Rant!!

[Zomboid]

Yep heating expanding stuff...

That's what happens EVERY time I miss.

[BTDT]

Would it have an effect if the internal volume of the cylinder had been reduced? Both of these had been short stroked I believe. Without excess volume the whole process becomes more sensitive I'd guess.

I'll need to have a think about that.

Surely though that would mean that when cooled the evaporation wouldn't be reabsorbed and the MV would stay low? In my experience it doesn't. It's really not uncommon in target shooters to see MV drop in heat, and increase in cold, and then return to back to where it normally is when the normal conditions are repeated, all without changing the lube.

I did state that I was specifically addressing the OP's problem, where the muzzle energy dropped, and stayed dropped, Rob.

Springer muzzle energy can indeed temporarily rise or fall with temperature, I believe entirely due to kinetic friction. That's very common.

[RobF]

I'll need to have a think about that.



I did state that I was specifically addressing the OP's problem, where the muzzle energy dropped, and stayed dropped, Rob.

Apologies Jim, I mssed that.

Springer muzzle energy can indeed temporarily rise or fall with temperature, I believe entirely due to kinetic friction. That's very common.

Yeh, aint it just

[Terry D]

Got home cleaned guns, chrono the 98 650fps. Strange she shot well at the bash.
Chrono the TX. Even worse. Fitted 2 power washers still only just 10ft/lb. Stripped the TX today, can't see anything wrong. Re_assemble 11.25 - 11.17.

Yeah, I had a chrono like that once.



























Hope that helps.

[Robet]

Bloody springers
Had a nice plink Saturday at LVAGC. Noticed that the 98 started shooting low after a 100 or so shots. TX worked well though. Got home cleaned guns, chrono the 98 650fps. Strange she shot well at the bash.
Chrono the TX. Even worse. Fitted 2 power washers still only just 10ft/lb. Stripped the TX today, can't see anything wrong. Re_assemble 11.25 - 11.17.
The 98 still low over chrono. Sort that tomorrow I hope

Rant over

Pete

I have the same experience with my 77K, as temperature rises, power drops & as temp drops power rises. That's why I check with my chrono in winter to make sure I'm not over the limit.
Rob

[TonyL]

Family duties tonight and tomorrow so may have to wait until Thursday to strip the 98

Pete

Yeah, I had a chrono like that once. :


Hope that helps.

Did you manage to have a play today, Pete?

Mr D.......you could have a point there.

Hope you're keeping well.

[barrel]

Yes Tony, TX was around 11.25 & 98 11.4. Pellets from the same batch, so thats ruled out. TX must have wanted some love. Don't know why the 98 is sulking though

Pete

Could be a hell of a lot worse, you could have a regulated PCP that sulks.

Kindest regards

Barrel

[flyingfish]

Well, stripped the 98. Piston seemed tight. So re-sized the seal. Put in a power washer and re-lubed. Up to 10.9 chrono before and after. Temperature had dropped a lot today.
Chrono seems OK as my pcp was showing it's normal readings.
TX still where it should be.
Just strange that they should both drop by a similar amount of power at the same time

Pete

[flyingfish]

Reading through the posts from all those that understand a lot more than me about these things (thanks lads). I wonder if the heat had softened the seals. So firing the guns deformed (spread) them?
A fellow lea valley member has a 98 that dropped to 9ft/lbs last year. It will be interesting to see if that's a tight seal problem.

Pete

[Charlie123]

I was at the Buxted round of UKAHFT last weekend Pete and there was 8 rifles that failed the chrono test,some of which were top end regged stuff.Although no springers failed the chrono, 2 of them had dropped over 30 fps from their normal setting.
Bloody British Summer eh.

[flyingfish]

Hi Charlie
Long time no see
I think the action of the heat on the lubricant is a major factor. The excessive friction would cause more heat than normal on firing.
Still sorted now

Pete