HW50 - velocity expectations

[evert]

A synthetic sealed Hw50, of the old type with screw-in back block came home with me some days ago. Its new enough to have 11mm dovetails and synthetic seal, but old enough to have the steel spring guide.
It needs new seals and a spring, plus spring guides.
I know people on here have gotten close to 12fpe from HW55's, which are a very similar action, but that means custom pistons, but
what energy can I expect to get from the gun with the original stroke? Its a .177".

[TonyL]

In .177, I'd have thought about 7.5-8ft.lbs max if you wanted to maintain pleasant characteristics and promote longevity. Lovely guns. Guessing this will be a very rare beast - .177, screw-in end block and factory synthetic seal?

[Mach 1.5]

My HW55T runs at 10.7 ft lbs. The only way you would get more is by changing the barrel to .22 cal. On the HW50 my venomac tuned one in .177 runs fine at 11 ft lbs. Mach 1.5

[evert]

My HW55T runs at 10.7 ft lbs. The only way you would get more is by changing the barrel to .22 cal. On the HW50 my venomac tuned one in .177 runs fine at 11 ft lbs. Mach 1.5

I have a few ideas about a custom piston. But will likely just run the gun on the original piston and do some experiments with seals and piston weights first.

[evert]

The "Blue book" is never a good source for anything, but I find these velocities for the different version built on this mechanism:
-HW50, made from 1972 until 1995, 700fps
-Different HW55 versions and differing velocities: 590fps, 660fps, 700 fps
-Beeman Rb, madefrom 1983-1997, 720fps

So Tony, your predicted 8 fpe is probably max of what I'll see from the gun with the original piston.

I'll have to shoot dads gun over the chrono to see what it ended up with.

[HW777]

The "Blue book" is never a good source for anything, but I find these velocities for the different version built on this mechanism:
-HW50, made from 1972 until 1995, 700fps
-Different HW55 versions and differing velocities: 590fps, 660fps, 700 fps
-Beeman Rb, madefrom 1983-1997, 720fps

So Tony, your predicted 8 fpe is probably max of what I'll see from the gun with the original piston.

I'll have to shoot dads gun over the chrono to see what it ended up with.

I think it all depends on what kind of firing cycle you want to end up with Evert.

Between 9.5-10.5 ft lbs can be obtained in .177 with a standard piston and synthetic seal but you do need a stiff spring.

While you have yours apart, please can you check whether the transfer port is straight or angled on your 50.

I have a 50 project going at the moment and it took me by surprise to find the transfer port is angled.

All the best

HW55T

[evert]

Guessing this will be a very rare beast - .177, screw-in end block and factory synthetic seal?

Not that rare over here, my dad has one with the rekord trigger (which I tuned some years back, but I cant remember how fast it shoots), and I have seen another one for sale some years back. I guess they must be made some time in the 80s?

I'm making up a spring kit for this one right now, using Jim Maccaris E3200 spring which he sold me for these some years back. I'm hoping for 8.5fpe. but that may be a bit optimistic without a custom piston.

The nice thing about these is the factory honed cylinder, it easy to get a good seal even with the old seal in the gun.