possible headspace issue?

[RaunchyRifles]

Hello all!
I was at the range today with my no1mk3 and I fired some rounds through it and noticed the brass looked weird. Further inspections showed a small bulge around the casing. Is the gun out of headspace? should I go to a gunsmith? Please send help

Information

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[smle addict]

Nah... That's normal for the 303 round. If you reload it for it, full length re-sizing will eventually cause case-head separation.

If you don't reload, just enjoy it. I have some cases that look similar to yours, if not worse.

Hope this helps.

[RaunchyRifles]

Thanks that helps a lot. How bad is a full separation?

[smle addict]

Not too bad, so long as you have a stuck case remover on hand. I have one for the M-60 machine gun (I took a couple when I was in the army), and it works well.

See attached pic of over-worked brass. After about 5-6 reloadings, I start to see cracks forming, and throw them in the trash. These got by me, and came apart.

[CINDERS]

I have the same appearances nothing to be overly worried about unless they are hard to extract you may want to polish the chamber very lightly with Iosso paste and I mean lightly as if it is too smooth some suggest the brass will not grip the chamber walls as good and increase bolt back thrust well that is what I have heard. I have snapped a couple or rounds fired from one of my 303's showing the same bulge the first one is on its 5th reload the last case is the one you have to watch out for and this is suffering a partial head separation (bin job, usually they are gone at about 10-12 reloads per case in my rifles). Looks as though you are getting a good seal around the case neck.

You can check your cases by putting a small leg 90 degree bend on a piece of thin wire and sharpen a point onto the tip have it long enough to reach to the bottom of the case place the tip against the side wall and slowly scrape upwards along the wall if you feel a slight indent then this is a sure sign it is on its way (see 2nd pic for approx location).
Others will come along shortly to also assist my advice is based what I have seen on this site and 30 years of reloading and shooting 303's

[RaunchyRifles]

Hmm I guess 303 has a rather short case life, too bad so sad Do you think that annealing would help? I've got annealed 308 casings on the 8th reload and still holding up strong, but it seems that it's not neck splits that shorten 303 brass life.

[Richard Hare]

Just neck sizing helps, but if a case separates it's nothing to worry about, and you won't even know until you jack the hind end of the cartridge out. No gas problems with a L-E!

Had one come apart the other day, so ran the next round in, and it pulled it out . No worries.

[browningautorifle]

.308 and .303 are two very different cartridges and you don't have the same separation problems. .303 is just like that and don't worry about it. Shoot and discard...

[Bruce_in_Oz]

If you ARE reloading, just use a NECK sizer most of the time BUT be sure you keep that set of reloads for use in that particular rifle.

The "working" of the brass, during full-length sizing, in that region where the "disfigurement" is, will lead to rapid hardening of the metal and embrittlement.

Set the neck sizing die to JUST contact the shoulder of the case and NOT shove the shoulder back. It is the regular displacement of brass back and forth, (and "in and out", radially) that "work-hardens" the brass.

The ONLY variation to this regime is that my loads for hunting are usually either on brand-new cases or brass fired ONCE in that rifle. I do not want to be embarrassed by a separated case out in the "woods".

For my .25-303 "wildcat" hunting rifle, the cases are sized to JUST fit the chamber. Most of it is formed from once-fired, ex-mil brass that was primed with LEAD based primers. Reloads on cases previously fired with the original classic Mercuric-based primers (copper-coloured, 1/4" diameter) are a "crap-shoot". Sometimes the cases crack diring forming or seating, sometimes they crack after one reload, a few last four or five.

As for annealing: Necks should be annealed after several reloadings; it depends on the quality of the brass and the initial factory annealing. NEVER "anneal" any part of the case except the neck and shoulder. Cartridge cases are cleverly "hard" at the rear and "soft" at the front. Hard at the rear to stop the primer pocket expanding and leaking high-pressure, super-heated gas back into your face, and soft at the neck to retain the bullet with some degree of elasticity and to expand under pressure to briefly "stick" to the chamber long enough for the bullet to leave the muzzle, and then "spring back" to allow easy extraction.

[Son]

+1 on what Bruce said...
Once "fireformed" to your chamber you can neck size and trim the case to length to reload your cases. Check the neck sized cases will chamber without resistance. Once you get more than a very little bit of resistance closing the bolt on your reloaded case, it is time to full length resize your cases using an adjustable FLR die. Wind the die back until it does nothing, then keep bringing it in a quarter turn, resize the case and check it in the chamber. Once the die is adjusted to allow for easy chambering, lock it off and use that setting for all. This will only work the brass the absolute minimum, and allow you to neck size and trim only for a couple more loads and will maximise case life. I usually get two neck sizes before FLR, then two more neck sizes etc.

Have some cases loaded to MkVII ball spec 7 or 8 times without any signs of failure.
Bear in mind, most commercial brass is made below .303 British Mil Spec in all dimensions including brass thickness. Winchester are the popular pick for the WORST cases in .303BRIT. PPU are known to be good. HXP milsurp rounds seem to have the best cases all round.