Rifle zero climbed when it got hot yesterday

[NuJudge]

I have a Maltby No 4 Mk I with a very shiny bore which I was practicing 200 yard 'sustained fire' (what we used to call 'Rapid Fire') with yesterday. The rifle is slathered in black paint, and has a big screw through the forestock ahead of the magazine, indicating Indian Army use I believe. In between strings I would let the rifle cool for a few minutes. I was using 1938 Greenwood and Bately Mk VII ammo, on chargers, straight out of the crate.

The first 4 strings all fell in a nice group of about 5 inches centered in ther Bullseye, with the occasional flier that I put down to a very occasional cracked neck or slight hangfire. After that, the groups walked up the target, most falling in about a 9" group about 14" above the center of the Bullseye.

I was paying close attention to uniform head positioning, body position and trigger squeeze.

Is this anything to worry about?

[KCLRPC]

First off would be how many rounds per string? I've never seen a No4 in black paint, is it original?

Other than that, you may find that the barrel is beginning to warp after sustained fire (lets face it, heat dissipation in an enclosed barrel sucks at the best of times), and that the barrel begins to bear more heavily on one part of the forend than another, hence the drift up the target. I wouldn't worry about it at the moment, but if the group were to remain high when you next fire, then I think the problem may be more serious.

The only way to solve it if it doesn't sort itself is, I believe, to work on the inletting around the barrel. I've yet to experience it myself, and someone else may have come across it, but thats my two cents worth.

Nick

[dromia]

Very possibly wood warp, have you checked the king screw is turned in tight?

Sounda like the Ishapore screw but when they did FTR they usually ground off the original markings.

Are we talking black paint or suncorite?

I have seen the odd rough jungle proofed No 4 in Malaysia, but can't recall an Ishy screw, but them my memory is one of my most unreliable features.

[Niner]

1938 Greenwood and Bately Mk VII ammo would also seem worth considering too as a possible cause. Even if all of the ammo was of the same lot, 70 year old ammo would be something I'd suspect first.

I'd think I'd try some new fresh ammo and see what it does before I did much of anything to the rifle.

[KCLRPC]

Would ammunition be able to affect that sort of change in zero? I would expect fliers in a group, but to then have the MPI move 14" higher sounds like something more extreme than just ammunition. Unless its a batch defect, but then why wasn't it across all of them? Also, the widening group might be batch related, but I wonder if it would be a combination of both?

[NuJudge]

Only one oops, that being that all the markings are scrubbed except the SN and 'M47c' on the action body socket for the butt, which I should have remembered as BSA Shirley, not Maltby.

The black paint did not seem as 'bulletproof' as Suncorite is supposed to be. I'd expect BSA to neatly paint, not glop it on like this. The Indians slopped paint all over the rear sight too, and I had the devil's own time getting that off.

The first box of twenty I opened had a Mk I charger. The second box had a Mk II. The rest have been Mk III.

I will recheck the King Screw. Any other suggestion is welcome.

Christopher Dingell

[24626151]

Check that nobody has packed the barrel for competition and got it wrong!

Good find on the Mk1 Charger!