Hello All,
 I recently shot a friends AR in .45ACP. The receive is a Colt and we would find no manufacturer's markings on the upper. Any idea who makes one? or is this some weird Colt short run?

Regards,
Deven

There's a company that makes them primarily for law enforcement.  I can't remember the guys name right now.  What magazines were being used?  Were the front handguards different than standard ones?

it uses Uzi style 20 round stick mags. and the front hand guards short versions of the A2 guards. Similar to the "shorty" commando style 16's seen in many commando style movies.  :-)

LaFrance was the name I was thinking of.

I believe OLYARMS makes a 45acp Upper,but i have No idea what mags you would use.??? Troy??

LaFrance uses Thompson mags. Olympic uses Uzi mags. $585 from your local Oly dealer, for the upper I mean.
Cavalry arms is supposed to be coming out with a lower that will accept both AR/M16 mags and either Thompson or M3 Greasegun mags early next year. They won't tell us which kind of 45 mag though, the big ol pooh butts.

Tim LaFrance is a master machinist and builds top quality firearms.  The M16 .45 cal you are referring to is for LEO only.  I have never seen one up close but I assuming he notches out the mag well to accept Thompson mags.

You can now buy a semi-auto version of his firearm.  For $2450 I think you could find something much better or even buy a few AR-15's for that much money.  Ouch!

www.m16k45.com/m161.html

I have a Dalphon 45 upper that has never worked for me.  I believe the problem is that it is short-stroking the bolt and it is not cocking the hammer back after I fire it.  I have called them for customer service and have never been able to get through.  I will be playing around with different weight buffers to see if I can get it to work.

I to am waiting for these new AR 45 lowers to come out.  I prefer the stopping power of .45 over a 9mm.  

"Big fat slow moving lead bullets do the job!"

Quoted: Hello All,  I recently shot a friends AR in .45ACP. The receive is a Colt and we would find no manufacturer's markings on the upper. Any idea who makes one? or is this some weird Colt short run? Regards, Deven

Well, if the receiver is Colt.... and the upper is a 45ACP.... that must mean it is an Oly Arms upper...since they are the only ones who make uppers in 45ACP for use in a regular AR (not dedicated like LaFrance).

i have owned the oly 45acp upper.
it worked fine and was very accurate
even out to 100yrd. i was using mags
from dalphon with 28rnds and integral
mag block. i was not impressed with
the mouse trap ejector spring thing.
but it worked. i sold it and got a
458socom. oh yes!!!