Ok this sounds crazy, but i just noticed it....

i have a colt bolt and bc that i use frequently in my ar's.  i find that it just always seemed to operate "smoother" and feel like it was guided on ball bearings when ever i would charge a rifle w/ this bolt+bc in it. i have other bolts+bcs made by various manfacturers, and they never feel as smooth as the colt does.  i mean they opperate fine, but they just dont feel as good.  i was playing around with a carbine setup i just put together, and decided to swap in my colt bolt+carrier to see how it felt.  I just noticed this.....look at the pics.....

A "regular" bushy carrier top and the basterdized colt one bottom
side view

top view



the metal on the rear of the carrier on the colt has been completely machined off.....
is this the reason for the smoother feel, perhaps less mass?
will this in anyway fuck with anything, and what is the purpose of teh machining?
i consider myself to be pretty knowlegable about ar's, but this one has me stupmed.  i have never seen anything like it.

my only idea is that it is a colt carrier, and colt being the pc fucks that they are, made a carrier that would not actuate a lightning link if one were installed?

are all colt bolts like this?  i KNOW sp1 and sporter ones arent like this

please help!

left to right........RRA AR15 carrier, RRA so-called 'enhanced' AR15 carrier, Colt M16 carrier.

i dont think u get what im sayin......look at the metal "ramp" in the back of the carrier shaved off of the colt one as opposed to any regular ar carrier.....

Its designed by Colt to make full auto impossible.  The pin ramp is removed to expose the AR15 firing pin so the notched hammer can catch it and jam up your rifle good if you have a disconnector malfunction.  The removed shelf is so you cant pu tone of those spacers that converts the carrier back to M16 spec so it can trip an auto sear.  This is a big problem for Colt as its so easy to drop an auto sear in their lower with that sear block and how easy it is to find large hole auto parts.  Essentially it was done for the purpose of making your upper not work with a full auto lower.  It does decrease reliability and speed up the guns action.  I only run M16 carriers in my uppers for this reason.  This may never be a problem for you... much like M4 feed ramps, or green followers in your mags, or stronger extractor springs, or H buffers, or chromed barrels and chambers, or... well you get the point.

People seek those carriers out for ultralight builds if you wanna sell it in the EE and buy an M16 carrier to replace it.

Quoted: i dont think u get what im sayin......look at the metal "ramp" in the back of the carrier shaved off of the colt one as opposed to any regular ar carrier.....

Some call that a non-full circle carrier.  These were made for clearing the lower reciever block that Colt feels they needed to install to keep they're owners from putting in a Lightning LinK or RDIAS.   Won't really mess up anything but they cause the carrier to be much lighter than Eugene Stoners original design.  Heavier=better.

i c, i forgot about those stupid colt lowers with the pinned in sear block....i get it now, so basically, you could only use this bolt carrier in one of those guns, but it will function in "normal" spec lowers as well.

another thing i just noticed is that you can clearly see that this carrier started life as an m16 carrier.....you can see where the "circle" was machined away at teh factory, pretty neat actually.....

one more thing.....aren't m-16 carriers illegal in an ar-15?

isn't a ar-15 with ONE single m-16 part an unregistered machine gun?

i know most parts are the same, but i mean m16 specific parts like the hammer, carrier, diconnector, etc

Quoted: another thing i just noticed is that you can clearly see that this carrier started life as an m16 carrier.....you can see where the "circle" was machined away at teh factory, pretty neat actually..... one more thing.....aren't m-16 carriers illegal in an ar-15? Nope isn't a ar-15 with ONE single m-16 part an unregistered machine gun? M16 carrier can be used but it puts you one step closer to a machinegun.  IOW if your rifle doesn't double its not a machinegun i know most parts are the same, but i mean m16 specific parts like the hammer, carrier, disconnector, etc

Colt seems to be smoother, even the SP1 carrier I tried was like this, and its in between AR15 and Colt full cut.

I think its the finish they used and the surface machining quality.