L39a1 magazine issue

[Merlin266]

I have only just started using the rifle, I'm not sure of its past use. The magazine came with the rifle, it's a bit of a dog to fit. Requires a little bit of manliness to engage properly, if peter says they're meant to match then I reckon this one doesn't. Would the machining indicate acceptance of this type of magazine

[Peter Laidler]

Don't understand the Question in the last line re what machining?

[Brian Dick]

Some 7.62 as well as .303 magazines do fit very tightly which isn't a bad thing. Get a set of smooth jaw pliers, three dummy rounds and just carefully watch the process of feeding. Adjust the feed lips a little bit at a time as already explained until it feeds and extracts/ejects properly. Then your magazine WILL be matching.

[Thunderbox]

Is the OP's rifle a genuine L39A1, or is it a gunsmith replica? If the latter, it may be an un-modified No4 action that magazine simply will not fit.

[Peter Laidler]

There was quite a bit to the actual dynamics of the 7.62 magazine. The first bit was the shorter round obviously and then, the smaller diameter too of course - but more importantly, the base rim diameter (the BRD). Because the 762 round was shorter within the old housing aperture, there was a distance where the round was not a) under control of the front and rear feed lips and b) not under the directional control of the breech opening. We call this no-mans-land or 'limbo-land' for obvious reasons. (The reason why the 762 mag was placed much further forwards in the L4 body)

That's why the rear lips of the 762 mag extend for further along the magazine and the reason why there is a circular machining away of the rear of the mag housing, simply to a) accommodate the increased length of the rear lips and b) Much MORE IMPORTANTLY, to allow thge new magazine to sit much higher in the opening so the the much reduced BRD to also sit higher and be engaged by the bolt on its way forwards.

This raising of the top cartridge to suit the bolt face is very tenuous at the best of times and is all down to the rear feed lips angle and radius as Brian points out.

At the front, the feed lips are more to the rear of course because as the round is being pushed forwards now, they have to control the angle of approach into the breech. Once the nose is in the hole, then it's under control and can't go anywhere else. It can't flop left ot right or stub itself on the breech face or anything else. Only THEN can it be released from control of the rear lips.

Problems then arise with the front lips that are too closed in where the bolt face pushing the round forwards and the round not being released by the front lips causes the nose of the round to then lift . The rear of the round dips, the bolt overrides it and slides over and into the case...........

Hey......., if you know all this then just ignore it. There were loads of short slow motion film/video of these magazines theories and design faults on the student design courses but in short, magazines are a one-gun dog. By that I mean if youaredesigning another mag for a gun or using another mag in your new gun, your problems are just about to begin.

If your L42 magazine fits and works well, number it to the gun. 'They'* say they are interchangeable and some might be, but because the bodies and mag catches all differ, albeit slightly, the mags don't all interchange. THAT'S WHY WE NUMBER THEM TO THE RIFLE
* 'They': we never hear who these people are of course

[RobD]

It is explained with pictures here:
To Which I Replied...: Enfield magazine feed lip tuning
Just ignore the annoying adverts, all the text and pictures you need are there. The magazine illustrated is a 7.62 one, too, which is useful.

[Merlin266]

It seems to me that the issue may be with the left hand magazine lip(s).

The magazine sits up high enough (courtesy of the machining in the well) to allow the bolt face to strip the round off the top of the stack, so that is good.

After about 10mm forward movement, what COULD be happening is that the cartridge case is being caught on the bottom side of either lip, which deflects the round downwards enough that the bolt-face rides over it. Suggest try the feeding again, and see if there is any downwards movement
there.

Llikely contact points are the front of the rear lip, or the rear of the forward lip.

Having looked at it carefully, the rear left side lip seems to be the issue. I have given it a subtle tweek as suggested and the rifle loads consistently now.
Cheers everyone for the help, everyday is a school day 😀