KAC Rail Off Center – Can I Fix This?
I have a KAC MRE rail that is off center as seen in the pictures below. I would like to know if there is anything that can be done to correct it.
Looking from the top with the muzzle pointed away it the space between the barrel and the rail is smaller on the right. I do not have measuring tools to determine exactly how far it is off but I used a pin from an AR upper receiver block (about .25") as a simple indicator.
On the left side the pin slips easily between the barrel and the rail, I can move it back and forth without any friction.
On the right side the pin will not slip between the barrel and the rail except for the tapered end of the pin. The diameter of the body of the pin is too large.
The alignment problem has to be in the relationship of the rail to the upper since the carbine zeros and shoots properly.
Before I completely tear the upper down I was wondering what part determine the alignment of the rail to the rest of the upper? Is it the handguard collar?
When you assembled the rail to upper, did you use both Alignment Pins?
However, at this point I assume so.
What I have found successful in the past when this condition occurs, is to make small shims from aluminum foil and placing them above and below an Alignment Pin in order to "cant" the end of the rail in the desired direction.
This only requires a strap wrench to loosen the handguard nut. There is no need to loosen the barrel nut itself.
Yes both pins were used, I thought the pins just prevented rotation. You mean they bottom out in the hole they go in and can cause these types of problems?