HW95 + Titan No.8 = pain in the arris

[DCL_dave]

I have a .177cal HW95 that is fitted with a Titan No.8 mainspring and it keeps going hot no matter how much I chop the spring and/or collapse coils. The gun has its standard original HW piston seal fitted, well sized and freely sliding in the comp tube. running with virtually no lube, it does not diesel (just the lightest smear of moly grease on the piston skirt and guides, non on the spring. Lock time is very quick and snappy.

The Titan spring started out at 295mm long and I have chopped it and collapsed coils down to a free length of 192mm (pic here) it has 20 active coils with 2 fully collapsed coils at either end. I have had to pack the spring guide with spacers up to about 4mm of preload...this results in a bouncy shot cycle because of the limited preload, any more and it just runs way too hot again!. I could still cut the collapsed coils off and glean another 12mm off this spring without affecting power (if I pack it back out with slip washers).

Tested at the club this morning it peaked at 805fps with AA fields (4.51) - this was tested on one of those phone chronos...not sure what the make was.

Tested it again when I got home on an F1 chrony before taking it apart...again!

782
785
784
782
783

So, the consistency is good but the firing cycle is still bouncy/slammy...


Guys...help me out here please because I have had this 95 apart a dozen times or more chasing this problem and it is pissing me off...is the Titan N0.8 too much spring for the gun?

[robs5230]

In my opinion Titans are too harsh for the majority of springers.

I'd start with one of the HW 3.1 wire springs and go from there.

[Mach 1.5]

Ditch the titan and ask Venomman for a VMach spring for a 95. Mach 1.5

[Shed tuner]

yup.. you need 3.0 or 3.1mm wire

a titan #8 is apparently 3.3mm = way too stiff

[DCL_dave]

Thanks guys, I know I can swap it out for a softer spring but would prefer to work with what I have for the time being.

does the weight of the spring add to the potential power and piston weight?

if I chop the dead coils off and perhaps chop/collapse another coil, thus further reducing spring weight and stored energy, will this reduce felt recoil?… obviously I’ll have to pack out the spring guide to get some preload back on the spring… trying to find a balance between spring potential and preload to reduce power and the snappy shot cycle…does this make sense?

[maximus]

Thanks guys, I know I can swap it out for a softer spring but would prefer to work with what I have for the time being.

does the weight of the spring add to the potential power and piston weight?

if I chop the dead coils off and perhaps chop/collapse another coil, thus further reducing spring weight and stored energy, will this reduce felt recoil?… obviously I’ll have to pack out the spring guide to get some preload back on the spring… trying to find a balance between spring potential and preload to reduce power and the snappy shot cycle…does this make sense?

I'm afraid if you want it to shoot nicely you're going to have to let go of the Titan no. 8. Do you still have the original HW spring? Fitted guides in that should be an improvement although many of us struggle to get the 95 shooting as sweetly as it should do on paper. Regards Max

[look no hands]

I was always led to believe that collapsed coils act like piston weights and can effect the power, I'd remove the end that sits in the piston and collapse a single coil, are you using any delrin top hats or slip washers?

Pete

[BTDT]

yup.. you need 3.0 or 3.1mm wire

a titan #8 is apparently 3.3mm = way too stiff

If the wire is 3.3mm, the active coils just 20 then, assuming the spring OD is 20.8mm, the spring is making circa 31 ft. lb. available to the piston, and the only way to keep it legal will be to make it horribly inefficient, which 4mm of preload will do admirably.

Problem is the spring is placing a force well north of 200lbf on the piston at release, so recoil acceleration will be fierce. At the point of piston bounce, the spring will offer in the region of just 10 to 20 lbf to resist piston bounce force probably approaching half a ton, hopelessly inadequate, so mucho surge to add to the impressive recoil.

Jon's right. 3mm to at most 3.1mm wire.

[DCL_dave]

If the wire is 3.3mm, the active coils just 20 then, assuming the spring OD is 20.8mm, the spring is making circa 31 ft. lb. available to the piston, and the only way to keep it legal will be to make it horribly inefficient, which 4mm of preload will do admirably.

Problem is the spring is placing a force well north of 200lbf on the piston at release, so recoil acceleration will be fierce. At the point of piston bounce, the spring will offer in the region of just 10 to 20 lbf to resist piston bounce force probably approaching half a ton, hopelessly inadequate, so mucho surge to add to the impressive recoil.

Jon's right. 3mm to at most 3.1mm wire.

Thanks BTDT, I do not understand the maths involved but the Titan No.8 spring has an OD 20mm, not 20.8mm...


Think I may have given the wrong impression here... the shot cycle/recoil is snappy but not uncontrollable (never said it was!), I can hold a 1" group at 25m and was hitting knockdowns out to 40m with regularity today at the club, even hit the 55y spinners a couple of times (off the bench).


As stated the shot cycle is snappy, I would liken it to that of a gas ram (I have owned a few Theobens and HW90s, so speak from experience)


please correct me if I am wrong - the spring has a finite potential... OK, it is still too much in its current configuration, hence the damn thing keeps going hot especially when more preload is added (or too close for comfort anyway) but if I reduce this springs potential energy still further, then introduce more preload to try to balance out the bounce/slam in the shot cycle, I should reach the point where the gun behaves itself and the shoot cycle/recoil is reduced?...am I wrong?

It is what it is...I have this spring to play with so may as well experiment with it for now.

[u.k.neil]

In my opinion Titans are too harsh for the majority of springers.

I'd start with one of the HW 3.1 wire springs and go from there.

I have found exactly the same with these springs, never had a good result from using them, and agree with the suggestion.


Neil

[eyebull]

Is there a reliable online source for springs which are softer/thinner gauge than HW factory spec?

Perhaps we need more springs branded as 'Sylvanian family' rather than THE TYRANNOSAUR PISTON SMASHER 9000?

[TonyL]

Is there a reliable online source for springs which are softer/thinner gauge than HW factory spec?

Perhaps we need more springs branded as 'Sylvanian family' rather than THE TYRANNOSAUR PISTON SMASHER 9000?

Have a look in on the Mainspring Data Thread for specs. Exactly why it was conceived.

[eyebull]

Have a look in on the Mainspring Data Thread for specs. Exactly why it was conceived.

Thank you Tony, I'd forgotten about that resource, very handy for cross referencing.
It would however still be nice to find a supplier of generic springs (not necessarily 'airgun' springs) listed by spec, in case there isn't an off-the-shelf spring for another rifle that corresponds to the one desired.

[HW777]

I have a .177cal HW95 that is fitted with a Titan No.8 mainspring and it keeps going hot no matter how much I chop the spring and/or collapse coils. The gun has its standard original HW piston seal fitted, well sized and freely sliding in the comp tube. running with virtually no lube, it does not diesel (just the lightest smear of moly grease on the piston skirt and guides, non on the spring. Lock time is very quick and snappy.

The Titan spring started out at 295mm long and I have chopped it and collapsed coils down to a free length of 192mm (pic here) it has 20 active coils with 2 fully collapsed coils at either end. I have had to pack the spring guide with spacers up to about 4mm of preload...this results in a bouncy shot cycle because of the limited preload, any more and it just runs way too hot again!. I could still cut the collapsed coils off and glean another 12mm off this spring without affecting power (if I pack it back out with slip washers).

Tested at the club this morning it peaked at 805fps with AA fields (4.51) - this was tested on one of those phone chronos...not sure what the make was.

Tested it again when I got home on an F1 chrony before taking it apart...again!

782
785
784
782
783

So, the consistency is good but the firing cycle is still bouncy/slammy...


Guys...help me out here please because I have had this 95 apart a dozen times or more chasing this problem and it is pissing me off...is the Titan N0.8 too much spring for the gun?

With the V figures you quote and a 8.44 grain pellet, I make that 11.55 fpe what's the issue here

[DCL_dave]

With the V figures you quote and a 8.44 grain pellet, I make that 11.55 fpe what's the issue here

the gun peaked at 805fps, albeit with a different chrono at the club, that is over.