New barrel advice

[JohnyRingo]

Ask your smith to give you the specs for the reamer he used? He should at a bare minimum be able to tell you the neck diameter. Most reamers have a drawing number on them, Many are marked with neck dia and freebore right on the reamer or it is marked "Sammi" Or "CIP" which will be easy to look up.

Many reamers will also have revision numbers on them too.

I also agree with another poster who said that opening the chamber another .0005. was not the right approach, Magnum chambers should be cut as tight as possible and still function. Magnum brass when it suffers a case head separation always breaks just ahead of the belt, This is because it headspaces on the belt, So different FL sizing dies may place the shoulder datum slightly differently but the case always flows from the belt unless it was neck sized.

I trust my gunsmith. He said he could barely get the bolt closed on a factory round, so he went another 0.005". It was a brand new reamer and this was its first chamber cut.

 

[Harry Knutz]

The difference in length between most go and no go gauges is 0.004 Just sayin.

 

[rdr59]

Maybe the Smith said .0005.

 

[JohnyRingo]

Maybe the Smith said .0005.

Yeah, I don't really remember. He did say that the bolt was really tight (too tight) on a factory round and he said he was going to go back in with the reamer a little further. I know the bolt still closes pretty tight, so it couldn't have been too far. I trust this guy. He shot that round through it and there was nothing to see on the spent case. I haven't had a chance to shoot it yet. I just got it back and cleaned the barrel. I'll be shooting it this weekend.

 

[JohnyRingo]

He did say "Five, ten-thousandths"... 0.0005" .

 

[dougduey]

Went through this a couple of years ago when I had my smith rebarrel my 6.5-284 Norma from the factory barrel to a Krieger. None of my FL sized old brass from the old barrel would fit. My smith basically yelled at me to always use new brass for a new barrel.

 

[Lee7588]

Have you measured your reloads and compared to the new brass?

 

[Teri Anne]

Yep. He even went another 0.005 in with the reamer to make sure the factory ammo fit. I was just hoping that the 100 or so rounds of reloads and brass weren't wasted. New brass for this 300 H&H are $100 for 25 and there isn't anything available. Luckily, I have about 50 rounds of factory ammo to start over with.

A friend of mine ran into a similar issue a few years ago with a 30-06. He full length resized his cases and the problem disappeared.