How to ream 9mm throat?

[TedH]

I have a AR-9 and would like to shoot a 147 gr cast bullet. They will not freely chamber unless seated very deep. So deep that some brands of brass will bulge the mid section. Obviously a less than desirable situation, the best answer was to simply deepen the throat.
I'm a little bit handy with tools, so I rented a 9mm throating reamer. It came with warnings about super hardened steel in some 9mm barrels. Well mine is one of the super hard kind, and the reamer wouldn't do so much as put a scratch in it.
Are there other options for throating these barrels?

[Shingle]

If its melonited you can forget it get another barrel. Wilson arms sells a nice barrel with a nice throat. I have six ar 9 uppers that I had to ream due to no throat. Stainless is the easiest to cut. Good luck.

[TedH]

Looks like I need to find a different mold.

[DougGuy]

Carbide is the ONLY thing that will cut the salt bath hardened barrels. Problem with that is no on makes carbide throating reamers, you have to have them custom made, they are 3x and 4x the cost of HSS reamers, you wait for months for delivery, and they go away FAST. Lucky if you get 10-12 barrels out of a carbide reamer before you have to send it and have it re sharpened.

I would get another barrel. It's pointless fighting a barrel with NO freebore, if it was even remotely close to SAAMI spec, you would have tapered freebore before the leade ins and you wouldn't be fighting it.

[Tackleberry41]

More than a few 9mm AR barrels are done this way. A brand new AR stoner barrel from Midway had no throat. It would not even work with factory jacketed stuff. Sort of worked, it would load, but murder to unload as the bullets were jammed into the rifling. Second barrel I bought from another company was not any better. But a standard 9mm tool did fix both of them.

[BD]

Doug, have you throated any 9mm sig handgun barrels? I'm looking at getting a 365 and since I don't own any other 9mm barrels, if it needs be throated I'd send it to you.

[TedH]

I removed the barrel, and slugged the bore. Groove diameter measures .3528", and bore diameter is .3475". SAAMI 9mm groove diameter is .355" +.004"/-.000". Returned it to Midway and replaced it with a 416 stainless barrel. It measures .3552, and shoots very well. Still needs the throat opened up a bit, but that's an easy fix now.