Sterling Mk6 Carbine jams HELP!

M

Miller

New member
Finally found a Sterling Mark6(semi auto carbine imported by Armscorp) after much searching and picked the gun up today from my dealer. Tried 3 varieties of 9mm ammo, but couldnt get any to reliably feed. Wolf was the worst. I could only get one or two shots off before clearing a jam (usually a spent case caught in the action stopping the next round from entering the chamber). It didnt seem to like UMC either. The spent UMC cases were bulged out noticiably. The best was from some unidentified surplus stamped 1945 that I had lying around. The cases didnt bulge as bad as the UMC, and I could get 5-6 rounds off before clearing a jam. The gun looks like it has never been fired. The cartridges do sit an little loose in the chamber and they dont seat flush with the rear of the chamber. I am told this is the way it should be with this rifle, bieng a semiauto version of a subgun. From all that Ive read about the Sterling, I thought it would have been a very reliable gun. Maybe in making it a closed bolt semi auto that reliability was lost. Any help would be appreciated or maybe someone knows of another forum that might be helpful.
Thanks
 
First post - Bear with me as I figure all this tech fangled stuff out... I had the same initial problems with both my Mk 6 and Mk7C4 - would reduce seemingly quality ammunition to brass crunchies, they just lacked the "oomph" to kick the bolt far enough back. What I have found to work (for my Sterlings at least) was: a) Fiocchi 124gr works sometimes in the carbine, b) 147gr subsonics seem to work all the time in both the carbine and pistol, and c) Hirtenberger produced L7A1 "smg-only" ammunition works the best - but only in the carbine. I was going to order some smg-springs and check their function (supposedly they are "lighter" than those in the carbine), but never "got around to it." Hope this is helpful.
 
Thanks for the replies. Im going to try some hot ammo this weekend, hopefully with better results. Do you notice bulging in the spent cases? Particularly on ammo it doesnt like? I took the barrel out to see how a cartridge would sit in the chamber. I was a little surprised to see a bit of the rear of the cartridge hanging out. Maybe 1/8 inch or so including the "rim" of the case doesnt go into the chamber. Im guessing this is typical of the Sterling and other SMGs?
 
Hmmm - I don't recall any particular bulging in the fired cases. I'll have to pay more attention to them next time. I haven't had an opportunity to check if a chambered round looks like you describe - I'll try to check that out and let you know. From "The Guns of Dagenham" by Laidler and Howroyd do describe the Sterling chamber in some detail - it is different than a SAAMI chamber, being more "relaxed" to ensure reliable function with most any nominal 9X19mm ammunition - a carry-over from the STEN if I recall correctly... Anyway - do tell how your experiments with the hotter loads worked out and I'll try to check my chamber tonight.
 
Good morning;

I've not seen any of the problems you're describing with either the Mk6 or Mk7; mine digest any sort of ammo I've tossed at them. I'll have a quick check on mine when I get home, but here's something you might try.

With the firearm unloaded, no magazine in place, retract the bolt all the way and ride it forward slowly. When it stops, is it in battery, or can it be pushed a little bit further forward?

I've noticed that when one gets extremely dirty it will occasionally do this if the bolt is not allowed to cycle fully. A good cleaning and lube should take care of the issue.

Hope this helps.
 
The problem seems to have been solved by using hotter ammo. I picked up a box of Winchester (white box) and to my surprise, the gun loved it! A whole box of 50 disappeared without a hiccup. I only wish I had bought more! The spent cases showed no expansion.
I was certain it wasnt an ammo problem, because I had tried a total of 5 different types, without any luck. Glad I was wrong! Im going to a gun show this weekend and will pick up some of the other brands suggested. Ill post the results if anyone is interested.

Serval, I tried riding the bolt back and it does stop just short of bieng in battery. A slight nudge snaps it closed. I took the gun apart this weekend and it was spotless, apparenlty it hadnt been fired much or at all. I gave it a wiping down anyway, so I know its clean.
Would you happen to have a manual for the MK6 (or any Sterling manual)? Id gladly pay for a photocopy.

L2A3, Id be interested in what the "Guns of Dagenham" book has to say. I really need to pick that up soon.
Thank you all for your advice!
 
Miller;

Glad to hear that the ammo solved the problem. Just sounds like yours is a little tight as of yet.

As for the manual, I'll dig mine out this coming weekend. If you'll drop me a note at the hotmail address listed in my profile I'll be happy to forward a copy for your reference.
 
Miller -
Cool beans! I'm going to check out the Winchester "white box." I did check the chambers on mine and they look just as you describe. I looked in "Guns of Dagenham" to try and find the comments on the chamber and could not - I'm beginning to wonder if I confused "Guns" with the other book by Laidler "The Sten Machine Carbine," d'oh! I'll find out and let you know. From personal experience, I highly recommend both books - actually any books at all from Collector Grade (even the one on the Chautchaut :) )

Serval -
An very interesting point - I find that my 6 goes to battery, but my 7 stops just as you describe. I had always associated any "roughness" in the action to the change to closed bolt fire (see below) and like Miller, both are clean and I would swore that the 7 had more rounds through it before I acquired - sooo...

Of the three semi-autos Sterlings I've presonally taken apart there has been little real uniformity: My 6 has a bayonet lug, my pal's doesn't, though he has the scope mount buttons. My 7 has the "dogleg" extension on the sear cradle spring guide as described for 6's & 7's, but my 6 does not - looks like a Police Carbine Single Shot trigger group with a narrow nose sear. Things like that. My question would be what features do your guns have or not have?
 
I suspect that a lot of the semi's were done with a variety of parts. Mine both have the mount turrets and the notched trigger groups with matching lug on the receiver. Neither has a bayonet lug. The only real difference between mine is barrel length, the end cap (MK7 isn't fit for the stock), and the barrel nut, which on the 6 is the spring loaded type, while the 7 has the set screw style.

They're fun little guns, though the 6 is definitely more useful for me due to the stock. Of course, PSArms is now carrying the 7 stock, IIRC. Would make for an interesting SBR if the paperwork could be gone through.
 
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