Firing pot !!! ?

[underdog]

Hi did the balloon test on my s400 on filler and barrel the filler one's ok, but the barrel one failed I asked at my club and a technique guy said it would be due to firing pot plunger he at to leave at this point so could not grill him I've looked on chambers and can not see any sort of "O"Ring in there diagram for firing pot only along type tube screw on end followed by a spring then a thin plunger with a plastic type stopper on the end of it so what do I have to do to these parts to stop air leaking into barrel may be replace the whole lot or is that over kill ? PS can see the brass firing pot
As a grub screw stopper so can any on help with what I need to do thanks from Frank

[Blackbaronfish]

Try dry fireing a few times, as you may have dirt trapped .

BBF

[underdog]

Try dry fireing a few times, as you may have dirt trapped .

BBF

Thanks I did dry fire it prier to balloon test I also dry fired it up side down hoping some crud would come out but in the morning there was air in balloon
Still don't understand how dirt or crud would stop nay keep firing plunger open I'm not being Rude would you explain it.As if it's just a matter of shooting the air off and getting firing pot firing pin and spring out and clean them in white sprits it's not a problem but I would want to know how and what would be damaged in there I'm taking it that the plastic type washer on end of firing pin valve holds back the air so may be that's damaged if I'm on wrong tack tell me ATB from Frank

[TenMetrePeter]

ive found Rothery's diagrams clearer than Chambers usually.
NB click on "CLICK HERE to Download Printable diagram" link.

http://www.bisley-uk.com/product_v3.php ... 500S&c=184

[Roger5]

If there is no anti tamper it's quite easy to do,make sure cylinder is empty, unscrew it, undo bolt in gauge mount just enough to twist the mount to one side, under firing valve body is a small Alan bolt, loosen it and then you can unscrew the brass pot, unscrewing this will release the firing valve and spring once out you can clean out the valve seat, I use cotton buds, make sure you clean the valve aswell, if this dosnt sort it you will probably need a new firing valve, when you come to put it back together, measurement from firing valve body to the end of the brass pot is 57mm. Have fun. Rog

[Mark112]

Hi,

If the valve has been in the rifle for a few years it's best to change it anyway. They can suffer from extrusion and form a step on the sealing face of the valve. A new valve will give a better power curve and thus more usable shots. It's item 4 in the above diagram. While it's apart give the hammer rail a good clean and polish with autosol or similar. Make sure the hammer itself is also spotless inside the two bushes as crud can build up here. This will improve shot to shot consistency. Make sure you chrono it afterwards preferably with a heavy pellet (JSB heavies or similar) and at about 130 bar as this is typically where they make the most power.

Mark

[underdog]

Thanks 10 yes a better Diagram alot clearer can see now what's what
Thanks Roger5 I'm going to take your advice strip her down see what I can see it may be just a case of crud
And crap over the years how it gets there I do not know as this s400 was going for a song and we'll I thought spend a few bob on her and she will be back to her Glory years.The air cylinder as on it 9/2006 so may be that's when she was made no sign of any anti tamper but that means nothing as most over the years are taken off thanks to utube, it's been stowed in a blokes shed up in roof recess so away from the damp will see when I open her up well all thanks for all the advice you have given me well made up now to get done to it ill keep post alive some one may be intrested on how she turns out ATB from Frank

[underdog]

Thanks Mark for your advice I was thinking of Renewing all of that section so you think renew just the firing valve plunger well we will see when I crack her open
She is a 177 so what would be classed as heavy pellet in the 177 range to test her after she's fixed I have a chronograph so test her at 130 bar she was using jsb 8.44 and I it was a 4.52 head size so any idea what 177 heavy pellet I could use and what power setting to use I would like a 60 to 70 shot count from probly 170bar fill I would be hoping for 50 good shots in the sweet spot sorry getting carried away first things first so what heavey pellet to test a 177 with please.
ATB Frank

[underdog]

Hi,

If the valve has been in the rifle for a few years it's best to change it anyway. They can suffer from extrusion and form a step on the sealing face of the valve. A new valve will give a better power curve and thus more usable shots. It's item 4 in the above diagram. While it's apart give the hammer rail a good clean and polish with autosol or similar. Make sure the hammer itself is also spotless inside the two bushes as crud can build up here. This will improve shot to shot consistency. Make sure you chrono it afterwards preferably with a heavy pellet (JSB heavies or similar) and at about 130 bar as this is typically where they make the most power.

Mark

Hi Mark
Bang on mate yes it as a dammed great big step up ordering the whole set new firing pot, spring, and firing valve she deserves it
This rifle is 177 what heavy pellet would you say to test it after I've made her better p's she is having all her seals renewed also a good polish on her hammer and rack
I can see to the back where the firing valve goes so when I clean it out should I put anything on a cotton bud to clean it out or just a dry clean??
Your advise is valued
ATB Frank

[Raj]

http://www.uttings.co.uk/p103514-bisley ... 9SWtpgrKUk