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Posted: 3/14/2009 3:38:20 PM EDT
| I was having a look at my dad's pair of Colts today and on both of them the safety selector is very difficult to move. It move freely from the fire position to about half way to the safe position and then requires much more pressure to get it all the way to safe. I opened them up to see if I could tell why that is, and there is an extra part there above the safety selector inside the lower. This part is not present in any of my Armalite, RR or TI lowers. I really can tell what this part is or what it does, but I did notice that it is held in the lower with some rather large pins that are visable on each side of the lower. It looks like a square bare of some sort and "COLT" is imprinted in the top of it, so I guess it is some sort of Colt specific thing? Can anyone tell me what this part is and why it might be causing the safety to be difficult to move? |
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Was the hammer down/cocked? If not, the safety cannot / will not go into the 'safe' mode.
If the hammer is down and the selector is still difficult to move, then the pin that holds the selector switch might need to be checked. To do that you'd have to remove the pistol grip. The receiver block should not interfere with the selector. |
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Yes, the old style sear block is what I'm seeing.
I took the grip off one and removed the spring and detent, and the safety was still difficult to move to the safe position. The hammer is not down. the selector will still go to the safe postion, it is just much harder then it should be. My dad tells me he had the trigger groups replaced recently, so I think these need to go back to the smith that did that work. |
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You have the infamous Colt sear block, a device designed by Colt to prevent the great unwashed from converting their rifles to full-auto.
It is not supposed to interfere with operation of the selector, but as you can see from this drawing, the selector (part 220 in the drawing) does pass through the block and is quite close to the selector. I would bet that you have some shavings or something in there that is causing it to bind. I would pop the selector out and flush the receiver with compressed air or a cleaner of some sort. 
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| I have no idea if the trigger group is colt. I was reading the text on that patent info posted above and see where it says it restricts the type of group that can be installed. Iam begining to suspect these might not be the correct groups. I would take one out, but these were installed with anti-walk pins with "C" clips, and I don't have the tooks to mess with them here. I'm going to see if I can get one of the safety selectors out. |
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The sear block is removable, the following is copied from an archived thread:
I got tired of looking at the blocks in my 2 Colt prebans, and when I couldn't install RRA 2-stage triggers because of them, they had to go. I have done this twice now, and if you are very careful, you won't scratch your lower, at least not on the outside. The drill it/Marvel mystery oil/hydraulic method has been proven to be bunk by a few that have tried it, besides, whenever you push the blind pins out it creates an ugly raised lip on the aluminum at the edge of the hole. My method leaves the pin in and preserves the stock exterior look of the lower. PS these lowers only had one blind pin thru the side; I have seen some with two and even three blind pins thru the side of the lower - this won't work on those - you'll have to mill those out. Here's how I did it: Strip the lower internals and find some duct tape. Using a Dremel with a new cut-off disc (buy the little jar full of them - you're going to need a lot of them), I first CAREFULLY make a thin cut thru the block close to the edge of the lower, and then a second one down thru the raised portion of the block - you need clearance here for the Dremel shaft to make the 1st cut as deep as you can. I used a bit of Kroil as a cutting agent and went slowly - I still broke a lot of wheels. 
1st cut is started on right, 2nd cut thru the raised portion almost done. 
Make a sideways cut to remove the piece of upper block. 
Cut the thin slice as deep as you can, use some tape on the lower so the Dremel shaft doesn't mar the finish. You want to cut thru and well below the blind pin. I then cracked off the thin piece by bending it back and forth. Once this is done, grab the block with a big pair of channel lock pliers and wiggle it until the inside blind pin (a roll pin) breaks and the block can be wiggled forward and out. All done. 
Another view. 
Pin is still in, looks stock. 
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Quoted:...it says it restricts the type of group that can be installed. Iam begining to suspect these might not be the correct groups.
That shouldn't be a factor. The parts that are restricted by the sear block are the hammer, disconnector and bolt carrier. Any selector should work OK. All US patents are freely viewable at the Patent & Trademark Office website, if you are interested in the whole thing. You will need to download a TIFF viewer to see the full images. |
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I would try this:
Remove only the selector switch and the detent pin/spring and pistol grip. Reinstall. Hammer cocked back. (careful not to drop the hammer without upper/BCG on) Insert the selector; it should move freely in both positions, safe/fire. Align selector to vertical 'fire' position. Hold selector in with thumb pressure. Check to see if the trigger will drop the hammer freely (CAUTION: don't let the hammer slam against the bolt catch––-catch the hammer with your free hand/fingers...ride the hammer slowly forward. Now see if you can move the selector to 'Safe' position...should not be able. Cocked the hammer down/back. Install the dent/spring and pistol grip. If problem still persists...then you'd have to make sure all the other trigger components are properly installed. It's very easy to have the springs installed incorrectly. Little minor thing can throw the entire unit out of wack. |
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Quoted:
Yes, the old style sear block is what I'm seeing. I took the grip off one and removed the spring and detent, and the safety was still difficult to move to the safe position. The hammer is not down. the selector will still go to the safe postion, it is just much harder then it should be. My dad tells me he had the trigger groups replaced recently, so I think these need to go back to the smith that did that work. Are you saying the hammer is not cocked? It is not supposed to be able to go to safe if the hammer is not cocked. If it does there is a problem. |
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