40 headspace

[Flyin40]

The gunsmith just emailed me and stated the headspace is .10 over maximum. It seems the guy who originally built the topend screwed up. I only shot it about 10 times.

What does this mean exactly and what are the options or is the barrel ruined???

Flyin40

[wide45]

I had a .40 barrel that was about .01" past max. It ran fine, and showed very low pressure signs.

Yours is close to shooting a .40 in a 10mm. It can be done, and few say it is dangerous, but reliability must suffer.

My bet is that a round will eventually get in front of the extractor.

You could rechamber it to 10mm, but the cost of brass will amount to more than a new barrel if you shoot it as much as you should.

I'd get a new barrel, and check very carefully for other problems.

EDIT

Just saw your other post. This is an open gun. You will be wanting to run light bullets at high pressure. There is no way I'd run that barrel with that much headspace.

[Flyin40]

I talked to the orginal gunsmith of the topend and he stated he would buy me a new barrel. He said he would need to check it out himself and if it was it would be no problem.

Flyin

[wide45]

[benny hill]

From the hood to the case, it should be about .007 head space.

[Flexmoney]

From the hood to the case, it should be about .007 head space.

Benny,

I've never check to see how much 40 brass stretches and shrinks in length (had to grab a reloading manual).

I am reading that a 40 case ought to be 0.850, so you are recommending 0.857 then?

Or, is it better to stick some of your actual brass in there and just measure the difference?

(BTW, since I have my book out... 10mm cases are 0.992)