Very loose in the compression chamber compared to the original. I was debating getting JM's "Old School Buttons" from ARH think it would help center the piston for a better seal. I am not sure if there are other piston seals that may work better because every forum seems to say Vortek seal is the best.
The ARH seals are oversized a hair by design and you size them down to fit. That would be a good start. Buttoning is a good plan too and if you haven't already seen it, Pellets and Pistons has a video on that as well
By the way Newcastle England is 3,690 miles from my house LMAO! 
It probably will. I have one in mine and it works great. I'm throwing the 8.44s at exactly 900fps with my current tune. Unfortunately guns are sometimes a bit out of spec and throw a curve ball with repairs
Everything else internally looks fabulous, the mainspring is straight as an arrow and the guide appears to be in good shape as well, the piston seal looked a little ragged at the top and that's it. The rifle is still powerful it was just getting a little catchy right when you first cocked it and it seemed to be shooting harsher than normal. The breech seal looks great too so I'm hoping things will go together just fine
The rifle is very accurate as is, hopefully the new piston seal will fix the recent increase in noise and harsher shot cycle. It's always been a little harsh, I've just noticed an increase. Someone here suggested it might be due to a worn piston seal and after taking the rifle apart the piston seal is a little ragged around the thin top edge. The seal should be here before the weekend, I'll let you guys know if it helps at all.
Just get the whole Vortek 12fpe kit. It will come with a new piston seal. Long story but about 10+ years ago I introduced air rifles to a local archery range. It took off. Everyone wanted a good rifle but didn’t want to spend much on a “BB gun”. I convinced people to at least spend enough for a 34. Once the first person took the dive others followed. Before I knew it we had a bunch of guys shooting a 34. Eventually somebody broke a spring so I learned how to work on a 34. We ended up installing a bunch of Vortek kits. The rifle just shot better (not saying more accurate just a better shot cycle). The best was the 12fpe kit From Vortek. If you are going to open it up, which is easy to do, then replace everything. On HW rifles I always found they get better the more they are shot. Shoot 3 tins of pellets in an HW and it breaks into a smooth shooting rifle (too many people don’t have the patience and think they have to open up a HW right away). The 34 will never be as good as it can be until you install the full Vortek kit. It will instantly be better.
Thanks for the advice, but I'm not interested in making my rifle less powerful, which it looks like the HO kit might do after reading ArcherBronson's post and posts made by others who have installed the kit. I hunt with my rifle and we're not talking a lot of power to begin with, I realize the Brits get by with 12 ft lbs, but I don't want to just get by. The rifle has performed wonderfully for the past 23 years, all I want to do is replace the piston seal, by the time it needs another one I'll be taking a dirt nap. I inquired about the Vortek kits mostly to see if they deliver as advertised and almost to a man people say they lose velocity and power after installing them. The man who owns Vortek needs to take those results down, they're nothing short of false advertising. I live on a fixed income, spending over $100.00 for a kit that's supposed to increase your rifle's velocity when in fact it causes your rifle to lose power doesn't make any sense to me. Hopefully this $30.00 piston seal does what it's supposed to or I"m going to be really upset. Thanks again for your reply have a wonderful day.
Sometimes I think people just parrot what other people say without having any personal experience themselves, if the piston seal I ordered from Vortek fails like the one you have I'm going to be extremely upset.
While my 34 shoot more consistent chrono numbers with the old oem piston seal the shot cycle is much better with the vortek seal in the rifle. I should have taken a picture when I had the gun apart, but my piston showed a lot of rubbing on the bottom side of the metal. This is why I think my compression chamber does make a perfect seal, probably why the old parachute seal is giving better numbers, more forgiving of inconsistencies. Honing the chamber with some 3000grit sandpaper and a wooden dowel may be my next step. I discovered taking the rifle apart and tinkering with it is just as much fun as shooting, so I don't mind.
I agree is is a lot of fun taking them apart, my rifle has the original piston seal and it's a little frayed where it contacts the front of the compression tube so I thought while I had it apart I'd try one of the Vortek seals. After reading your post I'm very concerned about how it's going to affect my rifle's performance. I don't want to lose 100 fps for the sake of having the rifle shoot a little smoother. You aren't the only one who's lost power by intalling these kits, I've searched other forums and most say they've lost velocity. I'm not interested in making my magnum springer less powerful, it shoots really well, I can put five H&N FTT inside my pinky nail at 10 meters, I just want to replace the worn piston seal and hopefully return my rifle to it's original performance level. Good luck pal, thanks for the reply
This is definitely true but not about the Vortek piston seals. They really are top notch. I've got close to 50 springers and probably 30 of them have that seal in them.
I've owned my 34 for 23 years I can put 5 H&N FTT pellets into a one hole group the size of my pinky nail at 10 meters. It's a hunting rifle neutering it to 12 ft lbs makes no sense at all. Thank you for your encouragement, I should get my piston seal either today or tomorrow, I'll let you know when she's all back together how she shoots
