Well I treked out behind my house and put the last 150 Thunderbolts I had through it, once again it ran like a champ with the exception of one dud round.
And 2 deer walked up about 20 yards from me to get a better look at the Walther as i was shooting lol (figures now that the season is over and I only had a 22)
I'd check out the barrel for lead if I were you. My friend managed to gunk up his P22 in about 150-200 rounds of that stuff. It was so bad that the gun started shooting bullets out sideways. (I'm not kidding, they were hitting the paper sideways)
This is the only complaint that I have with the P22. It even liked the PMC ammo better than the Thunderbolt. I had a bitch and a half cleaning the lead out of the barrel of the P22 when I fired Thunderbolt. It keyholes like crazy after about 100 rounds.
The copperwashed ammo runs through it much better.
I have also heard reports of slide cracking issues, but mine seem to be fine.