https://vortekproducts.com/ourstore/PG4-TUNE_KITS?product_id=376 Here's the link I thought it sounded optimistic too LOL
I'm not opposed to trying different parts as long as it doesn't get too complicated and I maintain the original power level. So you used everything in the Vortec kit except the spring?
A bad piston seal and or breech seal can absolutely make the shot cycle harsh. Have you put your gun over a chrono recently?
I don't have a chronograph, but it has plenty of power It's not grouping as well as it once did but I attribute that to the 4x32A/O UTG scope that I have mounted on it, just recently I lost the windage capability with it and I need to replace it, but the rifle does jolt a lot when you fire it. The breech seal looks good, I haven't taken the rifle apart to check the piston seal, it does make a grinding kind of noise when I cock it, well not really a grinding noise more like a grating noise, things like this are hard to describe in text. If I could just get a complete set of OEM rebuild parts I'd be happy.
If you want OEM and can’t find here try T. W. Chambers. If you go after market I’ll second the vote for ARH spring and guide with Vortek seal. Or even with the OEM seal if it’s in good shape. That’s what’s in my D52 and it’s very smooth. Solid, but smooth.
You can insert the Diana 48 mainspring and grease-sleeve the piston with the proper thickness PE (from a shampoo bottle or so), remove all grease in the compression chamber and reduce the TP to 3 mm and you're getting about smooth15 fpe @ 0.177 without any vibes. You can try and insert the titan N0. 4 spring for higher power which I wouldn't suggest.
Keep shooting it. Both the new seal and spring will settle in plus you'll burn off any excess lube that may have been pushed forward when you reinstalled the piston.
I allowed 200 shots before testing and I stated that I only used rubbing alcohol to install the piston seal onto the piston as it was giving me trouble. I followed Pellets & Piston YT video for the install process and degreased and lubed accordingly. It was clear the Vortek seal was not a good fit for my rifle.
Gotcha and that makes more sense! Kevin is a good dude and his channel is fantastic. Was the seal too tight or too loose?
While I think your numbers are a little low, they may improve with more shooting. In regards to Vortek's claim of 1,200 fps with the 7.9 CHP's I think it would be wise of the person who owns Vortek to remove it from his website. I just ordered a Vortek piston seal for my 34 I hope I don't lose power as well. I'm thinking I should have just bought OEM replacement parts, the rifle has worked just fine for 23 years with them. I don't have a chronograph right now, but years ago I remember chronographing the 7.9 CHP's at 920-930ish FPS. Although I won't have precise numbers I should be able to tell if I've lost over 100 fps right away. I'll post again when I get my new seal installed and let you know. Thank you for your post by the way, I hope your rifle's performance improves.
