1 in 9 twist. Got questions

My wife's new AR has the typical 16 inch 1in9 twist barrel. We are sighting in in on Saturday and pig hunting Sunday. My question is, what's the heaviest bullet the barrel will handle? I'm looking to over the counter ammo. My choices right now are the Winchester Razor Back in 64grain, Remington Hog Hammer in 62grain, and Fusion 62grain. What's my best option besides buying a box of everything and trying them out?

Any of the bullets you listed will be fine. You shouldn't see any issues as long as you stay under 69 grains. Yes, you could shoot up to 77 gr. but accuracy will start to suffer.

^^^ This.

Perfect. Thx guys

When sighting in my AR, I first tried the 64 grain Razor Backs. My gun didn't like them very much, didn't pattern well at all. Then I tried the 64 grain Winchester Ranger ammo and that was that. Now I'm shooting a group that I can cover with a quarter at 100 yrds with night vision (Pulsar N-750).

Ditto what btp said. Any of those will be fine with a 1:9 twist.
If anyone cares to know, the Texas State Troopers use the 64g Winchester Ranger ammo in their rifles (Bushmaster).

Nobody wants to hear this, but M193 (plain old 55 grain FMJ) makes a fine pig round. It makes a great pink mist...

My 1:9 rock river was key holing at 50 yards with 70 grain TSX. The cheap federal American eagle 62 grain fmj group very tightly. But each barrel is slightly different and what may work in one 1:9 twist may group poorly in another.

I don't know about the others, but the Remington Hog Hammer uses the Barnes TSX bullet. It is an all copper round, and while it may be a 62 grain projectile, it is longer than a 62 grain lead projectile. The 1:9 twist barrel may not be fast enough to stabilize it.

Yep, and so does cheap 62 grain Silver Bear soft point. Much cheaper than the rounds considered by the OP.

Yes, the 70 grain Barnes solid copper bullet is much longer than a 68 or 69 grain bullet that works in a 1:9" twist. Bullet stability and twist rate needed is based on bullet length, not the actual weight of the bullet. Most heavy bullets are naturally longer. But copper is less dense than lead and a 70 grain copper bullet will be longer than a 70 grain lead bullet. So the copper bullet will need more twist to stabilize.

I have a 20 inch SPS tactical it likes 73gr Berger BT and 69gr SMK.

Good looking AR.

I used to shoot Remington 62 grain SP and they work great... Way, way more expensive than the silver bear, though.

Here's a somewhat relevant YouTube experiment involving the 55 grain M193: https://www.youtube.com/watch?v=3kZsS05HX3w

There's an article on the use of Russian ammo vs US ammo in an AR15. I'll see if I can find it when I am on my computer. They put 8-10k rounds through a set of identical factory new rifles. What they found was the copper jacket on the Russian ammo was harder than the US stuff so it would wear out the barrel faster. What you save on ammo, you end up spending to replace the barrel.

Some of the Russian crap is steel jacketed with a copper wash. That will do a number on rifling in any rifle/pistol. You get what you pay for.

That was from lucky gunner... they also ran the ammo so fast that the guns got extremely hot.

Quoted from the article...
"Excessive upper receiver heat did cause thermal discoloration of and cosmetic damage to the EOTech sights. Also, one CR123 battery in the XPS 2-0 ruptured – possibly due to heat"

Lucky Gunner Ammo Test

The barrel is a wear item... If I shoot it out with cheap ammo, I will have saved more than enough in ammo costs to replace it.

All the test gun barrels got hot.

Personally, I spend enough money on the barrel the first time. Don't want to have to replace it.

Even if you save just .04 cents a round, buy the time you hit 10k rounds (which very very few shooters will ever get to In their AR) you will have saved $400 in ammo costs. And you can save way more than that. The .04 was just a number I pulled out of the air. Saving $1 a box is .05 a round. And Russian ammo will be far cheaper than that.

I know all the barrels got hot, but I think that it accelerated the wear. But at any rate, if you shoot it enough, you will replace it.

Did you read the article? The Brown bear accuracy dropped off after 4K rounds and the barrel was considered "shot out" by 6K rounds. If you are fine with 8-12 MOA out of an AR at high round counts, then go for it. Accuracy shooting the Federal didn't drop even after 10K rounds. You can keep on shooting that barrel.

Then wear would have accelerated in all the barrels. And there was the 9 failures in the Brown Bear and 15 in the Wolf. Those barrels were allowed to cool some so the jam/stuck case/whatever could be cleared.

Granted, this was a torture test on the guns to compare ammo. But I think it does show the abuse your barrel takes so the owner can "save" a little on ammo cost. It's your gun, feed it what you want.

You are correct. I did not read the article, but I remember it being posted a while back. Just forgot about the accuracy dropping off. I was just commenting on the statement that it will cost you more in the long run. But even at 4000 rounds a guy shooting a budget AR can replace a barrel with another entry level barrel and still come out ahead, albeit not by much. Obviously, if you bought a high end barrel, it wouldn't make sense.

Also, a lot of AR owners will never come close to putting 4k rounds through their gun in their lifetime. So for the guys who will never come close to shooting out a barrel, it's all savings up front.

I don't shoot steel, but based on the test results in the article - my arithmetic says that you can keep buying new barrels every 3K to 4K rounds and always be ahead financially. In fact if you shoot enough, you could buy a whole new spare AR-15 with the savings!

Do the math based on your own ammo/barrel costs, but cheap steel ammo is running about $0.08 to $.12 per round less than the Federal brass 5.56 brass that many of us use.
Again, pick your own averaged out numbers - but here are mine:
Russian steel ammo .223 = $.27/round
Federal brass cased 5.56 = $.38/round

So if your barrel is shot out at 4K rounds, you have $440 in your pocket to buy a new barrel - because you used cheap steel cased ammo. If you buy a barrel for $340. you still have $100 in your pocket for the next barrel - or more ammo.....

Yes, I know that some folks spend a lot more than that on a barrel - but the test was based on barrels that cost a whole lot less than that! Again, I shoot brass - but I can see the logic of steel for higher volume shooters.

Marc

Edit to add: We use identical S&W MP-15 Sport's for all purpose rifles around the ranch, including truck gun duty. The one I carry in my own truck has well over 2K rounds through it. With 5 adult kids and 8 Grandkids, blowing through 10-15 mags on a family weekend at the ranch, is not uncommon at all.

Again, I buy Federal 5.56/62gr in bulk quantities so that every rifle patterns pretty close to the others. There are some exceptions, but overall it works.

That's exactly what I was getting at. I don't shoot enough to ever shoot out a barrel. So I shoot the cheapest ammo I can find. In my pistols, I'll shoot steel cased, aluminum cased, whatever. When I had my AK, I would only shoot steel through it. When the day comes that I build an AR, I'll do the same. Granted, I'm not a super precision shooter, so it's not as big of a deal to me. Of course hunting and self defense rounds are a different story.

This is my point. The range I shoot at does not allow FMJ, so the cost difference between a brass cased hollow point and the Silver Bear hollow point is enough to replace the barrel every few thousand rounds if needed. The barrel is a wear item... it's like tires. When it no longer will group well, I will replace it.

If I couldn't shoot fmj at the range, I'd find a different range. That go for handguns as well or just rifles? I shoot at the farm, but when I do go the range, their only rule is no metal core.

Rifles only... outdoor range. Pretty standard rule for ranges here in the Dallas area.

Ah ok. That makes more sense then. The only outdoor range I've ever shot at is alpine and that was just to sight a deer rifle in. I'm blessed that I can just drive 45 minutes to the farm and shoot how and what I want, but not everybody has that luxury.

The reason why is that FMJ rifle rounds do not flatten out like a typical lead bullet will. They want to hold together and bounce of things, even dirt mounds. If the gun range is insured (which most or all are), then the insurance company requires them to not allow FMJ rounds. It's not the range's fault.

Well, another thing to think about is that there are many, many hunting AR15s that see regular use but probably chamber and fire less than 100 rounds per year. Those barrels may not start to drop accuracy on their way to being shot-out until they have been inherited by next of kin and are well into their second or even third tenure regardless of what they are fed. I also have to wonder how different a barrel fed a steady diet of 100 bimetal bullets per year for 100 years would look next to one fed 10,000 in a day...

Then again, if you're shooting 100 rounds per year the difference between a $0.27 bimetal jacketed, steel cased cartridge and a $0.35 copper jacketed, brass cased cartridge isn't necessarily that significant either.