Canadian Airgun Forum

Hi folks

I just bought a .177 TX200 sub 500fps version from another member and wanted to change it to full power. I already had a full power spring on hand so swapped it in.

Problem. The cocking stroke is short and rough. It stops at less than 90 degrees while my hunter carbine travels to about 130 degrees. It does however actuate the anti-bear trap and auto safety but it’s only shooting 460 to 480fps.

Question. Is there some additional mechanism in these Canadian spec rifles that restricts the full compression of the spring? If so, is it possible to change out any additional parts that would get this up to full power?

Thanks (and yes I do have a pal so it’s all kosher)

Rae

I'm pretty sure the HP spring is too long. I have experienced this myself trying to install a short stoke kit. There was no additional travel allowed for the extra 1 cm required to fully cock. I could only engage to the first point of the bear trap. Check to see if you have an additional extender on your piston which would be a short stroke kit. If you do have it, take it off. You would need a new piston seal. If you don't then you would need a new hp spring that compresses to the same length as the current spring.

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I have some airguns.

You need the spring and a fac piston latching rod combo approx 100 mm stroke vs likely 75 mm stroke you have now,or you could have a longer latching rod made and remove the one you have now from the piston you have,kelly

Thanks for the tips guys. Looks like I need to call AGS and order some more parts.

It depends on how much you want to spend. All of my three TX200 guns are short stroked to some degree. The Mk1 came with a longer latch rod, therefore a shorter stroke. My other two guns have Tony Leach (TL) kits in them. An FAC piston, if you can get one may be one easy way to go. It would have a shorter latch rod and a longer stroke, so the 12 ft/lb or high power spring would jump the power considerably.

Another concern I would have is the size of the transfer port (TP). If it is smaller to restrict air, then enlarging it to allow the air necessary to increase the power might work. I have not seen a sub 500 fps model, so I am not sure how big the port is. If it is smaller, I would keep the short stroke piston, enlarge the port and see what effect that has. The short stoke is something many FT shooters are now using. The shot cycle is very quick and linear. I believe the TP on my two TL guns are 4 mm. The stock gun is 3.74 mm, so if yours is smaller than that, it may be the cause of the lower power. Reaming the TP to 4 mm can be done fairly easily and may solve your problem.

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Tim
CAFTA Governor and lifetime learner

Thanks Tim

I called Travis at AGS and he said an FAC piston was needed. So I had him send me that and installed it. Put it all back together including a new piston seal and vortek tune kit and … no change. Still short stroking and only making 535 fps. I’ll have to look at the transfer port. But I can’t imagine getting full power when the spring is never fully compressed? My HunterCarbine is set up with all the same intrrnals and everything works the way it’s supposed to. One thing I did notice though is that the side of the breach (not sure what that part is called) has 2 notches while the HC has 3. I assume these notches engage the anti beartrap so I wouldn’t think that would cause this particular issue. But maybe that’s a tell tale sign of more FAC parts needed. At this rate I might have well just bought a brand new rifle as there won’t be much of the original left.

Rae

I think you are referring to the compression tube and the notches are for the anti-beartrap. Seems strange that it only short strokes. The compression tube on my HC has no notches and no beartrap and cocks normally and engages the safety. So the beartrap should not affect the length of stoke; the stroke should continue until the end of the latch rod engages the trigger and safety.

My guns are short stroked so the cocking lever does not move as far to complete the stroke. The FAC piston rod should be shorter and need a longer stroke to engage the trigger and safety. The angle of the lever should be noticeably larger. Are you only cocking the gun until the second beartrap grove engages or are you doing the full stoke to engage the trigger and safety?

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Tim
CAFTA Governor and lifetime learner

The lever goes to about 80 degrees to a hard stop after two clicks of the anti bear trap mechanism. Second click engages the auto-safety and resets the trigger. Firing cycle is smooth and feels totally normal- just low FPS.

Sounds like the piston rod is longer to reduce stroke.
How was the firing characteristics in terms of recoil and noise in the lower power configuration? I have a 177 HC coming soon and I'm considering putting together a low power setup to use in the yard if it's too loud at 11-12fpe.

I would compare the new piston/ rod to the old one ,sounds like the same length instead of shorter rod,again it should be about 1 inch shorter,75 mm vs 100 mm stroke ,kelly

Post pictures next to a ruler ,should be easy for one of us to tell

Well indeed the issue was the piston. I stopped in at AGS on my way up to Ottawa on Monday and Travis discovered he had mistakenly sent out the wrong piston. Swapped in the right one and voila - problem solved.

Thanks Kelly, Tim and others who replied for all the suggestions and ideas.

Rae