AR 5.56 Twist Rate

Sure, we all want 1/7 in order to shoot the heavies, but is it really necessary? Most of the time won't we be shooting the cheap stuff anyway, that 1/9 would work better with? Is 1/8 the best compromise or will the 1/7 shoot anything I want? I'm looking at about four ARs and two are 1/7 and the others are 1/8. I'm still deciding on how much to spend and whether this is going to be a cheap truck gun or something nicer. In any event it's going to be used for plinking (65%), varmints (30%), and maybe deer(5%) and hogs if we ever get any or I go with some buddies. So which rate is best all around?

My 22-250 bolt gun is a 1:8 and I run 75 gr A-maxes. My AR-15 is a 1:9 and I'm fine with that, I'll run 55-69 gr bullets.

So how heavy of a bullet do you want to run?

All I have for AR's are 1/9 twist. They all shoot up to 69 grain bullets very well, but that's just because I've not tried anything heavier in them. For my uses if I want to shoot a heavier bullet, I'll go with a hand loaded bullet in a bolt action with a faster twist or I'll use a .243 Win.

I have 3 AR's, 2 1:8 twist .223 wylde chambered rifles, and 1 1:9 5.56

My experience is in line with what JG said, the 1:9 will run light to medium bullets just fine. But so do my 1:8 rifles, with the added ability to go heavier if I want to. I'd do the 1:8 just b/c I haven't seen a real downside to them.

I'd say 1:7 is unnecessary unless you want to run really heavy bullets, like 80 gr and up, which I personally don't

I think the only reason I'd ever want to run anything over 80 grs would be for deer (as a backup to the backup to the backup rifle), but if I have an accurate load with anything 60-65grs and up in a good bullet, that would do what I needed and the additional weight would be unnecessary. Sounds like 1/8 should do everything I need. If we had enough family hunting at our place at one time that the AR was pressed into deer service, it would likely be at a spot with a pretty limited shot, anyway. And Mills County whitetails aren't exactly known for their incredible size .

Thank you all for your input, gents.

The 1:7 is supposed to be too fast for light weight bullets. I've never tried. If you want to do something like a 36-40g bullet, skip the 1:7. 55g+ should shoot fine.

I think the 1:7 is only a fraction faster than a 1:8 so I don't see the need. I use a 1:8. I get great accuracy with heavy and small bullets.

1/8 wylde

1:7 is used by the military because the have tracer rounds that are very long.

Hence the proliferation of 1:7 twist.

1:8 would be my preferred, but it's not that big a deal.

I opted for the 1/7 when I bought my Stag AR. I was upgrading the gun and the 1/7 was part of the offerings and I thought that there was a small chance I might want to use the heavier round (they actually make a 75gr round)so I included that option, but I have no idea if I'll ever need it.

I doubt you will get an 80gr bullet in a mag. OAL is too long. I could not get 75gr amax in mine, but could just barely get the 75gr bthp. Some 9 twist will stabilize 75gr bullets, I had a savage 12 that would shoot 75s.

I don't know if all Savage .223s are 1:9, but my 14 American Classic is.

Until you start overspinning bullets' structural integrity, there's not a lot of downside to "too much twist." Usually.

Hornady's reloading book says 70-80g bullets require at least a 1:8 twist to stabilize.

It states the same on Sierra 77 grain bullets too.

I recently rebarreled one of my AR rifles to a 1/7. I haven't had time to take it to the range and do the break in but once I do I can get a good indication of shooting the heavier bullets with it. I know anything over 64 grains gets erratic in my 1/9 twist gun and I had and extra one to work with so I thought I would try it for better pig hunting rounds.

Most of mine are 1/7. No problems with 55 to 70+ grain pills.

But, if I were spec'ing a new barrel I would go 1/8. Many think it's a better all around twist for light to heavy.

Were you using PMags? Steel Mags will allow for that little extra room to use 75gr A-Max