Well, I finally got to print some groups with my BUIS (ARMS #40 rear and "F" FSB).

I found the gun shot about 5 inches right at 100yds.  It seemed to take quite a few clicks on the ARMS 40 to get her straightened out.  However, now that I have, the rear sight aperature is VISIBLY to the right.

Is there any reason for me to modify the index pin slot?  I was planning on putting a red dot sight on at some point, maybe and EOtech.  Will this misalignment cause problemswith than in any way?

The index pin seemed to slip in nice and tight when I built it.  I torqued and loosened the barrel nut a few times, and it seemed to take a good amount of torque to get to the next gas tube hole (so it shouldn't be loose).  Does this stuff just happen?  

BTW, it's a Denny's Gun Operator barrel in a CMT M4 cut upper.

Gundraw

Absolutely.

Here you go:




You can see that I have used quite a bit of adjustment to the right.  It doesn't seem WAY out of line, but enough I wanted to make sure I shouldn't do something about it.  The barrel seems plenty tight.  I remember installing the barrel nut with quite a bit of torque to get to the next gas tube hole (and, I did the tighten loosen 3 times routine just to be sure).

Thanks!
Gundraw

taggage

Mine does the same thing, but it shoots way off tot he left.  I have talked to ARMS about it and they still have not done anything to remedy the situation.  This has been going on for 2 years.  It is on a Bushy 14.5 AK.  When I put the carry handle back on it shoots just fine.