Need help with my AR

smores · Nov 22, 2007

When I had my AR upper built at the Chantilly show (from Tony's Custom ARs), I forgot to ask what caliber/twist rate my barrel is.

There are no markings on the barrel anywhere, it's an 11.5" heavy barrel (thicker under the handguards than the exposed section) with a 5.5" CAR-style permanently attached flash hider. I'll look closer for markings but I really can't find anything.

Is there a way to tell the difference between 5.56 and .223 by looking at the chamber somehow?

GunnyHwy · Nov 22, 2007

Run a patch or a bore brush down the entire lenth of the barrel. Put a mark on the cleaning rod and see how much it turns then divide into the barrel lenth and you will have your twist rate.

coinboy · Nov 22, 2007

I was told the easier way. This is thanks to KernelKrink from the Ak Files:

"You can measure rifle bbl twist easily. Insert a cleaning rod down the bbl with a tight fitting patch on it. When you reach a point a couple inches in, use a sharpie to make a mark on the rod at muzzle level. Make a second mark as a vertical line up near the handle, facing directly at you. Push the rod down until the vertical line is once again facing you directly, this will complete one turn of the rifling. Make a second mark on the rod at the muzzle level. Withdraw the rod and measure the distance between the marks. The result is the one turn in XX inches."

coinboy · Nov 22, 2007

As for the caliber I have no way of knowing how to tell you how to figure it out. Did you take off the handguards and look at the barrel under them? Sometimes they like to hide the info under them.

mdjamesd · Nov 22, 2007

This thread is useless without pics!

Numidian · Nov 22, 2007

Pop of your handguards, the caliber will be engraved on the barrel.

It's very easy to pop handguards off btw... Just pull down on the ring at the reciever and pull your two halves out. I've found it's best to put the stock of the gun on my thigh or sit indian style and put the stock on the floor, then use both hands to pull the delta ring back and then once it's back, I can hold it with one hand while I pop off the shells

smores · Nov 22, 2007

I've pulled the handguards off (I used to be in the Army and ROTC, I've disassembled the M16A2 hundreds of times), and still nothing. The barrel is totally naked from what I can tell. I've heard sometimes it's marked under the barrel nut, but I don't have the tools to disassemble it down that far.

I would put some pics up but my bro's gf stole my cable for my camera. I don't know if I'd get good enough resolution on a camera phone, but it may come to that. I'll try the twist trick, sounds simple enough!

SigMatt · Nov 22, 2007

Twist is 1:9. All of the 11.5 inch barrels listed on his site are 1:9. My barrel in the exact same configuration is likewise 1:9.

Caliber is harder to tell without marks. Assume .223 for safety. All that will mean is you can't fire military surplus or milspec ammo out of it. Given that almost all of the ammo I shoot is commercial loading (Federal American Eagle .223) and almost all of the ammo you get off the shelf will likewise be the same, it really isn't that big of an issue. Just avoid the stuff marked as 5.56mm (SS109, M855, M193) until you know you have a 5.56mm milspec chamber vs. .223 spec.

You can't tell by looking. It is all about the steel and how the barrel was made. Chamber pressure is the difference and the only way to truly find out if you have a .223 chamber is to shoot military loads through it. If it blows up next to your cheek (assuming you survive), you'll know you had .223. If it doesn't, it might be 5.56mm. At least, until it blows up on you in the future. Get an answer to be sure.

My barrel has no marks. I ordered it to milspec so I am really trusting the vendor to have gotten it right. Most barrels are made with 5.56mm chambers. It doesn't cost much, if anything, more. Mine didn't. Price was the same for .223 or 5.56. All my guns are 5.56.

His site doesn't give specs on the chamber. I say give him a call tomorrow. Phone (419) 822-9578 • Cell (602) 432-9583.

Matt

SigMatt · Nov 22, 2007

smores said:
I've pulled the handguards off (I used to be in the Army and ROTC, I've disassembled the M16A2 hundreds of times), and still nothing. The barrel is totally naked from what I can tell. I've heard sometimes it's marked under the barrel nut, but I don't have the tools to disassemble it down that far.

If you want to tear down that far, I have the tools to do it.

Matt

smores · Nov 22, 2007

It's funny because I definitely asked if the barrel was chrome-lined or moly, and he said moly. I have no idea why I would forget to ask about chambering... I guess I figured it would be stamped on the barrel, since he had a couple dozen of them sitting up there and probably wouldn't know off the top of his head.

I know .223 is gonna work fine. That's all I have on hand to shoot right now anyway, and I've read all about 5.56 vs. .223 and know well enough not to shoot 5.56 unless you know your gun is chambered for it.

Thanks for the contact #'s, I could have sworn I had his card, but misplaced it. I'll definitely call him up and find out what's up.

Not that it matters much, but ylfotevoli received his 20" HBAR A4 upper from RRA and the barrel also appears to have no markings on the barrel.

Again, thanks guys for the help.

zoostation · Nov 22, 2007

I would think odds are it's .223. When I went barrel shopping a couple months ago neither Midway nor Brownells had any barrels with 5.56 military chambers available. It was much harder to find barrels chambered in 5.56 at most stores. I ended up having to buy one direct from Oly. Reason is the .223 is so much more popular with civilian shooters, I guess for that tiny extra bit of accuracy.

Numidian · Nov 23, 2007

My J&T barreled upper is 5.56 marked

smores · Nov 23, 2007

I'd prefer to have it 5.56, but I wouldn't mind .223, since again pretty much all ammo available to us is .223. But there's that chance that 5.56 starts popping up, and what if it's cheaper than .223? I'll be wishing for that 5.56 chamber!

But it's ok, since my AK is chambered in 5.56, at least I have one military-chambered rifle

I'm gonna call these guys soon, it's still early and I don't want to be that guy that calls when the shop is opening up or whatever

E.Shell · Nov 23, 2007

smores said:
. . . Not that it matters much, but ylfotevoli received his 20" HBAR A4 upper from RRA and the barrel also appears to have no markings on the barrel. . . .

I just tore down a (alleged) RRA free float upper assembly and the barrel was stamped with the rifling twist under the float tube's barrel nut. I've never seen the "chambering" marked anywhere except on top of the barrel, forward of the front sight assembly, but the twist rate seems like it can appear almost anywhere. . . Not worth tearing one down, IMHO, to see only the twist when it's so easily measured.

smores · Nov 23, 2007

E.Shell said:
I just tore down a (alleged) RRA free float upper assembly and the barrel was stamped with the rifling twist under the float tube's barrel nut. I've never seen the "chambering" marked anywhere except on top of the barrel, forward of the front sight assembly, but the twist rate seems like it can appear almost anywhere. . . Not worth tearing one down, IMHO, to see only the twist when it's so easily measured.

I've only got about 1.75" of barrel between the FSB and the flash hider, and there's nothing there. I know that's where the military barrels are stamped.

I tried calling Tony's but got some weird voicemail...

Maybe I'll look around on arfcom or something

Need help with my AR

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