TX200 HC .22 tune

[inmhs]

I got a walnut TX200 HC .22 from AoA a couple of days ago. It's a really pretty rifle; the stock just needs a little more finish.

The first thing I noticed when I cocked it was the effort. It's lots higher than my full-power HW77k .22. I'd like to reduce the cocking effort and smooth the shot cycle. I'm fine with reducing the power some.

I have some experience tuning airguns, I have a small machine shop and have made lots of spring guides and various other parts. If I tune this myself I'll probably order a new spring from ARH, and make tight delrin guides, and maybe new bearings for the piston if they aren't snug. Maybe an O-ring seal.

I've read lots lately (last few days, just joined this forum) about Tony Leach's 22mm conversions. Does anyone have experience with these in a low-power tune for a .22 HC?

Any other ideas for a really nice shooting tune?

Thanks, Mark

[Motorhead]

Shorter barrel and shorter cocking arm over the TX MK-3 full size = MORE cocking effort 

[inmhs]

That makes sense, but why is it so much worse than the 77k?

What tune would you recommend for moderate to low cocking effort, moderate velocity, minimum recoil?

[inmhs]

I had some spare time, so I opened the TX up to see what it was like inside. Lots of dark gray grease. I took out the piston and compression chamber, machining looked good, piston seal was too tight, but not terrible. It looked almost new inside, barely shot, consistent with the outside. The spring was very loose on the steel guide, and on the massive steel tophat. It was around 29 coils, 0.130" wire. I looked around in my parts drawer, and found a nearly identical spring, but 0.113" wire, trace smaller ID, with a delrin tophat tightly fitted. Probably from 5 years ago or so when I was tuning my ProSport, not sure.

Anyway, I cleaned up the insides, tophat was a great fit, and the spring was a tight fit on the factory guide.

With the factory spring, very hard cocking effort, lots of vibration and recoil, about 680fps with 14.3 Crosman pellets. With the new spring, very light cocking, almost dead, pellet stays on the scope cap, 550fps with the same pellets.

I'm very happy with this as a first attempt, taking about an hour. I think I'll shoot it for a while and see how I like it.

I'm very likely to finish the stock better, the wood is really nice, maybe try an O-ring seal (there was one in the drawer), maybe do something so the link from the cocking rod doesn't slop around. Might disable the beartrap. My full-length TX is a MK1, so I"m used to no beartrap.

[Yarddog]

While Motorhead was tuning my TX200, I laid on Jim Maccari's Royal London Oil to the walnut stock. I opted for his professional method.  Came out very well. Satin finish.

[inmhs]

I've always used Formby's or Minwax tung oil finish, but have read so many good things about Maccari's that I would like to try it. It's out of stock. Do you know of another source for it or something similar?

[inmhs]

Not all is paradise. I decided to address the slop in the cocking link, so I removed it, this time I noticed that the holes in the cocking arm were oval. This is not at all consistent with the rest of the rifle, which looks almost new. On closer inspection, it looks like someone intentionally enlarge the holes on the side to the back, maybe to loosen lockup? They opened them up around 0.02", not very consistently. I'm pretty sure the front edge part of the holes is original, it still has a bit of chamfer there.  It looks like there's plenty of material left, and that if I open the holes up to 0.25" (from around 0.196" originally) it will clean everything up. I'm not quite sure how to locate the holes, probably I can get very close using the radius of the remaining factory part of the hole. I might clean up the cocking arm first, then use that to locate the link hole.

Should I set it for compression-chamber to barrel contact with no barrel seal?

[inmhs]

Also, the front of the cocking shoe has been altered, don't know how much has been removed. It would be nice to set it up correctly with a shortened shoe, then just put in a stock one if it gets loose.

[inmhs]

Forgot to add, all the parts that are messed up can be bought shipped for less than $70, so considering the stock I would buy it again.

[inmhs]

Try for  a pic?

[inmhs]

And that's with the so-so finish.

[inmhs]

Test?

[inmhs]

It seems that I can't do pics anymore. Maybe not enough posts?

[inmhs]

Egg pic

[inmhs]

No pic. Retry.

[inmhs]

Smaller file?

[inmhs]

Finally worked. Top left edge of the hole shows factory bevel, bottom right shows whitish ridge of metal, looks like it was enlarged intentionally. If I stay centered on the original hole, opened up to 0.25", should remove all the defects.

[AmBraCol]

Hey, Mark. Looking good. Lovely stock, that one.  The brits love their sub 12 FPE 22's. There's just something "right" about the lazy thump of the shot cycle.  You might try a power washer to bring the power up a tad. I"d opt for a larger wire diameter, probably around .120" give or take. Can't remember what all Maccari has for these rifles, but they shoot dandy at the 12 FPE level. Over that they seem to be reaching too hard to get there. 

Yes, your problem with posting pics was probably low shot count. Welcome to the forum!

[inmhs]

I can't wait to see the stock with a little work. It seems almost unfinished, lots different than the older ones I've had. I probably will bump the power up a little, but with tendonitis in my elbow now I'm very happy with the low cocking effort.

Thanks for the welcome.

[inmhs]

I got ambitious a few hours ago and decided to fix the cocking arm. I put the arm in the mill, and aligned it off a pin gauge through the holes that the arm pivots on. I opened up the damaged holes with a 1/4" end mill, they were so bad I ended up going to 19/64. I made some steel bushings and pressed them in, all seems well now. No more slop in the link, should last a long time.