Perhaps you got a 26mm seal. The R7 (HW30) uses 25 mm seal. The Vortek seals have considerable drag when first installed but shouldn't get stuck. Although I'd think you'd have to be a gorilla to get a 26mm seal in a 25mm tube.
1, All the R7 springs are the same.
2, the cross hatch is normal on an early Beemans. It's totally fine.
3, Is there any visible scores in the piston stroke part of the compression tube?
4, I believe the original piston seal was synthetic, is that what you put back on?
5, if somehow that gun had a leather seal. Check the size of the transfer port. If it's bigger than 1/8" it would need a leather seal replacement. This is a Longshot because I believe all the Beeman models had synthetic seals.
6 let's see pictures of your original seal. I'm thinking it's whooped. If you cover the transfer port with your finger you shouldn't be able to push the piston forward much. It should hold pressure at any point and spring back to the start point when you let up on it. If you can push it to the bottom slowly with the port covered the seal is shot.
I've probably installed a dozen Vortek kits in HW30 platform guns for people in the last 6 years. I own three myself. All made 8 fpe or more when done without dieseling. Something basic is wrong and I'm betting it's the old piston seal.
You can message me for my phone if you'd like some direction.
