Piston seal

[Stokie99]

I've been playing with a TbT short stroke kit in my TX for a week or so now, gun already had the drop in kit, found (as expected) power dropped off after fitting S/S kit, added some washers, still couldn't get it up to 11ft lbs. stripped it again, added different combo of washers, ( now getting very hard to cock, and get trigger block bolt back in) chrono'd again, couldn't believe it, dropped to under 8ft lbs.
Will play with it again later this week, could it now have become 'springbound' ? Do I need a MK2 or after market spring ? Any ideas please.
Thanks

How much did the power drop when fitting the kit and what was the starting point ? Cheers stokie99

[eddie666]

I believe power in a springer is derived to a large part to the swept volume of the piston in the cylinder. A shorter stroke results in a lower swept volume. Increasing the preload on the spring will make a more harsh shot cycle with little improvement in power.

well said

[roadrunner]

What weight and style of pellet are you using
my .177 prosport is fitted with a welsh willy guide kit with an uncut titan spring and no preload washers,it shot a little warm until the spring settled but now its epic 815 fps or 11.5 fb with a AA express pellet and its smooth as you like

[Stokie99]

hi guys just a quick update my kit arrived today and has been fitted I have fitted the drop in kit and the short stroke with the hw 25mm seal , the power started at11.9 before the alterations which is to high for a springer in my opinion it is now running at 10.7 it was running at 11.5 but I removed a power band ,it has less vibration and quieter and feels smoother to shoot but I wont know what difference its made with shooting until I get it down the range and shoot some paper to see if its less hold sensitive ,the only drawback at the moment that I can see is I can only get 1 click on the anti bear trap but it cock fine. I will keep you posted stokie99.

[Lord Long]

What weight and style of pellet are you using
my .177 prosport is fitted with a welsh willy guide kit with an uncut titan spring and no preload washers,it shot a little warm until the spring settled but now its epic 815 fps or 11.5 fb with a AA express pellet and its smooth as you like

This sounds like what I'm after, I'm using 7.87 Exact Express, maybe a Titan is the way to go then ?

[eddie666]

i would put the washer back in for the 11.5 and run it in with that , as things will start to settle and on a .22 it will not clime up much from 10.7 the tx200 like it better just over 11.2 or put a thinner washer to get it to about 11.2 11.3 11.4 then you will know how it likes to be held as you run it in, or latter you will have to add a washer and start to hold again ,
get it close now,
if you only have a thin steel washer , put it on the trigger end guide , or you can sand the plastic washer down a bit, one third
should give you about 11.00

[Stokie99]

i would put the washer back in for the 11.5 and run it in with that , as things will start to settle and on a .22 it will not clime up much from 10.7 the tx200 like it better just over 11.2 or put a thinner washer to get it to about 11.2 11.3 11.4 then you will know how it likes to be held as you run it in, or latter you will have to add a washer and start to hold again ,
get it close now,
if you only have a thin steel washer , put it on the trigger end guide , or you can sand the plastic washer down a bit, one third
should give you about 11.00

Thanks for the advise that sounds like a plan stokie99

[Stokie99]

Just a quick update the power has settled at 11.1 and is totally different to shoot there is very little recoil or vibration and the whole shooting cycle has speeded up it is also less hold sensitive and accurate at 40 yards now so I will run it in now about 3 tins -and see how it goes but first impressions is a vast improvement on factory out of the box .
Ps it now has a 8ft spread over 20 shots