Benjamin Discovery 22 cal Problem

[alamoflyer]

I've owned my Discovery for over 2 years and it's never leaked an ounce of air pressure, even when stored for long periods of time. I've probably fired over 1500 Discovery 14.3gr pellets through the rifle with great success. Very little paper punching, but lots of pesky squirrels have met their demise. I've even killed several raccoons and possums, so I'm very impressed with my rifle. My only mod was to add a muzzle brake when I first got it. So much for the good.

The bad started a couple of weeks ago. I started to notice a loss of velocity and some inconsistent velocity from shot to shot. I noticed a decided difference in the sound of the pellets striking the squirrels and the loss of penetration on some of the shots. Yesterday it seemed like some of the pellets weren't much faster than my Daisy Red Ryder. Now my Disco has stopped shooting all together. It is filled to 2000 psi. The bolt will fully cock. When the trigger is pulled, there is a dull thud sound and only a small breath of air exits the barrel. The barrel is cleared and there is no obstruction or stuck pellet.

The rear of the main tube has what I thought was a degasser bolt. The threaded knob could be turned in or out. However, when it was screwed all the way in, it did not release any pressure. Upon disassembly of the end cap, it appears I have a power adjuster. The end of the threaded bolt rests on a rod that pushes on the hammer spring. However, even with the adjuster screwed all the way in, there is only a dull thud and no air is released into the barrel.

OK, here are my questions.

1. How can I safely release the pressure from the reservoir? Should I try to install a longer screw in the end cap, or should I try to slowly loosen the pressure gauge and let the air bleed out?

2. What's your best guess as to the problem with my Discovery?

Thanks in advance.

McD

[WxRadarman]

Sounds like maybe the valve is not opening. If the gun would fire, you could dry fire till all the air was gone, but since you can't, you need a degassing tool.

[cobalt327]

1. How can I safely release the pressure from the reservoir? Should I try to install a longer screw in the end cap, or should I try to slowly loosen the pressure gauge and let the air bleed out?

2. What's your best guess as to the problem with my Discovery?

Thanks in advance.

McD

I'm not an expert. Research first before trying any of this.

1.

• The pressure can be bled by using the degassing tool, there's one available (GIYF) for $10 plus shipping.
• There's a way to use the bleeder on your air pump to degass it.
• In some cases the valve could be manually opened if you can gain access to it, by carefully tapping on the valve stem. This will require some disassembly and that's something I hesitate to recommend unless you're familiar with disassembling your gun.
• I would not loosen the pressure gauge!

2.

• The problem might be valve lock- did you just recharge it? If it was accidentally over pressurized, the air holding the valve shut could exceed the ability of the hammer/striker to open it.
• The tip of the valve might have broken off.

[fivestar45]

I've owned my Discovery for over 2 years and it's never leaked an ounce of air pressure, even when stored for long periods of time. I've probably fired over 1500 Discovery 14.3gr pellets through the rifle with great success. Very little paper punching, but lots of pesky squirrels have met their demise. I've even killed several raccoons and possums, so I'm very impressed with my rifle. My only mod was to add a muzzle brake when I first got it. So much for the good.

The bad started a couple of weeks ago. I started to notice a loss of velocity and some inconsistent velocity from shot to shot. I noticed a decided difference in the sound of the pellets striking the squirrels and the loss of penetration on some of the shots. Yesterday it seemed like some of the pellets weren't much faster than my Daisy Red Ryder. Now my Disco has stopped shooting all together. It is filled to 2000 psi. The bolt will fully cock. When the trigger is pulled, there is a dull thud sound and only a small breath of air exits the barrel. The barrel is cleared and there is no obstruction or stuck pellet.

The rear of the main tube has what I thought was a degasser bolt. The threaded knob could be turned in or out. However, when it was screwed all the way in, it did not release any pressure. Upon disassembly of the end cap, it appears I have a power adjuster. The end of the threaded bolt rests on a rod that pushes on the hammer spring. However, even with the adjuster screwed all the way in, there is only a dull thud and no air is released into the barrel.

OK, here are my questions.

1. How can I safely release the pressure from the reservoir? Should I try to install a longer screw in the end cap, or should I try to slowly loosen the pressure gauge and let the air bleed out?

2. What's your best guess as to the problem with my Discovery?

Thanks in advance.

McD

Here's what I'd do....that said, whatever you do you do at your own risk.
The three things you don't want to do is try to remove the fill plug, gauge, or any of the three valve anchor screws. When you removed the end cap with the spring adjuster you were almost there. Just remove the adjustment knob/screw, the spring and rod or spring guide just leave the striker in place put the end cap back on and thread a long screw into the end cap. Continue to to turn it in by hand and when you feel a slight resistance hold the trigger back and continue to thread the screw in. When the striker is against the valve stem you probably won't be able turn the screw by hand any more at that point be sure the bolt is closed, point the muzzle in a safe direction and use whatever tool is needed to continue to turn the screw into the valve stem. You should start to hear the valve venting then just wait until it's empty. Double check the gauge, and try to push a pin into the check valve in the fill plug. If the tube has no pressure that check valve stem should have no resistence, in fact they usually can be heard rattling around when the rifle is shaken.
After that you can safely continue to disassemble and remove the valve as needed.
My guess, you will end up needing a new stem.

[moorepower]

A threaded rod from the hardware store can be used as a degassing tool.

[Lmgunner13]

I made my own degassing tool. it is just a 4" 10-32 machine screw. couple of things I would check.

remove the action from the stock, remove the rear screw on the trigger group and the rear screw on top of the breech to access the spring and striker. Once the spring is out the striker (hammer) should fall forward and back on it's own weight. if the tube is gummed up or the spring is damaged that may be causing your problem. it will be necessary to remove the breech if you need to clean the striker and tube. Be careful what you use to lubricate your Disco. I use just regular 30 weight motor oil and just a drop on the striker and the tube.

Hope this helps.

Phil 

[alamoflyer]

Well, I wasn't able to use the degasser but I got the pressure out. Earlier today I thought a miracle had happened. The Disco began to fire again. Rather than the dull thud, it was actually pushing air out the barrel. The gauge showed about 1000 psi, so I pumped it up to about 1600 psi and tried it. No joy. Back to a dull thud. After a few "shots", I could hear air escaping when I opened the bolt and drew it back about 1/4". The bolt was not "cocked" but just slid back a little. I decided to let the air bleed down that way. After a while it stopped leaking so I fired it till it was empty. So now it's safe, but still broken.

This is my first Gate, so I don't want to break any rules, but I need some recommendations on where to send this Discover for repairs. I don't feel confident enough in my abilities to undertake a full rebuild. I'm a EE by education and profession. I can make electricity behave, but my plumbing skills not so good! Everything I "fix" leaks. I like this gun too much to muck it up.

I understand the there are strict rule against advertising, so If some of you could suggest several repair facilities, maybe that would not be considered advertising. If no one posts, then I'll just contact Crossman Customer Service.

McD

[Bentong]

Did you get the disco used?  New ones don't come with power adjuster. When you adjusted it all the way in you could have caused the spring to bind or the hammer is fouled. You will not be able to use a disco degasser because withe the power adjuster it had to have a spring guide to compress or decompress and that woulde block the degasser to push the hammer then it pressing the valve stem. Only way to find out is to de-stock it and remove the endcap removing 2 rear screws. Don't touch any other screws, this should able you to remove the endcap then the spring...inspect it for coil bind. You should be able to degass by pushing the hammer forward. You don't have to if you find the spring is the culprit, just replace it. Normally if you screw the power adjuster all in you won't be able to cock the bolt.. Need to open up to find out. Be safe.

[Lmgunner13]

Well, I wasn't able to use the degasser but I got the pressure out. Earlier today I thought a miracle had happened. The Disco began to fire again. Rather than the dull thud, it was actually pushing air out the barrel. The gauge showed about 1000 psi, so I pumped it up to about 1600 psi and tried it. No joy. Back to a dull thud. After a few "shots", I could hear air escaping when I opened the bolt and drew it back about 1/4". The bolt was not "cocked" but just slid back a little. I decided to let the air bleed down that way. After a while it stopped leaking so I fired it till it was empty. So now it's safe, but still broken.

This is my first Gate, so I don't want to break any rules, but I need some recommendations on where to send this Discover for repairs. I don't feel confident enough in my abilities to undertake a full rebuild. I'm a EE by education and profession. I can make electricity behave, but my plumbing skills not so good! Everything I "fix" leaks. I like this gun too much to muck it up.

I understand the there are strict rule against advertising, so If some of you could suggest several repair facilities, maybe that would not be considered advertising. If no one posts, then I'll just contact Crossman Customer Service.

McD

You can check the Vendor gate and there is also a gate where members talk about their experience with vendors and products.

Phil

[moorepower]

Are you sure the hammer spring is not broken? That is a REALLY easy check/fix.

[moorepower]

double post

[Geoff]

Mike

It is amazingly easy to work on the 22xx platform.

Heck, i would be willing to video chat via hangout or even skype so i could more easily guide with a teardown.  PM me if you want to try doing it yourself.

also, when i drain my disco double i just start a fill then open the bleed valve just a tad.  takes a while however i do other things while it drains.  i often have to crack it a tad more to get it all out.

[KnifeMaker]

Well, I "can"t" make electricity work. No way, Now how!!!

AG's on th4e other hand, love playing with them. 

Easiest way I have found to degas is to start filling, and once you hear the fill port pin click open, slowly shut the  fill valve, and open the blade on your hand pump or bottle until you hear the slightest his and go no further.

Go on the net to the GTA for a few minutes, and when you come back, the guns reservoir will be empty. Some times there will be a bit remaining. Simply open the exhaust valve a very little bit more. Easy-Peasy!!!

There could be a coil bind or breakage issue, or just as likely, a worn or snapped poppet. Both easy to address.

If yo wish to send her in for a through check out, I would consider Joseph, here on this forum. He is often on anything having to do with Discos or Maximus, and is now the man behind Discos-R-US. As a vendor here, he is well respected. 

Check out the Vendors at the bottom of the forum pages, Discos-R-Us.

Knife

[Wayne52]

It does sound like a bad hammer spring

[alamoflyer]

Bentong - Got the gun brand new from a dealer, Tim I think. Little better price than Pyramid if I remember correctly. I never adjusted the knob, it was almost all the way out and I got 30 or so good shots before I needed to pump it back up. When I screwed the knob all the way in, the bolt would not cock. I could back the knob out one turn and the bolt would cock fine.

Geoffrey - Thanks for the generous offer, but I think I'll wait till I get my second PCP and this one is the backup before I undertake any Disco Surgery.

moorepower - I removed the spring and it looked fine - no broken coils. Hard to tell the "springiness" of a spring. With the spring and its rear pin removed, I reinstalled the end cap and used a long screw to try and degas the gun. I pulled the trigger, tightened the screw, and felt the hammer go all the way forward, but no air escaped.

Still think it may be best to send it in. I'm making a shipping box this evening and I plan to check out the vendor gate.

Thanks for everyone's help. I'll post the problem and cure when I get the gun back.

[farmerjoe99]

Hi Mike,
Hard to say exactly what it is but from the sounds of it your valve isn't opening on firing
except at low pressures which suggests valve lock, and from a gun that has been working fine, I would guess either a spring broke or something is out of alignment. But its hard to say until you have it in hand.
Do the cocking effort, bolt travel, and trigger all feel normal?

Definitely take a look in the Vendor as well as the Tuners gate, there are more than a few great people that can help you out,
and check with whoever you end up sending it to, but I recommend my customers only send the rifle action, its helps save on shipping as well as
reduce the chance of damage to the stock etc. in shipping.

Best Regards,
Joseph

[alamoflyer]

Thanks Joseph. I took your advice and looked through the vendors gate and discovered that Mac1 originally sold me my Discovery.

Tim was very helpful and I'll be sending my Disco home to California for a rebuild. BTW, he agreed with your diagnosis of an exhaust valve problem.

McD

[farmerjoe99]

Happy to help Mike, Tim will take good care of you!

[alamoflyer]

Tim finished the rebuild on my Disco and said the valve was trashed. He'd never seen a failure like this one. When I told him that I bought this one from the very first batch of Disco's when they were first offered for sale, he was concerned that this type of failure might be a trend that we will be seeing in the future. I hope not. For now, let's chalk this one up as a freak failure and move on. Thanks to all who helped me diagnose the problem. If Tim sends the failed parts, I'll try and post some pictures.

McD

[Tater]

Thanks for following up with the post Mike. I've watching this thread since I have a similar problem.