folks,
just got a KAC ambi-single-point-sling-mount... you can see an example of this mount here:
ar15.com/forums/topic.html?b=7&f=25&t=165705&w=myTopicPopi have a problem with attaching my new mount, however, and i was wondering if anyone has seen the same thing. it seems that the protrusion on the KAC ambi-mount is too large to mate with my bushmaster lower receiver. let me be a bit more exact; out come my digital calipers...
the protrusion on the KAC ambi-mount measures 0.505" in dia. but the mating hole on the rear face of the receiver measures only 0.495". so there is 0.010" (10 thousandths of an inch) interference. i don't know what the design dimensions were supposed to be on either the mount or the receiver but it appears somebody is off one way or the other.
losdos.dyndns.org:8080/public/verymisc/KAC-oversize-boss.jpghas anyone else had this problem? note that my lower is a flat-top purchased from bushmaster in the last few months.
ps
be advised there was another problem with the KAC ambi-mount; the roll pin which prevents rotation of the buffer tube was pressed too far into the mount. thus, initially it was not possible to slip the ambi-mount over my buffer tube. i had to use a hammer and a punch to drive the pin back into the mount by some 0.015" or so -- until the mount could accept the buffer tube. driving the pin back in is, of course, very cumbersome because you can't hit it straight on; instead, you have to hit it an angle and hope it doesn't distort too much. i tried using a C-clamp but one small enough to fit into the buffer opening wasn't strong enough to budge the roll pin. anyway the folks at KAC should know of this problem as well as the more critical one described above.
jim aka ar-jedi