Definition of Case Bulge

[ocabj]

I'm new to the reloading scene (just ordered an RCBS single stage kit and various other accessories, ie: tumbler) since I've been shooting a little bit more often (and due in part of me purchasing my first .45acp). Most of my reloading will be .45acp, 9mm, and .223.

I was wondering what exactly a case bulge is. My curiosity was peaked mostly by posts in various forums about Glocks and .40cal and most mentioned case bulge as a reason why people didn't like to load Glock fired .40 cal brass.

I was assuming case bulge was simply the brass expanding beyond spec. But wouldn't the resizing die fix this issue? Or am I totally misunderstanding this issue?

 

[PaulS]

Ocabj,
Case bulge can be repaired with full length sizing BUT in certain firearms the bulge is related to an unsupported case in the chamber and the bulge is large enough that the case is compremised. Sizing it hides the damage and the next firing can rupture the case.

Most weapons will allow some case bulge but not to the extreme that the Glock allows. My 03A3 (3006) has a chamber that allows the brass to bulge but I don't worry about fl sizing because it is a bolt action that has no problems associated with the case expanding to fill the chamber - as long as I don't work the brass back into "factory" spec dimensions.

PaulS

 

[trapshooter]

ocabj,


PaulS pretty much covered it. It can be a problem in any case/firearm combination where the rear portion of the case is unsupported totally within the chamber and heavier powder (higher pressure) charges are used. If you don't already have one, buy a 'good quality' vernier caliper. This will allow you to measure all case dimensions accurately. You can compare these to spec before and after firing in your gun, which is the relevant issue for you.

Many sources for these, and other useful measurement tools.

Most, if not all, reloading equipment manuf. offer calipers. You can also get them from a number of 'outside sources, like Brownell's, Dillon, etc., ot at places like Midway and Midsouth Shooter's Supply that cater to the reloader.

I would recommend metal calipers, not the less expensive plastic ones, and if you have the extra bucks, I'd get one with the digital readout (less chance for 'operator error', once you learn to use them).

Useful links:


Brownell's

Midsouth Shooter's Supply

These are just a couple I have handy, there's a ton more.

Hope this helps.

 

[ocabj]

Ah. Good info to know.

So is there a book with a list of the max. acceptable "bulge" or case expansion for the various calibers? I also ordered the Speer Reloading #13 manual from midway. Should it be in there?

I was actually looking into a digital caliper. I have a few "analog" calipers in my garage.

 

[mete]

There is no absolute when it comes to bulged cases . Bulging thins out the case , resizing brings it back to size but hides the damage. Eventually the case ruptures. It varies as to chamber dimensions and pressure. Keep count as to number of times the case has been reloaded and cut open a case each time you reload to check thinning . This will give you an idea of how many times you can safely reload for a certain load in a certain gun.

 

[cheygriz]

With modern guns, to the best of my knowledge, case bulging is only a concern in Glock factory barrels chambered for .40 S&W and 10MM. 9MM, and .357 Sig Glocks are just fine with the factory barrel. My .45 ACP Glock 21 bulged cases, but most Glock .45 barrels are fine.

In my .40, 10MM and .45 Glocks, I solved the problem by replacing the factory barrel with an aftermarket barrel.

 

[Jeeper]

Some case bulge CANT be fixed with full length sizing since the sizing die doesnt go all the was to the base of the case due to the shellholder. There is brass that wont fit in certain guns after it is sized due to this. One other thing I would suggest getting is case guages. They are basically a metal sleve that you check your brass in after it is loaded. They are very usefull and available in most catalogs. I know that dillon sells them. It really is only a problem in trying to fit 40 glock brass into any tight chamber. I have never had a problem except in 40.

 

[kidcoltoutlaw]

does anybody have a pic of a glock shot case. what does the smile look like .i have an idea but have never seen one.i did buy some once fired brass from wideners.im sure some of it must be glock fired but i have not seen a smile on any yet,thanks,keith

 

[cheygriz]

does anybody have a pic of a glock shot case. what does the smile look like .i have an idea but have never seen one.i did buy some once fired brass from wideners.im sure some of it must be glock fired but i have not seen a smile on any yet,thanks,keith


__________________

Kieth,

Sorry, I don't have a picture. The "smiley face" is usually a bulge at the chambers' six o'clock position.

The bulge that I experienced with my Glock barrels was all the way around the case. The entire rear portion of the chamber is quite large, not just the "unsupported" six o'clock position.

You can tell if your brass is "Glock fired" by the square firing pin indentation. Brass that is "once fired" in a Glock may be useable in other guns. You would need to try it.

The bulge can be completely removed by "roll sizing." The case is placed in a special machine that resizes it from the mouth to the rim. Bear in mind, however, that if the bulge is large, as in the case of many Glock barrels, the case is weakened, and roll sizing only serves to cover up the original problem.

A quality case guage is the best method of determining whether or not you really want to keep a case, in my experience.

 

[kidcoltoutlaw]

i took my .40 S&W barrel off and the cases fit in no problem at all.that is the un fired cases fit in before going through the die.i shoot them in a SIG p229 or p239 or an HKUSPC with a barsto barrel.to me the .40 is very tame but then again i dont push it like i sometimes do the 357 SIG.