Shot a friend's AR yesterday - he was clueless about twist rates, but I informed him last night

[chief38]

I was at the range as I typically am on Friday's and one of my shooting buddies brought his AR out. I had just mounted a Sig brand Scope for him a few days ago and I was sighting it in for him. Don't ask me who the rifle manufacturer is because it was made by a company I never heard of and I already forgot. He told me he paid under $300 for it two years ago when Sportsman's Warehouse opened its new location nearby and had a giant sale. He just purchased the scope I installed for him and he said the scope cost him more than the rifle. After sighting in the rifle at 50 yards this 30 round grouping was the best I could do with the 55 grain, foreign manufactured ammo he had. Yea, it's OK, but considering I was bench resting it with a descent scope it was not all that great.

The rifle performed admirably, the scope was great but the trigger was a horrible nightmare! In fact when I first started shooting the gun I thought I had left the safety on because the trigger pull was so stiff, creepy too. He told me last evening that he wants to buy an after market trigger for it - can't blame him for that! I will say that after firing 150 rounds, the cheap rifle worked 100% of the time without a hiccup, so I'd say it is a reliable rifle and accurate enough for many purposes - just not a tack driver at least with the light 55 grain ammo. With heavier bullets it might really perform - to be determined.

I am certainly no maven on AR's and never owned one - doubt I ever will as I am a blued steel (or at least Parkerized) and walnut guy - lol. I do know a few things about them and for one I am aware that the twist rate and grain weight bullet you shoot does play an important roll in how much accuracy you can squeeze out of it. I sent him the .556 twist rate chart and informed him that the next time he buys ammo for it he should try some heavier bullets which might make it more accurate. We were shooting 55 grain bullets out of a 1:7 twist barrel which is just OK, but not optimal according to the charts. I am an accuracy nut, however he seemed pleased with the groups we shot. While it grouped ok, at only 50 yards from a sandbag rest and with a good quality scope the groups should have been better IMO.

My friend told me he had no clue about twist rates and bullet weight and bought the gun "blindly" because of the ridiculously cheap price. Well, I have informed him so next time he said he will buy heavier bullets. I am now wondering how many AR owners blindly buy a rifle without knowing what twist rate it has, without knowing there are choices and why one might actually care. Below, there is a link to a twist rate chart just in case anyone is interested in looking at it.

We had a fun day although it was really hot and I was not shooting my own guns as well as I usually do. Could have been the heat, the fact that I slept only 2 hours the night before, or just had a bad day - it happens.

5.56 Twist Rate Chart - Bullet Weights & Twist Rates

A 5.56 twist rate chart for reference - we'll let you know what commonly is the best combo of bullet weight and twist rate for your AR-15.

www.ammoman.com

 

[The Kid]

55gr FMJs are generally some of the most poorly made bullets available. They’re oftentimes very inconsistent with much variation in weight. I think most manufacturers know that they are more than likely going to be blasting ammo most of the time and they make or source them without as stringent QC as the more expensive bullets.

I’d bet that a good quality 55gr soft point or tipped bullet would show much better accuracy.

I make it a point to buy only 1-7 or 1-8 twist .224 barrels anymore as it opens up so many more possibilities RE bullets. I have a couple of barrels that shoot groups well under an inch with a variety of quality bullets from 40-77 grains.

 

[Erich]

I hope he appreciates having a friend who can inform him about such things.

 

[rockquarry]

I've never purchased FMJ 55s for use in anything as the 55 FMJ bullets in cheap bulk ammo don't shoot very well. Component 55 grain bullets are (comparatively) so inexpensive I figured they probably weren't very accurate and I don't really know what purpose a cheap and inaccurate bullet serves. Waste of money and time unless maybe for military use.

For those that have a need (?) for a 55 FMJ bullet, Sierra might be the only one worth trying. I'll bet they'll outshoot all the others, but I'm sure they cost more than the lesser bullets.

 

[chief38]

Good suggestions. I am all about accuracy - some people like my buddy arejust happy to hit anywhere in the black. lol

 

[yeti]

I would not have high expectation for a <$300 complete AR. That being said, I am flabbergasted by how well some of the econo AR's run.
Good advice. Spending a little extra for some decent longer bullets in 1:7 or 1:8 barrels usually show pretty good results.

 

[SF VET]

A 1 in 7 twist will group better with a longer and heavier bullet. Try 62 and 78 and it will shoot better. SF VET

 

[S-W4EVER]

I believe barrel twist rates will never be relevant to most shooters. I own several quality AR’s made by ArmaLite, BCM, Colt, and S&W and I’ve never paid too much attention to barrel twist rates or the ammo I shoot, other than no steel case ammo. Close enough for me.

 

[Imissedagain]

Seems like a waste of 30 rounds, unless there was a star, and blowing it away, got your Gal, a big teddy bear, at Coney Island.

Six, five shot groups might be better.
I always keep targets, with 2" black outlined circles, in my range bag.
Use the same ones for my bows, in the backyard.

 

[67tempest]

My 1:8 AR with an 18 barrel is capable of sub 1 inch groups at 100 yards with surplus SS109 62 grain ammo. Matching the right bullet weight to the barrel twist rate makes a huge difference with accuracy. My brother has a Remington 700 in 5.56 with a 1:12 twist, if he shoots anything heavier than 45 grain ammo the bullets keyhole at 100 yards. When using 45 grain varmint ammo you can put 5 rds through one ragged hole at 100 yards.

 

[rwsmith]

That's a little different than when I assembled my ARs. Back then, it was said that 1:7 twist was good for 55 grains on up. I shoot mostly 55 grain BT bullets. But I've got some 65 gr. What I'm going to do is load up some 55 and 65 grain and shoot them the same day. Will I be able to tell the difference at 25 yards or should I wait for when I go outdoors?

 

[HardToHandle]

That's a little different than when I assembled my ARs. Back then, it was said that 1:7 twist was good for 55 grains on up. I shoot mostly 55 grain BT bullets. But I've got some 65 gr. What I'm going to do is load up some 55 and 65 grain and shoot them the same day. Will I be able to tell the difference at 25 yards or should I wait for when I go outdoors?

Each rifle/barrel is it’s own, but I don’t see much difference at 100 yards.

The whole projectile story is fascinating. The 55 grain in 1:12 twist came from the initial development of the AR, generally using a 20 “ barrel. It was a shorter ranged, unstable cartridge. The core cartridge (in military use) would get progressively more stability as time progresses over the next 60 years.

In the 1980s, the 1:7 and heavier projectiles were a mix of desire for (1) more armor penetration, (2) longer range and (3) Belgian marketing of the SS109 loading. Those concepts all made some sense in fighting on the North German plain. I carried National Guard M16s that were 1960s M16A1 receivers that had 1:7 M16A2 receivers on top in the 1990s. Best and worst of both worlds.

As the U.S. did the Global War on Terror, there was a mix of funding, evolving technology and operational use that drove the 5.56 loading into heavier+longer bullets. That was initially pushing bullets into the 800+ yard range in 1:7 twist barrels, but the realization that heavier bullets also worked well in the 10.5” to 14.5” shorter barrel guns that widely saw fielding under the Mark 18 and M4 designations. Those heavier bullets just poke holes at bit better, as long as the twist of the barrels is faster… 77gr bullet is rather unstable in a classic 1:12 barrel.

The long and short is lots history and lots of options.

 

[chief38]

Seems like a waste of 30 rounds, unless there was a star, and blowing it away, got your Gal, a big teddy bear, at Coney Island.

Six, five shot groups might be better.
I always keep targets, with 2" black outlined circles, in my range bag.
Use the same ones for my bows, in the backyard.

I always tried doing that many times at Coney Island when I was a kid in Brooklyn. The guy who ran the concession always managed to find a teeny weenie spot of red! HA! can you imagine actually shooting a real 22 in Brooklyn (NYC) these days - that would never happen! I think they did away with real shooting gallery's in NYC in the late 1960's or early 70's.

 

[LVSteve]

There is a very instructive piece on the Box o' Truth website on AR-15 accuracy. TL;DR version: Run of the mill 55 gr FMJ is rarely better than 4 MOA fodder regardless of the rifle build and scope.

 

[mtgianni]

I have 3 rifles in 223. Twist rates are 1 in 12, 1 in 9 and 1 in 7.5. Use the right bullet for the right task. The TC contender 1 in 12 gets the most use, 1 in 7.5 AR the least.

 

[RebCop]

55 grain bullets can be very accurate. With M16-A1's we qualified back to 500 yards with iron sights and it did fine. That weapon had a 1-12 barrel which is optimum for the 55.

 

[hkcavalier]

1:7 is really only great for the longest projectiles (which are usually the heaviest). Back in "the old days" most ARs were 1:9 because it was a good compromise for the 55gr and 62gr common stuff. But then every Tom, Richard, and Harry seemed to want an M4gery with a 1:7. A faster twist rate is not inherently "better" but some people seem to think so.

Both of my 5.56mm ARs are 1:8 20" guns, one is set up for 75gr Black Hills OTM (semi-bull barrel) and the other for 62gr green tip as it's the pencil barrel and not intended for pinpoint accuracy.