case bulge

[Luke45]

Cases are buldging on my 280AI, usually starting out on only one side of the brass. Trying to figure out if its a saftey concern or not. Ive only fireformed and neck sized, total of 3-4 fireing. Barrel is headspaced to .004 crush fit.


Brass is undersized, and chamber is at the high end of tolerance. Sure looks like case head separation, but seems so unlikely due to the ackley design and neck sizing only.

Is my chamber out of round? this gun is extreamly accurate 1/2 moa 5 shots all day.
I asked mcgowan about it, and they said to send it back to them- which i really do not want to do if its something as simple as brass being undersized, or the extractor/ejector holding the case to one side of the chamber durring fireforming.

Has anybody had a similar issue and got to the bottom of it?

[LoneWolf]

i would try new brass and work up a load again. And definitely get rid of any cases that look like the one pictured. If the same thing happen to new brass I would send the barrel back. Remember it's an explosion 4 inches away from your face and not worth the risk of your safety.

[Luke45]

Im in the same boat as you, no need to risk anything. but i just really want to know what exactly is causing it. because if it isnt case head separation or anything, and just the brass being at the low end of tolerance or the extractor pulling the brass to one side of the chamber drurring fireforming, i really dont want to send back a barrel that shoots 1/2 moa

[LoneWolf]

McGowen does good work. I haven't heard of someone saying they didn't get 1/2 MOA with McGowen barrel. Let them fix it.

[Luke45]

http://www.4-dproducts.com/submenu/T...ly%20Bulge.pdf

very interesting read on this topic

[DanSavage]

Winchester brass tends to do that in one of my guns, Federal brass is a bigger diameter where your measuring .4645, and I don't get the bulge. Try different brass and take note if the bulge is still significant, you may need to have the barrel rechambered.

[emtrescue6]

Remove your extractor and try a couple?

[bootsmcguire]

How far up the brass is the bulge line?

[Luke45]

Remove your extractor and try a couple?

I literally though the same exact thing a couple hours ago! Just fireformed them then punch the shell out with a cleaning rod.

And boots, not sure left my calipers at work I'll measure and share tommorow, it's just still making me uneasy

[bootsmcguire]

Luke, I totally understand, after we talked the other night I tried to upload that pic to my computer to get a better look at it and not on my 4" phone screen. Seeing it here enlarged, it does raise a couple of new questions. In your above pic, the bulge looks a bit more prominent.

[FW Conch]

I have the same situation in a 30/06 I have, but it is a $250 Handi rifle. As time goes on, it's going to bother you more and more.

Since McGowan stepped up and offered to replace the barrel, I would take them up on it.

I would expect a better chamber from a stock factory barrel.

Good Luck :-))....Jim

[DanSavage]

Take a look at the case dimensions print for the .280 (google),, where your measuring .4645, it should be .470, the brass is the culprit and being your chamber is showing .4710 it is well within spec.

[Luke45]

Thanks Dan! I'm going to go to the store with my calipers and see if ican find a brand of shells or brass that's closer to .47, and see if it fixes it.