Bonehill britania springs...?

[draitzer]

The flange halfway up the rod is the spring stop. If it weren't there, you'd need a spring about twice as long (and consequently much thicker wire) to get the force required.

Don R.

[Shed tuner]

The flange halfway up the rod is the spring stop. If it weren't there, you'd need a spring about twice as long (and consequently much thicker wire) to get the force required.

Don R.

yes and no.... you'd certainly need a spring about twice as long, but why thicker wire so long as it;s properly supported by the guide ? A longer spring creates a more uniform acceleration, a shorter one far more acceleration at the beginning of the stroke than at the end. This is largely why FAC designed guns with a lot of spring room, when properly converted to 12 Fp (e.g. sleaved down HW80s and Pro Elites) shoot so nicely.

And if they wanted to use a shorter spring, why not have a shorter cylinder, and save some weight ?

/starts searching the bay for a bonehill rear guide/end cap that I can machine to take a better suited spring...

[greenwayjames]

The stop on the rod for the spring to sit on is how they were as others have said. Probably not worth Bonehill changing from the original guns he imported form Germany and rebadged as Britannias. Perhaps they knew more over 100 years ago than we think we know now

[draitzer]

yes and no.... you'd certainly need a spring about twice as long, but why thicker wire so long as it;s properly supported by the guide ? A longer spring creates a more uniform acceleration, a shorter one far more acceleration at the beginning of the stroke than at the end. This is largely why FAC designed guns with a lot of spring room, when properly converted to 12 Fp (e.g. sleaved down HW80s and Pro Elites) shoot so nicely.

And if they wanted to use a shorter spring, why not have a shorter cylinder, and save some weight ?

/starts searching the bay for a bonehill rear guide/end cap that I can machine to take a better suited spring...

If you kept the same number of coils in your twice-as-long spring, then wire diameter would remain as is. I was expecting the coil spacing would be kept as-is, which would give twice the coil count, hence lower spring rate and the need for thicker wire. By the way, in some cases at least, shorter springs are favored for a less traumatic shot cycle - e.g., in the U.S., Jim Maccari's FWB 124 kits have considerably shorter springs than original and get rave reviews.

Don R.

[Shed tuner]

If you kept the same number of coils in your twice-as-long spring, then wire diameter would remain as is. I was expecting the coil spacing would be kept as-is, which would give twice the coil count, hence lower spring rate and the need for thicker wire. By the way, in some cases at least, shorter springs are favored for a less traumatic shot cycle - e.g., in the U.S., Jim Maccari's FWB 124 kits have considerably shorter springs than original and get rave reviews.

Don R.

Ahh, sure, then yes, of course... or a narrower diameter, or whatever else to increase the stiffness.

Short vs long depends on preload really - Jim did an excellent article in AGW a few months back on this - not sure if you get it in the US ?

Peronally I'm not a fan of the shorter spring kits in the FWB, but Jim's seals can be quite good.