SP1 Buttstock Question

[Ironlip]

I just bought a 1967 vintage, four digit serial number Colt SP1 in great condition. The intent was to have some fun shooting and and to hold as a collectible. The butt stock appears to be a replacement to me. It has a solid lower sling swivel, not a moveable one pinned to the stock. The butt plate has two screws rather than one and it has a trap door in it. My limited research indicates that the M16 had this type of butt configuration but not until 1969. I cannot find any data base on SP1's.

I have looked on gunbroker and found several 1964 - 1968 SP1's with lots of pictures. All of the lower swivels are of the moveable, pinned variety and all have solid buttplates. I did find one 1968 vintage rifle with the solid siwvel and a buttplate.

I am a total SP1/AR15 newbie so I am out of my element here. I have three questions:

When did the SP1 first have a butt trap?
When did the SP1 switch to a solid swivel rather than a pinned and moveable one?
Can I find an early buttstock in great condition easily, or should I just return this rifle to the seller and keep looking for an all correct original example? (This is what I am inclined to do)

All input appreciated. Thanks

Rick

[RCS]

I have a Colt SP1 four digit from 1966, it has the solid buttplate. Check www.ar.15.com for the data base on SP1 rifles. Any four digit SP1 is difficult to find in original condition, you might have other parts that were changed too such as the bolt & carrier or the 1 in 12 twist barrel. Parts are around.

[Roscoe Snyder]

Definitely a replacement. People will do that. More often you see a later one that someone has put an old stock on just because they want the look. SP1s came with the old stock to 1971 and maybe 1972.

[epa223]

Your first two questions are essentially the same. Roscoe Snyder is correct, around '71 is when Colt started to transition to the "A1" stocks, with the fixed swivel and trapdoor. My 1974 Colt catalog shows an A1 type. As for finding parts (M16 Buttstocks at least), yes they are available in a wide variety of conditions.

[George in NH]

My 12 thousand range S/N SP1 has the one screw butt plate and the sling swivel on the stud that allows the swivel to rotate. I bought this rifle used, during or just before 1980. I believe it to be unaltered. HTH George in NH

[Roscoe Snyder]

12000 makes it 1968 so that would be correct.

[Ironlip]

Gentlemen, thanks for all of your input. It confirmed my internet research. I just spoke with the seller and he said there was a pretty good chance that he had swapped out the buttstock. He is going to check his gun room and let me know tomorrow. He agreed to take it back if I was unhappy.

[boykin]

I think I have an extra early stock if you can't find one.

[Bill D]

I need an early "no trap" buttplate if anybody has one for sale or trade. It needs to be correct for a 1971 SP1.

[Nick Riviezzo]

I'm no help here all of my SP-1s are sliding stock carbines. Nick