Crosman in the Gamo Silent Cat.

I have three Gamo break barrels (Hunter 30 years old, Mach I 3 years old, and a Varmint 5 years old. All have a couple of thousand pellets through them and NONE have had any issues at all. I also have an Urban and have killed more tree rats with it than I have my BSA, HW44, or Pulsar. 

All of my break barrels do ok with CPFPs but I have gotten the best results with H&N FTTs in 4.51 diameter. They seem to like the snugger fit of the larger diameter. You may wat to consider trying a sample pack on H&Ns at different diameters to see if that improves your accuracy. You can get them on Amazon. Nice vid.



H&N Field Target Sampler Pack .177 Caliber Baracuda Match and Field Target Trophy Airgun Pellets (240 Count)

Brand: Haendler & Natermann
 
I don’t know what the diameters are but I would call the FTTs and Hollow points a snug fit in the gun. The pointed were loose and the Piranha were tight. I’ve got some sample packs I can try but just wanted to give it a go with the cheaper pellets. 
It’s a preowned gun so if something goes South, I’m not out a whole bunch of cash and I will have had some fun in the mean time.