Have a question. I am gettin ready to get another AR15 - this time I wanted to get a Pre-Ban, but the other day I was told that not every PRE-BAN AR15 can be made into a full auto rifle.  This man at my local gun shop said that only certain AR15's don't have what is called a sear blocker.  Does anyone know what this is and what to look for when purchasing a PRE-Ban?

On Colt's its a big honking piece of metal behind the trigger assembly marked Colt. You will see it when you split the rifle.

OK, first off, since May 19, 1986 you can no longer convert a new rifle to full auto on a form 4.

Which means that you are not going to be able to drill the hole for a standard auto sear to drop in.  The only way to convert an AR-15 for civilian ownership is to buy a  pre-registered conversion device such as a RDIAS or RLL.  Now here is the rub, since the device, which was registered before the cut off date, is the MG it's self, the rifle becomes a host and does not need to conform to the pre/post ban rule (as long as the device is in the rifle).

The reason that I bring this up is once you have the registered auto device and installed in a rifle, no matter whether if it's a post or pre ban, the rifle is simple a host for the NFA item and the semi auto rifle rules go out the window.  If you’re looking for a rifle to drop a RDIAS in, buy a post ban receiver, M-16 parts kit and be done with it.  As for the COLT pre-ban to full auto, your going to need to change out a lot of parts for a DIAS, and will waste your money since once the NFA item is installed, the rifle is a NFA host, and not a pre-ban rifle any more.

Hope this helps.

Xyerik, do you plan on buying a [b]REGISTERED[/b] Drop in auto sear (DIAS) or lightning link (LL) and filling out all of the proper paperwork?

This is going to cost you about $6000 to $10,000 to do.  Just the needed legal parts.  Plus the tax stamp and background checks, and chief LEO signatures and such.  In the end you would be better off just finding a transferable m16.

If he stands (as he rightfully can) on the Second Amendment, then: "IBTL."

[;)]

I was actually looking at getting a drop in auto sear I have seen a couple for sale from time to time, but never knew of all the issues that I would have to deal with.  As to just buying one already set up, If possible, I would much rather build my own - that way at least I know what I am getting.

I would recommend you do some research and learn all the "issues" first.  It's not as easy as buying one off ebay and dropping it in.

Do your homework.