Custom Air Seals Short Stroke Piston Seal Feedback

[oldskoolzzz]

On my 95 thread I’m considering a Custom Air Seals short stroke piston seal (26mm) 10mm Short Stroke.

I’ve tried a search but can’t really find any feedback on them

Has anyone tried one and if so what’s your thoughts, feedback etc.

My only other short stroke experience is using the Tinners (TBT) nose but as I’m more than likely wanting to replace my seal as well I’m thinking the CAS route will kill two birds so to speak.

[Dragonboy]

I have one in a HW98. Fitted it the same time as a tbt extension / kit in another. The custom seal took a little time to settle/wear in but has been fine since. Hard to tell the difference now.

[oldskoolzzz]

I have one in a HW98. Fitted it the same time as a tbt extension / kit in another. The custom seal took a little time to settle/wear in but has been fine since. Hard to tell the difference now.

Thanks for the reply

Would you say it maybe needed resizing a tad?

I’m assuming that’s what you mean perhaps a tad too tight at the start until it worn in.

Was there much power difference from when you first fitted it to what it is now?

[Dragonboy]

The resistance when placing the piston in the cylinder wasn’t too bad. Only marginally more than the standard HW seal. I didn’t think it warrant resizing at the time. Power was lower initially before creeping up and settling around 11 fpe with low spread. Bear in mind it was a new rifle, new spring and drop in kit. Guess the whole internals were bedding in. I can’t tell the difference between the two rifles now, both shoot nicely with a shorter lock time.

[oldskoolzzz]

The resistance when placing the piston in the cylinder wasn’t too bad. Only marginally more than the standard HW seal. I didn’t think it warrant resizing at the time. Power was lower initially before creeping up and settling around 11 fpe with low spread. Bear in mind it was a new rifle, new spring and drop in kit. Guess the whole internals were bedding in. I can’t tell the difference between the two rifles now, both shoot nicely with a shorter lock time.

Sounds good buddy thanks for the info

[32:1]

What’s the bore and stroke of a 95 and is this a ballpark SS amount for a 95 tune

[Shed tuner]

What’s the bore and stroke of a 95 and is this a ballpark SS amount for a 95 tune

26 x 86 IITC ? losing 10mm is a good place to be. HW99 that everyone likes at 11 fp is 72mm stroke IIRC.

So the sweet spot for a sub 12 26mm bore rifle is defo just around or a bit more that 72mm stroke. I think a 95 at 74-76mm is perfect.

[evert]

26 x 86 IITC ? losing 10mm is a good place to be. HW99 that everyone likes at 11 fp is 72mm stroke IIRC.

So the sweet spot for a sub 12 26mm bore rifle is defo just around or a bit more that 72mm stroke. I think a 95 at 74-76mm is perfect.

Someone should manufacture a short stroke piston for the 95.

[32:1]

Someone should manufacture a short stroke piston for the 95.

Most manufacturers should offer that I feel, but high power markets dictate what we get it seems. I’m not that familiar with hw stuff but having a few Cometa’s I know the 300 has the best sub12 powerplant, and thats 26x75 if I remember correctly, Ive knocked 16mm off the 400 to 26x81 and found it works well.

Would you lighten a SS 95 piston too or does it need the weight

[TonyL]

The 95 piston isn't overly heavy at circa 250g, although a few people have reported pleasing results once lightened a little. It'll all boil down to the balance of the action.....the stroke decided upon, transfer port size, spring force, preload, pellet start pressure etc.....

[Shed tuner]

yeah, as Tony says it's balance. Witha shorter stroke, you are probably more able to lighten the piston, as there is less air up front to counteract the bounce against (will it happens later int he stroke)... but I'd not trim loads off. Extrapolating the "ideal " 200g for a 25mm gun, you probably want to stay in the 220-230 g range for a 26mm

But as per Tony, it depends on overall balance, inc spring, preload, calibre

[32:1]

yeah, as Tony says it's balance. Witha shorter stroke, you are probably more able to lighten the piston, as there is less air up front to counteract the bounce against (will it happens later int he stroke)... but I'd not trim loads off. Extrapolating the "ideal " 200g for a 25mm gun, you probably want to stay in the 220-230 g range for a 26mm

But as per Tony, it depends on overall balance, inc spring, preload, calibre

That’s why it’s so simple then

😂😂😂😂😂

[Shed tuner]

That’s why it’s so simple then

😂😂😂😂😂

and why your rifle has been apart so many times already

The JSB 8.44 / 7.9 comparison test will you you some idea if you are erring towards too much bounce or too much slam, but it's not perfect.

[oldskoolzzz]

The 95 piston isn't overly heavy at circa 250g, although a few people have reported pleasing results once lightened a little. It'll all boil down to the balance of the action.....the stroke decided upon, transfer port size, spring force, preload, pellet start pressure etc.....

yeah, as Tony says it's balance. Witha shorter stroke, you are probably more able to lighten the piston, as there is less air up front to counteract the bounce against (will it happens later int he stroke)... but I'd not trim loads off. Extrapolating the "ideal " 200g for a 25mm gun, you probably want to stay in the 220-230 g range for a 26mm

But as per Tony, it depends on overall balance, inc spring, preload, calibre

I’m probably looking to lighten my piston a little.

From memory though I thought they were a tad heavier seem to recall circa 270g but I can’t remember if that was with/without the factory liner

When I start my project, I’ll weigh everything and see what the craic is although I might save this for a project at a later date.

I’m tempted to just try it in standard guise for a few months first which will also give me time to collect parts and all those goodies.