I have never been very satisfied in the way people have said to test seals.
I have now tested my HW80, 34, and old type 45 like this.
First cock the gun then slide a wooden rod into the mussel up to the breach then push a tight fitting pellet about 10mm in then close the barrel then put the barrel on the floor and pull the trigger wait about 10 seconds then slowly open the breach, you should get a rush of air and hear the piston hit the bottom of the cylinder. My HW80 and 34 passed the test but the 45 failed.

So you are saying, jam a piece of wood in the bore almost the entire lenth of the barrel, and then push a pellet in about 10mm and fire that pellet into the wooden rod? I don't understand.. is this safe? What if the pellet pushed the wooden rod out of the barrel? I mean the wooden rod fits loosely in the barrel right? And what if the "tight fitting" pellet does not create a 100% air-tight seal in the bore and some air leaks out slowly? The reason I say this is because when you push them further in with a rod, you are risking bending the skirt.
What do you do with the stuck pellet afterwards? You push it out of the muzzle I assume. Isn't it deformed which means it could scratch or damage the rifling since force will be required to push it out? So all the air is kept were? In the 10mm space between the pellet and the breech? Not so sure this is safe for the piston.

Sounds like a good idea but I am not sure it's 100% full-proof or without any damage to the gun.

This method is too complicated. I suggest rolling up some toliet paper really tight
and stuff the barrel full of it and silicone the end shut. Then submerge the whole gun into
a full bathtub or pool. If the toilet paper gets wet then the seal needs to be replaced.



Ok, for real I didnt understand about the wood into the barrel either.
Can you explain further Lee?

loool..,the easier method is just fine, thx alot jay!!
from this all there is an easier way ..,almost dry firing ,i mean no pellets just put ur finger on the top of the rifle "close the muzzle "..fire ..keep ur finger a little bit then release slowly,
u should hear the air flow if the seal is ok
this works..,but don't do it alot cause dry firing is not good for ur rifle
keep up the good work n' God bless

I like my finger just the way it looks I don't think my finger would look the same after I dry fire a 24FPE springer in it at point blank range. I fired a cleaning pellet through my 350 after I put a couple of hundred pellets through it, and it sounded like a canon! Never again, and not good for the gun at all.

Anonymous, thanks for the clarification. Where do you get those plastic pellets from anyway?

Harry, the pellets are Prometheus or Paragon look at there web site if you dont know about them, but dont shoot the Prometheus in your gun they are only 9 grains in .22
Lee.

I dont think that I explianed properly, first I used those plastic sleeved pellets they seal nicely and will not distort. My guns are .22 so the wooden rod is quite thick I use sticks from the garden center and size them with sand paper, the soft wood would not harm the barrel, then cut the rod so about 20mm protrude from the mussel so it can be held on the floor when you pull thr trigger but the gun hardly moves, the piston justs lands on a cushion of air the only harm this can do is to the seals if they are leaking it might them a bit worse I would not have done this to my HW80 if I thought it would harm it as I have spent a lot of money on it but I have always suspected the breach seal would not hold a lot of pressure I now no it dose.
BUT these guns are within 12ft/lbs ? Lee.

Invest in a chrony and periodically test your rifle and note the velocity. If a sudden drop off in power is observed you may have a problem. In that case, open up the rifle and take a look.

Inserting anything but a pellet into the barrel of a gun is asking for trouble. At best, you might only wreck the gun. At worst, you might hurt yourself. If you suspect a problem. take the gun apart and check if you are competent with repairs. If not, send it out. Don't go putting dowels or anything else in a barrel.

"but I'll be needin' that gun, fer squirrels and such."

Bill I can only agree with you in part,I have a chrony and I am competent in repairs but the reason for this test is to see if the breach seal has any small leaks at high pressure but would still give a consistent reading on the chrony,a HW80/R1 is very dependent on the breach seal as there is a 8,thou gap between the breach and the cylinder and I wanted to test it under pressure, and what better way than to hear the piston hit the bottom of the cylinder after more than 10 sec after the trigger has been pulled when you release the air.
I DO AGREE if you are not fussy or not competent dont even attempt this but what is all this danger you are talking about from airguns? the worst that I have seen is a 52 with the sliding cylinder with a bulge from continual violent dieseling, and a soft wooden dowel has never done any harm to my guns and I am fussy.
BUT I admit what would happen if there was a diesel I dont know? I think at worst a broken spring if poor quality but you tell me?
I appreciate any comments on this test but it has worked for me. Lee.

Sorry for bringing up this old thread (I was using the search function for something else...) but I have a question.

Assuming the breach seal of the gun tested with this procedure is ok and does not leak. After 10secs when we open the breach and "proudly" hear the piston slamming at the chamber's end, isn't it as BAD as dry firing???

This testing procedure does not sound very sound to me. I mean pieces of wood picked up from the garden, stuck in the barrels, slamming pistons...

No It is not like dry firing because the cushion of air is released slowly, and the sticks of wood are cleaning rods, you could also use softer plastic, if you get away with it the ultimate test.

BUT BE WARNED if it were to diesel the piston could slam back in the trigger, so give this one a miss.
Barry.

breech seal problems;

start with a chrony, don't have one then go to step 2

put a piece of tissue between the breech and shoot, does it LIFT the tissue

go to 3rd step, put 2 pellets inside the chamber breech, fire and find out what happens, it's either nothing happens or both are spit out of the barrel

put your fingers on the end of the barrel and fire a pellet is a NO GO

warren

and remember "it's 30% the gun and 70% the shooter"

I usually throw a few sardines there way,If they respond they are ok. If not I just go get some more.



welcome back Kotter! (I mean Harry)!

Missed you

dave@vabch

I fire the gun at a close target & make sure the pellet comes out & hits the target. I DONT set the gun down or walk away from it. I open the brl. & look to see that the brl is clear. I close the action & blow in the end of the brl. Im not talking like your blowing up a balloon,,, but using your tounge in such a way as to create the highest preasure you can. If you can "blow" air thru,, you have a leaky breach seal. Simple but effective. DONT TRY THIS AT HOME!!!!!! This is a fool proof method I learned from someone that is HIGHLY respected in the airgun comunity!! And please,,,, spare me the hate mail,,, I am an ex law enforcement firearms instructor,,,,, I said,,,, DONT TRY THIS AT HOME!! "Old Tim".

Perhaps an improvement would be to substitute the old lungs with a foot pump attached to the barrel's end using plastic hose and clips.This increases the pressure considerably and should show even the smallest leaks.
If all is well and the pump is up to it, one should be able to push the piston a fair distance back using just foot-pump air pressure.
If one wants to get a bit more technical, a one way valve in the air supply hose will enable you to see how slow or fast the seals leak and it allows you to pinpoint the leak if any.
Shooting an airgun with a blocked barrel to see if it leaks sounds a bit like destructive testing to me.
D

The cushion of air is there as long as the breach is closed. When you open the break the compressed air is suddenly released, the cushion disappers and the piston slams forward, right?

It's not me that first mentioned the slamming piston. Isn't this like dry firing with a shorter piston stroke?

Maybe Im reading this all wrong but no way Im dipping my gun in water let alone dry fire it or jamb any wood in the barrel. To check any seals take the gun down remove the spring and cock the gun. Close barrel. Use a wooden dowel that fits inside the piston. Either stand it on end or mount it in your press and put your finger over the barrel. You should immediately feel resistance when the piston is pushed forward. It should also spring back after 30 or so seconds. You can do this for over a min if you have a good gun press.

Chris your method is like the one that I use when servicing except I use a old spring to push the piston.

The other method comes from the old days of the tap loaders when people used to cock a BSA Airsporter then open the tap and release the piston holding the leaver to see if it would hold the air, that was OK but then people started to just pull the trigger, that was when the danger of dieseling started,I have heard of ruined guns doing this so not worth the risk.

breech seals or piston seals here, I seem to got lost in this issue

since they are not the same

warren

PS: air escaping piston seals are easy, breech seals are a BEAR to catch they go slow, slowest and slower

Take the gun apart just like you are going to replace the seal when you have the spring out and can reach the piston hold your finger in front of the transfer port and push the piston to see if their is any pressure also you can push the piston in the chamber all the way and put your finger over the transfer port to see if their is any suction this is a safe way to check seals are leaking , their should be resistance both ways that can be felt if not the seals are leaking.And no holes in your fingers or any other parts of your body. Unless for some other reason you like to be able to blow smoke out of your cheek, Howie PS while the gun is apart if the seals are bad now is a good time to replace them we are talking ablot the piston seal.