Beeman Chief???

What caliber? My son in law has one, quite accurate with JSB pellets. There is a video on YouTube on how to adjust the trigger for a better feel. A TKO moderator will make it easy to shoot since it makes it much quieter. His is very accurate to about 70 yds (15.9 gr JSB) in .22 caliber. It has a low shot count with a consistent drop at range, a chronograph is really useful to figure out the shot count. Once you get used to estimating drop at various pressures, it is easier to shoot. A scope with mildot reticle would be advisable.
 
Thankyou for the replies.
I got the Chief 2 in point .177 cal. First .177 pcp. I have worked on the trigger and have it about where I like it.
My question at this point is about the O rings on the bolt probe. It had two when I got the gun . after 50 or so shots they where both gone. My packet had one so I put it on. Five shot later it was gone. It don't seem to be the most accurte gun I own but I can't tell any differance with or without. Could a fella use a small hose over the probe? I can't see spending a lot of money on Orings if they are only last a shot or two.