Col. Harrumph
Member
Just curious... What's the difference between a "Mk IV Series 70" and an earlier, post-war 1911? Other than the roll mark, and not knocking off a corner at the lower front of the slide, what changes did they make?
What's with the Colt Series 70
- Thread starter Col. Harrumph
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Master Blaster
Member
They used a fingered collet bushing instead of fitting the bushing to the barrel. This was supposed to improve accuracy, but they broke sometimes. I have one and I replaced the collet bushing with an Ed Brown and fit it myself
Old Dog
Member
Actually, I still have one with the collet bushing, going strong for the last 40-plus years. Still a tack-driver, too!
The defining feature of the 70 series was a collet barrel bushing and the matching barrel which was larger at the muzzle end. The idea was to hold the barrel under tension for more consistent lockup.
The issue became one of consistency of the profiling of the barrel and the front of the slide. If they weren't "in spec" they would put uneven tension on the bush fingers and could cause one to break off during shooting...which would tie up the action
The issue became one of consistency of the profiling of the barrel and the front of the slide. If they weren't "in spec" they would put uneven tension on the bush fingers and could cause one to break off during shooting...which would tie up the action
Jim Watson
Member
I think one source of broken collets was mishandling in disassembly. Horsing the bushing around with a wrench without drawing the slide back a little to release the collet; then routinely yanking the bushing off the flared barrel.
Unfortunately, Internet English calls anything without a firing pin block a "Series 70." Even the Colt advertising department which ought to know better.
Unfortunately, Internet English calls anything without a firing pin block a "Series 70." Even the Colt advertising department which ought to know better.
OP
OP
Col. Harrumph
Member
Oh I see, thanks everyone! So I guess my recent vintage 'series 70' is really just a series 80 with a couple of little bits missing.
JTQ
Member
No, a pre-Series 70 style would be a better term.
Or better yet, just don't use Series 70 or Series 80, and say your Colt 1911 doesn't have a firing pin safety.
Jim Watson
Member
Colt is - or was - using some S80 parts in their "Series 70" guns.
Firing pin, extractor, and firing pin stop notched out for the firing pin obstruction and lawyer levers will work in a standard action, so why inventory two sets of parts?
Firing pin, extractor, and firing pin stop notched out for the firing pin obstruction and lawyer levers will work in a standard action, so why inventory two sets of parts?
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