Is it possible to have a headspace problem with a rimmed case like a 30-40 Krag? I have some R P brass that shows a slight bulge just ahead of the web. I have some Win. ammo too but that looks fine after being fired in it. No signs of a bulge at all. I cut one of the R P cases in half length wise but it looks normal. It doesnt show any sign of thinning at all.

Here's a little about headspace from Brownell's tech section. Often a case will show a slight bulge ahead of the web and be perfectly safe to fire. The best I can say is take it to a gunsmith and have him check the headspace.

Here's the article.

Headspace Gauges And How To Use Them
by: David Kaiser

A question that gets asked over and over on the Tech Help Line is “What is headspace?” and “How do I check headspace?”. Hopefully, this article will help answer some of those questions and provide some useful information on a very important aspect of gunsmithing.

Headspace is defined as the distance from the bolt or breech face to a measuring point within the chamber forward of the breech. With rimmed cartridges, such as .22 long rifle, 30-30 or .357 Magnum, the measurement is to the front of the rim cut. Straight- walled rimless cartridges, such as .30 Carbine, 9mm Luger or .45 ACP, are measured to the mouth of the chamber. Rimless bottleneck rounds, like .223 or 30-06, are measured to a point on the shoulder at a certain specified diameter. Belted magnums, .300 Win. Mag., or .375 H&H, are measured to the front of the belt cut, essentially like a rimmed case.

Checking headspace should be a part of any job that involves action work, especially if the job will require the gun be test fired. Headspace should be checked before any gunsmithing work is done. That way, if an excessive headspace condition exists, the customer can opt to have it corrected before expensive work is done to a gun that may not be suitable for the intended use. Checking the headspace first helps to protect you, the gunsmith, from firing an unsafe gun or from doing work that you may never be paid for if your customer abandons the gun to your shop.

Headspace gauges are used to check one aspect of a firearm’s suitability for use. If the headspace is less than minimum, factory loaded cartridges may not fully chamber in the firearm, the action may not close fully, and it may not fire. If the gun does fire, you could have excess pressure problems, and in the case of semi-automatic arms, possible serious damage to the locking system. It’s possible, with autoloading guns, to have slam fires due to insufficient headspace. If headspace exceeds the maximum limit, excessive case stretching can occur, even to the point of a case rupture or head separation from the case body. Other problems associated with excessive headspace are: failure to fire, misfires, poor accuracy, and very short case life. With rimfire guns and their thin brass cartridge cases, excessive headspace can lead to ruptures of the case at the rim, or even a complete head separation on firing. The sudden “dumping” of powder gases into the action can wreck an action or stock, and in the case of many rifles, send powder gases back along a bolt body to blast the shooter’s face. For this reason, eye protection when shooting is a must!

Modern headspace gauges are made of heat treated tool steel. Even though the steel is quite hard and tough, you must treat the gauges as though they were made of glass. If they are misused, they can break, cause damage to the gun being checked, or can give false readings on the correctness or incorrectness of a particular gun’s headspace and its suitability for use. Our recommendation is that you use headspace gauges in sets from the same manufacturer. An example of this would be GO and NO-GO gauges from Clymer, and not one from Clymer and the other from Forster. Your results will be more uniform if you stick to this recommendation rather than mixing different brands.

Under normal commercial circumstances, a gun whose bolt closes completely on a NO-GO headspace gauge (even if it does not close on a FIELD gauge) should not be put out for sale or returned to a customer as being suitable for use, until the headspace situation is corrected. Keep in mind that a firearm may have perfect headspace, but may have other chamber problems or action problems that could keep it from being used safely.

A bent paper clip used to "feel" that area will answer your question.

30-40 is a great round.

Cheezywan

Could you explaiin the paper clip thing in a little more detail? I'm not sure what you mean

Use it to "scratch" the inside bottom of a fired case. It will allow you to "feel" a stretch ring(if it is present?). The stretch ring would indicate excessive headspace. You can sometimes see it on the outside of the case as well. Appears as a bright ring around the case. This is where a case would likely stretch if it was able to.

Cheezywan

I would suspect its the diference in the brass.as you stated one brand did a the other did not bulge.
put a piece of card stock on head of case[empty] and try to close bolt.if it wont close you would good to go.dont force bolt

I'll add one more thing to Cheezy's fine description. If your cases stretch to much they will seperate and when you eject the seperated case you only get the head and about a 1/4 inch or so. the rest of the case stays stuck in the chamber. These can be a bummer to get out and if you don't know how you can damage a chamber to the point you have to rebarrel.

There is no thinning of the case where the bulge is. I mic'd the cases with my calipers and they are only .002" longer than an unfired case. It seems to me that if they were stretching they would be much longer.

I put a piece of cardboard from the flap of a box of 22 shells on the face of the bolt and tried to close it with an empty case in the chamber but it would not close. The cardboard was .012" thick.

All firearms have headspace, a problem may occur when excessive headspace is encountered. I suspect that most of the hundreds of thousands of surplus military arms sold over the years were never checked for excessive headspace and were used by their new owners. The British Enfields that I own really stretch cases and I correct the situation by backing off the resizing die to accommodate the headspace issue. Many lever action may have a bit too much headspace and are used year after year. Headspace has to be really bad to put a firearm out of action. A lot of folks worry about headspace and I agree it should be addressed, but it is not as serious as some would lead us to believe. All the best...
Gil

It just makes me wonder what would cause the Remington brass to get a ring around it and the Winchester brass shows no sign of a problem at all. Odd isn't it?