I just bought a new TX200 MKIII and am getting ready to disassemble, clean, and drop in a spring kit. I have a Vortek PG4 HO for it and was curious as to whether anyone here has any experience with the TX and these kits. Experiences and opinions would be great.
Quote from: Pierre Toutant on February 13, 2022, 09:41:24 PMI just bought a new TX200 MKIII and am getting ready to disassemble, clean, and drop in a spring kit. I have a Vortek PG4 HO for it and was curious as to whether anyone here has any experience with the TX and these kits. Experiences and opinions would be great.I'm curious if you discover yours has the OEM spring packed with thick grease like my 2018-2019 model did. Mine's a .22 HC so I put an ARH slightly softer spring in it to ease up the cocking effort and harshness. Now the gun is lighter to cock and still has plenty of punch and no twang even without the thick grease. Let us know how you like your Vortek kit.
The TX was designed and was intended for use by shooters who shoot at 12fpe.
Quote from: Frank in Fairfield on February 14, 2022, 09:41:33 AMThe TX was designed and was intended for use by shooters who shoot at 12fpe.Frank, Not quite so. The TX200 has a long, 95mm piston stroke (depends somewhat on the Mark) and quite a large swept volume. British airgunners point out that the stroke is too long for the 12 fpe limit. The gun certainly shoots with it, but the OEM TX200 is optimized for a higher output. Many 12 fpe shooters opt either to short-stroke their TX's, or use a Tony Leach conversion to make them shoot the best.
My TX200 (and the TX200s that took all three top places in the last National Recoil HFT Championship) have extended piston rods to give an 85mm stroke, coupled with the UK factory spring and 41mm of preload.
Hi Jim,Do you happen to go by the handle "Nomads HFT" on the Shooting the breeze UK forums?I ordered one of the TL 22mm kits for my TX back in Feb but it's apparently on a slow boat and isn't here yet. Almost 2 months now and counting.I'd like to try the standard bore with the old MK1/MK2 stroke in my MK3 TX....but those parts are hard to come by over here in the states. It was suggested (perhaps by you) to contact ISP for the extended latch rod but I never got a reply from them (tried FB and email). Also, airgunspares has been out of the TX320S piston for a while...no luck there. I also tired airarmsspares but I didn't get a reply from him either (I understand he might be having some health issues). We certainly don't have the thriving spring gun community and parts support over here like you have in the UK.
...whereas fitting the export spring in an 85mm TX will cook the breech seals in short order.
I appreciate the continued discussion on this Jim. Can you go into a bit more detail on the statement above? What specifically cooks the breech seals?Thanks!-SS
Quote from: sps3172 on April 12, 2022, 01:14:43 PMI appreciate the continued discussion on this Jim. Can you go into a bit more detail on the statement above? What specifically cooks the breech seals?Thanks!-SSIn a word, heat - around 1,000C in the cylinder at peak pressure. There is a temperature drop across the transfer port, but it's still plenty to cook the front o ring.We tried an export spring in my 85mm TX on an Air Arms visit. The o ring lasted one shot.
How do we get away with using the export (FAC, I presume) spring in our rifles over here? Or do we? Thanks again for the info - SS
I had to telephone Shaun at ISP to order piston rods. He is a very pleasant and helpful chap to speak to, but I don't think he gets on with modern electronic communications. Other machinists here have made extended rods, but I trust Shaun's metallurgy. If you can't get a piston rod, then simply replacing the piston weight with a synthetic top hat, fitting the UK spec spring, and preloading it to 25mm gets you most of the way there (about 0.5mm more recoil displacement than 85mm stroke), and a return to export muzzle energy levels is just a spring swap away, whereas fitting the export spring in an 85mm TX will cook the breech seals in short order. I was aware that Airarmsspares weren't taking orders, but the last I heard was they were back in business. Might be worth giving them another try.
Hi Jim,Knibbs got the TX320S MK1/MK2 piston assembly back in stock so I ordered one along with a TX355 spring. Is 41mm preload set in stone with this setup or do you preload for a given ft/lbs? I'm shooting the AA/JSB 8.4gr pellets, if that matters.Do you guys always stick with the AA factory piston seal? I've seen mention in a few places of a seal made in Australia....I didn't know how popular (if at all) it was on your side of the pond. Next, I'm hoping to land a set of Dave Upton trigger sears. I've been in touch with him and it sounds like it might be a while until a new batch is made.
The Australian CAS seals are very popular in the UK, from what I see reading the UK airgun forums. Reportedly they work splendidly in the 12 fpe guns there, but beware that the seals may not work well with FAC guns. My 350 Mag lost 60 - 100 fps using the CAS seal, which wasn't even oversized. The seal also introduced a weird, corkscrew motion into the shot cycle. Apparently, the CAS seals are just too soft to work well on 18 fpe guns.