New gun lost power

[Dornfelderliebe]

Thanks chaps. The spring appears to be quite soft 2.8mm wire according to my middle of Lidl vernier gauge, 33 coils long. Crossing threads I have used a nylon slip washer and spare power washer totaling 6.4 mm of preload.
It did boing badly so I've put a Guinness can piston sleeve in to make close sliding fit and gently polished the bearing end of the piston with 1500 grade wet & dry. The spring ends have come up nicely with file & 1000g.
I'm still to polish the cylinder with 1000 grade and report the piston weight when the scales arrive.
I'm quite impressed with the spring guide, metal with a stepped plastic collar/sleeve which would allow rotation of the spring rear end.
I will test for leaks upon reassembly and look up a Titan in the meantime.

[david j]

God I wish I knew half as much as these guys.

[Shed tuner]

do you not have kitchen scales (just wait for the head chef to be distracted )

[Dornfelderliebe]

do you not have kitchen scales (just wait for the head chef to be distracted )

Nope but Evri still have a set in the 0-500g range I've ordered for weighing pistons.

[TonyL]

Thanks chaps. The spring appears to be quite soft 2.8mm wire according to my middle of Lidl vernier gauge, 33 coils long. Crossing threads I have used a nylon slip washer and spare power washer totaling 6.4 mm of preload.
It did boing badly so I've put a Guinness can piston sleeve in to make close sliding fit and gently polished the bearing end of the piston with 1500 grade wet & dry. The spring ends have come up nicely with file & 1000g.
I'm still to polish the cylinder with 1000 grade and report the piston weight when the scales arrive.
I'm quite impressed with the spring guide, metal with a stepped plastic collar/sleeve which would allow rotation of the spring rear end.
I will test for leaks upon reassembly and look up a Titan in the meantime.

You're proceeding in the right direction and will have it right soon.

As Jon says, you can use a set of kitchen scales to weight the piston. Place the piston in a sandwich bag, or similar, and you're fine. The Devils are those impressive little 25mm Gamo clones, aren't they? These rodless pistons can often be on the very light side, so adding weight here could help.

[TonyL]

P.S.....When you re-commence power testing, you might do well to try a good selection of pellets, especially those from the JSB stable, like Jumbo RS or Express. The Superdomes can often rob power, most especially in set-ups employing a very light piston and soft spring. What might be "comfortably under" with a 'Dome might not be with some of those JSBs.

If going for a slightly more stout spring, and especially if introducing some piston weight, you might find that things even out a little with a wider range of pellets?

Spring wise, I'm wondering if the TX200 Mark 3 spring would suit / be enough spring for this rifle? Failing that, what about one of TbT's HW97/95 springs would fit okay (wondering about the OD here). And also worth looking into the recently introduced Welsh Willy spring to check the specs etc.

[BC312]

If you leave a spring cocked for a length of time causes a spring to lose its strength.

[Dornfelderliebe]

If you leave a spring cocked for a length of time causes a spring to lose its strength.

It won't be me doing that BC. too great a chance of accidental discharge.
I once viewed a Meteor at a Nottingham auction house, picked it up, put a bit of pressure on the trigger and it was cocked.
I decocked it and complained to a staff member. Oh they do that sometimes he said meaning other viewers. it wasn't loaded but can you imagine the bang it would have been made if dry fired.

[Dornfelderliebe]

P.S.....When you re-commence power testing, you might do well to try a good selection of pellets, especially those from the JSB stable, like Jumbo RS or Express. The Superdomes can often rob power, most especially in set-ups employing a very light piston and soft spring. What might be "comfortably under" with a 'Dome might not be with some of those JSBs.

If going for a slightly more stout spring, and especially if introducing some piston weight, you might find that things even out a little with a wider range of pellets?

Spring wise, I'm wondering if the TX200 Mark 3 spring would suit / be enough spring for this rifle? Failing that, what about one of TbT's HW97/95 springs would fit okay (wondering about the OD here). And also worth looking into the recently introduced Welsh Willy spring to check the specs etc.

I have a selection of 'lighter pellets including JSB 13.73 gr waiting to a test a project Meteor so I'll bring the Kral to that party.
Last night I dug out a Titan #13 meant for my paratrooper but was too tight on the spring guide. It fits the kral sleeved piston a miniscule bit looser but Lyndons spring lube will cure that and is a tight fit on the guide but not so tight that you cannot wind it on like an acetal version.
I'm definitely going to fit the OE spring first and if it does not improve then it will be fun & games with the Titan.


Yes it is very Gamo esque just some parts better made.