The cases are neck-sized (Lee Loader) Prvi Partizan with WLR primers. The load is a minimum charge of Varget (weighed out) as advised in the Lee Loader insert chart, over a 174gn Hornady FMJBT, seated to the Cannelure.
Before starting, I had fired 28 minimum loads with similar features, except 150gn Hornady SP's, likewise seated to cannelure. I then started on the 174's.
At about the 10th round into the string of 19, I started getting failures to extract. No sticky bolt lift, no hard tugging, the bolt just came straight back and the cartridge stayed in the chamber. Passing a clearing rod down the barrel got them out with practically zero effort. The primers looked fine. After each one of these, it would load, fire, extract a few more without an issue and then the problem would repeat itself. Reclosing the bolt on the empty case and attempting re-extraction did not solve the problem.
Suggested causes:
1) Extractor is stuffed (most of these cases have seen three or four reloads already).
2) Brass is stuffed & extractor is not binding.
3) Chamber is overheated and binding on the brass; extractor claw is slipping off.
I understand from speaking to the gunsmith who built the rifle that the barrel was "donated" from a P14 and then fitted in some Frankenstein fashion to the Lithgow SMLE receiver. I shot 40 rounds from it a couple of weeks ago without a hassle, though there was quite a bit of time between shots on that occasion. Looking at the fired primers and judging from the rounds that extracted and ejected cleanly (no sticky bolt lift, extraction smooth and effortless when it worked), I do not think I have pressure problems.
Maybe it's time to just invest in a huge quantity of new unfired .303 Brit brass and take the hammer to all this stuff?
Before starting, I had fired 28 minimum loads with similar features, except 150gn Hornady SP's, likewise seated to cannelure. I then started on the 174's.
At about the 10th round into the string of 19, I started getting failures to extract. No sticky bolt lift, no hard tugging, the bolt just came straight back and the cartridge stayed in the chamber. Passing a clearing rod down the barrel got them out with practically zero effort. The primers looked fine. After each one of these, it would load, fire, extract a few more without an issue and then the problem would repeat itself. Reclosing the bolt on the empty case and attempting re-extraction did not solve the problem.
Suggested causes:
1) Extractor is stuffed (most of these cases have seen three or four reloads already).
2) Brass is stuffed & extractor is not binding.
3) Chamber is overheated and binding on the brass; extractor claw is slipping off.
I understand from speaking to the gunsmith who built the rifle that the barrel was "donated" from a P14 and then fitted in some Frankenstein fashion to the Lithgow SMLE receiver. I shot 40 rounds from it a couple of weeks ago without a hassle, though there was quite a bit of time between shots on that occasion. Looking at the fired primers and judging from the rounds that extracted and ejected cleanly (no sticky bolt lift, extraction smooth and effortless when it worked), I do not think I have pressure problems.
Maybe it's time to just invest in a huge quantity of new unfired .303 Brit brass and take the hammer to all this stuff?