Reamers,1.4 Clymer,1.35 PTG, 300 Aac
 

Got my 300 aac reamer in and checked it out. Measuring it I get the necks are close and the case at shoulder has about .004" bigger on both PTG's. I cut a case gage with the 1.35 ptg.Then cut with the 300 aac.It did cut a hair of metal at the throat and shoulder.
The 1.4 Clymer is the smallest and true to 221 specs.I have a 221 reamer and it fits the gage.I have a 1.4 gage I used for this.So taking the 1.4 into the ptg gage.Only the shoulder touches.No throat cut at all.So the winner here is the 300 aac.The 1.35 ptg is pretty good.I thought the 1.4 had more throat cut,but not so.The 300 aac reamer doesn't cut pretty and needs some polishing.I was disappointed here but thats a mfg issue.My customers can send your barrel only and I will recut it no charge.Case gage also.Happy holiday.

Thanks TP! I am sure alot of other people besides myself were wondering how the chamberings compared. I will send my barrel in for rechambering after the SBR tax stamp comes back.

-jd

tp555,

So ... is it worth having you recut the chamber and gauge for a barrel you built a year ago? And acquiring new reloading dies?

What are the chances factory 300 BLK ammo will chamber and be OK for pressure in the older chamber?

Thanks VERY much!

Mike


(And wouldn't you know it ... just finished 500 pieces of new brass for the old chamber!)

Thanks for doing this. Have you checked out the reamers by PTG? They are also going to produce conversion reamers that do not cut on the shoulder so it will not affect head space. Seems like a safe way to convert a chamber.

http://www.quarterbore.net/forums/showthread.php?t=4642

On edit. rereading this I realize that it IS a PTG reamer that you used. So, what do you think of the idea of using a conversion reamer that does not cut the shoulder?

300 AAC BLACKOUT will have elevated pressure in most previous chambers. 300 AAC BLACKOUT compared to 300 Fireball, 30-221, or 300 Whisper(R) is like comparing 5.56mm NATO to 223 or 6.8 SPC-II to 6.8 SPC - the throat is longer and can generally be loaded hotter. This is the reason why the velocity potential is higher from 300 AAC BLACKOUT.

How much it matters, I cannot say. But yes, if you want to shoot 300 AAC BLACKOUT ammo you want to run a new reamer up it.

Hotlead, you might want to send in your rifle before you get the tax stamp. That way you and your gunsmith are not dealing with an NFA firearm and there's less threat of NFA law violation and liability.

Gunsmiths can work on NFA firearms.

http://www.atf.gov/firearms/faq/gunsmiths.html

Q: May a licensed gunsmith receive an NFA firearm for purposes of repair?

A: Yes, for the sole purpose of repair and subsequent return to its owner.

Fellas,

Gonna be OK to use LC brass formed for the 300/221 but has not yet been fireformed? Going to need new dies immediately or can they wait some?

Gonna send my bbl and gauge back to tp555 but after deer season. Gonna look for bambi the next couple of three weeks.

Don't know about new dies.Old dies will work. Clean up cutting the chamber isn't a problem if you have a delicate touch and have done a few hundred barrels or so. I started making 30/221 barrels in the early '90s.My chambers are close to dead on.So an extra thousandth won't matter. I only need the barrel to work on. My ffl days are over. With the extra room the new formed brass should fit easier. Somebody try it out and tell us. I don't get to play much.I have peeps wanting their stuff and have to work.

Yes, I know, but there is less hassle, less exposure to accidental NFA rules violations (there is a whole lot of fine print), and less liability exposure when dealing with non-NFA firearms. Given a choice it seems it would be best to actually ship and repair/alter a weapon before it's declared an NFA firearm.