x valve velocity issues

[Sniper Steve]

I have been having some problems with my x valve velocity issues. I am getting some fluctuation with velocity at times and when I shoot real fast that is when I notice it the most and some times the trigger pin sticks and then I have to turn the air off then back on to get it to reset. It is lubed ok and the orings and the pin in the stack have been replaced recently.

[gmiller0]

I have been having some problems with my x valve velocity issues. I am getting some fluctuation with velocity at times and when I shoot real fast that is when I notice it the most and some times the trigger pin sticks and then I have to turn the air off then back on to get it to reset. It is lubed ok and the orings and the pin in the stack have been replaced recently.

Level 10 bolt stick maybe???? Instead of degassing the gun, push a squeegee down the barrel and push against the bolt to see if it resets, and let us know.

[Coralis]

sounds like you might need to go up one spacer size

[Sniper Steve]

yes I have to push the bolt back in place when it sticks, I will try a different spacer. But would that affect the velocity issues?

[kcombs9]

yes I have to push the bolt back in place when it sticks, I will try a different spacer. But would that affect the velocity issues?

I had a carrier that was too small and my velocity would jump all over, went up .5 size and it calmed down, so yes bolt stick will affect your velocity.

[93klauss]

Velocity issues without bolt stick? any ideas?


I had a carrier that was too small and my velocity would jump all over, went up .5 size and it calmed down, so yes bolt stick will affect your velocity.

[kcombs9]

Velocity issues without bolt stick? any ideas?

the reg in the valve needs to be cleaned/rebuilt?

[Sniper Steve]

it has all new orings and it has been lubed and serviced recently. I tried the next size spacer and that didn't work, I kept leaking down the barrel. I have added some shims and that seems to be helping some with the bolt going back and reseting right, and the velocity is not swinging as much but I still get the occasional big drop in velocity on some shots from time to time.

[athomas]

Bolt stick will cause velocity fluctuations during firing because it increases the bolt cycle time. This leaves less time to recharge the chamber between shots. If you fire again before the chamber is fully charged, the velocity will be lower than it normally would be.

You should be able to operate the gun without any level 10 shims installed. They are not for fixing issues with bolt stick during normal operation. They are a band-aid fix for the real problem. The shims can actually cause the oring to be too close to the vent hole and cause leaking with the proper size carrier. This will lead you to install a carrier that is too tight. Remove the shims. Then retune your level ten. When changing carriers, always use the same white carrier oring. Its the tension on the specific oring that you are tuning. If you change orings, you need to tune for the new oring. Sometimes a flaw in the carrier oring causes you to have to use a tighter carrier size to prevent leaking. This causes bolt stick. If you can't find a carrier size that operates smoothly without leaking, change orings and start again.

Also, if your sear is worn, it can cause the bolt to sit too far forward. This also exposes the vent hole and will cause you to use a carrier size that is too tight in order to stop the leak.

[Sniper Steve]

Thanks for the explanation of how that works, that is the simplest easiest way to understand it that I have ever heard. I will try agian with out the shims, but I have tried multiple combinations, the carrier I have in it now is the only one that doesn't leak down the barrel, and I have several carriers the same size and I have tried them too. I have tried several orings as well. I have lots of parts and have tried lots of different combinations. I do understand what you are saying and I do think that the bolt is tighter than it should be but again the next size up is too loose unless I am missing a carrier size that is the only conclusion I can come to at this point. I have also tried two different sears both are in good condition.

[athomas]

The shims are numbered by lines and dots. A line = 1, and dots = 0.5. So, a line and dots = 1.5. You can tell if you are missing a carrier by inspecting the sequential series of sizes. You should have a series of carriers, probably 0, 0.5, 1.0, 1.5, 2.0, 2.5. It should be a sequential series from 0(no lines or dots) to 3 or higher. The kit sizes don't go as high as they used to, but you can still buy the larger sizes if you need them.

The reason I listed that the shims are a band-aid fix is because they are designed only to allow the bolt to reset if it goes forward and hits an object in the breach, but not far enough to vent the air pressure in the chamber which would allow it to reset. In that case, you would need shims to shorten the distance that the bolt needs to move in order to expose the vent hole. Most of the time, no shims are needed because the bolt will always move far enough to vent air on any breach blockage. No shims are needed if the gun cycles, chuffs, or vents air at all in any way.