Based on comments I have seen here, I decided to go ahead and order a MK 2 piston for my TX200HC. But now I have to decide on spring sizing. Currently I have a Vortek PG3 12 ft-lb kit installed which provides about 22/160 pound intial/final spring loads during cocking. To keep the same power with the shorter stroke I have two easy options: buy a longer spring for the PG3 kit which would give 54/160 pound initial/final loads, or use my old PG2-HO kit with its heavier wire which would give 37/200 pound loads. Either should work, but the longer spring for the PG3 would give more uniform recoil forces and maybe less piston bounce, so I think that is the way to go. Unfortunately it would also mean higher initial cocking force. Am I thinking this through correctly?
TX200 Short stroke kit question
- Thread starter Michigander
- Start date
Why not try the spring you have in there? Might not lose as much power as you think. Id start by adding some spacing to the spring you have if necessary, might get you right back where you need to be.
Upvote 0
Thumper: If I stick with the 27 1/2 coils I have now, it will take about a 0.7" spacer to get back to 11.8 ft-lb which will give about 48/166 spring forces. Also with the spacer stress will be very high when cocked. I have to pick up a new seal anyway, and springs aren't that expensive, so if more uniform spring forces (lower rate) gives a smoother shot cycle I thought I would just go with the longer spring. The question still remains as to whether the TX benefits from the approach of using a longer, lower rate spring versus a shorter, higher rate spring. What I have been able to find online seems to suggest that it does. I'm just looking for confirmation from someone with more experience tuning these guns than I have (zero). Thanks for your reply.
Upvote 0
josh3rd: Thanks for pointing me in that direction. I took a look at my MK 3 OEM spring and it does look to be a good performer. With the MK 2 piston I come up with spring forces of 44/186 pounds and about 12.6 ft-lb pellet energy. And because of the large diameter, stress is low so it should last a long time. The spring forces aren't quite as uniform as the 54/160 pounds from a longer, lower rate PG3 spring, and pellet energy is expected to be a little higher than what I was targeting, but still a very interesting option. I may make a tighter fitting, longer guide for the OEM spring and start that way.
Upvote 0