N/A Lightened Piston

[wamf]

I thinky you better study air gun dynamics, heavier can be better, as a heavier pellet or a lighter spring,it is all about harmony

What do you think this thread is about? It is about the differences made by adjusting the equipment used it is not the end all be all of what is best

 

[boscoebrea]

Sorry,I did not explain right.The heavier piston can be better at tuning down harmonics or damping the shot cycle; a heavier pellet does a little of this, as does a lighter spring....for every effect, there is another effect; that is why I used the word harmony. Each one of the things I have mentioned has some effect on what you want to achieve; how you go about or how you choose to go about it is what your outcome will be.
Do you want to have control of the outcome? That is why a study of air gun dynamics can help to figure out how and why things are done in such a way, also how you influence them by choosing the methods to do about the change you want to achieve.............

 

[Mycapt65]

It's more a case of shoots not so bad than shoots so well. I made the gun heavier with a laminate stock and hw98 barrel and use the ARH low power kit for hw80 and a slightly tight Vortek piston seal. I don't like the firing behavior of my .177 30 very much

Thank you for responding. To each their own . I'm opposite. I don't like shooting big heavy guns. Even off a bench. My 97 and R1 get the least use of my rifles. My 177 Hw30s the most with my 177 Hw50 next. I like a quick clean snappy shot cyle. On a bad recommendation I ran a 128 wire Vortek kit in a R1 and it was about 12-13 fpe IIRC and the shot cycle was lazy two step process. It was more a ker thump than the single snappy thump I like. I've heard of people getting them to run well at 12 fpe but always wondered how to move that much air with quick clean cycle without enough spring to push it well over 12fpe. I imagine opening the TP would do it but I hesitate to mess with TPs due to the complexity of retuning them to original size. I've also heard of people sleeving them down to a smaller piston. I could see lightening the piston might be helpful to in 12fpe 80 platform.

There's so much stuff you can play with. It's definitely interesting stuff and I thank you for your input.

Be well
Ron

 

[JP806TX]

Just lightened a friend’s Tx piston.
See pictures below.

We chopped it until only 1.5 inches was left? (Yeah it was an aggressive chop, we’ll weight it next time)

Initial testing with an after market ? spring was not good. I think we dropped from 10.5 FPE to about 8FPE.

We were told to switch to a HW 50 spring. Now power is around 10.9 FPE. The owner reported the shot cycle was smoother and quicker and it was "significantly" easier to hit what he aimed at. I’m hoping with one power washer we can reach 11 + FPE with no change in recoil. Shooting 8.6 grain pellet with the heavy OEM top hat and the OEM spring guide.

I’ll get some weights the next time we open up his TX.

 

[Temesvar]

Just lightened a friend’s Tx piston.
Should have taken pictures and measurements (next time)

We chopped it until only 2.5 inches was left? (Yeah it was an aggressive chop, we’ll weight it next time)

Initial testing with an after market ? spring was not good. I think we dropped from 12FPE to about 8FPE.

We were told to switch to a HW 50 spring. Now power is around 10.6FPE. The owner reported the shot cycle was smoother and quicker and it was "significantly" easier to hit what he aimed at. I’m hoping with two power washers we can reach 11FPE with no change in recoil. Shooting 8.6 grain pellet with the heavy OEM top hat and the OEM spring guide.

I’ll get some pictures and measurements the next time we open up his TX.

Factory piston is 255 g. At least that's what my .22 weights. Adding some slots, i reduced the weight to 205 g.
With Vortek kit, shoots 700 fps. with 14.66 gr. pellets. 16 fpe.

 

[Temesvar]

Just lightened a friend’s Tx piston.
Should have taken pictures and measurements (next time)

We chopped it until only 2.5 inches was left? (Yeah it was an aggressive chop, we’ll weight it next time)

Initial testing with an after market ? spring was not good. I think we dropped from 12FPE to about 8FPE.

We were told to switch to a HW 50 spring. Now power is around 10.6FPE. The owner reported the shot cycle was smoother and quicker and it was "significantly" easier to hit what he aimed at. I’m hoping with two power washers we can reach 11FPE with no change in recoil. Shooting 8.6 grain pellet with the heavy OEM top hat and the OEM spring guide.

I’ll get some pictures and measurements the next time we open up his TX.

You can shorten the piston as much as you like and will reduce some weight. But will have to keep the guide slot, or there will be much more involved in this mod!

 

[JP806TX]

That looks like a HW97 piston.

The TX 200 has a different design. It has a sliding compression tube and the piston rides inside the tube. This gives us the option of cutting out a lot of weight from the piston. One disadvantage is we lose the rear Derlin guide.

Here's another option for a lightened TX piston for $106 (currently out of stock). This mod keeps the rear Derlin guide.

Air Arms TX200 & Pro-sport Lightweight Piston

TX200 / Pro Sport Lightweight Piston, a genuine Air Arms part machined as a direct replacement for the standard piston. Weighing approximately 208 grams, this lightweight piston offers reduced lock time and recoil by minimizing moving mass. Normally the pistons are approximately 205g once...

www.apexairguns.com

 

[Temesvar]

That looks like a HW97 piston.

The TX 200 has different design. It has a sliding compression tube and the piston rides inside the tube. This gives us the option of cutting out a lot of weight from the piston. One disadvantage is we lose the rear Derlin guide.

Here's another option for a lightened TX piston for $106 (currently out of stock). This mod keeps the rear Derlin guide.

Air Arms TX200 & Pro-sport Lightweight Piston

TX200 / Pro Sport Lightweight Piston, a genuine Air Arms part machined as a direct replacement for the standard piston. Weighing approximately 208 grams, this lightweight piston offers reduced lock time and recoil by minimizing moving mass. Normally the pistons are approximately 205g once...

www.apexairguns.com

Right. TX pistons need no locking. Thanks for sharing the picture.

 

[Temesvar]

Just lightened a friend’s Tx piston.
Should have taken pictures and measurements (next time)

We chopped it until only 2.5 inches was left? (Yeah it was an aggressive chop, we’ll weight it next time)

Initial testing with an after market ? spring was not good. I think we dropped from 12FPE to about 8FPE.

We were told to switch to a HW 50 spring. Now power is around 10.6FPE. The owner reported the shot cycle was smoother and quicker and it was "significantly" easier to hit what he aimed at. I’m hoping with two power washers we can reach 11FPE with no change in recoil. Shooting 8.6 grain pellet with the heavy OEM top hat and the OEM spring guide.

I’ll get some pictures and measurements the next time we open up his TX.

A lighter piston will decrease not only the recoil, but also the velocity. That is when a stronger spring comes in. You can order from Vortek the length you want and/or coil dia. you want. I ordered a od sized, and they cut it, flat and grind the ends.

 

[Mycapt65]

A lighter piston will decrease not only the recoil, but also the velocity. That is when a stronger spring comes in. You can order from Vortek the length you want and/or coil dia. you want. I ordered a od sized, and they cut it, flat and grind the ends.

Stronger springs are required for lighter pistons because they are more prone to bouncing. It's the bouncing that reduces efficiency and causes the loss of power. Stronger springs are typically heavier and accelerate the piston quicker. Both increase the recoil you were trying to reduce in the first place. You can sometimes reduce bounce by opening the transfer port or using lighter and or loose fitting pellets. That reduces back pressure. Increasing the TP diameter also increases lost volume which can sometimes hurt velocity. Everything is about finding a fine balance of forces and opposing forces. You could go nuts chasing this forever. But it is fun to play with.

 

[beerthief]

I'm spit balling here on this one as I've never actually tried it. With some experience building racing engines, I've long considered reducing pistion weight to increase power and reduce recoil. Here's my thoughts on lightening which are only theoretical. I'll start with what I have done with piston weight and work it backwards.

Its been common practice to make piston weight heavier with steel top hats to reduce piston bounce. This I have proven to be somewhat true, the results vary wildly because less bounce is more efficient and can produce more energy. Accelerating more weight saps power. Often its wash because the sapped power equals any gains from reducing bounce. Typically adding weight increases efficiency more notably with heavier or tighter fitting pellets that are more prone to piston bounce. Adding steel washers above the top hat is one way of tuning weight. The extra preload the washer creates can offset the weight penalty. I've had very mixed results with this. It varies greatly depending on spring and gun design. I've gotten away from this as a practice.

The subject of the OP was lightening. Reducing piston weight and spring weight does reduce recoil. Look at the running 25mm pistons in HW77 and 97s. That's a quick way to make a nicer shooting 77/97. Obviously 25mm Hw30s are easy to shoot while 30 mm R1's are notoriously difficult to shoot. That's an extreme example and piston speed has a lot to do with it but you get the idea. So there's something to reducing weight that reduces inertia and thus recoil. Felt recoil isn't just the movement of weight in one direction. Often pellets that produce more bounce and are less efficient feel less smooth than pellets that produce less bounce. Therefore it's possible that a lighter piston with more bounce may lose some of it's smoothness. I believe one way to reduce bounce is to run more preload. Not necessarily a stronger spring but a lighter longer spring. The compressed pressure will be the same but the extended pressure will be greater and more bounce resistant. Perhaps a lighter piston with a lighter spring with more preload? A lighter power spring also reduces physical weight that may also reduce recoil. There's so many variables the combinations of pistons and springs becomes endless. Then throw in transfer ports which throttle back pressure you can go crazy. Personally I think being more prone to bouncing, lightening will make the gun more pellet picky. Not necessarily a desirable trait.

With my varired experience playing with adding weights I've binned the idea of reducing piston spring assembly weight. I'm also not a competitive shooter. There are tuners in the UK that this is their thing and they got it all figured out. At a hobbiest level it's a crapshoot at best. I'm not saying it's not worth trying. I'm saying is all the variables make theories fun to discuss but you won't know until you do it. If you're serious about this I'd recommend contacting someone like Tony Leech that has a lot of experience with this and purchase a matched set of parts. It'll be expensive initially but the time and money it'll save will likely be worth it in the long run.

when i bought my first quality air gun it was a HW97 .177 , shot it for a week and did not like the bouncy recoil . I ask about a tuner and got Tony in PA . sent it to him and said "i want this to be the smoothest cycle and 11.6 FPE using FTT 8.64 ." Tony did his magic and i i have a wonderful gun, . that was 6 years ago , I am thinking of sending one of my TX200 to have tuned to 10.5 FPE . I do not like to tinker ,so i will gladly pay to have what i want done .