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Discussion Starter · #1 ·
I really like the PS90. It just feels right and is a fun gun to shoot.
I really hate the PS90. it's expensive to shoot an lord only knows here the bullets are going.
OK, it may be me. Started with about 200 rounds trying to calibrate the red dot sight. Got the elevation somewhere near right but the windage was all the way out and the bullet strike was still at the edge of the paper target at 25 yds. I hate this gun.
Look at the rail and it was all the way against one side of the channel. Off to the auto parts store to buy a set of feeler gauges and get the rail centered.
Back to the range, 25 yd zero range and getting very nice shot groups feeling real good. I love this gun.
Home, clean it, put it away for another week and back to the range to shoot at the 100yd targets. Where the heck are the bullets going? There is a 24” square target on a virgin 6’ square backboard and after 15 rounds not a hole in sight. I hate this gun.
Then I notice the rail and sight are loose. Somehow the set screw loosened and the sights are somewhere but nowhere close to where they should be. Put the gun away with a curse. Pick up the 10/22 and put a bunch of holes in the target just to make me not look so bad.
Home, Clean the gun, pull out the laser boresight tool reset the rail/sight, refill the magazine and wait til next week when we go back to the range. I want to love my gun again.
Ugh: My wife actually picked up and likes the 9mm Beretta CX4 Carbine.
 

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Loctite is your best friend with the PS90. I had the same issue.
 

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I really like the PS90. It just feels right and is a fun gun to shoot.
I really hate the PS90. it's expensive to shoot an lord only knows here the bullets are going.
OK, it may be me.Started with about 200 rounds trying to calibrate the red dot sight.Got the elevation somewhere near right but the windage was all the way out and the bullet strike was still at the edge of the paper target at 25 yds. I hate this gun.
Look at the rail and it was all the way against one side of the channel.Off to the auto parts store to buy a set of feeler gauges and get the rail centered.
Back to the range,25 yd zero range and getting very nice shot groupsfeeling real good.I love this gun.
Home, clean it, put it away for another week and back to the range to shoot at the 100yd targets.Where the heck are the bullets going?There is a 24” square target on a virgin 6’ square backboard and after 15 rounds not a hole in sight.I hate this gun.
Then I notice the rail and sight are loose.Somehow the set screw loosened and the sights are somewhere but nowhere close to where they should be.Put the gun away with a curse.Pick up the 10/22 and put a bunch of holes in the target just to make me not look so bad.
Home, Clean the gun, pull out the laser boresight tool reset the rail/sight, refill the magazine and wait til next week when we go back to the range.I want to love my gun again.
Ugh:My wife actually picked up and likes the 9mm Beretta CX4 Carbine.
Solution.....

TROS mount.
 

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Before you go to the range ( or even at the range) take the upper off so you can look down the barrel. Put it on a table and look through the barrel at a point 25 ft away. Now look through your sight and line up the sight to what the barrel is pointing at. This will save you a lot of ammo and get you close to your zero. Blue Loctite does help keep those screws from loosening. :target:
 

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Before you go to the range ( or even at the range) take the upper off so you can look down the barrel. Put it on a table and look through the barrel at a point 25 ft away. Now look through your sight and line up the sight to what the barrel is pointing at. This will save you a lot of ammo and get you close to your zero. Blue Loctite does help keep those screws from loosening. :target:
That is a top notch idea!
 

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Loctite is your best friend with the PS90. I had the same issue.

+1 on the LocTie thread locker.
That damn setscrew loves the screw you over and back out.
I hav not heard of a single PS90 from which that stupid screw loosened out.

+1 on the Tros mount too. That is a well designed piece and it even loweres the sights so you do not have to deal with a sight heights offset when sighted at 100yrds but firing at short ranges.
 

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Discussion Starter · #8 ·
For those who may be interested: My PS90 came with the red dot sight. to center up the mounting bracket and sight I hit the tool box for a set of feeler gages. Found that the mount has .046 total spacing so I used a .023 strip and tightened everything down. Rechecked the zero (using the above method) and it is still spot on. Find out at the range Friday.
 

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Is the TROS mount standard piccatinny from which I can mount anything? On his website it states specific optics.

Cliff_Chambliss, that would be quite frustrating. I know you will love it again once you get this problem sorted out.

Here is a mount that TROS offers that is a piccatinny rail, you would have to contact Mark to see what will work with this ULTRA LOW rail.

 

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This is why I decided to SBR my tri-rail and not my standard white ring sight PS90.

Have to have the locking bolts nice and tight.

Yes, thread lock will help with your issue.
 

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Little bit on the center Alan head screw should do it.
 

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The vertical one at the ass end of the rail?
His description is missing critical info.
The setscrew he is referring to is inside the big knob that dials in windage.
The setscrew is inside that dial.

Before you can adjust the windage left or right, you have to loosen this setscrew, the screw that likes to back out.
Once your windage is dialed in to where you are zeroing your shots, with a toothpick or a q tip, apply blue Loctite onto that setscrew inside the windage knob before you tighten it back down.
 

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His description is missing critical info.
The setscrew he is referring to is inside the big knob that dials in windage.
The setscrew is inside that dial.

Before you can adjust the windage left or right, you have to loosen this setscrew, the screw that likes to back out.
Once your windage is dialed in to where you are zeroing your shots, with a toothpick or a q tip, apply blue Loctite onto that setscrew inside the windage knob before you tighten it back down.
I got it now.

However in my case, the windage was dead on and I didn't have to make any adjustment. Should I just leave the damn thing alone or should I loosen up the set screw and Loctite it?
 

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I got it now.

However in my case, the windage was dead on and I didn't have to make any adjustment. Should I just leave the damn thing alone or should I loosen up the set screw and Loctite it?
If it was me I would loctite it. Because if that thing comes loose it's going to make for a bad day at the range. There is a good chance that the recoil will work it loose one day.
 

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There are 2 kinds ( primarily ) for this application 242 & 243 . The 243 is the grease & oil ( i believe ) type... which I prefer. I would dbl check that but I used all the 243 up.... The big bottles are about $99 now a days....
ouch !
Just for the record, loctite works best when both mating surfaces are cleaned , I use alcohol or contact cleaner. Blow off with air & apply.
I myself agree with Kam, sooner or later it will work loose and be a spoiler.... just about the time your lending it to a range budd to share how flat shooting & consistent it is..... !
 

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I also hate having to adjust the fn sight. But it is awesome, uses sunlight to power it and when needed I flip on the back up power modification done by m1bullpup. Now far as the ps90 goes I hate it so much I plan on eventually buying another one. It will likely get a h1 aimpoint or a micro red dot rmr or burris fast fire. Also I want it to have an original p90 flash hider. Of course it will be sbr`d.
 
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