In the 3rd AD in Germany, we were issued stocks with traps to replace the ones without in the fall of 1972. I don't know when commercial ARs made the change. All the M16s I saw in Viet Nam in 1969 and 1970 were still the early trapless stocks as were all the ones we had in the training center at Fort Campbell 1971.
The trapdoor buttstock and birdcage FH on the "later version" model R6000 SP1 should roughly coincide.
The 1969-70-71 mentioned timeframes sound reasonable.
Some with mixed features would not surprise me.
I wouldn't be surprised that when the military began specifying the trap-door stock Colt simply continued to use up the solid butt pad on civilian AR-15 production until inventory ran out then converted to the same the military was using. It makes sense to do so and we know Colt never really threw anything away when it was still usable otherwise.
Berkeley 492, Very nice - looks minty - and I'm interested to see this! Thank you. So you have an original 71 sp1 with a three-prong flash hider and and a type D butt stock. May I ask, what are the barrel markings and is there a knurled crush washer or a lock ring with wrench flats holding the flash hider in place?
Here are a few pictures of my 1971 SP1 posted above showing the barrel marking, the flashhider and lock washer and the butt stock. The lock washer appears to be very lightly knurled. I don't think I've ever seen an original 3 prong flash hider that had wrench flats. There is a special wrench slotted for the 3 prong flash hider that is used to remove and replace the flash hider.
Here's a picture of the barrel markings on my M16A1 upper assembly. The lock washer is knurled, barrel marking is different and the A1 flash hider has wrench flats.
Does anybody know about the barrel markings for '69 or '70 SP1's? Would "MP" and just "C" with no "B" mean the barrels with chromed chambers but unchromed bores?
I think the chromed chamber started in about 1967 for the M16's and then switched to C MP C. By 1969 the M16's were getting the C MP B barrels with chromed bore. That would follow what is being described here, using up outdated M16 components on the SP1.
I have a Colt Modular Carbine in 6.5 Creedmoor, it has feed issues, it will either not pick up a round and the bolt will close without picking up a round, or it will pick up a round and fail to feed it.
1) I have used both Magpul Magazines and AR Stoner Metal Magazines, I do make sure the...
My grandfather left behind some firearms when he died and my Uncle gave them to my Brother and I over the last few years. My Grandfather worked for Colt and The story we were told was that one of the rifles was a prototype Coltsman chambered in 300 H&H magnum. Its a sweet rifle but I know...