Home Forums Hunting & Shooting Gunsmithing Cuttign an improved chamber with a hand reamer?

Thanks for the clarification Butch, got your PM too. Sorry for the misunderstanding, carry on.

Steve, you continue to show your petty nature. I guess it really hurt your feelings that one time I disagreed with you. Maybe someday you'll get over it?

You're going to make me cry. It's really too bad that you are such a pompus ass.

Learn to get along with people or hush.

I hope my story helps

In 2002 I paid for a Jet 13x40 lathe and Clausing mill and put them in a buddy's garage.
My plan was 4 of us were going to build Mausers rifles and go deer hunting.
I got 4 Lothar Walther light varmint barrels and a 257 Roberts Ackley reamer from Brownells.
My rifle was first.
We used a new piece of Winchester 257 Roberts brass as the headspace gauge.

When I shot the rifle, the brass broke.
It seems the firing pin pushes the 257 case forward until the narrow ring at the base of the 257RA chamber makes contact.
That narrow ring makes a cut into the brass before it stops the brass forward movement.
The brass goes too far forward.
When the powder goes off the case expands and sticks to the chamber wall.
The back of the case is pushed back by the pressure.
This lengthens the case beyond elastic deformation into plastic deformation [it is not going to return to previous shape].
The brass was so deformed, it cracked.

I learned that if I put 10 gr pistol power in the case and covered with cream of wheat, there would be enough 40 degree shoulder formed on the next firing of that brass... to stand up to the firing pin push.

I warned the other guys. They headspaced 0.004" tighter and never had a problem.
In 2018 I chambered a couple 280 Ackley rifles. I used a PTG go gauge to headspace. Many deer died, but no cases failed...the Nosler brass was already formed:)

ClarkM - Lubing the cases can help, but ultimately cutting the barrel back .004 are whatever is required to get that is the best option.

What is the length of a go gauge for 280? If my faulty memory is correct it is only about .002 shorter at the SAAMI minimum?

The "GO" gauge of the parent cartridge is the "NO GO" gauge for an Ackley chamber. This allows FACTORY ammo to safely chamber and fire form in a improved chamber. Only new brass or factory ammo should be used for fire forming in your improved chamber as they both are rounded at the base of the neck. This is required for safe fire forming. Brass previously fired in a parent chamber lacks the rounding at the neck base needed to support fireforming but a expander one size larger can be used on previously fired brass then carefully neck or partial size leaving the larger diameter neck junction...hope this helps

I've rechambered a couple 223 barrels to 22-204. I leave the barrels in the action and have a bushing on the reamer handle that fits the action to keep the reamer straight. I've put a 6mm pilot on the reamer and opened a 6x47Rem to 6mm-204 again it worked perfect.

Hell, it ain't difficult, Bubba does it all day long and his come out perfect

Grey dog is dead nuts, better listen if you want a quality job.

Why pay someone and wait for 6 months for something you can do yourself in a couple hours. You just have to know your limitations.

Can't argue with that logic BUBBA he should know