FX Boss leak

I have not noticed any leak but haven't shot it down that low. 140 -145 is as low as mine has been.

Just a sidenote, be very careful to shoot a Boss or regulated Royale any lower than it's factory reg. setting.
At low pressures, the force of the air pressure behind the valve gets a lot less, so the amount of force needed to open the valve is also a lot less at low pressures.
Because the hammer is striking the valve at the same force, the valve opens as far as it can, and the hammer is going to hit the action at the valve guide hole.
That hole will get deformed, causing the valve to stick and stay open.
I have experienced this on a friend's Bobcat 30 cal. which had an air leak through the main valve.
After I asked him if he had ever shot it to below the 160bar mark, he confirmed that he had shot it down to as low as 100 bar several times.

His Bobcat's hammer had literarily swaged the valve guide hole to a smaller diameter. I needed to ream the valve guide hole with a 4mm reamer to remove the burr and get it going again.

Regal -New - Used,? sat for long period?wont change what it is-maybe why- Sounds like the valve,for whatever reason,and I havent had that apart on either royal block I own, according boss list A-25-7 and A 33-8 couple o-rings a stem and a seat,being its intermittent,gives hope to an easy cheap fix ,hope someone who been in the valve for some-reason can help Well i guess ya throw a 203gr.hammer at an almost empty valve, few hundred times,that could do it,also

"Regal_US"

"weatherby"Just a sidenote, be very careful to shoot a Boss or regulated Royale any lower than it's factory reg. setting.
At low pressures, the force of the air pressure behind the valve gets a lot less, so the amount of force needed to open the valve is also a lot less at low pressures.

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Very useful to know. Wish FX had included this information with the gun ... they don't even tell you what the regulator is set at! What was the behavior of your friend's Bobcat before you reamed the valve guide hole?

I think there is a reasonable chance that I may have damaged the valve guide hole, but by how much? I'll chrony the gun and see how consistent the strings are.

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My friends Bobcat valve stayed open after a shot. I asked him to reset the valve by hand by removing the valve retainer and pushing the valve back in it's seat.
After he fired 1 shot after refilling, the valve got stuck in open position again, dumping all the air.
Then he brought it to me, and I discovered that the guide hole was damaged. It was a quick fix with a 4mm reamer, and after I put it back together, it was shooting fine again.

It is actually very easy to check, just unscrew the bottle a couple of turns to make the action pressureless, then take a screwdriver and push in the valve pin from the side of the action. (There is a hole in the side of the action where you can actually see the tip of the valve pin sticking out.)
If you push it in, the valve spring should be able to reset its position. When it stays open, or it doesn't move smoothly, you have a chance that the guide hole is slightly damaged.
I'm not saying that you have the exact same issue, but it sure is a possibility But it could also be that your valve pin is not OK.

Good luck

your numbers look fine,I'd shoot it more often when ya can-remembering it acted up and at-least have the rings handy,,

Decent string indeed, seems there is no need to worry
As long as you keep it above 150bar it should be fine.