I picked up a Surefire X300 Ultra A the one that slides on to the rail with the pressure plate, not the B model that uses the side set screw.
I have the P pressure plate on and it will just barely slide onto the rail before I am met with a lot of resistance. Does not even make it to the first lug before getting stuck.
Certainly not trying to force it on there.
Anyone else had this issue are they meant to be this tight?
Should I put a drop of oil on the light to help it slide on the rails a bit?

Don't know if this is officially sanctioned by Surefire, but I've heard you can adjust the fit by slightly loosening the six rail screws.

quote:

Originally posted by kkina:
you can adjust the fit by slightly loosening the six rail screws.

That’s what I finally did to make the process easier after many frustrating efforts to get the thing on and then back off. And now the light sits in my “maybe I’ll need it someday” drawer.

Don't know if this would work either, but have you tried using the U plate?

I’ll loosen them up a touch and see how it goes.

quote:

Originally posted by kkina:
Don't know if this would work either, but have you tried using the U plate?

I got it second hand and only have the P plate.
I saw where folks used the U on the pic rail and the light moves a lot.

I slightly loosed the six screws and it’s fine. I don’t recall if they had thread lock already or if I added some blue but it’s been fine. I have no concerns.

A light sanding can help, I think it’s just a tolerance stacking issue.

The U plate was only ok on Glock, it would rattle on a rail on the Sig or CZ or AR-15.

It would be helpful if you told us which pistol you're trying to mount this light.

I've used first the X200, then X300, and now a X300U all that have this system. It's a tad finicky depending on the pistol you are mounting it on.

It works superb on all Glocks using the "U" plate and the standard spring and pinch down method (made to be taken on and off).

First, make sure you are supposed to use the P instead of the U. This varies from gun to gun.

Then you may have to play a little with the screw tension to get it "just right." Once you have found the perfect screw tension, a minuscule amount of blue Loctite or clean nail polish will hold it place.

quote:

Originally posted by parabellum:
It would be helpful if you told us which pistol you're trying to mount this light.

Picatinny rail on a rifle.

That's the reason I never liked their Type A mounting since they first came out.

quote:

Originally posted by Black92LX:
Picatinny rail on a rifle.

This is where the B model shines.

In your situation, I'd remove the rails entirely, then screw them back on while placing lateral outward pressure on the rails while screwing them back down.

You can also try removing the locking bar and then putting the rails back in place to see if the locking bar is the source of the hangup, in which case you could trim a bit off the top of the locking bar.

Surefire cs is should be open tomorrow.
On my first had issues mounting to the Glock
They assessed my hardware and sent the correct plate for mounting.
I can not remember if their websight lists the correct applications for the plates

I mean, you can look up the manual on their website:
https://store-fecqh2764q.mybig...300%20ULTRA_RevE.PDF

U = Universal
P = Picatinny

Since it's a rifle, it's likely Picatinny, but as he stated, he only has the "P".

I will look and see if i have the other adapter and i will send to you. Don't remember which one i used on my 226. I had to file it down a bit to fit.

My FN is the only railed pistol I have without a light on it currently.
I tried to put the light on it and had similar results to the rifle rail. May have slid on a hair more but nothing noticeable.
When I get a chance to sit down and fool with it I’ll try loosening the screws.

I like Para's idea of removing the locking plate completely, and seeing if it's just the rails that are too tight.

I looked for the other adapter and can't locate. I must have chunked after i got the U adapter to fit.