Colt AR-15 Lower

[hunter46spring]

I have a post ban Colt 6601 Match Target; Match H-BAR with a sear block. I use this rifle to shoot National Match Service Rifle competition. I am looking for advice on what to do with the lower. I want to replace the trigger group with a 2 stage and know that you can run into problems with the sear block. Does any one have any experience with machining out the sear block on these rifles? Does the entire block need to be milled out for a trigger group replacement? Will this leave 2 huge holes over my safety selector? My other thought was to replace the springs to get a lighter pull and try to polish the trigger sear. I like the idea of having a Colt Match Target lower and am trying to avoid replacing the lower (which I know is probally the easiets route)

 

[vellnueve]

Why bother? Find a new lower. Having it machined out will probably cost you a good chunk of what a new lower costs anyway.

 

[hunter46spring]

I like the idea of having the matched Colt upper and lower. I dont mind spending the money on the machine work I just didnt know if it could be done with out having the left over stud end of the pin falling out leaving a large hole on each side of the lower

 

[matt]

Timney will do the machining for you and install the trigger for an additional fee.

I don't know if the other brands require it, you might have to check brand by brand.

 

[SemiAutoSam]

Is this the block your talking about ?

If so when you machine out this piece you may be left with large holes where the pins were that secured the block.

I have a post ban Colt 6601 Match Target; Match H-BAR with a sear block. I use this rifle to shoot National Match Service Rifle competition. I am looking for advice on what to do with the lower. I want to replace the trigger group with a 2 stage and know that you can run into problems with the sear block. Does any one have any experience with machining out the sear block on these rifles? Does the entire block need to be milled out for a trigger group replacement? Will this leave 2 huge holes over my safety selector? My other thought was to replace the springs to get a lighter pull and try to polish the trigger sear. I like the idea of having a Colt Match Target lower and am trying to avoid replacing the lower (which I know is probally the easiets route)

 

[Dan S]

The Colt lowers with the sear block have large pins. Armalite makes a large pin 2 stage trigger, it should be cut for the sear block.

 

[7.62x39]

.. Does any one have any experience with machining out the sear block on these rifles? Does the entire block need to be milled out for a trigger group replacement?

Wouldn't machining out the sear block make the receiver capable of accepting a FA trigger group? Isn't that why they were installed in the first place?

 

[SemiAutoSam]

That was one of the reasons from memory but I dont recall there was ever a law that caused that sear block as some call it to be installed.

Colt just did it out of their own desire.

That area on my Colt receiver does not have that area milled out.


Pics and discussion here.
http://www.thehighroad.org/showthread.php?t=216816

Other sites of interest here.
http://www.google.com/search?hl=en&q=Sear+Block+in+Colt+Lower+Receiver&aq=f&oq=

Wouldn't machining out the sear block make the receiver capable of accepting a FA trigger group? Isn't that why they were installed in the first place?

 

[hunter46spring]

Wouldn't machining out the sear block make the receiver capable of accepting a FA trigger group? Isn't that why they were installed in the first place?

The lower reciever would still need to be cross drilled to accept an auto sear. The sear block takes upt the area wher the auto sear sits. If you look at the side of a FA there are 3 pin holes (trigger, hammer, and auto sear) rather than 2 in a AR config.

 

[Rob Boudrie]

Wouldn't machining out the sear block make the receiver capable of accepting a FA trigger group?

This is why the sear block is attached with pins much larger than structurally needed to keep the block in place - you have a big hole where a little one is needed for full auto.

 

[SemiAutoSam]

Your forgetting about the DIAS.

As it does not require a hole to be drilled.

The lower reciever would still need to be cross drilled to accept an auto sear. The sear block takes upt the area wher the auto sear sits. If you look at the side of a FA there are 3 pin holes (trigger, hammer, and auto sear) rather than 2 in a AR config.

 

[hunter46spring]

I installed a JP Enterprises light weight trigger in the rifle today. Between the reduced spring weight and polishing the sear surfaces I got a very crisp light trigger at @ 5lbs. I am very happy with the few rounds I put through it and it was a hell of a lot cheaper than machining out a sear block...who needs a 2 stage????

 

[MinesBroken]

If you ever do want to use a 2 stage - Jewel 2 stage triggers will fit in a Colt lower w/ sear block. I use one myself.

 

[Timberwolf]

Your forgetting about the DIAS.

As it does not require a hole to be drilled.

IIRC that was the reason for the block.

I had an SP1 that I could use a DIAS. The date of manufacture was about 1978.

 

[hunter46spring]

what is a DIAS? I assume it is an accronym for something something auto sear?

IIRC that was the reason for the block.

I had an SP1 that I could use a DIAS. The date of manufacture was about 1978.

 

[Timberwolf]

what is a DIAS? I assume it is an accronym for something something auto sear?

Drop In Auto Sear.