Theoben Evolution

[Sqwirl57]

I just picked up an Evolution for my collection (don't have it yet) and was looking for some pointers. From what I've read these guns do require a little extra attention in a few places and just wanted to hear what owners would recommend doing and/or issues to look for. Thanks in advance.

 

[KWK]

Shouldn't need anything special. One of my Theobens has been going 35 years without anything. You just have to add air to the ram, but rarely. I shoot mine. That one is in beautiful condition.
Yours is 12 ft lb so should go 35 years NP.
Due to commitments to our family that one sat for several years unfired. Our 3 sons were in all manner of sports and I worked extra to keep my wife a "stay home mother". Best thing I ever did. Put your wife and children first. Maybe 7-10 years the gun sat unused. When I went to cock it the seal honked in the cylinder and shot very inconsistent and weak. So I thought, I got nothing to lose by doing the unthinkable. I put a little chamber lube in it. Then fired it some at about 12 ft lb. It woke it up! Eventually, I pumped it back up to 16 ft lb (That's closer to the max for this model) and I'm still shooting it every once in a while with no issues. It's been several years again. I have 4 new crown seals for them but never needed one yet.

 

[ChuckHunter]

What caliber?
I'm sure Lewis will be chiming in on this one
Biggest thing on any Theoben rammer is the trigger! It's a single sear and needs some polishing if it hasn't already been done!
And check the breach seal it's just an oring set up and they get hard after a while! Also have to put a small notch on the outer edge on the new seal to release pressure on the the firing cycle! Otherwise it will pop out every shot. Also keeping it below 14fpe is good rule! Short stroke and not really designed for power. I have mine set up at 12.5fpe energy with 10.3 JSBs and it's a sweet shooter!
James from Michigan

 

[Sqwirl57]

Shouldn't need anything special. One of my Theobens has been going 35 years without anything. You just have to add air to the ram, but rarely. I shoot mine. That one is in beautiful condition.
Yours is 12 ft lb so should go 35 years NP.
Due to commitments to our family that one sat for several years unfired. Our 3 sons were in all manner of sports and I worked extra to keep my wife a "stay home mother". Best thing I ever did. Put your wife and children first. Maybe 7-10 years the gun sat unused. When I went to cock it the seal honked in the cylinder and shot very inconsistent and weak. So I thought, I got nothing to lose by doing the unthinkable. I put a little chamber lube in it. Then fired it some at about 12 ft lb. It woke it up! Eventually, I pumped it back up to 16 ft lb (That's closer to the max for this model) and I'm still shooting it every once in a while with no issues. It's been several years again. I have 4 new crown seals for them but never needed one yet.

Good to know thank you! This one is in .22 and I was hoping to put it somewhere in the 15-17fpe range but I'm not against lower. I guess I'll play it by ear. I did want to get the probe for it now just in case. Does this look correct?

https://spares.bagnallandkirkwood.co.uk/product/theoben-gas-ram-charging-filling-adaptor/

 

[Sqwirl57]

What caliber?
I'm sure Lewis will be chiming in on this one
Biggest thing on any Theoben rammer is the trigger! It's a single sear and needs some polishing if it hasn't already been done!
And check the breach seal it's just an oring set up and they get hard after a while! Also have to put a small notch on the outer edge on the new seal to release pressure on the the firing cycle! Otherwise it will pop out every shot. Also keeping it below 14fpe is good rule! Short stroke and not really designed for power. I have mine set up at 12.5fpe energy with 10.3 JSBs and it's a sweet shooter!
James from Michigan

Thanks! Mine is a .22 caliber. Ive read they aren't power houses but was hoping something in the 15-17fpe range was reasonable. If a .177 is pushing 14 then I would think 15 is fair game in .22 cal.

Do you know of any good sources for parts state side?

 

[Lewis]

Great gun, Congratulations. Love them.

If it were mine, I would not consider firing it until it is completely serviced. The soft parts can deteriorate over time, even when stored in ideal conditions. These are robust and impressive guns but they can self destruct if the piston is allowed to slam home without the appropriate amount of resistance offered by the soft parts. This service can be done by yourself if you have the proper pump and are familiar with the way they operate. Otherwise David Slade is the best in the U.S. with the Theobens, and can even sort the trigger for you.
One other thing to know about most of them including your new Evo is NEVER attempt to cock the action outside of the stock. The stock guides the cocking arm, and the shoe WILL break the very first time you try. As for power levels, I agree with ChuckHunter, the lower side is likely safer. I have no problem shooting them but we need to be responsible custodians. These were never mass produced, and nothing like them is likely to be made again. They should be cared for in a way that reflects this. 12-14 FPE is plenty, even for a .22. There are many other high powered springers currently available and plentiful that could fill the desire for more power if it is needed.
Driving an original muscle car is a wonderful, wistful, experience. Modifying them, swapping engines, and drag racing them is a blast, but almost always a one way trip.

Just 2 cents from a nostalgic old goat.

Cheers.

 

[Sqwirl57]

Great gun, Congratulations. Love them.

If it were mine, I would not consider firing it until it is completely serviced. The soft parts can deteriorate over time, even when stored in ideal conditions. These are robust and impressive guns but they can self destruct if the piston is allowed to slam home without the appropriate amount of resistance offered by the soft parts. This service can be done by yourself if you have the proper pump and are familiar with the way they operate. Otherwise David Slade is the best in the U.S. with the Theobens, and can even sort the trigger for you.
One other thing to know about most of them including your new Evo is NEVER attempt to cock the action outside of the stock. The stock guides the cocking arm, and the shoe WILL break the very first time you try. As for power levels, I agree with ChuckHunter, the lower side is likely safer. I have no problem shooting them but we need to be responsible custodians. These were never mass produced, and nothing like them is likely to be made again. They should be cared for in a way that reflects this. 12-14 FPE is plenty, even for a .22. There are many other high powered springers currently available and plentiful that could fill the desire for more power if it is needed.
Driving an original muscle car is a wonderful, wistful, experience. Modifying them, swapping engines, and drag racing them is a blast, but almost always a one way trip.

Just 2 cents from a nostalgic old goat.

Cheers.

I appreciate the advice and will heed your warnings! I love lower powered .22s so I guess I'll just count this as yet another one. Like you said, if I need power, I have many more options at my disposal.

plan is to do a full disassembly prior to shooting it. Ive seen that advised a few times. I posted a link above for a probe to refill the piston. Does that look correct? The description is kind of vague and basically says to me "this may or may not work"... Given the slim jim pumps are unattainium would a standard PCP hand pump suffice?

https://spares.bagnallandkirkwood.co.uk/product/theoben-gas-ram-charging-filling-adaptor/My

 

[KWK]

I don't think it's recommended to go over 12 in that gun.
This Sirocco looks and shoots like new after 35 years. Never serviced. The trigger guard I made STILL needs blued! I just don't like the original one.
I'll probably shoot it tomorrow. Running 16 ft lb. I shot it a lot on plinking forays the first 10 years I had it. Last few years it is in service about every month or so again. Mostly shooting soda cans off hand at longer distances. 40 to 60 yards. Shoots little groups off the bench at 25 y like an Anschuts barrel should. As good or better sometimes than my Weihrauchs, etc.

 

[KWK]

You can buy a pcp pump adapter on ebay UK. Some bought a Rockshox pump at the bike shop for reasonable.

 

[KWK]

Brad Troyer said the gun he tested does 13.5 so I'd be cool with that and no more.

American Airguns - The Theoben Evolution Air Rifle

American Airguns Website - The first website about airguns, air pistol, air rifle, and accessories.

airguns.net

Don't you just love the How much are my guns worth first posts? Savvy sellers!
And buyer.
You gotta jump on those with both feet.

 

[Sqwirl57]

Brad Troyer said the gun he tested does 13.5 so I'd be cool with that and no more.

American Airguns - The Theoben Evolution Air Rifle

American Airguns Website - The first website about airguns, air pistol, air rifle, and accessories.

airguns.net

Don't you just love the How much are my guns worth first posts? Savvy sellers!
And buyer.
You gotta jump on those with both feet.

Lol yes you do. I was nice though and gave her what the gun was actually worth and didn't play games. I wouldn't want someone to do that to me so I won't do it to someone else.

Somehow I missed that article in my search. Thanks for the link sir!

 

[Lewis]

Sqwirlfugger57​

Yes you can use a regular hand pump. You just need the adapter for the Schrader valve. There are 2 different styles. The adapters from Best fittings come with both.

Theoben / Weihrauch HW90 Gas Ram Charging Pump Kit – Slim Jim – Best Fittings

www.bestfittings.co.uk

 

[RM100GUY]

Congrats....Your gunna' like it...I love the stock design...their very nice shooting guns! I used a Hill hand pump on an SLR years ago...it doesn't take much, gas rams are low volume go very slow...I would send that gem to David Slade myself...this one was his personal gun .177...I pestered it out of him a couple years ago...I've been looking for a .20 cal example...for years...in vain.