Vortex Viper finally showed up for my FNX-45.  Problem is, the viper has locking screws that keep its windage and elevation adjustments from wandering. The locking screws are on the back of the RDS, facing the shooter, and are blocked by the suppressor-height sights.

Before I ship my slide off with $30 for this mod, anyone got a better idea?  I drifted my rear sight back and forth a bit last night, and this seems somewhat doable, but I'd like a long-term solution.

http://primarymachine.com/drill-access-holes-in-rear-sight-for-vortex-viper/

Could you cut an Allen wrench down close enough to fit it in there. It's pretty close to the sight but if its small enough it might work?

It's actually a flat-head screw instead of an allen head.  But no, given the time-value-of-money, this would not be worth it.

Then i would send it to be milled.

Milled? FNX-45 came milled from the factory. Am I misinterpreting what you're saying?

Primary machine says they can't/won't do the work.  There's not room to get even the smallest of hex keys between the rear sight and the RDS.

I have a glock MOS with a Viper RDS, and am interested in what you find out.

What service is Primary Machine not wanting to do?  Drill the sights on your FN or modify the Viper RDS?

You can try the above post about unmounting and remounting it, but are you going to loose your previous zero when you remount?

Lose*, yes.  That's a non-starter.

Primary Machine doesn't want to drill the sights.  He didn't say why.  Just asked me to send pics of my gun and replied that he couldn't do it without affecting the hammer spring.

I called Vortex. They said just loosen the lock screws and leave them that way.  Said they've done lots of testing and haven't had any issues with the zero moving around.  I may run with it this way, or I may drift the rear sight left and right as needed to access the lock screws.  After a day of pondering I think my original way is still the best way.

That sound like a Bullshit excuse. Where he would be drilling is no where near the hammer spring.

Agreed. I don’t reward laziness. On the shit list they go.

Hmmm.  I wuz thinking, how about making some custom adjustment screws; something with a thicker head, that would extend out past the housing but not touch the rear sight.   Something with aggressive enough cuts in the heads that could be used to turn the screws with a flat-tipped screw driver?  I'm looking at the heads on your two mounting screws and thinking something very similar to those might do the trick.  Or if present screws will not remove, pin and epoxy extensions directly to heads.

Option two.  Same as above, but drill small holes through same extended screw heads and fit with a roll pin to aid in turning screw.  Might not get full range of motion, depending on length of "cheater bars", but might be enough for fine-tuning after rough zero.

Option three.  Same as above, only leave holes empty and fit with "cheater bar" (modified allen wrench or similar) when adjustment required.

Option four.  Same extended screw heads, but drill multiple holes around perimeter of head (maybe three through-holes for six adjustment points).  Now use "sight adjustment tool" to turn as required.

Not perfect but good field expedients.

Sell your viper and buy a new red dot with adjustments on the sides.

The adjustments *are* on the sides.  The locks for the adjustments are not.

Ah! You can buy a rear sight adjuster. Mark it where it is. Move it to the left then right (just enough to reach each lock dial) and lock each dial then move it back to your mark.

I have a rear sight adjuster.  It's called a punch and a vise and a brass gunsmith hammer.  Works fine.

Will the tapping move your red dot before you set them?

Have not specifically tested for this but guessing the reciprocal movement of the slide is more force than a couple tappy-tap-taps with a drift punch.

Simply zero your red dot with the rear sight removed, then lock the adjustments in place and reinstall & zero your iron rear sight. This would work best if you don't feel the need to keep adjusting the red dot for some reason.

Dr. Who sonic screwdriver?

Is there any reason to not add the hex set screws, and maybe have a shop mill the rear sight length shorter?

That's not a bad idea, the second part specifically. So far I have not had any movement of the dot.  I wouldn't trust my life to it, but for a hunting sidearm it's fine.

seems the smartest so far.  i'm confused at the complexity.