Well, I finally got to put my new build on paper.  The problem is that I noticed initally I was probably 5" to the left.  So I adjusted over.  However, by the time I got there, my rear sight (ARMS 40) is visibly over to the right... not ALL the way, but enough to suggest something isn't perfectly in line (I'm going to assume my indexing of my barrel is the culprit).

However, my question is this. Will any of this be a issue if I choose to slap a red dot sight on top?  Will this make me adjust optics too far?  Is it worth tearing this down to try and find the alignment issue, or am I okay?

Thanks,
Gundraw

You could try to re-index your barrel, if you have the proper tools. There is also the slight possibility your FSB is mounted a little off as well.

If the windage adjustment  doesn’t bother you, and you obtained a good zero, you can leave it as is. It will not effect the installation of a good red dot optic such as Aimpoint or EOTech. They are built with ample adjustment room, the EOTech for instance has an adjustment range of +/- 40 MOA travel! Not sure on the Aimpoints travel, but I’m sure it’s close.

I had an ARMS #40 and had the same problem. I switched to an RRA Dominator and didn't have that problem. One of the better moves I made regarding my weapon.

How do you reindex a barrel? I may have to do this also as my ARMS #40 is all the way right and I'm still boresighting and shooting left.

I happen to have a barrel extension wrench already.

Quoted: How do you reindex a barrel? I may have to do this also as my ARMS #40 is all the way right and I'm still boresighting and shooting left. I happen to have a barrel extension wrench already.

Go HERE scroll down to the barrel install section.

or just whack the fsb with a mallet in the direction you need it to go. usually there is minimal "play" or room for the bbl's index pin to move within the upper's notch for it to allow that much sight cant.

majority of the time it is a canted front sight base which is easily fixed with a mallet.

Thanks for the info!

Quoted: or just whack the fsb with a mallet in the direction you need it to go. usually there is minimal "play" or room for the bbl's index pin to move within the upper's notch for it to allow that much sight cant. majority of the time it is a canted front sight base which is easily fixed with a mallet.

I'm a little nervous about doing such a thing.  Should I just whack the FSB closer to the top?  Will this cause any adverse side effects, like galling, or stressing the barrel, or putting the FSB pins in a bind.

Is there any way to check if the barrel is tight enough?  Now that all this has come up, I'm second guessing myself.  I know when I installed the barrel, it felt like it took a nice amount of torque to line up with the gas hole, but the DPMS wrench isn't REAL long.

Any suggestions (as you can tell, I'm getting paranoid now...)

Gundraw