1/7 Twist rate / 55gr

[TX69]

So with the change in markets I am curious as to what experience TGT members have with shooting 55 grain factory ammo (M193) through a 16" carbine barrel. I am not interested in getting into heavier bullets but rather checking to see if I can get by with a 1/7 twist barrel (16") while shooting 55gr (M193) bullets. I do have some 62gr M855 ammo that I do not shoot regularly so I am again not interested in buying equipment to suit that round.

Will "all" 1/7 barrels reliably shoot 55 grain M193 ammunition?

 

[PBR]

i have couple 1-7 twist ar's and they shoot 55gr just fine -- now i havent tried out to 300 yds (anything that far i use my ar10's) or more but 100 to 150 they shoot just fine no issues -- yea they might not raghole at 150 or so yds but they all group enough and are kill shots -- im not trying to argue the ol 1-9 is better than 1-7 or vise-versa but personally i dont have any issues with 55gr out of the 1-7 twist but again im not out shooting massive distance out of them either

 

[Bozz10mm]

1:7 seems to do just fine in my PSA AR 15 with 55gr. At least out to 100 yards. That's the longest shot my range allows. Seems to to shoot as well as my Bushmaster 1:9. But I don't have a scope on either. Just a TRS-25 red dot and PA MD-ADS, so my groups are usually 4" or so.

 

[BigBoss0311]

Works great. No issues.

 

[mantawolf]

If you get a good load, should be fine. My barrel won't group factory 55gr ammo, about a 7-9" groups at 100 yards.

Sent from my MotoG3 using Tapatalk

 

[Mowingmaniac 24/7]

TX69,

My 1:7 twist rate on my Colt AR shoots American Eagle (Federal) ammo beautifully.

The heaviest I've shot is 62 grain in three different mfg's ammo and all shoot very well.

Note though, I don't shoot Russian/Steel case ammo.

The stuff I shoot isn't match grade, but good, reliable ammo.

 

[Charlie]

It will work fine. The "longer" the bullet the better it will work in that twist ('cause it's the length of the bullet not really the weight that makes the difference). There are long "skinny" 55gr. bullets and short "fat" 55 grain bullets. The longer bullet needs a faster twist than the shorter.

 

[diesel1959]

None of my ARs or HKs & HK clones in 5.56/.223 have a problem with 55gr and my barrels represent 1:7, 1:8, 1:9, and 1:10ish. No problems with 55gr ever for me.

 

[TX69]

It will work fine. The "longer" the bullet the better it will work in that twist ('cause it's the length of the bullet not really the weight that makes the difference). There are long "skinny" 55gr. bullets and short "fat" 55 grain bullets. The longer bullet needs a faster twist than the shorter.

I thought there was a milspec standard to M193 clone's? My goals for this rifle (as is for my 1/9 rifles) is too shoot past 100 yards. If all I am getting is 100 yards out of this I'll stick with the AK platform for that yardage. My Sabre M5 16" 1/9" rifle has no problems with 300 yard shots (55gr-69gr)but after that I am not sure.

 

[zackmars]

I've only shot 55 gr out to 100, but it works fine, I know people who claim that it works well at least to 300, but that is anecdotal.

However, if you know that all you will ever shoot is m193, get a 1/12 twist, since the military pretty much built it around m193 after reports of poor accuracy from m16's with 1/14 barrels

 

[ed308]

As I recall, the 1/7 was designed for the 62 gr bullets. My ARP barrels are 1/8 and are very accurate with 69-77 gr HPBT bullets. My go to plinking bullet is 69 grs Nosler Custom Comp bullet sitting on 24 grs of Varget with LC brass. I buy those in bullets in boxes of 1000 anytime I can get them on sale for $100.

 

[Charlie]

The 62 grain will work in several twists. The numbers regarding twist rate and bullet length are not finite. The ogive will have a small effect also. Just because a 1/7 was coupled with the 62 gr. bullet does not mean it won't shoot other length bullets. The best way to determine the limits of you rifle barrel, in my opinion, is to load or buy a range of bullets weight (lengths) and shoot them out of the same gun and make comparisons.

 

[35Remington]

My colt 6920 1:7 barrel shoots about 3 MOA.

 

[Southpaw]

i have couple 1-7 twist ar's and they shoot 55gr just fine -- now i havent tried out to 300 yds (anything that far i use my ar10's) or more but 100 to 150 they shoot just fine no issues -- yea they might not raghole at 150 or so yds but they all group enough and are kill shots -- im not trying to argue the ol 1-9 is better than 1-7 or vise-versa but personally i dont have any issues with 55gr out of the 1-7 twist but again im not out shooting massive distance out of them either

Same thoughts and results here.

 

[Charlie]

A lot of commercial manufactures have made several models with the 1/9 twist as it shoots pretty good with a variety of bullet weights (as to other twists but a 1/9 is kinda' in the middle). There are a great deal of variables in accuracy besides the twist rate. One can't accurately say their rifle shoots great (or terrible) because it can only get X amount of accuracy at this range. I try to find the bullet my rifle likes, along with the powder amount, the powder manufacturer, the COAL, the primer, etc., etc.

 

[TX69]

A lot of commercial manufactures have made several models with the 1/9 twist as it shoots pretty good with a variety of bullet weights (as to other twists but a 1/9 is kinda' in the middle). There are a great deal of variables in accuracy besides the twist rate. One can't accurately say their rifle shoots great (or terrible) because it can only get X amount of accuracy at this range. I try to find the bullet my rifle likes, along with the powder amount, the powder manufacturer, the COAL, the primer, etc., etc.

I understand this part. What I was asking is that if say five or so guys come back and say that their 55gr ammo (which ever mfgr) is over stabilizing, exploding, or is only good to 100 yards then I would go a different way in terms of the equipment. Reason being is that "I" do not have the personal experience with the 1/7 twist and have read plenty about its limits. Asking a few questions here costs me nothing and there is a wealth of information to learn from others that in turn costs me nothing.

What has happened is that a supplier has shipped an upper claiming that it was a 1/9 twist barrel and from a certain manufacture. When I opened the box the barrel says 1/7 on it and there are no roll marks to identify the manufacture.

I am not sure if I have been caught up in the shell game of them just trying to get me to accept what they have simply because its an upper. I am not wanting to do that since for over $600 bucks that upper should be what I was told it would be, no?

 

[TX69]

I have started checking barrel mfgrs and even Green Mountain doesn't have what I am looking for which is a bit dis-concerning.

Anyone have a barrel manufacture that they know has the barrel in stock that I am looking for?

Here is what I am looking for:

16" 4150 1/9 twist mid length gas system would prefer chrome lined but any of the newer coating is acceptable. Will consider ALL barrel contours at this point.

 

[Charlie]

I understand your predicament. And ya' never know exactly what you have even with a stamp on it. It could be 1/7, 1/7,5, etc. I've come to the conclusion that the 1/8 is the best compromise for me. It's known to shoot 55, 62, 69, and maybe more, satisfactorily. Good luck. in your search.

 

[BigBoss0311]

Charlie beat me to it. 1/8 might be your best bet. A great 'do-it-all' twist. Plus, readily available from manufacturers in the specs you want.

 

[Charlie]

As BigBoss said, one in 8 and 1/9 are usually the go to twists for shooting lots of bullets.