Hatsan 135 needs a heavy pellet to be sub sonic.

[GunnerAl]

I got 1376 fps out of my RWS48 with the .177 SSP's.

When the Diana 52 first came out I bought one, and at the time Diana claimed they were the first spring airgun manufactutrer to put out a rifle that could break the sound barrier in the "out of the box" form. I don't know if it was fully true (maybe there were others companies that did also),, but mine sure hit above the sound barrier, with lighter pellets anyway... I only fired them a couple of times because I knew it might not be the wisest thing to do, but it was surely impressive. Nowadays, it's not uncommon to buy such rifles, from so called quality manufacturers, and also from manufacturers of more average quality. I have a couple of them but I use much heavier pellets to try to prevent this occurance...

[Nicholas440]

I agree with you Al,   using a pellet thats to light isn't a good idea in these magnum springers.  I am using 10.34 grain pellets now and  I really doubt that I can do any damage to the gun at the weight.  I would think a 5 or 6 grain might be hard on the piston but not a 10 .  What puzzles me is  Hatsan knows the power and force these magnums produce and you think they would include a  " Warning"  label on the rifle,  not to use anything under say a  8 grain pellet or you might damage the gun.

Just my thoughts,   because this 135 is so loud I'm constantly looking over my shoulder when I'm out in my yard hoping the neighbors dont call the law because it's exactly like a .22 rimfire sound.  I doubt that the law would do anything because it is a pellet gun however looking at it you could mistake it for a  30-06  easily.  It also shoots through 2 x 4's with ease.