RVA for 98 custom

I'm new to paintball and only been playing a year. I and both my sons own custom 98's. We upgraded the barrels,also new bolt and JCS RVA. My question is about the RVA. Is that OK for our 98's because it seems to be louder and occasional it would hammer like its low on air,which is not the case. It doesn't seem to maintain constant FPS  any better than the RVA screw thats on the gun. Maybe there's a trick to the set up using both VA on the gun. Anybody that offer advise to help me out....Thanks

When you say bolt, do you mean the front or rear? Also, did you replace the powertube? In general, I and a lot of others have found Tippmann internals to work better than aftermarket ones. You may want to try putting the stock ones back in and seeing if that helps. You can still keep the RVA, it will just give you more flexibility.  When I used an aftermarker powertube and bolt, I had nothing but issues with my 98. When I returned it to stock internals, all of the issues dissappeared.