Hi there, The collar fitted to the end of your piston will have the effect of lengthening the piston, and reducing the available space for the spring to expand, thus placing the spring under greater compression (which increases power). With the depth of the compression chamber being a constant; the longer the piston, the shorter the relative distance to the bottom of the compression chamber which is the origin of the term "short stroke". As the spring expands on trigger release, it will also generate a twisting motion (torque). The Delrin top-hat (which should be a snug fit) will in turn seek to accommodate that torque and in so doing reduce the stress imposed on the spring thus reducing fatigue and increasing its longevity. However, as the end of the piston does not rotate during the firing cycle without a washer installed against which the top-hat can slip/spin the top-hat becomes much less effective (which could very well be the reason that your spring failed). It is for this reason that you were given the very wise advice to add a slip washer between the top-hat and the piston bed. Please remember, that it is an offence to possess and air rifle which has an output exceeding 12ft/lbs without an FAC and that the law applies even if the rifle in locked in a gun case and never taken out! One may well find that their rifle is just under the limit with their pellet of choice and assume that they are safe and within the law (which technically they are). However, what many fail to realise is that if their weapon is confiscated, it will be tested with different weights of pellet, any one of which may push it over the limit (even by 0.1 ft/lbs) and as the authorities offer no exceptions or exemptions in such matters, one is guaranteed to be charged with illegal possession of a firearm and end up in court. It would seem prudent therefore to heat the spring at one end until cherry red and collapse one coil (then leave to air cool or quench in oil). Add the slip washer and test. if it is still too hot, heat the other end collapse a coil and re-test. If you are able to get the power down to around 11.7 ft/lbs, you will probably be OK regardless of pellet choice. But a word of caution to us all. It remains our responsibility to ensure that we stay within the law and that ignorance is no defence.

Personally i use a tbt replacement tuneing kit ,i have fitted these to quite a few rifles that i have had never had any problems with them, the power has always been spot on with one power washer, if you want more there is extra washers in the kit , 😁👍

Always always always de-bur HWs before reassembly, rough as a bear's bum and will shred your piston seal. Go easy on the moly.

The cold weather definitely increases the output of spingers. It has the opposite effect with PCP rifles. Obviously the new spring and piston seal needs to run in as well. 👍

They either come apart and reassemble nicely or can be a right faff. I changed the spring to a Vortek kit and the power was ridiculously high, 891fps with 10.34gr, needed to take off 2 coils in the end. A good thing with the 97 is that it can be cocked and shot without the need for the stock unlike other break barrels. Managed to get it down to less than 10 mins from take down to reassembly and testing

Now, this is a video you can learn from. Never seen any springer opened up. If I ever need to, I won't be afraid of messing up now 🙂Thanks for taking the time to show us how! Merry Christmas!

Great way of showing how easy it is to do the job yourself. Thank you.

Nice to see a maintenance video. I recommend if it's you first time doing something like this, is too take a few pics on your phone as you go as an aide memoire when it comes to reassembling the gun. I know I'd need it.

I always use a small container for the pins, tiny springs, nuts etc when dismantling an air rifle. Keeps them from being knocked onto the floor and if the rifle is apart for a few days you can put them away safely. An old pellet tin does the trick.

Another great video and nice shooting with a broken spring in your competition. I think your power may rise as your new piston seal beds in. Looking forward to part two. Thank you.

Once again Jeff, excellent video.. its always a good watch seeing you solving problems that unexpectedly pop up..😂😂 you've got a lot of patience Jeff, but you always get there in the end 😃👍🤘👌 and it helps us all out if we wanna tackle something that you just did for the first time.. 👌🤘👍

Thanks for another great video

I would have left it as it was as time goes on the spring will weaken in time 😊

Try setting it up over powered. Then cock the rifle and leave it for a few hours or days. This will set the spring.

Interesting video thank you. 8-)

Yo, if I was doing it, that mug would be on the floor by now😅

Is this jour first time dismantling a 97 ? 😁👍

I wonder if that spring had been heated and compressed prior,thats why is shorter?

A washer or something to short stroke the piston a bit more should work shouldn’t it if it’s still a bit too powerful? I’m guessing the spring wasn’t broken but intentionally cut because the person before you was having the same drama

was there any change in sound? more or less spring noise?