Whenever I look for a replacement spring for my Hw77 (or most other springer guns for that matter) it seems there are manufacturers/suppliers who only talk about what spring 'numbers' will fit in a particular gun.
They don't generally tell you what spec spring the 'number' refers to (such as the outer diameter, inner diameter, coil thickness, number of coils, total uncompressed length, the length at which the spring would become coil bound. How much the outer / inner diameter changes between uncompressed and compressed.
There doesn't seem much information on the internal specs of guns either. The inside diameter of the piston, the diameter of the factory spring guide, the compressed length and uncompressed length.
Is there a table somewhere with all this information? It is a minefield for anyone with a technical interest who might want to apply some of their own thoughts/reasoning to try to achieve what they want out of the gun, such as say a tight fit in the piston / on the guide, lack of preload or lots of preload.
It would be better if spring makers gave more info like "Your early 25mm HW77 has XYZ internal dimensions, we find best results come from a spring with A and B clearances in the piston and on the guide when uncompressed and C and D clearances on the piston and guide when compressed. We also find a spring of overall length works well in your gun, which gives a distance of E between coils when compressed if no spacer is used to increase preload. For that reason we recommend our S1 spring for your gun if you are trying to achieve 1 or S2 spring for your gun if you are trying to achieve 2 but you might have other ideas in which case you will find our S5 and S7 springs will also both fit but S5 will have less clearance and more clearance so might increase power and S7 will have more clearance but will decrease power". But instead they all say something like "Our number 1 for your HW77 or a number 3 would also fit". You ask them for more info and they haven't got a clue. So much for trusting them to be in a position to advise on springs, they don't even know what the spec of what they're selling, it makes all the sales talk about 'tuning for better X and less Y' seem just like the bs sales talk it probably is.
They don't generally tell you what spec spring the 'number' refers to (such as the outer diameter, inner diameter, coil thickness, number of coils, total uncompressed length, the length at which the spring would become coil bound. How much the outer / inner diameter changes between uncompressed and compressed.
There doesn't seem much information on the internal specs of guns either. The inside diameter of the piston, the diameter of the factory spring guide, the compressed length and uncompressed length.
Is there a table somewhere with all this information? It is a minefield for anyone with a technical interest who might want to apply some of their own thoughts/reasoning to try to achieve what they want out of the gun, such as say a tight fit in the piston / on the guide, lack of preload or lots of preload.
It would be better if spring makers gave more info like "Your early 25mm HW77 has XYZ internal dimensions, we find best results come from a spring with A and B clearances in the piston and on the guide when uncompressed and C and D clearances on the piston and guide when compressed. We also find a spring of overall length works well in your gun, which gives a distance of E between coils when compressed if no spacer is used to increase preload. For that reason we recommend our S1 spring for your gun if you are trying to achieve 1 or S2 spring for your gun if you are trying to achieve 2 but you might have other ideas in which case you will find our S5 and S7 springs will also both fit but S5 will have less clearance and more clearance so might increase power and S7 will have more clearance but will decrease power". But instead they all say something like "Our number 1 for your HW77 or a number 3 would also fit". You ask them for more info and they haven't got a clue. So much for trusting them to be in a position to advise on springs, they don't even know what the spec of what they're selling, it makes all the sales talk about 'tuning for better X and less Y' seem just like the bs sales talk it probably is.
