xs 25

[waterman]

Hopefully you guys can help me I have a xs 25 that has velocity numbers all over. 585 to 650 after 2000 rounds . All I can find is a loose piston. Replaced both seals. Lubed cleaned ect. Can I just reseat that piston with a short pipe and hammer?  thanks always den

[jfrey]

Hi Den
XS-25 pistons are made by crimping the outer body onto the piston head.   These crimps can get a little loose sometimes.  It happened to me.  I read that some folks leave it that way, other's get it fixed.    I haven't read that anyone was experiencing performance problems because of the looseness but there's always a first.   Mine was loose just a bit and it bothered me enough to get fixed.   Not hard to imagine a very loose piston causing problems.

I fixed mine by drilling a 1/4 inch hole in each of the three crimps and then counter sinking the hole a bit so the welder would have some surface area to work with .    I then made a jig to hold the piston rod in the center of the piston while it was being welded.    I can explain that further if your interested.    Took it to a weld shop to have it done professionally.   It took the guy less than 10 minutes to weld all three spots.   Filed the weld down smooth when I got it home.

[TooJung2Die]

Must be a common flaw. I found a loose piston head on the second Ruger Air Hawk (XS25) after returning the first one for a defective barrel. I welded it.

http://www.gatewaytoairguns.org/GTA/index.php?topic=66672.msg662663#msg662663

[longhunter]

i get the feeling that the slop in the cocking rod may be intentional. think about it. as the piston is pushed back, it naturally wants to ride the top of the cylinder. if the cocking rod has a little play, it will center itself as it enters the latch plates. if the rod has no play, it will bind on the latch plates, during the cocking cycle, causing premature wear, and eventual failure of the plates. that could result in a dangerous condition.

just thinking out loud.

[chet]

  Hi Scott

   I can see that the rod and piston skirt is left a bit loose intentionally, mine was too loose and could turn it approx 30 deg. i made a fixture to hold the rod in the center of the piston by using the outside of the piston not the inside,  reason is when i was measuring my piston skirt there was a variance in the wall thickness, so just to safe before i welded the 3 crimp spots, when done i put it in a lathe and checked for TIR, was around .003 which is well in tolerance. worked out good.

    Chet

[Paul68]

Erratic velocities in the 25's can also be a sign of the breech seal sitting too low on these rifles. Try shimming the breech seal with a piece of dental floss to bring the seal up some for better sealing. Just lay one or two strands in the breech seal groove, then install the seal.

[waterman]

I put some floss under seal as you all said and as long as I had it out I flossed the piston seal and it tightened it up good. This is just to test it. I'm also thinking I put a red d-34 seal on it maybe that is a mistake. I'll let you know when I can do a therough test thanks all

[mikeiniowa]

use a hard seal in the 25's, makes a difference...

[RCO]

Are the stock  seals hard? If not which ones are?

[mikeiniowa]

the factory seal is harder than almost all the after market ones...

[RCO]

Thanks, Mike.