How close in FPS should a regulator perform? I have an AT44 on my Hatsan Bullboss

I have a Hatsan Bullboss and I installed the AT44 regulator.

I filled the gun to 200 bar and then fired 20 pellets. The first 20 ranged from 979 fps to 965, the last one 970 fps.

The next 10 eventually dipped down to the high 950s. The gauge on the air tube was still plenty in the green.

The regulator is designed to put the same psi on each pellet, right? Then why do the pellets still slowly slow down? Isn't that what already happens when it's not regulated? I'm ignorant on this, and don't want to have unrealistic expectations.

So, is this a good performance from my AT44 regulator, or is it subpar?
 
I think it sounds pretty decent especially with hatsans being notorious for having a totally descending shot curve un regulated. The problem is that you really can’t just throw a reg in an un regulated gun and expect perfection. The hammer/spring adjustment needs to match whatever the reg output is. If you play with the hammer spring adjuster you will probably find a sweet spot where the extreme spreads tighten up.
 
My buddy has a Hatson, unregulated, he put a Huma regulator in it and its VERY Consistent shot to shot speed wise, ONCE he took it all apart and got rid of the Grease that was everywhere. Re-Lubed in the required area and it is spot on speed wise.
No it only good for 20 yards, anything after that and the group is to large to even waste a pellet on.

Smitty
 
Read this info about setting up a regulator in a pcp: https://www.airgunnation.com/thread...he-95-tune-plus-m3-tuning-simplified.1242157/

It's easy to understand, take some tear downs and adjustments but it helps to learn more about your gun, and if you plan to only use pellets that speed is to high, Hatsan uses some pretty stiff hammersprings so it can be a idéa to buy some springs in varius sizes to see if you can get more shots on the same powerlevel