I have an older Colt 6520 Government Carbine (produced just after the AWB). It has the SA non-shrouded firing pin. In my research, people “suggest” a shrouded BGC over the non-shrouded.
Their logic makes sense, but has anyone actually experienced a failure due to a non-shrouded BCG? While I can understand the theoretical reasoning, I haven’t read any facts.
Several years ago I fixed a Colt that had very rough ragged edges at that bevel cut and clean up the edges at that cut because it was causing functioning issues interfering with the operation of the firing pin firing pin and jacking up the hammer. Had it had a non-notched hammer and a shrouded carrier it wouldn’t have ever had that issue.
Neutered BCG’s are a waste of time and money and exist solely because of stupid laws (previous or imagined).
Thanks Robb. That’s the kind of response I was looking for. Everyone has an opinion and I’m looking for answers that can back it up with fact rather than opinion.
If I opt for changing the OEM BCG, will I need to change the hammer too?
You don’t have to change hammers but I always prefer a non-notched hammer when using a stock/OEM type trigger group since it was designed that way.
It wasn’t an opinion. The AR15 as designed was supposed to use an auto BCG. All of the neutered crap came about as ways to make people happy that the weapons couldn’t be converted to auto.
So you should use whatever BCG that isn’t neutered in your particular weapon.
Because of the Colt anti-FA block in the lower, it appears that I’d have to use one of the two middle BCG pictured above. My BCM BCG obviously doesn’t fit. Again, thanks for your help.
Cut that thing off or better yet sell your rifle to a collector and buy a new one with the correct carrier and pin sizes. As a tool I don’t think there is a good reason to keep a non standard AR around (unless you need a pre ban in your state).
They’re called sear blocks. They can be cut out. I took one look at one and decided not to do it myself (or even to buy the lower). ADCO has a good track record of successfully removing them. Suggest you give them a call, get it cut out, and get a non-homo BCG. I’ve never had to use a non-shrouded BCG so I can’t directly answer your question. Just offering an alternative solution that would allow you to use standard parts.
Discussion about this “Era” of Colt rifles comes up around here every so often. Some “Knowledgeable” folks put them down while other “knowledgeable” folks say run with them they are fine. The parts in them still went through the same testing as non neutered rifles but were just made to be harder to convert.
I asked this question a few months back:
Has anyone ever run one of these Colts hard, like through a carbine course. No one replied, but my guess is that they would run just fine.
So…has anyone done this ? Or, are these opinions just based on conjecture ??
They chew up firing pins and FP retaining pins from what I have seen. They would probably run just fine, but there are other reasons that make a standard AR a better choice for hard use.
They use a special FP, can’t interchange BCG because of the sear block, and have non standard FCG and take down pin sizes. If your carbine goes down it is more likely nobody will have a spare that fits. Swapping parts from a known good AR to trouble shoot is also going to be difficult.
OP,
With due respect, I think your question is moot. The original stoner design was engineered that way for a reason. The modified design that you possess was modified by law makers who didn’t know dick about guns. With no experience, they passed a series of laws because they thought that you were a bigger danger than the Ruskies.
I would take whatever measures are most cost effective for you to employ a FA bcg from BCM/LMT/Colt/DD.
As has been previously stated, a collector would most likely pay good money for your carbine. You may be able to get a brand new carbine for little or no money out of pocket. If it’s me (and it’s not) I explore that option.
If you plan on running the gun hard, why mess around with variables when there are known-quality parts that are certain to fill the bill. Eliminate as many variables as you can.
It’s not a “moot question”. It’s a good question. Ted wants to know if anyone has had the carrier in question actually fail on them. In other words, do these carriers actually fail , or is it just folks duped by another internet myth? Look how well the internet keeps alive the myth you can get Colt quality and save money by buying an AR of questionable lineage. It’s good to get the facts out
(Let me be clear- I do not claim that the SA non-shrouded causing problems is a myth. Quite contrary I have seen the facts for myself)
Thanks for you answer Todd but you kind of say two things. First that they chew up firing pins and retaining pins and then that they would probably run just fine. I totally get the fact that if given the choice one should go for the “Un - neutered” rifle. However, there are many neutered rifles out there, so…are they better then perceived ?
Remember, good old Colt just went back to the correct size fire control pins a few years ago. (would have been tough to change these parts in the field) And, they have finally stopped carving the LEO / Military info on the sides. Both, in their own ways types of neutering.
If you want to go to a carbine class, and shoot a few hundred rounds every month then just buy a couple spare firing pins and FP retaining pins. It’s not going to self destruct.
If you want a gun to run hard I think you should choose to make it a standard AR. If you are running hard you should stock spare parts and then eventually you will want a back up/go to carbine. You can try to find another old Colt when you do, or you will end up needing to stock two different spare parts sizes.
You can make those ramped carriers useful in a Rifle gas system where the bolt cycle is less violent. On a carbine gassed gun, definitely get a 16 carrier.
During the late '90s, I sold Colt SP I and SP II uppers and stocks, retaining the BCGs and lowers. I bought Colt uppers, barrels and carbine stocks from from YTM. (Quality Parts, i.e. Bushamster, was pretty much the only other source of parts.) From 2003-2006 we ran several (three) of these FrankenColts through 1300 to 1500-round EAG Carbine Operator Classes without issue.
In 2006 we took Colt armorer instructor Dean Caputo’s AR Diagnostics class in conjunction with an EAG class. Dean said using the original unshrouded Colt bolt carrier was GTG but might result in more wear on the firing pin and retaining pin. However, given that Colt was then shipping ARs with standard BCGs, he opined that, if possible, changing shrouded for unshrouded BCGs was a good idea.
Last year we sold the last SPI carrier in the gear locker, replacing it with one from a 6920. Until that time, still had no issues with the unshrouded BCGs.
YMMV.
During the 90s my Dad bought an LE Colt that came with the Ramped carrier. He qualed with it and took their class. That gun never had any issues.
Not sure how hard they were running those guns back then though.
The modified design that you possess was modified by law makers who didn’t know dick about guns.
Not really. Colt elected to make the changes.
Back to the original question. I have a 6721 that was purchased around '95 for a patrol carbine. It had the shaved half-moon carrier with exposed ramp. That carbine was ran hard, went through several high round classes and there were no function problems. However, the carrier eventually experienced unusual wear (from hammer contact), firing pin retaining pins were beat up and swapped often. A few years ago I finally swapped out the carrier, not because it had failed, but because there wasn’t really a downside (other than cost) to having the originally designed part in place.
Yep. That’s the model I was posting about. The LE6721.