[Adventurer_96]

Does a Colt SP1 use a normal sized pivot pin? I'm curious to see whether or not you could swap out an SP1 upper with a current production upper from ArmaLite or Rock River.

[444]

No, the Colt SP1 does not use a "normal" sized pivot pin. However you can buy an adapter pin from Bushmaster, Brownells, etc.

[Dave T]

Actually the SP1 has a "normal" original pivot pin. The later sanitized, politically correct (if you have a bayonet lug you must be a criminal), version is the "not normal" pin!

[BigG]

Dave T, I can tell you are a Colt man like me. :evil: You are right, of course, but he means does it have a 1/4" front pin like the military Colt AR15/M16 and the answer is "no" it has a larger pin, more like 5/16" :D The aftermarket uppers also can be had with a SP1 type front pin hole. There are also the larger pushpins available to get rid of the hinge screw. I recommend them.

[444]

Actually it isn't a normal pin. Those Colt models are the only ones that have it out of the dozens of manufacturers of AR15 rifles. For example, A Bushmaster lower will take any upper made by any company accept those Colts, that ain't normal. A DPMS, ASA, CAv Arms, Olympic Arms, RRA, Wilson, Les Baer, and even other Colts .................. will all completely interchange, but not those Colts.
I personally leave my SP1 alone. I like it just like it came out of the box. But, you can buy an adapter to make it normal if you want to.

[BigG]

It's a matter of perspective, 444. For those of us who believe the only REAL civilian AR15 is the Colt SP1, it IS the normal pin. :neener:

[444]

Those of you who believe the SP1 is the only civilian AR15 arn't normal either :neener:

[gun-fucious]

Didn't Colt make the front pin a different size on the Sportsters, as a CYA, so military uppers would not directly mount?

[Adventurer_96]

I wouldn't be looking to permanently swap out uppers, I'm just curious to see if I'd need to jump through fiery hoops to install one of the NM uppers with the normal sized pin hole.

[BigG]

Gun-fucious: Yup.

Adventurer 96: The offset pin costs about $5 or so. You can mount the late model upper on your SP1 as somebody mentioned. AR parts guys at gunshows alwys have it or you can order from Brownells.

[Adventurer_96]

Thanks for the tips. One of the strong points of the AR in my mind is its modular capabilities. You can have several rifles with one lower and a few uppers.

It figures, I finally have the $$ in the bank for a Colt preban AR, and I still haven't found the exact one I'd like. Now, if only I can get a good deal on the LNIB SP1 at the estate sale next week, I'll be in business. What did they originally come with, box, manual, what else?

[444]

Adventurer, the AR is everything you say it is, but.... most people I know start out working along the same lines as you are. Buy one complete rifle and then add a few uppers to suit your fancy. But this is where the problem begins because not only are there variations in uppers, but there are variations in lowers as well. A1 stock, A2 stock, collapsable stock, Ace Skeleton Stock, stubby entry team stocks. Then you get into triggers; if you get a scoped heavy barrel upper, you are going to want a "match trigger" to go with it, but rumor has it they arn't very rugged, not something you want to count on for a defense gun. You want to trust your life to a mil-spec trigger, but you want a light crisp match trigger too. So you decide that you need lowers to go with your uppers to cover all bases, and your safe begins to suddenly seem very crowded. You start reading a lot about the AR15 family and you run across a novel concept. They make these things in other calibers. Wouldn't it be fun to have one in 9mm ? But, you are going to need a mag block in the lower, and it sucks to keep taking it in and out, so you go ahead and just get a complete AR in 9mm. Hey, what's this ? An upper in .458 Socom. Now that is a real cannon. I can use this to hunt big game, anything in North America, but I don't want to subject my tricked out defense rifle to the pounding recoil, and I don't want to risk my super accurate varmint rig to that kind of punishment either, so I will get that upper and it's own lower too. Then you discover that you can build these rifles yourself. That sounds like a fun project, something to keep you busy in those long cold winters nights, and what better way to learn the AR15 from the inside out ? So you build a few. You might assemble a couple lowers and think to yourself, this is a piece of cake, but now I have these lowers here and nothing to do with them, so you think, I wonder if I can also handle building an upper ? A few more complete rifles magically come to life. Then you find out about finishing an 80% receiver. That is the logical next challenge in your new found hobby within a hobby. So you finish a lower or two. Now you have a couple completed lowers with nothing to do with them ..................................................................................................................................................................................................................................................................................................................

[Adventurer_96]

Thanks for the tips. I'm just hoping I can get ahold of the most recent SP1 I located this week.