From the pix, one thing to check is if the autosear pin hole was drilled absolutely perpendicular to the receiver wall. Inthe horizontal pic, it appears that the autosear is slightly canted to the rear, compared to the takedown pin. This is not uncommon for RR conversions –– the drill started out in the right location but the bit cut at a slight angle, so by the time it reached the far receiver wall, it was out of position.

An autosear with a slight angle to it can pass the "static" release test and still move freely by hand, but the geometry is off just enough that when running at 12 cycles per second (750 rpm), it fails to function correctly.

If that is not the culprit ... I will second the above vote to go back to Gene Stoner's original design.

Get Colt fire-control parts and all brand-new springs. They are a known military contractor/supplier, and you know that their parts are not just attempting to reach the milspec, they have passed .gov quality control.

Install a USGI rifle receiver extension (buffer tube), with a correct milspec rifle-length buffer and a new rifle-length recoil spring. Make absolutely certain that it also is straight and alinged with the receiver.

Borrow a low-mileage Colt 20" milspec FA upper, preferably an M16 or M16A1. Use a new Colt BCG, or else make sure the bolt carrier is properly staked, the gas rings as-new and correctly aligned, etc.

Use only as-new USGI contract mags that have been test-fired in another gun for function.

In other words, build a complete, as-new GI-issue 1960s era Colt M16/A1 around your receiver, as originally designed by Gene Stoner and manufactured by Colt to Armalite's plans. That way, you eliminate all the variables.

If it still does not run, send your receiver off to M60Joe, because there is something seriously wrong with it.

If it does run, start swapping in one of your components at a time, until you have tested them all.

And keep the Colt FCG parts and new springs. Trust me, you need them.

HTH.

Brownells, or Specialized Armament Warehouse (http://www.specializedarmament.com), or Dennis Todd ([email protected]) ... authorized Colt LE dealers and distributors often either stock them or can order them for you.

Yup. That's the problem with non-Colt "milspec" parts. Here's what the Colt, true milspec looks like:



You can see how you can have functional issues. Sigh.

Also BTW, if the hammer is that far off ... who knows what dimensions are off on the trigger, disconnector and selector.

Bite the bullet, buy Colt. And start shootin'.

BTW, if you have a C&R FFL you can get dealer pricing for parts from Brownell's, which cuts the price for the "A1" hammer from the $55 retail to $44 ... and if you watch the boards (in particular subguns and sturm) and know what true milspec parts look like, you can often find a complete NIB Colt set for well under $200, sometimes as little as $100.

Good luck!

James, over the years I've dealt with several Oly conversions that had a too-high top deck –– the top edge of the lower receiver where it meets the upper receiver –– as well as incorrectly located rear takedown pin holes. In some cases, you could modify the parts involved rather than touch the receiver itself ... but it often caused functional issues down the road.

You are correct about replacing the autosear –– I consider that part of the fire-control group, and when replacing the FCG, the sear needs to be done as well. Sorry I didn't point that out.