Tuning Atanman m2r no velocity

I picked up an Ataman M2R Bullpup in .357. The gun is brand new, the guy was disappointed with it to say the least. Problem is it has no velocity, jsb pellet 157fps on a 300bar fill. I haven’t even tried to do anything yet wanted to see if anyone else has had the problem. I’ve never had the brand of rifle before but it seems to me to be extremely raptor cock. I was thinking maybe hammer spring adjustment but not sure. The only thing he told me was that he didn’t cock the gun before the initial fill. He was saying that the regulator maybe locked up?? 


any insight would be huge help. 
sorry it’s been a minute since I’ve been on thought due to getting ready for deer season here where I live. 
 
I picked up an Ataman M2R Bullpup in .357. The gun is brand new, the guy was disappointed with it to say the least. Problem is it has no velocity, jsb pellet 157fps on a 300bar fill. I haven’t even tried to do anything yet wanted to see if anyone else has had the problem. I’ve never had the brand of rifle before but it seems to me to be extremely raptor cock. I was thinking maybe hammer spring adjustment but not sure. The only thing he told me was that he didn’t cock the gun before the initial fill. He was saying that the regulator maybe locked up?? 


any insight would be huge help. 
sorry it’s been a minute since I’ve been on thought due to getting ready for deer season here where I live.

😄
 
I had a M2R .357. I was a decent gun. I had the same problem. I had low velocity also. Mine was only like 500fps. The problem was the hammerspring. If you leave it cocked the spring will stay compressed and never regain it's spring. You can either buy a new one at PA, or stretch the old one back out.

If it is still low this may be the problem.
 
 

The restrictor was the problem. I removed it & put some 81gr jsb’s across the chrony they a consistent 849-851. I’m gonna give it back to the guy I got it from. I’m not a bullpup guy. So he’ll be happy.

Could you please tell me which is the restrictor ,where can I find it on the regulator? my ataman ap16 has the same problem to slove. thanks for huge help!