Colt Pre Ban AR15 Question
I see the above rifles advertised on Gunbroker Auctions with a "Blocked" and with a "Not Blocked" Receiver. What exactly does this mean? I own a preban Colt AR15 Rifle and have no idea what the above terms mean.
John
John in PA
Edited by - capecod on 09/14/2002 11:58:33
John
John in PA
Edited by - capecod on 09/14/2002 11:58:33
0
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The blocking described refers to the area in the lower reseiver just above the selector and ahead of the take down pin. Originally this was a hollowed out area- and still is in many AR types like Bushmaster. Over the years it was discovered that it was possible to convert an AR to full auto by inserting certain devices into this area AND WE WILL NOT DISCUSS THIS ANY FURTHER! Colt decided to eliminate this possibility by blocking off this area. Originally this was done with a sort of blind pin which ran through the lower and held an actual block of metal (marked COLT). I have a number of AR-15 law enforcement rifles with this feature. Later the entire area was left basically unmachined, with just enough opening remaining for the fire control assembly to function and clearence for the selector and take down pin. I have a some later Colt L.E. rifles which have this feature. I have never found any differnce in the functioning of any of these Colt types. The pre- 1989 rifles have no blocking and many people may find this attractive for their own reasons...besides being pre-ban! I would not pay a penny more because of this feature alone, as it in no way improves the rifles performance. This is a very brief look at a complicated subject- Colt AR-15's.
"Trust me, I know what I'm doing!"
Mark T. Christian
Edited by - mark christian on 09/14/2002 14:22:540 -
Thanks Mark: Thanks for the info - based on what you told me I have no interest in altering my AR15 in any way so block or no block becomes a non-issue for me. I just didn't know what the heck they were talking about in their ads.
Thanks again
John
John in PA0 -
Cape Cod, I never for a momment meant to imply that you might be interested in altering your AR-15. The methods of doing this are known to many of us in the business but I would never discuss them in such an open forum as you never know who is reading these posts and for what purpose. I have my doubts about one particular individual! Colt's modification to the AR-15 took place at the same time they re- introduced it to the commercial market as the "Colt Sporter", along with removing the bayonet lug. I am unaware of any other AR rifle maker who has done the same type of lower receiver modification. With the older pin-block rifles it is more difficult to clean that area of the lower receiver, but that is the only problem I've encountered.
"Trust me, I know what I'm doing!"
Mark T. Christian0 -
Mark - I never thought that you implied the above or took any offense - I am sincerely thankful that you took the time to explain the terms to me. I have a fine Colt preban AR15 Rifle - accurate as can be - but although I never would sell it, I was curious what the current prices were listed on the Auction - that's where I found blocked and no blocked mentioned so many times in ads. Well I learned something today - thanks again for your help.
Regards,
John
John in PA0 -
The one thing that the block does cause problems with though, is if you ever plan to use a different bolt carrier, match grade, hard chromed, etc. With the block rising up out of the lower receiver, you must use a bolt carrier that is open on the bottom from the firing pin all the way back to the back of the bolt carrier. A standard AR15 bolt carrier will not fit into a Colt AR that has the block that protrudes up into the traveled channel of the upper receiver. A standard AR15 bolt carrier has a solid area at the bottom at the back. It is there, in part for strength. 0 -
Ira, that would explain why the later rifles did away with the block and left the area above the selector more or less un machined. I just assumed it was changed to make that area even more tamper proof! Does anyone offer a match grade carrier that will fit a blocked lower? Mine are all LE sales samples and not target rifles but I'm interested
to find out more in case this question pops up at a demo. Thank you.
Mark T. Christian0
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