Author Topic: Colt AR-15 Extra Part (Read 851 times)

Doc Lisenby · « **on:** September 22, 2003, 03:31:24 AM »

A local law enforcement officer brought me a AR-15 which he said had fired accidently when the bolt was released to the forward position.
I removed the bolt carrier and noted that there was a part which I didn't recognize attached to the bolt carrier. It is two pieces attached together by an allen socket headed screw and was partially obstructing the inside of the ejection port of the bolt carrier. The illustrated parts breakdown I have doesn't show this part. Can someone please identify this part for me?
Doc Lisenby

gunnut69 · « **Reply #1 on:** September 22, 2003, 07:41:10 AM »

Sorry Doc.. Doesn't ring any bells with me but realize I'm not an ar-15 expert by any stretch!! I'll do a little research but can't help as of now..

Doc Lisenby · « **Reply #2 on:** September 22, 2003, 09:25:19 AM »

It sure stumps me. I said ejection port in the bolt carrier. It isn't an ejection port but is an opening through which the hammer moves to strike the firing pin.
I suspect that it is a support block to limit movement between the lower and upper receivers. This rifle has a Colt riflescope/mount assembly on it. I think maybe it is what caused the rifle to fire by this block hitting the hammer when the bolt went forward causing it to over-ride the trigger/hammer contact.(sear)
I sure would appreciate some help on this. I'm not an expert on them either and have only worked on a few of them. I can't imagine it being an aftermarket item, especially because it isn't a personal weapon.
Doc

gunnut69 · « **Reply #3 on:** September 22, 2003, 01:22:51 PM »

There were devices made and sold to convert the AR to an automatic weapon. Called autosears they basically acted as you've described... But unfortunately I don't know what they looked like... Wish I could be more help, but I don't remember anything in the AR that even resembled what you described..
Jerry

Doc Lisenby · « **Reply #4 on:** September 22, 2003, 01:49:29 PM »

Thanks for your time, but I think I figured it out. I looked at it real close and looked at some accessories for the AR15. Brownells has a similiar looking device on page 20, Cat. 55 which is called a Dry Fire Device. Now this one isn't as long as that one but it would do the same thing except for the problem I think was caused by it. It can be slipped back and forth which allows it to block the hammer when it is in the forward position. It was partially back and I still believe it hit the hammer. Can't prove it but it had been hitting something and was burred on the front.
It wasted my time and frustrated me all day. I took the damn thing out and will tell the cops that I will put it back in whenever they want to play games or snap-in (can't believe they would do that, it is too effective in teaching trigger control: these just spray and pray anyway)
Thanks for your help! Nice to be able to discuss these things with someone who will come up with some suggestions or support.
Doc

redial · « **Reply #5 on:** September 22, 2003, 04:28:20 PM »

Doc,

In addition to the intra-bolt dry fire devices, we service rifle shooters are fooling with weights affixed inside the aft portion of the bolt carrier. They are sometimes held in with screws, depending on whose product it is.

The idea is to keep the bolt locked shut a nano-second longer when using heavy bullets and slower powders, which increase port pressure and tend to get the bolt open too fast.

Just a thought. No telling what you've got there! :roll:

Cheers!

Redial

gunnut69 · « **Reply #6 on:** September 22, 2003, 07:48:04 PM »

Well I'm glad you've figured it out.. I also enjoy talking with others who share the same interests. I've resisted the urge to own an AR and am not really sorry.. They are OK I supposed but just can really get to like them as I do the Garand... The Garand just feels like a rifle, albeit a heck of a lot of rifle at the end of the day!!

Doc Lisenby · « **Reply #7 on:** September 23, 2003, 03:50:46 AM »

Where you been, Avatar? We could have used your input before I put my self in deep concentration trying to figure it out. Can't afford much of that!
This one is aluminum alloy, I think, but in my mind, it shouldn't take much weight to get that slight delay.
Just weighed it and it is 574 grains, so I don't thing it is aluminum. It is just over 1 1/4" long. Being that this is a law enforcement weapon, it is probably for the heavier bullet, but I pulled one that they gave and it is a 55 grain boat tail, but that doesn't mean much (whatdotheyknow?). The issue heavier M855A1 has a 62 gr. pill. I noticed that the powder is spheroid so being as they get Gov. ammo. This device probably is a weight for the purpose you described.
Anyway thanks for the info. I'm obliged.

I know what you mean about the M14, Sir Moderator, but I like it. Hell, I only weighed 132 pounds when I lugged the Garand up and down hills in the Frozen Chosin in '50. With scope, pad and barrel thingey it pushed 14 pounds. I never noticed the weight, but did notice the cold.
Love, Doc

John Traveler · « **Reply #8 on:** September 26, 2003, 09:11:39 PM »

Doc and Gentlemen:

(Hey! that has a certain ring to it! *GRIN*).

Doc,

After re-reading your description of those two pieces of metal attached to the commercial AR-15 bolt carrier, I think I can identify their function. Two possibilities:

1. Several years ago, when do-it-yourself AR-15 kits were all the rage, there was a shortage of military bolt carriers. The commercial Colt AR-15 bolt carriers are modified from the G.I. ones by having the bottom rear of the carrier milled off. This was done to prevent the AR-15 bolt carrier from being used in illegal full-auto conversions. The lower rear end of a G.I bolt carrier is round in cross section, and serves to trip the full auto sear on it's forward motion, bringing the bolt into battery.

Some "clever" companies sold bolt-on devices that restored the AR-15 bolt carrier to G.I. configuration. The two pieces clamp onto the bolt carrier (where the metal was milled off) and are held togeter with cap screws. This supposedly restored a commerical bolt carrier to full-auto use, but is very unreliable.

2. Another after-market gadget for illegal conversion use was a weight inserted and screwed into the back end of the bolt carrier. It was supposed to make the AR-15 a slam-firing open bolt weapon.

I encountered a few of these things in police confiscated weapons during law enforcement weapons training seminars, and consider them to be strictly half-a**ssed substitutes for the real thing. Several states have banned the manufacture and sale of these gadgets intended for illegal modification of civilian AR-15 rifles.

HTH
John

Doc Lisenby · « **Reply #9 on:** September 27, 2003, 01:58:16 AM »

John, I think you've hit the nail on the head. This was one of two firearms confiscated during an attempted bank robbery, the other was a full auto "MAC10" :roll: I was told.
I guess these badasses were trying for more years in the Fed Pen. Might as well go for broke while your are going. They tried to rob a hick town bank about 20 miles from here.
I don't believe I would trust this device to convert it to full auto but it was successful ONCE, which caused me to have it in the shop. I stay as far away as I can from these types of firearms. Thanks for the info. I couldn't have figured it out mechanically. I, like you, don't believe that it is a very sound method.
Doc

redial · « **Reply #10 on:** September 30, 2003, 03:36:37 PM »

I betcha John's got it right! The carrier weights I described are rare birds even among target shooters, so that probably ain't it.

Geez, I hadn't even considered the auto sear activator thingy, since I haven't seen one in many, many years. Good call, John!

At the time they were popular, you could still readily find drop-in auto sears at most bigger gunshows and F-Troop hadn't decided what to do about them (they're on Form 4's now), but you still needed the bolt carrier doo-dad to trip the sear.

In any case, looks like you have an interesting fishing sinker there, Doc! Ain't these boards great?

Redial

S.B. · « **Reply #11 on:** October 19, 2003, 02:15:41 PM »

And to think, this rifle belongs to a cop. I guess the adage is right "who catchets the catcher".