I recently purchased a Primary Arms Micro Dot with the removable base for my CX4 storm.  When i installed it the side to side fitment is
great, with no movement, but i notice that it still wants to slide front to back. I don't know if its because the bar is slimmer than the grooves
on the rail or not?
Has anyone had this issue? Or what type of base did you use to mount it?

I have a trs25 on mine and its rock solid. Could be the rail. Is it a beretta rail or other after market? Could be out of spec

I had the exact same issue when I first got my PA dot. It was weird but after getting frustrated and trying it again it fit fine. Didn't do anything differently.

I just had the same issue with mine. The rail is not mil spec. Just call the company and they will send you a new base for free. I put mine on this week and I hope to get a chance to shoot this weekend. I put a little blue lock tight on mine just to be safe.

The company has great customer service.

Call Primary Arms? So they'll send a new base that works with the Storm? I had asked and they said they didn't have any specific mounts that fit Beretta...do you remember what kind of base they sent so i can ask for it?

I know you have probably already checked this, but something us long time Storm users have noticed is that the rail on the rifle becomes loose after time. It will move around. I use a bit of blue LocTite on its screws to help retard this.

Any blow-back PCC takes a beating from that big heavy bolt slamming into the rear of the receiver so this is not uncommon.
Again, may not have anything to do with your problem but check closely just to make sure.

Yeah thanks, ive noticed that its come loose from time to time. The issue is the mounting base for the red dot...frustrating..but not the end of the world. I was just hoping to get a simple
solution to the issue vs getting a more expensive sight since its just a range toy.

That's what I did.  They sent a replacement for free.  I didn't get the rep's name but when I told him I was mounting it on a Storm he was familiar with the problem.  The base looks identical to the one that cam on the sight but the screw and clamp (I don't what to call it) are different.  I'll look when I get home to see if I I still have the spec. sheet for what they sent me.  When I first realized I couldn't tighten mine on the Storm, I tried it on my AR and it worked fine.  So I figured the problem was the rail. The rep said they have problems with the rails on the Storms and AK's specifically.  

Here's the number I used 713-344-9600.  Just call during regular business hours.  It's not like some places you call where you are on hold for 15 - 20 minutes.  My call went straight through, no waiting.  

I bought a sight from them previously and use it on my M&P AR15-22.  Works great, has a quick release base that works well.  It's just too tall for the Storm and the base on that one is not removable.  

Give them a try, they'll take care of you.

Update, went to the range and sure enough the sight went sloppy. Called primary arms and they said it's a well known issue because the storm rail is narrower than mil-spec. They are sending out a new base to fit.  Two thumbs up for primary arms customer service.

Mine just had this same issue last weekend; I just dabbed some loctite on it.



 

Got the new crossbolt. Installed tonight and it fit perfectly.

Looking back over this post and I am glad the OP got the problem fixed.  Thinking about this I realized something that might have been over looked.  There are in fact differences in how rails are machined as there are more than one standard. On your AR you have a "Mil-Spec" rail, a.k.a. a Picatinny rail a.k.a MIL-STD-1913 rail. These are spec by the military and are all the same. On the civilian side you have the defacto standard which is the Weaver rail. They are similar but not the same. A mount made for a Picatinny rail will be very slightly different than one made for a Weaver mount. The problem is not unique with the CX-4 at all, its with the standards that the rails and the mount on the device are made to. Of course another problem with the CX-4 has to do with which rail you have as it could be either the Weaver or Picatinny depending on who made the rail.

Someone at Primary Arms knew about this and helped one of the posters by providing them with a mount that was properly sized for their rail. Anther person called and didn't get the same response as the person they talked to may not have been aware of the difference. I grew up with Weaver mounts before I had to deal with Mil-Spec Picatinny's so I sort of didn't give it a thought at first but going back and reading these it hit me what the problem was.

Learn more here:   Picatinny vrs. Weaver rail...what is the difference?