M4 Mk2 fired brass problem

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Gentlemen:
I have a 303 Epps built on the above mentioned action. If I shoot case forming loads every thing is fine, but even a load to equal 303 standard loads will leave the brass stretched on one side, and the head of the brass not square with the cartridge. Any ideas?
Thanks
Of course it is a No. 4 Mk 2, it seems I cannot change a typo in the heading.
 
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Probably due to the sloppy 303 cartridge in the expanded chamber? What type/brand of 303 ammo are you shooting?
 
I have Herters brass, as well as remington brass, it happens with both. It is suprising that the brass would stretch on one side. It even happens when I shoot neck sized fire formed brass. When I fire form brass it comes out correct, so I do not think the chamber is expanded.
 
I have Herters brass, as well as remington brass, it happens with both. It is suprising that the brass would stretch on one side. It even happens when I shoot neck sized fire formed brass. When I fire form brass it comes out correct, so I do not think the chamber is expanded.



Perhaps the chamber reaming was out of spec....
 
I have Herters brass, as well as remington brass, it happens with both. It is suprising that the brass would stretch on one side. It even happens when I shoot neck sized fire formed brass. When I fire form brass it comes out correct, so I do not think the chamber is expanded.

Generous chambers, nothing to worry about. Brass will be laying on one side of the chamber, and it expands to fill the rest. That's why it looks lopsided. Again, neck size it and don't worry about it, all normal and all good.
 
I went to visit an 80 odd year old smith, and he looked at the brass and told me my bolt end was not square. I screwed the end off my bolt, he got out his little machinists square and indeed, it was not square. We checked to confirm that the bolt body was straight,We squared the end up in his milling machine, and made a shim on his lathe from a peice of drill rod, leaving the thickness just thin enough that the head would turn to the closed position as it came tight.

After this I fired three rounds, and it seems to be fixed. The brass looks ok.

My next test is to see how many times I can fire a case before it separates. As the rifle was, even with modest loads it would separate at the web, sometimes on the first shot after fireforming. Hopefully this is improved.

I hope that I get the improved brass life from the 303 improved that one would expect. My intention is relatively modest loads, I would be happy with 2400 fps with Steve Regwell's 200 gr bullets. I am using a 95% case full, which is 53 grains of a powder I bought from Higginson's, it is a Norma powder, and is in the 4831 class for speed. I got 2410 fps from this. The recoil is reasonable, even with the brass butt plate on the stock.

Looking back I probably should have got a P14 to make an improved on, as I am very happy with my improved swede 6.5. However the deed is done, and I will do what can be done to make a good shooter out of it. I do like the Lee Enfield action, an its ruggedness makes it the perfect ATV rifle.

The good news is that it did not have an original barrel, and was severely sporterized before I started. Nothing has been changed to keep me from rebarrelling it to an umimproved 303.
 
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