FX Impact velocity drop

[sidepass]

So a friend handed my Impact back to me. I asked if it was cocked and he said no so I cocked it and fired it. Nothing came out as it was plugged with 2 NSA 28.5 grain slugs. Bent slightly the probe. Pulled the barrel and replaced the liner and installed the original probe good so far. Upon resuming shooting over the crono I was now getting about 200 fps less velocity 960 down to 760. Tried a few things, now at 805 and that's it. Any one experience similar situation?

Thanks!

 

[hawkeye69]

Did you check the transfer port?

 

[sidepass]

Did double port down and clear. Will revisit the task, got frustrated so walked away for a few days to easy to make a mistake.

 

[cosmic]

Maybe a internal o ring is gone..

 

[Ozark]

The Top Hat on the end of the Valve Rod could have loosened

 

[Ozark]

Also your original probe that you put back in your rifle while swapping the liner could possible be misaligned to the barrel transfer port

 

[Chuck-in-Ohio]

If you bent the probe, you are probably losing air at the breech.

Possibly by exerting enough force to bend the probe, you might have changed the setting on the cocking link to the block and probe.

 

[sidepass]

They are notched right so only can be set in 180 degrees apart and line up with the pellet or slug ports I thought. Butt will check that out thanks.

The Top Hat on the end of the Valve Rod could have loosened

View attachment 309542

The C1 hammerseat? I'll have a look see.

 

[Ozark]

They are notched right so only can be set in 180 degrees apart and line up with the pellet or slug ports I thought. Butt will check that out thanks.

The C1 hammerseat? I'll have a look see.

Yes, the C1 Hammer Seat

 

[Ozark]

Also, do you hear a loud burst of air coming from the rear block (next to your cheek) while firing the rifle?

 

[sidepass]

If you bent the probe, you are probably losing air at the breech.

Possibly by exerting enough force to bend the probe, you might have changed the setting on the cocking link to the block and probe.

Reinstalled the factory probe. Will check out the setting on the cocking link.

 

[Chuck-in-Ohio]

Probe depth would be affected possibly, have you checked it?

 

[sidepass]

Also, do you hear a loud burst of air coming from the rear block (next to your cheek) while firing the rifle?

Did not.

 

[Rj]

Chamber a pellet....decock and pull the barrel. Look into the transfer port to see if the chambered pellet has cleared the port.

Pull the probe and slide it up to the chambered pellet. See if the probe port is lining up with the transfer port.

 

[Airgunmann]

The loud pop you heard was probably the probe o-ring inside the barrel blowing out which would cause air to come backwards and would lose fps

 

[Ozark]

Chamber a pellet....decock and pull the barrel. Look into the transfer port to see if the chambered pellet has cleared the port.

Pull the probe and slide it up to the chambered pellet. See if the probe port is lining up with the transfer port.

Second this! Easy way to check.

 

[sidepass]

Pulled the barrel and the transfer port O ring has a damaged spot. Will get it changed out after figuring out how. U tube my friend?

 

[sidepass]

Thanks one and all. Replaced the transfer port O ring. Checked to see if a slug cleared the port when chambered and yes it clears. The transfer port has a galled spot at the O ring groove so will order another transfer port but its working now. Chrono read 990 with the NSA 28.5 slugs but still have to check my grouping as I had just added a barrel tension kit when this happened.
Again thanks for the help.