Home Forums Hunting & Shooting AR and Tactical Rifles Bullets for a 1-7 twist

I'm new to the AR world and have a new 5.56 AR carbine with a 16" barrel with a 1-7 twist. It's a PSA upper with a barrel supposedly made by FN. I haven't shot it yet since ammo is hard to come by (at least not at rip me off prices) and finding small rifle primers to reload is even more challenging. However, I just purchased some GECO ammo (made in Switzerland) that has 55gr FMJ bullets that the box says has a velocity of over 3300 fps (I can't remember the exact velocity that is given). My questions are as follows: What can you tell me about this ammo, i.e. is it good stuff or not, and at that velocity would you expect accuracy in a 1-7 twist to be poor? Keep in mind I realize that the setup I have is not a match grade rifle so I'm not expecting to shoot incredible groups, I'm just wondering if it is even reasonable to expect decent accuracy with a 55gr bullet. More experienced shooters than me with ARs keep telling me not to expect much but I always was under the impression that you couldn't overstablize a bullet, so that the fast twist wouldn't be a big hindrance to me shooting 55gr bullets. I've also heard that using bullets less than 55gr might result in them coming apart at high velocities with this rate of twist. Is that true also in your experience?

Lastly, which particular bullets would you recommend I look at for reloading with the rate of twist I have on this carbine? At this point, my only goal would be to achieve the best accuracy on paper that the carbine in capable of, not for hunting or self defense or any other purpose. Just target shooting.

Thanks for the help!

The 1/7 twist is fine for 50-55 gr bullets, however the chrome lined PSA/FN barrel isn't known for accuracy nor is most FMJ ammo. Usually XM193 runs about 1.5-2" groups I don't know anything about your ammo.

I like 77gr bullets in the AR but have shot a ton of 50 gr NBT's as well. 1/7 is my favorite twist for the 223 especially in a carbine.

I've spun apart bullets in a 1in7 twist chrome lined Colt. The jackets tore apart, and the bullets either vaporized in flight, or created huge (1'+) groups downrange. My rifle did this even with 55gr Winchester FMJs if shot at over 3000fps in a 20" barrel. But that's a relative oddity. Many people shoot 50gr HP varmint bullets in their 1x7s just fine.
It's possible that your 1x7 could destroy bullets, but besides the twist it depends on how rough the bore is, condition of the bullets, velocity, and the type/construction of bullet as well as weight. No one here can tell you which bullets will work for certain, and which will fly apart in your rifle. The safe answer is to avoid thin jacketed varmint hollow points under 50-55grs when shot at maximum velocity. Thicker jacketed bullets like the 52/53gr SMKs almost always work fine. Even my Colt shot those well.

Curious to which bullets you had come apart. I want to be sure and stay away from them.

I've had a good half dozen Colt barrels along with a few Noveskes and never had a problem but mine were always carbines and I ran them at 31-3200 fps. Some of my Colt barrels had more than a few rounds down them.

This is why I ask the question...some people swear to their maker that you're nuts to even try to shoot anything less than 60gr bullets in a 1-7 and others say they never have a problem. Guess I'll see for myself. Somehow, though, I just don't see a 55gr bullet flying apart, but then again I have no experience to draw on with this caliber and cartridge. By the way Poodleshooter, I understand that no one can tell me what my particular rifle will do, I was just asking if others avoid bullets less than 60gr in their 1-7s or if the guys I've talked to are just full of it.

It just depends on your 1/7.

I"ve had thin skinned 64 bergers come apart in my 6.5 twist.

But in the 6.5 I've also shot quite a few 52s...

I just won't shoot junk like FMJ so can't help you there. At the worst, cheap bulk softpoints every time over the FMJ.

7 twist is one of my favorites, it will shoot 52/53 thick jackets. It will do great wtih 68/69. Shoots all of the Barnes versions. Works great with all the 70ish grain mag length loads. And does super fine with 80 single loads.

Can't beat taht IMHO. And I see no use in light bullets unless was limited to short range shots.

BTW the roughness of the tube and throat can have a LOT to do with it.

I blew up 64 bergers even in a smooth 7 twist Krieger once... buddy had em for his 9 twist and they were hot loads... I forgot all my ammo at home. Never had a single hit at 200 offhand. But won the sitting rapid, prone rapid and double prone slow regional match after I switched to his 77s.....

Last year I was loading and shooting 40 grain VMax bullets out of a 1-7 FN barrel at warp speed, no issues and they are very accurate.

rost,
Can you identify some of the "thick jacket" 52/53gr bullets for me? What about the 55gr Nosler Varmagetton or the Sierra 52gr Matchking? Do you consider those to be thick jacketed? Would you go with the Sierra 65gr BSP Gameking over the above two in a 1-7? Thanks for your help.

the only ones we used that I know work were the sierra matchkings. Match bullets almost always have a thicker jacket.

Sierra 60 jhp flat base super accurate, but thin and will blow in my 6.5s but not my 7 twists.

I'd have to assume that antyhing AMAX would be ok, but anything VMAX would not be.

Choice of bullets depends on what you are shooting at.... IIRC the 65 SGK is a hunting bullet hence a thick jacket

All we ever mostly shoot are match bullets, and will use them on game without hesitation, never had an issue there. And Barnes bullets. As far as I'm concerned when it comes to hunting game bullets there are Barnes and no others.

For what it's worth I've loaded 100 of the Sierra 65gr Gamekings to max load in the book we were using, and they grouped well out of my 16" 1-7 chrome-lined 5.56 chambered carbine. We do not have a chrono to test MV so I can't give you that. I'm not an experienced hand loader, I don't even own any equipment of my own. My BIL was doing it with me and we just used a max load straight out of the book for that bullet and I was satisfied with the accuracy given the optics and standard mil-spec type trigger I have in this fighting/working grade rifle. I intended to run that bullet through a mule deer or wolf, but alas I do not have terminal performance reports for you on game. It did expand, hold together, and track straight through 2 walls of a 16 gauge steel truck box, 2 phone books, and an old 2x6 plank though...again FWIW.

Oh and I shoot cheap 55gr fmj's all day long, with combat accuracy (easily 1.5-2"), thru this rifle as well.

Thanks, rost and 68W. Your information is greatly appreciated and very useful to me.

It's been 5-6 years since I sold the rifle. I know that the Winchester 55gr FMJ-cannelured bullets failed routinely, probably due to poor bullet construction. I bought a 500pk of them to load for plinking, so that was irritating. I think I had a problem with Sierra Blitzkings, but I can't recall the weight; probably 50gr. I remember that the 52 and 53gr SMKs worked perfectly. I used those for CMP reduced course. 60gr Hornady VMax also worked well if I needed a varmint bullet. I shoot 1x 9s now since I don't have access to a range over 300yds. I'm not shooting 90gr VLDs, over magazine length loads, or M856 tracer, so I don't need the 1x7.

I'm thinking or hoping at least that twist had less to do with your blow ups than a bad barrel.

I've shot a few hundred of the blitz kings in 50 gr in a Colt 1/7 with no issues and I'm pretty sure I shot some Winchester White box 45 gr hollow points in the same barrel. I know I shot them in a 1/8 Krieger.

I've had a few Colt 16" pencil barrels and 1, 14.5" Colt barrel along with a buddy who has a few himself. I used to shoot 40 and 50 gr bullets at coyotes and was always looking for a "better" bullet. My buddy still prefers the 50 gr American Eagle hollow point, which I know I shot at least a few thousand rounds in all of my AR's cause we ordered them by the case for $149/1000 shipped. We ordered quite a few cases and shot them for everything.

But I shoot 77gr SMK's or NCC's now, they handle wind better and kill very well, that's why I like 1/7 twisted barrels.

my 1 in 7 twist was on a bolt action... but it would shoot any 22 cal bullet except the fragile ones... from the 35 grain Lead Free to the 80 grain match bullets...

Sierra Blitzes and Hornady SPSX's would vaporize about 10 to `5 ft out of the barrel, even when it was 100 degrees outside, they would look your breath's vapor on a cold day....

Regarding the 60 grain Sierra HP and the 65 grain SGK: I shoot both through my 7 twist Colt with no problems. I use those bullets in that rifle as well as 2 8 twists, a 9 and a 10. Same loads in all five work just fine and really simplify life. The 65, IME is a pretty decent deer bullet.

There is also this bit of info, backed up by more than one AMU unit, that if shooting the heavier pills, the 7 produces better longer range groups more consistently, than what a BR shooter would do , IE go to the least twist required.

I know that in comparison a 7.7 twist vs a 7 twist and sample of lets just say more than one sample, that the 7 gave us consistently higher scores and smaller groups on the 600 yard line. The 7.7 should suffice. The 7 should be overstable...

Dont' know why, just did and so roll with what works vs arguing how it should or shouldnt by calculation etc...