i have a knights rail m4 but it seems to sit a little higher than my flat top a3 and seems to be off cant a little if looking fron the chmber to muzzle seems like it needs to go a little left how can i get this to line up
We had somebody here just recently with a similar problem Is the gas tube lined up straight?
if the rail is canted then the barrel nut isn’t lined up correctly as well (unless you have a defective RAS but I dont think this is the case)
I remember the other guy who posted this too.
I still don’t see how it’s mechanically possible. The gas tube goes in the upper at top dead center. The barrel nut has to line up to the gas tube hole. And the KAC rides the gas tube with the latch straddling the tube on either side.
The gas tube hole in the upper would have to be off center for any of this to get out of whack.
you guys talking about the larue rail? i was really hoping to get my hands on it… but now i’ll just have to dissassemble one to try to duplicate. going from memory, and the diagram of larue’s installation instructions, i just dont see how it’s possible either…
it’s kind of driving me nuts
HOW off is it? can you get a pic of the rails long-wise? i’ve never done a KAC rail, so i don’t know how they attach… but generally, if it’s just off by an emem or so, just loosening up the screws or lockring or whatever holds it on, bridging the gap with a rise or mount or something, and tightening it back down will fix it.
And if that were the case, the carrier key wouldn’t line up with the gas tube.
only problem I had with my KAC hand guard was I didn’t have a hand guard tool top rail went in fine after I removed the locking screw. The bottom rail I cursed for about 2 hours before it finely slipped in very next purchase was the hand guard tool [ I am not going through that mess again if I can help it]
markm right i would think that the barrel nut not being timed right would bend the gas tube and cause a problem with the gas key.
This is not an airsoft kac rail is it. Just asking …
What profile is the barrel ??
I think the KAC is only designed for the GI profile barrel.
its a bushmaster m4 barrel
Bushmaster uses a couple of different profiles is it thin or heavy
looks more like the top
i will remove the guard tomorow to make sure
yeah ill try to get u one
The barrel nut needs to be reset a little bit at a time until the RAS affixes to the rifle in top dead center.
The gas tube has enough flexibility in it that the barrel nut can still be off by +/- a few degrees.
Did you make sure the latch that markm is talking about–the one that straddles the gas tube–is correctly underneath the delta ring? Take the screw out of the top rail completely and install the top rail in a top up, horizontal fashion rather than holding the rifle vertically on a table to depress the delta ring. This should allow gravity to pull the latch down to clear the delta ring (as long as you have it pushed forward enough of course). I installed one on a bushmaster without a problem, but given their “issues” YMMV.
yeah did that it is snug under the barrel nut
In the past I had tried to install some KAC’s on Bushmasters and there was a slight fitting problem. Not sure where the issue was.
Have you contacted the MFG (KAC) to see if it is a KAC problem or a BM problem? There is a KAC rep on this board you know.
fit is all fine they said said it should fit all barrel dia on the model i have but its just that slight cant that drives me crazy its not loose fits snug
its just that i want to use a rail mounted front sight how much will that thro my poi off not sure