twist barrel, and are both "a production 5.56 NATO caliber rifles destined for Military use". The Steyr built rifles have 1/9, but the ADI versions in use in Australia and New Zealand have 1/7". The Netherlands are a NATO nation that at one time used the standard AUG w/ 1/9 barrel in general issue. The tiny NATO nation of Luxembourg still uses the AUG w/ 1/9 twist. France has redesigned the FAMAS G2 with a 1/9 twist, and they are a NATO nation. There are several non-NATO nations that never the less use the 5.56 NATO caliber, like Austria and Ireland and they are using the Steyr AUG with 1/9. *snip* All that said, the 1 in 9" twist has NEVER been used on a production 5.56 NATO caliber rifle destined for Military use. *snip* And that is just dealing with general issue, there are other nations using the Steyr (if not the FAMAS) in special applications that are none-the-less military use... There are 1/9 twist barrels in use on 5.56 caliber military rifles, but you are correct if you meant there was never a US rifle that used 1/9". |
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The STG77/AUG A1 and AUG A2 and FAMAS G2 have a 1/9 twist barrel, and are both "a production 5.56 NATO caliber rifles destined for Military use". The Steyr built rifles have 1/9, but the ADI versions in use in Australia and New Zealand have 1/7". The Netherlands are a NATO nation that at one time used the standard AUG w/ 1/9 barrel in general issue. The tiny NATO nation of Luxembourg still uses the AUG w/ 1/9 twist. France has redesigned the FAMAS G2 with a 1/9 twist, and they are a NATO nation. There are several non-NATO nations that never the less use the 5.56 NATO caliber, like Austria and Ireland and they are using the Steyr AUG with 1/9.
*snip* All that said, the 1 in 9" twist has NEVER been used on a production 5.56 NATO caliber rifle destined for U.S. Military use. *snip* And that is just dealing with general issue, there are other nations using the Steyr (if not the FAMAS) in special applications that are none-the-less military use... There are 1/9 twist barrels in use on 5.56 caliber military rifles, but you are correct if you meant there was never a US rifle that used 1/9". Fixed 
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The closest you will get to what you had in the military (outside of a Colt 6921 upper) is BCM. The closest I would have when I was in would be an R6551! But as stated yes 1/7 good to go. Bob |
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Well, I think I'm just going to keep pinching my pennies for the BCM upper. Sucks, though, because it'll cost me over $600 total (BCG and handguards). There's always Hannukah coming up in 4 months. And I will neither confirm nor deny who it was I talked to.
Called it. On the vaguntrader forum I seem to recall a thread on him. Their is one on here that is prob in archive by now as well. Might want to search for his name. Anyway I was going to tell you to look at spikes if you want to save some cash. Aimsurplus has them for around 500 bucks with bcg from time to time. Past that the bravo company uppers are good and I would say fair priced. I pretty much stick with BCM, but I have to agree that Spike's is an entirely acceptable alternative. Particularly if your budget is a little tight. |
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The flip side is that sometimes 1/7 can be excessively fast for accurate use of 55gr projectiles. One of my friends did a 20" build in 1/7 and it simply refused to group with anything below 62gr.
People get so horribly caught up on their "need" for 1/7 and the perceived inferiority of 1/9 that they lose sight of the fact that for most applications and users, 1/9 is almost certainly more versatile and effective. |
| While I understand the twist rates are generally followed by appropriate loads, that can all go out the window if your rifle don't like it. Me and two other buddies have identical bull barrels, 20 inch, 1/9 twist. I hand load my own ammo. One buddy's rifle likes 69 gr, the other 77 gr. Mine likes 55 gr. The manufacturer of the barrels is the same. You have to find the load your rifle likes regardless of the twist rate. |
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The flip side is that sometimes 1/7 can be excessively fast for accurate use of 55gr projectiles. One of my friends did a 20" build in 1/7 and it simply refused to group with anything below 62gr. People get so horribly caught up on their "need" for 1/7 and the perceived inferiority of 1/9 that they lose sight of the fact that for most applications and users, 1/9 is almost certainly more versatile and effective. Well heavier bullets than 62 gn are becoming more popular and for that you need the 1/7. When I shoot centerfire ammo I use 62 and 55 gn, 1/9 work fine with that. Just because I have no need for 1/7 I understand that some do. |
| FN specified a 1/9 twist for their new ammo, the ss109. Colt practically begged the Army to adapt the A2 rifle with a 1/9 twist. The ONLY reason that the Army picked the 1/7 twist, was to stabalize the abortion of a new tracer they developed, named the M856. This is NOT an FN designed bullet. The people who Designed the Issue Ammo and the People who actually design and build the guns, say 1/9 was the best twist. It was the Govt, in the infinite wisdon, that pushed the 1/7. And we all know everything the Govt decides is just the absolute best. All I ever shoot, or will ever shoot, is 55 to 62 grain ammunition. The best twist for those weights is 1/9. The reason, true reason that all of these walter mittys on ARFCOM want a 1/7, is because a few people "in the know" say if you don't have the faster twist, your gun is useless. So anybody who is anybody must have 1/7 to be somebody on ARFCOM. Some people are so fanatical about it that it's amusing. Point is, don't let a "hive mind" of lemming like behavior decide for you. Research you actual useage and realistic goals for the rifle, study the actual science and data of weights and twist, without the clutter of others feelings and opinions, then make your choice. |
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Very true. BUT I did manage to leave with a pair of PMags for $27. Granted, I STILL don't have an upper, I'm stocking up on everything else I need... He also claimed to have filled a "military contract" with 1/9 barrels. He's a bold faced liar. 1/7 is specified by the military's TDP as the only twist that qualifies. Maybe he built on the 1 in 9 bushmasters for Georgia... 
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