Main piston seal from Custom Air Seals Australia

[happymecanic]

Anyone use one in their rifle/pistol? What's your impressions? Just ordered two for my Ux Ruger BH and AH.

[Ronno6]

I have ordered Hatsan breech seals from them,and 28mm piston seals for Umarex/Ruger.
I believe they make good stuff.....worked fine.

However, I don't do impressions....my specialty was purchasing mechanical components......

[happymecanic]

Thanks Mr. Ron!

[Airnut]

I have used them many times and can't say anything bad about them but I do like the vortex products seals better. I use the pro moly seals in my Ruger Air Mag and they tend to be a little more consistent as far as velocity goes.

[Toxylon]

Some years ago, I bought a 28mm Diana piston seal from CAS. After waiting a month, the seal arrived from the land down under. It proved to be completely useless in my 28mm Dianas, two of them. It would shoot 30 - 50 fps slower than Diana OEM seals, while introducing a weird corkscrew motion into the shot cycle.

As I put the seal first into my 350 Mag, it seemed the seal was just unsuitable for magnum springers, the material being too soft for them (softness being a major selling point for the CAS company) - many magnum shooters have pointed out hard seals simply work better in this context. But as the same deal happened with my D34, a decidedly mid-power springer, I had to write the seal off.

The CAS seal I bought was of the red type, which means that it is supposed to be sized (or oversized as is, in other words) for exact fit. But the OD of the seal was just 28.2mm, which has zero sizing potential for 28mm guns, many of them being at least that much in actual chamber ID, some much bigger.

British shooters, with their 12 fpe limit, are generally fond of the CAS seals, although most seem to have switched to BritSeals the past couple of years.

[happymecanic]

Many thanks for the infos guys!

Toxylon, I ordered mine from a Canadian vendor. They're green (dubbed ''eco seal'' lol) and are said to be 28.5 mm: https://dlairgun.com/collections/custom-air-seals-parts/products/diana-ruger-rws-eco-air-rifle-piston-seal-28mm-30236600?variant=39713931591740

Mind you, these will be fitted to Canadian low-power rifles, really impatient to see how they'll do. Hoping to get more than the weak 390 fps I'm getting now...

Cheers!

[Airnut]

Its my understanding that the eco seal is a molded seal and is not molly impregnated.
While the purple seals are cnc machined and are molly impregnated hence the higher price.
When fitting to a magnum I hone the cylinder and hand fit the seal a little looser than I normally would due to the softer material.  The higher cylinder pressures of a magnum expand the parachute seal more than the harder seal. I have found that if you use the purple seal as is it will usually be to tight and you will lose some velocity and can experience weird harmonics in the shot cycle until broken in.

[happymecanic]

Finally got my seals today by snail mail!

At first they look to be a tad softer than the OEM AH and BH seals, and a bit bigger in diameter. Will be updating the thread this week-end after CAREFUL DEBURRING OF BOTH COMPRESSION TUBE . Stay tuned .

[happymecanic]

Just had the seals installed on the pistons, both are 28.55 mm installed, as advertised. When off the pistons they were 28.25 mm.

While having the pistons out of the guns I also nickel/silver soldered the heads to the piston body, as they were slightly loose. More to come.

[happymecanic]

OK so the rifle is back together, and I'm very pleased to say that it shoots much better than it did. Now it averages 453 fps on a 5 shots string with the same 7.33 grains pellets, far from the 390 fps I was seeing before, roughly a 34% improvement.

While the gun was apart I did the second screw mod, and also added a trigger stop screw. Really nice, clean break with minimal travel now .

[happymecanic]

Yesterday I didn't have time to do the maths for the AirHawk, but later I tested my trusty ol' BlackHawk, which I also re-sealed. Here are the numbers:

5 shots string using JSB RS Exact 7.33 grains pellets:

1- 451 fps
2- 443 fps
3- 444 fps
4- 450 fps
5- 447 fps

AVG: 447 fps
ES: 8 fps
SD: 3.53 fps

I'm very happy with these numbers, which are pretty similar to what I get with the AirHawk, and also with my Umarex Surge, which is another Diana 34 clone.