This really has me thinking Ronnie. Ok let's start from the beginning,...What specs does your rifle have,...eg,..factory seal, or Macarri seal. Spring,..Factory or Macarri spring. Top-Hat,...Did Mike instal a metal or delrin TH? What all pellets have you shot through this rifle? Name them all. If you do not seat a pellet correctly,..you will not get a consistant chroney reading. Did your rifle come with a champhered breech loading port,..or is it straight cut like a Diana? I'm not trying to insult you at all,...but these technicallities are very important for diagnosing your velocity and accuracy problems. Dieselling is perfectly fine,...if it's detonation,...when your gun goes "Bang" like a .22 rim-fire,..then we need to look into it. Heavy Dieselling can and will occur with light or loose fitting pellets,...and if dieselling is very prevelent,...this may result from light/loose fitting pellets,...resembling dry firing,...too much blow by during the firing cycle. I really am concernned here,...because your numbers are kinda low. Accuracy wise,...they are a trick to figure out how to shoot,...and that will come in time...besides the "irons" ain't all that great either!!!! LOL's Please give us a detailled desciption of you rifles make up,..parts wise,...and what pellets you've shot through it thus far. Then we can make a better judgement and accertation of what the hecks going on with your B-28. Mike's here for ya,..I'm here for ya brother,...the GTA's here for ya,...everybody here wants you to conquer this Dragon!!!! I know we can do this together!! tjk