Reamers,1.4 Clymer,1.35 PTG, 300 Aac

[tp555]

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.

[HotLead]

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

[mstarling]

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!)

[L1A1Rocker]

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?

[rsilvers]

Originally Posted by mstarling

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

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.

[robrob]

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.

[rsilvers]

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.

[HotLead]

Originally Posted by robrob

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.

I will only be sending in the barrel for the cut, crown and threading, after I get the SBR stamp. The receiver will be kept in my safe and I will take it to a local class III dealer for engraving.
-jd