Crazy to hear because I have been running Federal 150grn Syntech through my Shadow 2 Accu from CZC for about two years now without any issues. I probably have 3K or 4K rounds of 150 grn syntech down the tube. Only issues I had with the gun was my fault, one match I bumped the safety up while shooting is what I believe I did (big knuckles cause issues sometimes), the second time was the last stage at the end of a 2 gun run and gun biathlon were I limp wristed the gun after being tired from running and I think I had a crappy grip (combination of cramping up while trying to run a stage, being tired from doing/running almost 7 miles by that time, multiple other stages and carrying my gear).
The FED 130grn Syntechs are meant for PCC's.
My Shadow did NOT like Blazer Brass 124grn. I had failures every mag, maybe I just got a bad lot?
Everything else my Shadow seems to run fine. Blazer Brass 115, 147grn, Seller and Belloit (SP) 115grn, Eley, Syntechs, Fiochi all with no issues.