Loose MkII barrel

[tr63]

I have 2 barrels for my Bren MkII semi/auto . One locks up correctly the other one can rotate ,but there is no forward or reward movement . Is there a problem with it ? If so can it be corrected ?

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[Peter Laidler]

Can it be corrected? Yes, easily. Get some barrel shims. They come in 2 sizes. .002" and ,003" and officially you can use a max of 2 up to .006". You slip these, starting at .002" onto the end of the barrel dead square, using a special cupped tool. Then test for tightness until the barrel is as tight as a ducks ars................, er............ bottom. But don't forget that these are a bit of a double edged sword because you can exceed the CHS .074" limit. When fitted correctly the shims just seat into a tiny recess at the front end of the plain rear part of the barrel. Not officially permitted on the L4 guns but guess what.............

Anyone got any and the tool that TR can borrow?

And don't let anyone tell you that you can dolly the barrel threads to cure it!

[tr63]

Peter do you need the tool to install the barrel shims ?

[Peter Laidler]

Mmmmmmm. I have to tell you the CORRECT way to do it. But if you make a washer type tool that will do the job as well, then fair enough. But if you try to push them on using your fingers, you'll fail. I know that some of the real true experts with a lot more knowledge and experience than me will tell you that they have done it using their fingers and two matchsticks etc etc.............. Anyway

[tr63]

Peter I found a heavy walled card board tube that just slipped over the end of the barrel , placed the .002 shim on the barrel used the tube to push it against the shoulder without wrinkling it. I needed to use 2 .002 shims to have the barrel lock up tight , using the same lock nut that that works for my other barrel . The head space was rechecked with the field gauge .074 and the bolt would not close on it. I was able to get the barrel shims and additional barrel nuts from BRP CORP. here in the U.S. . I had tried using different sizes of barrel nuts , but found that when one barrel nut worked with one barrel it was not good for the other barrel. If anyone needs barrel nuts of different sizes BRP CORP has them . They have sorted some of their stock by the stamped number on the bottom end of the barrel nut handle . They also have new in the warp MK III barrel nuts . They are great people to work with and have gone out of their way to sort there inventory looking for sizes I needed . I now see they list the barrel nuts by sizes , on their wed site