Oversize locking shoulder

[Joonyer Doopety]

I have an L1A1 parts set that I got way back when Century first began importing them.
From the appearance of the parts it appears to have been virtually unused! Non of the internals show any wear or rub marks, the barrel looks like it's absolutely pristine. About the only parts that look somewhat used are the bolt and bolt carrier. I hand tightened the barrel onto my DSA receiver with the breaching washer it came with and it goes to 11 o'clock. The washer may have been refinished, but it looks like it is also brand new.
It also came with a locking shoulder, specifically a #4.
My question: what dimension is a #4 locking shoulder?
Thanks,

[ July 24, 2001: Message edited by: gary.jeter ]

[smart toys]

I'm not sure what demension a #4 is but even if I did I would measure it to be sure. You should measure it with a good vernier caliper or micrometer.

[gunplumber]

a number 4 should be a .2974 (std) shaft diameter with a .264" face



------------------
T. Mark "Gunplumber" Graham
gunplumber@arizonaresponsesystems.com
Arizona Response Systems
5501 North 7th Avenue, Phoenix, AZ 85013
623-873-1410 http://www.arizonaresponsesystems.com

[NZ L1A1 Collector]

I hate to disbute GP about a few thou. If the locking shoulder is a "inch" one, then a #4 has a shaft diameter of 0.2978 with a locking shoulder size of 0.264 http://www.fnfal.com/forums/wink.gif

Standard has a diameter of 0.2978
1st over size has a diameter of 0.2982
2nd over size has a diameter of 0.2990
3rd over size has a diameter of 0.2998

There is a total of 60 different sized locking shoulders that the Australian's made. 15 locking shoulder sizes 0.261 - 0.275 in 4 shaft diameters, as stated above

The above info is from the
Australian Electrical Mechanical Engineering Instructions, WPN D 254 Iss 7, Nov 92

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Kevin Adams
Rifle, 7.62 mm, L1A1 Collector & Researcher.
NEW ZEALAND

[This message has been edited by NZ L1A1 Collector (edited February 21, 2001).]

[gunplumber]

Well I certaintly won't dispute THE MASTER on this - I actually didn't have a listing for the standard shaft diameter. I had it for the .1, .2, and .3 which correspond with yours. Since I observed there was a .0008" difference betwewn a 1 and a 2 and a 3, I ASSUMED (shame on me) that there would be a .0008" difference between a 1 and a zero. so please forgive my error

------------------
T. Mark "Gunplumber" Graham
gunplumber@arizonaresponsesystems.com
Arizona Response Systems
5501 North 7th Avenue, Phoenix, AZ 85013
623-873-1410 http://www.arizonaresponsesystems.com

[This message has been edited by gunplumber (edited February 21, 2001).]

[W.E.G.]

moved to FAQ