I have a rebarreled mauser in 270 win. It groups 1 to 2 inches at 100 yards,but even once fired factory rounds need to be trimmed before reloading. Max case length is supposed to be 2.540in. My cases come out at 2.545 to2.552. Would this be an indication of excessive headspace or some other problem with the chamber?
Many thanks
Rick

This amount of case stretching really seems excessive to me. Do the cases show a bright ring just foreward of the base of the case, or are the primers excessively flattened or possibly even protruding? Have you had any case separations or impending separations? If so you may have a headspace problem, but not always. In any case, I'd first find a good gunsmith and try a set of go-no go gauges for 270 win. This will unquestionably answer the headspace issue. I hope you have checked that you have not excessively oiled your chamber or put some PFTE lube in the chamber as this could lead to excessive brass stretching. Excessively hot loads could also result in the degree of case stretching you describe.-Rob

To determine the headspace of your rifle, simply measure the distance from the base of the fired brass to the shoulder. A comparison with an unfired factory load will give you the relative headspace.

Unless you want to shoot primarily factory loads, rifles with a long headspace measurement need not be altered. Simply neck your .270 up with a 7mm or .30 caliber expander button, then resize until the brass chambers with a bit of resistance. It will now be headspacing on the false shoulder you've created. If you'd rather (and I would) start with .30-06 (or .280) brass and size the same way for the same result.

If it turns out to have excessive headspace, and you reload just form brass from .280 Rem brass. I have done this in the past for a 30/06 and .270 Win that had too much headspace.

All the cases show a bright ring just ahead of the base,factory and reloads alike. I have no case separations as yet. The primers are not flattened or protruding. I will be taking a 94 swede to a gunsmith soon so will take the 270 along to have him check with a set of go nogo gauges.
Thanks for your help. This clears up my thoughts on the issue.
Regards
Rick

If it has excessive headspace, don't fool with forming cases etc. Get if fixed,and have the 'smith that does it set it to min specs.

cricker.....take a paper clip and straighten it out but with a slight end on one end. Use it to scrape the inside wall of the case...if you are in fact beginning to get head separation you will be able to "feel" as you scrape the case. It will be at the same spot the outside ring is. Or you can cut the case length-wise and see it.

Cricker

I STRONGLY advise you NOT to fire the rifle any more untill you have the headspace checked.

Think about this...........When you pull the trigger you are unleashing 50,000 pounds per square inch only a couple of inches away from the only two eyes you have. Not to mention fingers, hands, etc.

It's just not worth the gamble. By all indications you have excessive headspace. There are a lot of people out there who are rebarreling 98 Mausers who don't know what they are doing. Think of the cost of having the headspace checked by a professional as very cheap insurance.

Good Luck

Craftsman

Amen.

I agree with Craftsman. The .270 is a very common caliber. I am sure there are smiths in your area that have the go-no/go gauges to check this. Won't cost much. Having a problem and not getting it checked could be very costly.