Any Love for the Colt SP1?

[birch]

I just got out my sp1 for some evening shooting and realized yet again why I am such a colt hound! What a rifle. The back field was just planted, so I could only do 25 yard groups. All of my groups were dime sized with wolf 55g pmr.


I was just wondering if there were any other sp1 owners. I have owned a few AR15s over the years. I even built a tacticool long distance rig. None of those compare on the fun scale, and I have never had a malfunction of any kind.

Also, if anyone has a favorite mould they would recommend, I would appreciate advise. I have not reloaded much for .223 in the AR platform, so I am beginning the journey of mould and powder combos.

[Bigslug]

Great guns to shoot! Can be somewhat irritating to work on depending on the task. Colt went fairly far around the bend devising ways to prevent installation of full auto parts (legit mil-spec or otherwise) on their older civilian guns that you often have to spend considerable time consulting various Rosetta Stones to figure out which parts you need to fix one. Colt and the market have now pretty much settled on standard GI trigger and takedown pins, so it's most likely a call to Colt if you need spares for one of the oldies.

One plus to the Old Ones - if you're making an SBR, especially a SUPPRESSED SBR, the thicker trigger & hammer pins better withstand the more violent cycling caused by having greater pressure / longer pressure duration at the port.

[smkummer]

Lyman's 45th used a Colt AR15 (1970 issue) so it was a SP-1. They stated it took a close to max. (13.5 grains IMR 4227) to make it function with Lyman's common 225415. In the 70's, I was loading that bullet for my late brother's mini 14. And I did get it to function but it had to be max. Pressure according to Lyman's 49th edition is in the mid 20,000 range and they are now stating 14.0 grains is max with 4227. And the newer Lyman has data for 5744 and many more powders as well. I am currently loading that bullet in my 60's vintage Colt/Sako bolt action with unique for about 2200 FPS. I believe I am simulating the performance of a 22 hornet and its a fun load to shoot. More effort with having to expand the neck to get the oversized cast bullets to seat without damage but worth it in a bolt action. I am getting about a 3/4 in. group at 50 yards and would like to get that at 100. I am water dropping WW lead and using a copper gas check. Lyman says unique will not function the action of a AR15.

[gnoahhh]

I had an extremely early SP-1 a long while ago. It had a 3-digit serial number (18X as I recall), undoubtedly made in the first month of production. What a sweetheart. With its original Colt 3X scope it would drop five into an inch all day long. I do so wish I had it back!

[Scharfschuetze]

I've worn barrels out on Colt SP1 HBAR match rifles (modified a bit) in National Match shooting and prairie dog busting. They've always been a good choice if they are available, although more moderately priced competitors will often shoot as well.

[birch]

Thanks a bunch for the load info. It is appreciated. I don't have that would. Is it 55gr? I have a new bator mould, but others have not had good luck. I'm going to give it a go.

Mine is a 1967. It has non chrome lined barrel ad Edgewater buffer--a real sweetheart and great piece of history. I am looking for a 3x colt scope if you happen to know anyone who might part with one.

[tygar]

I've worn barrels out on Colt SP1 HBAR match rifles (modified a bit) in National Match shooting and prairie dog busting. They've always been a good choice if they are available, although more moderately priced competitors will often shoot as well.

I shot my highest score ever using my personal SP1 for QUAL in early 70s. Was possibled until dropped 3 points in last 5 offhand. That sucker was accurate with 55s. Wasn't until started getting 1 in 7/8s & 20-24" w optics & heavy bullets that I could do better & farther.