Umarex I've gone through a dozen CO2's trying to load two different bb pistols in 2 days.....HELP!

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Bluemill said:
There is an indentation lip that perfectly fits an 8mm diameter seal at the bottom of the retaining collar. That lip is like 2mm deep so the seal is flush with it as the seal is 2mm thick and makes it a possible gas leak point. If the seal were 2.5mm thick or even 2.25mm it would be better I'd guess.
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The nose of a typical CO2 cartridge measures about 7.4mm, so the 8mm counterbore should allow it to dip in and press against the seal.

Granted, a thicker seal would probably work fine unless it stands so proud that it prevents the cartridge from being pierced. Another consideration is it is more susceptible to material creep and extrusion failure, as the perimeter of the seal is no longer supported inside the counterbore.
 
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Bluemill said:
The Crosman 357 pellet pistol is still one of my favorites. I know it looks very unauthentic, perhaps crude, BUT its strong points more than make up for its looks. Those points are: 6.25" RIFLED barrel, 400+ muzzle velocity, decent double action, 10 round clips that can be readily changed and are portable, and a Fully Adjustable rear sight for height and windage. If there is a varmint in the yard that needs a lesson this is the pistol I get out! Also the price is right for all that performance. Not sure these are still sold but the "Vigilante" looks to be similar.
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I haven't seen the version of the Crosman 357 that comes with the 6 1/4" Colt Python looking barrel for sale in a long time, but other versions of the 357 are still sold. The Vigilante is the same gun with the more modern looking 6" barrel with rails. They also sell a kit gun version called the "Triple Threat" that comes with swappable 8", 6", and 3" barrels, 2 mags, and holster. I recently bought one and for around $70 it's a great value. This is my 3rd C357. Just great guns, and so easy to work on. As far as I know all models use the exact same frame.

With regards to the PPK/S, mine must be an early one, as the valve assembly is not staked. Good to know when it comes time for a new seal.

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Yeah, I saw that triple threat too! Thanks for that though.

Trig, you must be an engineer or a gunsmith. Whatever is your line of work it's above my paygrade! I think I'm going to TRY to get slightly thicker polyurethane, ideally 2.25mm to make new seals. I have SUPPOSEDLY ppk/s CO2 seals on their way from Bagnall & Kirkwood from the UK. NOT inexpensive. I will look these over very carefully and measure them etc. and report back. The old spent originals seem to have lips on both sides, a definite clue of their design intensions. I think I had better luck for easy loading of carts by using a 9mm seal and stuffing it in the 8mm collar. Perhaps initially it made for a better bottom seal to the piercing floor of the air valve.

Yours,
Bluemill
 
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I got my shipment from the UK, Newcastle on Tyne, where they made the RMS Mauritania long ago, a long time holder of the Blue Ribband for the fastest liner to cross the Atlantic. Are you guys saying that the Crosman gaskets are the same thing as those sent to me by Bagnall and Kirkwood? The cost hasn't been finalized as it hasn't hit my card yet- with what exchange rate I got, but it's going to be close to $50 for three polyurethane "O" rings.

I tried one on my 2014 first generation PPK pistol and it did work but there was quite a loss of gas putting it in. Once I gave it a firm tightening it seemed very air tight and it had a very nice POP and firm blowback. I just checked after 24 hours and the performance is the same. I do think that these B&K gaskets do fit but are no better so far than the ones I've been making. The Gen. II PPK/S bb has a home made 8mm OD x 2mm thick x 3mm center hole. That gun has a deeper, more resonant bam when firing, which may be a product of the changes in hardware of the Gen II gun. I'm referring to a firmer trigger pull, and definitely a stronger hammer spring. With my home made "donuts" they often load CO2 in the first and second times with no hiss at all- The only draw back is that they last about 3-4 tubes before having to be replaced.

I'm attaching a picture of all varieties of the gaskets; A= An old original seal from a Gen.I pistol, note the reddish hue from Crosman Pellgun Oil, and the scooped out center indentation. This can be seen in all shown here except gasket E which hasn't been installed yet, the Bagnall & Kirkwood one. B= the gasket from my son's former 2014 gun which he only loaded one cartridge in. C= the gasket that came out of the like new Gen. II pistol I got recently, and looked like it had not been shot very much, perhaps never? D= My last successful homemade 8x3x2 80 durometer polyurethane. E= the B&K sold 8mm x 5mm x 2mm thick, appears to be poly of similar hardness to my DIY seals. They have a slight flat surface on the top and bottom of the donut. If they have a wonderful, long term durability, i. e., holding gas and the ability to be reused with numerous CO2 cartridges, I'll advise this forum.

In a post by me a while back I said I would put blue-medium hold Lock Tight on the brass collar to hold it place, and possibly to STOP air leaks caused by damaged threads in the airvalve. DON'T DO THIS!!!!! IT LOCKED THE BRASS COLLAR SO HARD I COULD NOT REMOVE IT!

Yours,

Bluemill

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