Tbt Tuning Stuff

[jonnie bravo 572]

Ey up folks

I fancied having a tinker with the prosport, she's currently got a vmach kit fitted and she's shooting well but a little hold sensitive and twangy so I have purchased a short stroke kit from tinbum. I have tea some good reviews about these as apparently the swept volume on the prosport is a little bigger than ideal (apparently hw77's and 97's are spot on) so these balance them out well. Time will tell!

 

Will keep this thread updated with pics as I go, and post said results.

 

I'm down the range tonight testing jsb RS and express against the std exact so will post those results too.

 

Cheers

 

J

[Rez 4,961]

Got one in mine. Well worth the strip down. Watch that lever cocking bolt in the cylinder... Once it comes loose and you loose tension, the lever popping open from time to time will get one your tits like nothing else and the more you take it apart the more it gets looser. I had to order a new piston cylinder in the end.

[jonnie bravo 572]

Got to admit I'm really looking forward to seeing what change it will make!

 

I did try the RS, express and RWS match pistol pellets.

 

The RS and express were good, nothing like the standard exact though. Although all were 4.52's the RS and express were definitely slacker in the barrel.

 

The 4.50 RWS were even tighter, and went all over the place, made a horrible noise too!

 

So I'm sticking with the 4.52 exact.

[Rez 4,961]

 

Got one in mine. Well worth the strip down. Watch that lever cocking bolt in the cylinder... Once it comes loose and you loose tension, the lever popping open from time to time will get one your tits like nothing else and the more you take it apart the more it gets looser. I had to order a new piston cylinder in the end.

 

3 easy fixes for that Rez, first of all loosen the bolt slightly and pull the cocking lever down a couple of inches, hold it there and nip the bolt up. That cures 90% of dropping levers. Next have a look at the cocking shoe, sometimes if the bolt isn't tight enough the shoe will wear on the bolt and the hole will go oval, also the hole and pin that links the shoe to the cocking rod can wear, just replace the pin and shoe. Lastly, look at the little housing on the cocking rod, that contains a spring which will wear over time, replace that spring.

Regards

Tim

Didn't bloody cure mine timmmmehhhhhh. I actually remember sourcing an old post of yours, (and passing pm's with you on THL) on another air gun forum as I was pulling my hair out. Having said that I did try everything you have mentioned, and found out that the rifle had been apart so many times, the thread had worn on the compression cylinder, thus the screw had no real grip on the unit, creating a weak point.

 

It's a shit design, let's be honest, hence my post months back about a PS not being as robust as the TX. If the rifle is apart so many times, I don't mean 100's, but enough there will eventually be a weak point created with what is perhaps an experimental cocking mechanism. Any other method, ie. The TX or HW under lever is fine and stays fine.

[jonnie bravo 572]

Well folks, fitted the short stroke kit tonight.

 

This gun already has a v-mach kit fitted.

 

Removed the stock, placed tension down onto the trigger unit and unscrewed the bolt. There was noticeably little preload.

 

There was a fair bit of grease in there though, so I had a good clean up. I tried fitting the TbT drop in kit, but the delrin spring guide refused to fit, full stop.

 

In the instructions it states that if you put the tophat and spring guide in the piston the spring guide should fit flush to the piston skirt.

 

But the TbT kit was standing well proud, probably 15mm atleast, so I fecked it off and stuck with the vmach kit.

 

I carefully removed the vmach piston seal and gently tightened the extension.

 

I have to admit the bits and pieces from TbT were a bit scruffy, rough around the edges, especially compared with the vmach kit which was super smooth. The delivery was really fast though and Nick has been great at communicating.

 

So I lightly greased the spring and popped it all back together. There was a noticeable increase in preload, and when I had the action back in the stock I had a couple of pulls on the lever and it seems quite stiff.... Not sure if this is going to be a step in the right direction! At least I can always refit the vmach seal.

 

Live and learn!

 

Deffo thinking of changing to a break barrel now, a 95 or 98 is calling me I think.

 

Will be going down the range on Monday night, so I'll update this thread with the good or bad news.

 

Cheers

[Rez 4,961]

I have to admit the bits and pieces from TbT were a bit scruffy, rough around the edges, especially compared with the vmach kit which was super smooth.

 

Well one is 70 quid and the other 15

 

Whats your PS outputting? Just out of interest.

[jonnie bravo 572]

More like 23 for a delrin spring guide top hat and power washers? Would have liked to have seen a better finish on them, I don't think that is asking a lot to be honest.

 

11.3 when I bought it, will hopefully be borrowing/buying one for Monday night to test her on

 

The short stroke kit was supplied with what looked like a good seal though, nick informed me it was a weihrauch one

[villaman 9,982]

For £39.95 the wonky donkey (Dave price) is a better kit IMO

[jonnie bravo 572]

Well headed down the range tonight with the short stroke kit fitted.

 

Didn't manage to get a chrony sorted, so thought I would just check pellet drop.

 

First few shots were all over and low. It did settle in though, dropping 15mm or so below zero. Popped a pellet on the elevation cap to check recoil and it only moved a tiny amount.

 

The more shots I fired the higher the POI got, eventually getting about 5mm below the crosshair.

 

So I think the extra bit of preload and reduced volume has dropped the power ever so slightly, but the recoil feels reduced a little. Think I need a couple of hundred more pellets through her to judge properly but the grouping was great and overall I think there is a bit of improvement. Time will tell! Definitely up for tinkering with a break barrel now though!

 

Think I really fancy vmaching a hw95

[jonnie bravo 572]

Just a wee update to this folks. Did an internal check of the prosport tonight. The short stroke kit had worked a little loose, though I don't think it had a big effect on the shooting cycle. However the weirhauch piston seal that was supplied with it was cut. On the outer edge, so I've removed the short stroke and replaced the vmach seal. Without the short stroke the preload is reduced so I'm pretty happy going back to the previous internals.

 

On a side note my scoring on benchrest targets has been 4-5 points lower with the short stroke fitted. I think maybe the short stroke kit is best left for AA's with the original internals, fitting it to a v mach kit hasn't worked in my favour! Hopefully this thread will help some.