Sten Magazine Mandrel

[tj214]

Does anybody have engineering drawings of the Sten magazine mandrel for straightening the feed lips? Since no originals seem to be available at this point, I'm thinking about fabricating one to fix the several dozen mags I have with lips so far out of alignment they stop or impede the bolt from slamming home.

TIA.

Information

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[stencollector]

There were two mandrels involved...one that went into the magazine and one that is hit from the top to reform the lips. Marstar here in Canada had the sets as did BRP in the USA. I bought my set along with the gauge when BRP first advertised them about 4 or 6 years ago. Both have sold out of the inner mandrel, but the outer mandrel is still available. Could I suggest getting that and making up a mate for the inside?
Links for these items:
Sten Magazine Gauge MARSTAR CANADA
STEN Magazine Repair Tool TOP - WORN CONDITION - BRP CORP
Sten Magazine Repair Tool Set MARSTAR CANADA

[Peter Laidler]

As I seem to remember things, al;though the only Stens we in the Army had when I joined were Mk5's (although the RAF had some Mk2's at the radar station at the top of the hill somewhere on the West coast) so we had loads of magazines. The top of the Sten magazine and feed lips were laminated with the thin inner and a spot welded thicker outer. You could re-shape the OUTER sheath part but not the inner part that was part of the actual case. The guide line was that the lips had to be parallel along their length and present the bullet at 8 degrees. That's the onl;y gauge we had or used so far as I remember

[tj214]

So, if the lips were parallel but the bullet was, say, flat or well below 8°, did you discard the mag, or somehow try to reshape the lips? I've got a dozen mags with parallel feed lips but the round sits well below 8°. Hoping there's a way to make them usable. I note from numerous previous posts this may turn out to be a fool's errand and perhaps the only (simplest?) solution is keep buying mags until enough usable ones are acquired. I don't feel right reselling mags I know are unusable, although this doesn't appear to bother some.

Has any member had good results actually using the issue mandrel and forming die? I've read posts where it didn't work, at least for long, but there could be many variables.

[Vincent]

[tj214]

Hey Vincent

Thanks much for the vid link. Very helpful. I'd seen that earlier, which is basically how I learned what might be necessary to rehabilitate my many unusable mags. Still searching for either a mandrel or the engineering drawings.

[Bruce_in_Oz]

If you can't find the actual mandrel drawings, have you seen drawings for the magizines?

With a bit of creative number-=crunching, and a close look at the mandrel photos, you should be able to get close to the required form, features and dimensions.

The truly adventurous would offset the "R & D" costs by offering them to less-well-tooled-up enthusiasts for a reasonable price.

[AmEngRifles]

Remember when Sten mags were $5.00? I would guess some here remember when they were even less!?

Tj214, I sympathize with your dilemma. I have a good number of mags (of all sorts) purchased on line that have proved to be really horrible. Hard to just chuck them, so I have a box of questionable/non-functioning magazines. I will not resell them. Just part of the cost of being in the hobby. Like buying a Horse on line, without a decent inspection.

It does look as if the inner mandrel would be a decent weekend project. Base on that, I will buy the top part from BRP. That being said, non of my Sten mags have given me trouble. Must be a lucky bastard? I find the Sterling mags can run into feeding issues and while I have no mandrel, I have managed to reshape their lips into parallel, with enough feed angle to have them return to service. Wonder if there are Sterling Mandrels about? All my mags operate thru a Sterling semi auto SBR.

Thanks for bringing this subject up.

[Brian Dick]

I imported 4000 Sten magazines back in the early 2000's. All were near new, assorted British manufacture and from Finland where they obviously didn't see much use. I still have a couple hundred here if anyone is in need. I bought an Erb tube Sten Mk.V that was a total piece of crap. I sent it out to Paul Krogh in Colorado who cured all of it's problems with distinction. I refinished it when he returned it and still have and enjoy it. One of my few transferable guns.

I've never had a problem with Sterling magazines in my Mk.4/L2A3 and Mk.6 guns. Old and beat up or new in the wrap, they all seem to work perfectly every time.

[AmEngRifles]

Hey Brian. I have a Century iteration that actually performs quite well. It does so well, that I SBR'ed it. Love that little gun.

I am not sure if I will ever own the full auto version? Would love to, but the jump from $600 to $25,000 is a big one. When I received the rifle, way back when, it came with two mags. Century would put one unmolested mag, as factory finished, and they apparently had a slew of second hand mags, because back when they were putting the little "Sporter" onto the market, the second mag was a refinished (parkerized) version. Very distinctive and you always saw the gun, in the box, with a black mag and a gray mag. I think I heard they had a slew of mags they refinished, obviously. One of those mags had the feed lips slightly spread. When I compared the two, I could see that the lips were different. Nobody go down the wrong path here, because the nomenclature can be suggestive, but when I closed those lips, and set them at parallel, the cartridge insertion returned to normal. So for the Sterling, I guess the mags need to be close to parallel? There must be some release angle similar to the Stens 8 degree, for cartridge feed? Obviously the cartridge needs to have some release point, in coming out of the magazine, just like almost every other feeding device. I did not worry about setting feed lip release point, only that the parallel feed lips looked nearly parallel. It has worked just fine ever since.