So I've tried taking the valve stem down to .090 in a dynamic and removed the return spring for some good power out of it running a tungsten hammer I did the same for the drs but left the spring in well the drs ended bending I belive it bottomed out the spring the dynamic is still running strong over a year now and putting out big power the harder it's leaned on higher reg pressure and more hammer spring and heavier slugs if your going to try this mod leave the spring out and you have less problems