Gunsmithing Scratchin' my head

[AKA-Spook]

I had a barrel chambered in .338 X 39 that I took all the time in the world to spin up, Hit all my numbers just perfect. It had .0015 runout at the back end when it was finished.
The performance was "less than stellar" after trying every load I could come up with.
Sooo I'm thinking the barrel is junk.

Just for grins I cut the threads off recut everything and chambered it for 338 whisper and its shooting cloverleafs @ 100.
Never touched the crown and did a pretty hurry up job with the rest of it. I even cut the tenon.005 undersize by mistake. Any idea's?

 

[deadeye]

Re: Scratchin' my head

Reaching here but "less than stellar" with what bullet?

Perhaps the twist rate and the load/s you worked just didn't make the right combination with that barrel - nothing wrong with your work.

 

[former naval person]

Re: Scratchin' my head

OBT

 

[FTF]

Re: Scratchin' my head

Sure hope you figure it out, and let me know. I am ready to cut the chamber for the .30 cal. Fat Bullet/39 that we talked about back when.

Totally ignorant questions, but I have already copped to knowing absolutely nothing about the finer points of "Chamber Reaming"! When you say you were out a thousandth and a half on the rear end, I assume this was concentricity of the chamber to the bore??? Or chamber roundness??

Maybe the Reamer "Bellmouthing"? Floating Holder, tailstock center, or ??

At any rate, "Inquiring&Febble Minds" want/need to know!! )

Thanks,
Emory Jones

 

[PFCSkoug]

Re: Scratchin' my head

What Brass are you using. If it is some sort of russian junk you might want to try some lapua .220 russian.

 

[AKA-Spook]

Re: Scratchin' my head

250 and 300 SMk's...before and fired them both beautifully after rechamber.
rear of chamber indicated .0015 deviation from original centering of bore.
IMI 7.62 X 39

 

[FTF]

Re: Scratchin' my head

FWIW,

Just reading the thread on action truing fixtures, and Roscoe posted a link to a www.Bryantcustom.com article and there I found another article that was about chambering/threading barrels etc. In it, the Bryant fellow related some experience with a barrel that he could not get to ream any closer than .001" out of concentric and that he could not get it to perform after trying twice. He went on to say that in his experience, anything over .0002" TIR wouldn't meet the requirements of "Shooting Well". The overall run down that he employs in chambering is quite exstensive, but a good read none the less.

Thanks,
Emory Jones