Original / Diana Mod 5.. Has Anyone Fitted a Tian Spring?

[D-Man]

My Origina Model 5 recently went through some total power loss.. Yesterday, I stripped it down, and found the central ring of the piston seal had partially disintergrated and lost it's place on the piston ( new seal ordered )

So then I got thinking about the mainspring ( it being somewhere around 50 years of age ).. a quick look on the Bay of E threw up a Titan item that fits the model 25 and 5. The size stated measures 15mm longer than the one I removed from the gun, Now, I understand that I may need to shorten the new spring.. BUT! Is the original spring likely to have lost 15mm over 50 or so years? or will the new one compress too tightly to cock the pistol? or should I make the new spring slightly shorter than the origins one due to it being a stronger one?

Has anyone done this upgrade? I'm already equipped with Solvol polish and Bumslide grease.

[abellringer]

The problem of disintegrating washers in original guns is really common. If you replaced this; I'd also replace the breech seal too. As for mainsprings, stay to factory spec. I've been repairing/ servicing these since early 1970's; In rare circumstances a titan spring is maybe ok; that said they almost always need shortening, their spec is way above factory ones, so cocking effort will be off the scale. Usually the gun is way more aggressive to shoot; in some cases the parts just break because of the higher working loads. Accuracy often suffers due to this problem too. My recommendation on over 50 years work for this era of gun, stay with as close as possible a factory spec spring of ''normal'' material. What folk never understand is only about 1/3 of spring power comes out of the muzzle, so even a titan spring might only give a tiny increase but a much worse experience.
Obviously the ultimate choice is yours, this is just me being honest and speaking from experience. I'm not a tuner and there's some brilliant guys out there that specialise in this, but there's lots of factors involved some way too complex for me, that's for sure, but it's an old pistol in real terms; never a mega powerhouse because of cylinder volume. Whatever you do, just carry on enjoying your shooting.

[D-Man]

The spring arrived today ( ordered from Knibbs Bay of E account on Bank Holiday Monday! ) I think I'll cut it level with the stock spring, then after dressing the end, it'll be a tad shorter to better the preload, I have a couple of unused power washers from a drop-in kit to fill any gaps.

As for breech washers, I ordered a couple a few years back, basically, they sent me 5 donut type spray gun washers that didn't even reach the flat of the breech, I ended up sticking a piece of a vinyl sticker to the existing one and trimming it with a modelling knife.

Thanks for the reply and advice abellringer I'm probably still stuck in my distant teenage years, where everything had to be bigger, harder, faster, longer!

[TonyL]

The problem of disintegrating washers in original guns is really common. If you replaced this; I'd also replace the breech seal too. As for mainsprings, stay to factory spec. I've been repairing/ servicing these since early 1970's; In rare circumstances a titan spring is maybe ok; that said they almost always need shortening, their spec is way above factory ones, so cocking effort will be off the scale. Usually the gun is way more aggressive to shoot; in some cases the parts just break because of the higher working loads. Accuracy often suffers due to this problem too. My recommendation on over 50 years work for this era of gun, stay with as close as possible a factory spec spring of ''normal'' material. What folk never understand is only about 1/3 of spring power comes out of the muzzle, so even a titan spring might only give a tiny increase but a much worse experience.
Obviously the ultimate choice is yours, this is just me being honest and speaking from experience. I'm not a tuner and there's some brilliant guys out there that specialise in this, but there's lots of factors involved some way too complex for me, that's for sure, but it's an old pistol in real terms; never a mega powerhouse because of cylinder volume. Whatever you do, just carry on enjoying your shooting.

Good advice, methinks.

Maybe you might find a more suitable spring amongst these from Protek Supplies, or from elsewhere, and keep the Titan in reserve for some other project? :-

http://proteksupplies.co.uk/mainsprings.html

Hope this may be of use.