My New Theoben Evo .177 (Converted To Spring Power)

[mattybugeye 884]

Well just picked this up a .177 evolution

 

was offered it a while ago but decided against it as gas ram can be bit touch and go but cudnt help thinking a spring conversion would make a fantastic rifle and sure the trigger can be improved on with a polish up so went for it!!

I've read about a few gas rams been converted and vice versa but anyone done one?

It's hard to cock which leads me to believe it's been overfilled at some point and firing at 11.9 (tad close for me)

But it's a tidy one to convert give a fair price for it so can't moan looking forward to doing this

Any others using gas rams either hw or theoben ?

Edited June 30, 2014 by mattybugeye

[Daz87 76]

I knew you wouldn't come home empty handed Matty!

 

Looks great & will be a nice project for you.

[mattybugeye 884]

Haha couldn't resist

very nice light rifle build quality is unbelievable

From what I gather it's quite straight forward (he says lol) but time will tell it's far too hard to cock and very snappy but guess gas rams are nice titan xs spring and delrin guides should see it right

[Skot Ruthless Teale 1,701]

Sure it will be a beauty when you've finished with it lad.

Seem to know your way around a gun LOL

[Rez 4,961]

It's flaming lovely that... Miss the old school theobens. 90's for the win.

[Ads 39]

Keep us posted how you get on with it mate!

[mattybugeye 884]

Will do might make a start tonight cheers for replys guys

[mattybugeye 884]

Well its running on spring power took a while to get my head round it but fully stripped and modified existing internals to make it possible. still needs work as used a old spring I had knocking around to sus how I was going to do it pics to follow ......

[mattybugeye 884]

I've hit a few snags on way though the cocking shoe is kaput it's fallen apart and dumped metal shards inside everything so needs a full polish of everything

New cocking shoe

A hefty spring as the spring I've fit pushing no power at all not even bothered to chrono it lol

Getting the spring in then fitting the sear clip in position going to be fun with it been .177 going to need some poke

 

Pics below

The black ram plunger I'm going to trim and use as a spring guide

Got a delrin rod I'm going to sit through the gold ram plunger top with seals on to seat spring central in piston and pre load the spring

So pretty much everything I have removed has been re used just in different places it's hopefully going to be a awsum rifle when built I k ow the triggers ate a bit agricultural but sure a polish will help

was a right state inside the gas ram seemed on its last legs and we'll over pumped up

The shoe has damaged the underside of cylinder so will need all cleaning up with dremal

Edited June 27, 2014 by mattybugeye

[Daz87 76]

Good going so far mate, bet she'll be a treat when you're done with her!

 

My TX will be on its way to ya after my holiday! ;)'

[mattybugeye 884]

Bit of a update

Been to Aaron wheelers today bought a beasty whierach round coil main spring was doing 19 ft lbs in a .22 hw so power should be good in my .177 may need trimming / pre loading will see when all built up

Had no joy on cocking shoe it's not a part that he stocks so he is machining one up today should be done tonight / tomorrow morning

Fit new piston washer and polished piston up

All greased up and back together now looking forward to testing it.

I've cleaned up all the damage to cylinder with dremal and reblued that bit

Pics

[bigmac 97kt 13,813]

Nice one matt it will be the dogs bollocks when your finished with it after being in your capable hands atvbmac :thumbs:

[mattybugeye 884]

Cheers mate Yea got a feeling I'm guna like this gun when done wish could test fire it and chrono it its doing my head in wondering what power is and how it shoots

Anything over 10.5 il be happy with

Will no doubt shoot nicer a tad under power too

[mattybugeye 884]

Still on with this its been tricky getting power up

Even with the Fac rating spring its doing 2 ft lbs without preload got it up to 6.8 with some pre loads will keep at it

Had to buy a sash clamp to put spring in each tie its been a bugger but will sort it

Got cocking shoe done and sorted though IL put some pics of what I'm doing tomorrow :-)

[mattybugeye 884]

Been bit quiet last few days as been plodding on with this the hw80 spring was just not long enough so I picked up a titan xs number 14 today bit of pre load and got it sat nicely in the 10.5s now if it wasn't so hard to get the spring back in I would pre load little more but for now that will do, I need to get a thin delrin tube to slot over the spring guide to stop the twang and add a top hat washer but thats a job for another day

It cocks nice and smooth very short to cocking too well impressed shoots OK bit twangy but very little recoil think a delrin tube will sort that all in all happy with it its been hard and wouldn't want to do another in .177 ID of thought a .22 would be easier as not as much power needed will get the viper on and test accuracy later few pics ,

Edited June 30, 2014 by mattybugeye