On Mar 2, 9:40*pm, "RogerN" wrote:
It seems the bolt carrier group is the hard to get part for AR-15's
currently. *I have found old Colt M16 A1 parts kits, "good to excellent"
minus lower receiver and barrel (plus missing auto-sear or disconnector).
Would the M16 bolt carrier group be good in an AR-15?

I found some bolt carrier groups in stock for $300 but the M16 parts kits
are available in the $500 - $600 range, seems to be a better value maybe. *I
read a review of one of these parts kits being assembled, they said it was a
good shooter.

RogerN

The M16 parts WILL fit in an AR, it was common practice back in the
first days of building AR clones to use surplus M16 parts from
scrapped rifles. However, BATF eventually frowned on that because,
with some added bits you can go full-auto, or even without, a
improperly timed build can double. So, if you use the whole kit, you
need to remove the secondary sear hook from the hammer, grind back the
auto sear trip surface on the carrier, and lose the full-auto selector
entirely. Disconnector tang needs to be ground to semi-auto
configuration, too. At one time, there was an AR FAQ on the ATF site,
might be it's still there. As far as parts quality, the kits I've
seen for sale were from Colt-made commercially sold M16s supplied as
military aid to several countries, warehoused and never issued. They
can't come back as complete guns, so current practice is to strip
them, scrap the lowers and barrels and import the rest. Some kits for
sale had the auto sear and spring when they were first imported, those
were taken out with later kits. You do NOT want them unless you like
10 year vacations. Quality on those parts kits is the same as new
Colt-made parts of the same era. Barrels can no longer be imported.

So the problems with M16 parts in AR builds aren't mechanical, they're
legal. At this point, somebody starts saying that none of this is in
any law( and they're going to do it anyway). And they're right, it's
BATF's own interpretation, subject to change without notice and with
every change in administration. Since Congress has left legal
interpretation of the law to BATF, this is the result. They can do
just about anything to your gun, should they seize it, to get it to
fire more than 1 shot with one trigger pull(and have done so). Then
it's a machine gun and you go to jail. Just having M16 parts along
with an AR has been taken as having "constructive intent", it's just
flat too easy to convert. If you've got the M16 auto sear and spring,
it's just one hole's difference. So they need to be altered just as
soon as you get them. You do not want to end up in court because M16
parts kits are currently cheaper than AR parts. Just using an M16
bolt carrier with all the rest being AR parts SHOULD be safe legally,
the trip surface should probably be shortened to be completely safe.
Your choice...

Stan