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38 Super chamber depth


TMC

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What's the best depth for a super chamber? My gun has had numerous stoppage and I can't figure out why. The brass is new, the primers are even with the brass, some only the slighest bit higher. When the stop occurs the slide will be out of battery about 1/8". I'm thinking the chamber is too short at .897 If I take the barrel out the offending rounds will fall right in, no resistance at all so I know its not too tight.

Any opinions?

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the primers are even with the brass, some only the slighest bit higher.

Primers should be flush, or slightly lower.

They do not have to stick out much to cause trouble.

Mike your brass, that will tell you if the chamber is short.

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Mike your brass, that will tell you if the chamber is short.

This is one of those "why didn't I think of that" moments. I "assumed" (my mistake) that a case of new brass would be consistent but taking your advice I went out and mic'd a bunch of once fired brass and found most are .883 - .887 but a few were as long as .894 So with that any piece of grit would make it too long.

I'd still like to know how deep most smiths set that chamber.

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Todd, that setting is called headspace ;)

You want a value of over one thousandth and under 5-6 thousandthsof breechface clearance measured with sized brass chambered without extractor in place (I used skinny automotive feeler gauges to do the final check). On my 9x21 I checked several batches of brass from the same supplier and then had it re-reamed to be three thousandths over the longest brass I found. I actually stood there with the smith and checked it myself as he made light passes.

It had been set to what a previous smith said was “9x21 standard“ and it was way too shallow for the brass I am using so I did it my way, no problems since. Of course, I have settled on one brass supplier and do not expect to ever change unless they go out of biz.

--

Regards,

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When the stop occurs the slide will be out of battery about 1/8".  I'm thinking the chamber is too short at .897  If I take the barrel out the offending rounds will fall right in, no resistance at all so I know its not too tight.

Any opinions?

1/8" out of battery sounds like a gun problem, not a chamber-depth problem. If ammo drops into the removed-from-gun barrel and the base is below the end of the hood, it fits.

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Thanks for the info. I found that the max case length for Super is .900. I feel I should it be set to the max tolerance on the brass ranther to specific brass that I have. I don't think a gun should be built to only run "certain" brass but any super available. Its not a match rifle.

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Next time it happens take the tip of your knife and push the bottem of the case up and see if it goes into battery.  It sounds like the rim may not be going all the way under the extractor.  One of my guns does the same when sprung to light.

It has an aftec extractor installed by the maker of the aftec (who had the gun before me) so I doubt that's the problem, besides the brass goes under it easily.

Its not always 1/8" out of battery sometimes it much less but still enough to keep it from firing. Its not mag specific, the gun is clean and well lubed, the breechface is nicely polished, the gun is solid with no noticable movement in the slide to frame fit but the slide moves like grease on glass. I'm spumted. The slightly high primers on a few of the rounds that came out of it when stopped lead me to think it must be chamber/brass issue.

Does anybody know how to contact Rusty Kidd?

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Does anybody know how to contact Rusty Kidd?

Call Davids Gun Room In Norcross, Ga.

I think you have an extractor problem. Mine did the same thing. Try removing the Aftec and compress the springs completely for 30 seconds with a pair of needle nose pliers. Squeeze kinda hard, but not so hard you cause the spring to collapse on itself.

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Hi Guys;

A little late on this but I had the same problem with my 38 Super Comp. Would stop just out of battery. Could pull the barrel and the round would drop freely in the chamber. Checked real close and notice that the brass was just a couple of thousands longer than the chamber. Measured the chamber and it was about .899. Checked some of my other guns (this was a new gun by the way) and they were .900 - .902. Out of frustration I reamed the chamber to .901 and have not had the problem since....

Just my experience with this....

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I ream all of my chambers +.003 over max case length ( 38 Super= .903"). This allows room for dirt/carbon (because we all clean our pistols so often) and gives me a little margin for error in case I get a long case. You'll never notice any difference in accuracy, but it will help your reliability.

Erik

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Thanks Bear & Benny that's the kind of answer I was looking for. I knew there had to be a specific dimension for this. I appreciate the other info. but I was looking for a specific number.

Todd

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Guest Larry Cazes

How could a few thousandths long on the brass cause the slide to stay out of battery by 1/8"?? Sounds like an extractor tension issue (too much) or a recoil spring issue (too light).

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Here's an update for those who care. I had the chamber reamed, its now .905" and the gun ran 100% today with the same batch of ammo that gave me problems a few weeks back. It looks like that was the problem.

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