Rws 460 t06 .22 power loss

[eezapz2101]

So even after vortek pg2 spring kit, new breach seal, new pistón seal, heavier pressure spring, shim under breach seal las week my fps was 580-600 fps oh forgot a preload washer for the spring.
And yet no fps increase but more loss

I'm very frustrated

What shoul I do? Send it to umarex for service? Should I look for a tuner?

Please help this it's way over me.

[Mark 611]

it not over you, sounds like maybe ur piston seal is to tight? or ur breech seal is leaking? that's a big power loss for a 460!

[bandg]

You might check the spring loaded breech closing arm.  It's the part that attaches to the bottom of the cocking lever and extends rearward.  There is a spring loaded attachment/mechanism at the rear of that link that is designed to fully close the breech but still allow some movement so that the cocking arm can cleanly latch.  It relies on a spring to apply pressure to close the breech fully.  The spring seemed very light to me and I had questions about whether it could reliably and repeatedly seal the breech so I put a heavier spring in that location. 

[JimL911]

Did you size the piston seal properly?

[eezapz2101]

You might check the spring loaded breech closing arm.  It's the part that attaches to the bottom of the cocking lever and extends rearward.  There is a spring loaded attachment/mechanism at the rear of that link that is designed to fully close the breech but still allow some movement so that the cocking arm can cleanly latch.  It relies on a spring to apply pressure to close the breech fully.  The spring seemed very light to me and I had questions about whether it could reliably and repeatedly seal the breech so I put a heavier spring in that location.

I changed the spring for a heavier one and still power loss

[eezapz2101]

Did you size the piston seal properly?

So I did not size the seal
Why? Well prior to instaling the new vortek pro seal I had a vortek oring seal and the compression tube was polished and in order to replace with the pro seal I crosshatched the comp tube with 250 grit brake honing tool.
And did not size the seal for I was worried that the seal might be to loose after the polishing and the crosshatching after that.

Some one suggested that 250 gritt was too course that I should have used 500 grit wet and dry sand paper.

Should I try that? What about the sizing od the seal how to know when the seal has the correct size?

[eezapz2101]

it not over you, sounds like maybe ur piston seal is to tight? or ur breech seal is leaking? that's a big power loss for a 460!

How to know it the seal its to tight?
Breach seal its maybe 6 months old.
 And what I did to try and fix the low power issue, by maccary web site that suggests that power loss in 460 its that the breach seal need shimming so I placed a brass washer under the breach seal.
Shloud i remove the shim?
I have a new vortek breach seal witch it's thicker that the oem breach seal
But that one just will not go in I might have to size it

[Roadworthy]

To test the breech seal for leakage place a piece of tissue over the breech and fire a pellet.  If the tissue blows away you have leakage.

If the piston seal is too tight it will result in a loss of velocity.  It should take less than a half kilogram of force to move the piston in the compression tube.

O ring seals are known to require less force to move than regular parachute type seals.  That could be why your gun has lost velocity.

[eezapz2101]

To test the breech seal for leakage place a piece of tissue over the breech and fire a pellet.  If the tissue blows away you have leakage.

If the piston seal is too tight it will result in a loss of velocity.  It should take less than a half kilogram of force to move the piston in the compression tube.

O ring seals are known to require less force to move than regular parachute type seals.  That could be why your gun has lost velocity.

So should I run 500 gritt wet & dry sand paper over the crosshatch and then see about sizing and test the pressure required to press the piston?
Or just size the seal and leave the 250 gritt crosshatch of the como tube as it is?

[Mark 611]

I would try to smooth up the tube, 250 is to course, then check ur piston seal fit JMO

[Roadworthy]

I just received and installed a new Vortek moly impregnated seal onto my Diana 34 piston.  I found it MUCH harder than the original seal.  The original seal was somewhat (a little) too tight in the compression tube.  Frequently you must compress the seal slightly to get it started into the tube. 

The new Vortek seal does not seem to compress at all.  I will need to size it to even get it into the compression tube.

Polishing or crosshatching your tube will not make a significant difference in its diameter, by the way.  If your seal is too big you will need to reduce its diameter.  Be sure to use a flat to back the sandpaper, not your finger.  Your finger has too much give and you'll be unable to control the profile of the seal.

[WolfyW]

I just received and installed a new Vortek moly impregnated seal onto my Diana 34 piston.  I found it MUCH harder than the original seal.

I have one of those moly seals in my .22 cal D34, it was a bit tight too. I will be swapping it out for an o-ring seal soon. I hunt with that D34 and found the seal was profoundly affected by cool temperature. It was sighted in, taken hunting at 1 deg above freezing. 2 inches low at 20 yards. Brought it back and shot it at 20 yards in warmer conditions, all better again.

[mpbby]

If you please, how would you compare the OEM and the Vortek piston seal in terms of lifespan and temperature effects?

[Mark 611]

Temp changes like that have nothing to with the piston seal, its the air temp that changes ur velocity's, cold air will kill ur power, 

[WolfyW]

Temp changes like that have nothing to with the piston seal, its the air temp that changes ur velocity's, cold air will kill ur power, 

But, but, but....I don't see that kind of power loss from my D34 with the o-ring seal. Took it out last spring in very cool temps to whack a groundhog at 20 yards. Both rifles have the same lube as well. I remember "nced" mentioning his preference for o-ring seals after experiencing
power loss at a FT shoot when temps dropped. Sure three's not something to it???

[Mark 611]

20yds is not a measureable distance unless ur shooting a 10m match rifle!

[WolfyW]

20yds is not a measureable distance unless ur shooting a 10m match rifle!

Good one!