Colt SP-1 Questions
I recently got my paws on a Colt SP-1 rifle (20" barrel). A1 configuration (no shell deflector, ridge around mag release, or assist, with birdcage suppressor with slot on bottom and all that), it has a Colt upper with C M on handle, chrome bore, trapdoor stock w/cleaning kit, serial # SP138xxx (assume around 1980), probably around 80% (I have a hard time judging parkerized condition but no wear through except for handle scope mount wear and small nick on right lower receiver). It seems all standard.
The fire selector is funky. It's installed 90 degrees out of position clockwise so that when on 'safe' it points up to the fire position. Another thing about it that makes me scratch my head is that the selector can be turned about 30 degrees beyond the 'fire' position (not the 90 degrees that an auto selector would). I don't know if this is just over-travel or if it's a functional position. I haven't fired it so I don't know if I'll get auto or 3 bursts. I haven't disassembled it and am unfamiliar with the works.
Questions:
* Can a selector be normally installed out of position like that, and what might I run into if I try to reposition it?
* Is there any chance that someone has messed with this and modified it so that I need worry about legality?
Maybe I'm just a wuss, but I thought I should check with someone who something about this before I start fiddling with it.
The fire selector is funky. It's installed 90 degrees out of position clockwise so that when on 'safe' it points up to the fire position. Another thing about it that makes me scratch my head is that the selector can be turned about 30 degrees beyond the 'fire' position (not the 90 degrees that an auto selector would). I don't know if this is just over-travel or if it's a functional position. I haven't fired it so I don't know if I'll get auto or 3 bursts. I haven't disassembled it and am unfamiliar with the works.
Questions:
* Can a selector be normally installed out of position like that, and what might I run into if I try to reposition it?
* Is there any chance that someone has messed with this and modified it so that I need worry about legality?
Maybe I'm just a wuss, but I thought I should check with someone who something about this before I start fiddling with it.
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Sounds like you have a frankencolt. The upper should not have the ridge around the mag release & should not have an assist. Obviously Bubba has worked on the lower; until you take the fire control system apart, you won't know if it is even safe to shoot.
You either need to get a book, or get on an AR forum, or pay a gunsmith to figure it out for you. The AR is not intuitive; you need to know what you are doing.
Neal0 -
quote:Originally posted by nmyers
Sounds like you have a frankencolt. The upper should not have the ridge around the mag release & should not have an assist. Obviously Bubba has worked on the lower; until you take the fire control system apart, you won't know if it is even safe to shoot.
You either need to get a book, or get on an AR forum, or pay a gunsmith to figure it out for you. The AR is not intuitive; you need to know what you are doing.
Neal
Misunderstanding here. It does not have the ridge, assist nor shell deflector. It is as it should be.
On the selector switch, I made a mistake. The selector is not positioned wrong. I forgot to consider that it does not go into safe mode when it's not cocked. [:I] Thus it has three positions, safe, fire and what would be the automatic position.
So now the question becomes, is the selector on an early Colt SP-1 supposed to be able to be rotated to the auto position? I would guess that the early AR-15 had the capability to move the selector into auto position before they required the civilian selector cam and lower receiver machining, but it is missing the components to fire full auto (trigger release, etc.). Is this the case or is Bubba still a suspect?
Agreed on the book etc. All in due course... this is just my initial query.0 -
The point on the selector should only point to FIRE or SAFE, or between the two positions. It should only rotate 90 degrees, no more. If it rotates > 90 degrees, there is a problem.
The AR-15 was engineered from the M16 design, but the selector functioning never permitted pointing to the AUTO position.
There is a simple test for FA functioning. With an empty rifle, selector on fire, pull & hold the trigger back. With the other hand, pull the bolt carrier rearward & then forward. If the hammer falls when the carrier reaches the forward position, the rifle is FA; if you must release the trigger & pull it again, it is semi.
Neal
EDIT: Great job of diagnosing the problem. I suspect that your rifle would not fire true FA, but, rather, fire only single shots. But, it might be manipulated to dump the mag on a single trigger pull. It sounds like it's current configuration would violate ATF rules prohibiting the use of certain M16 fire control parts in an AR-15; folks have gone to jail for that. Details can be found in ATF P5300.4. The correct bolt carrier will have a raised "C" on it; it may be smooth or have FA serrations, as both types were used in the AR-15 when yours was assembled.0 -
I do not know how proficient you are with taking the weapon down (please do not ever disassemble the front sight/gas block asssembly if you can avoid it.) into its component parts. If you are not well-skilled at dis/re-assembly, I suggest very strongly that you purchase a step-by-step "armorer's course" for the AR type weapons. In the past I have used the AGI dvd's if there was one for a weapon type I was unfamiliar with, but there are several others like them available through various sources. For your first run, just limit your efforts to tearing down the upper (no need to remove the barrel from the upper right now) and the lower receiver groups.
I also advise you to query the Internet and find exploded parts diagrams for the full-auto M-16 and the semi-auto AR-15 and study those to determine differences in the receivers and the internal parts configurations. In your case, pay special attention the the trigger group parts variations and the selector switch parts variations. There is also variation in other parts, including the bolt assembly, of the semi- vs. full-auto guns.
So, familiarize yourself with the gun and you will come to terms with the thing.0 -
quote:Originally posted by Wolf.
I do not know how proficient you are with taking the weapon down (please do not ever disassemble the front sight/gas block assembly if you can avoid it.) into its component parts. If you are not well-skilled at dis/re-assembly, I suggest very strongly that you purchase a step-by-step "armorer's course" for the AR type weapons. In the past I have used the AGI dvd's if there was one for a weapon type I was unfamiliar with, but there are several others like them available through various sources. For your first run, just limit your efforts to tearing down the upper (no need to remove the barrel from the upper right now) and the lower receiver groups.
I also advise you to query the Internet and find exploded parts diagrams for the full-auto M-16 and the semi-auto AR-15 and study those to determine differences in the receivers and the internal parts configurations. In your case, pay special attention the the trigger group parts variations and the selector switch parts variations. There is also variation in other parts, including the bolt assembly, of the semi- vs. full-auto guns.
So, familiarize yourself with the gun and you will come to terms with the thing.
I'm familiar with the AR and takedown. But I had never had an early model like the SP-1 before. I realized that the early ARs were not milled with a full auto block, so M16 parts could be used in it. I thought at first that this might allow the selector to be rotated to the full auto position. But I see now that I was wrong.
After examining the differences between the M16 and AR15 parts as you suggested, I do indeed have a altered SP-1. The fire selector is clearly milled in the M16 fashion, and the hammer clearly has a hook on the upper rear. Looking down into the trigger group it's hard to see for sure, but it does seem the trigger disconnect has an extended arm at the rear. However, the bolt carrier is clearly an AR semi, and appears to be an SP-1. But it has no markings at all on the carrier.
Also, working the hammer in the semi and auto modes tells the tale. In semi mode with the trigger pulled, the hammer gets retained, and then releasing the trigger lets the hammer fall into the sear. When I do this in auto mode, the hammer is not retained and freely moves back forward. Apparently, the only thing preventing it from firing full auto now is the AR bolt carrier... and ironically that would be legal had it been an M16 carrier <sigh>.
So now I must replace the fire control and trigger groups, and would want to replace them with original SP-1 parts. I don't know how hard they will be to locate. Thanks folks, I'm happy I discovered this. I look fat in stripes. [V]0 -
Go on the Fulton-Armory website. Get the AR trigger, sear, sear spring, hammer, selector and selector spring and detent. Your AR should have the small hammer/trigger pins. Make sure of the size pins you have prior to ordering..to avoid sending back the wrong parts. Both pin size parts are available online through Fulton Armory.
Sidenote: I can't find any markings on my 1974 vintage SP-1 Colt AR fire control group parts that would identify the parts as distinctly 'Colt'.
Fulton Armory will get you up 'n running. Best, Joe0 -
Thank you Joe, the parts have been ordered. 0
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