I have a Colt Competition Match HBAR with the sear block and I have just purchased a Colt preban 9MM complete upper with the semi auto carrier, can I use this without removing the sear block or should I just use my Colt green label lower without the sear block? Thanks John

If memory works correct, the upper may not close or bolt operate on the "blocked" lower. All you can do is attach the front at the pivot pin. and attepmt to close the upper.

You will have no problem with the "[green][size=2]GREEN[/size=2][/green]" label, other than the "large" pivot hole on the lower and hopefully your 9mm upper is a "large" hole upper also, or else you will need to get an adapter pin to assemble the rifle.

Also to use the 9mm upper on the "[GREEN]GREEN[/green]" label, you will need to obtain a hammer that looks like this --
[img]http://www.imagestation.com/picture/sraid58/p7a21929478de21856da2653f457a76fc/fc681fb2.jpg[/img]

I believe the advise above is correct as I have a pre-ban Colt Match HBAR that the previous owner had filed the top of the sear block down flat (about flat to top of lower receiver) and he said he did this for the lower to work with a 9mm Bolt.  I have used this lower with the filed down block with my 9mm and Ciener conversions and it works fine.

In the past, and I don't have it now, I did have another that didn't have a filed down sear block and that lower would not close on a M-16 carrier which is a VERY GOOD indication that it will not close on a 9mm Bolt.  Back then, I didn't have a 9mm Bolt so I can't say for sure!

Good Luck!

Thanks for the good info. I'll just use the Green label lower instead of messing with the sear block. Also where do I get one of those hammers, thanks John

I've milled out the part of the bolt that would hit the sear block for a few people. Easy fix.

If it were me, I'd just file/dremel/mill off the top section of the sear block.  This is (apparently) totally legal to do, and this way you don't modify your (somewhat) valuable bolt (If you ever want to use it with a RDIAS or RR lower, you won't be able to anymore), and just modify the worthless part of the problem (the POS sear block).

If you ever sell the Colt with the block hacked up, people tend to shy away....just cause they don't know you don't have to have it....