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]

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.

[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]

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.

It is straight! Is yours synthetic sealed?

[TopDog]

Recently sold my HW50S which was tuned to two specs depending upon innards; one set for Bell Target work at around 6.5fpe and the other as a "full power" setup at around 10.5-10.9fpe.

One can play tunes with the setups depending upon whether one wants an easy cocking subjectively smooth firing cycle or an better MV consistency.

Eg/ a 24 coil 3.15mm wire 20.2O/D spring with oal 200mm and a PL of 38mm gave 10.9 fpe with 9.8 fps pk-pk MV variation, and
a 28 coil 2.85mm wire 19.6O/D spring with oal 209mm and a PL of 37mm gave 5.6 fpe with 15.2 fps pk-pk

Spring stiffness is of the essence since it determines the energy released for a given stroke and PL and also the PL force resisting bounce so one pays one's money and takes one's choice!

In the end it comes down to what one feels happy with for the shooting type being undertaken! If it was easy . . . . . . !

The same principles apply to any springer; best though that one can measure what one needs to and assesses why it feels as it does! In the final analysis it's performance, shooter and gun combination which matters!

Happy airgunning!

atvb
David

[evert]

Set up the chronograph, and went over to dads place and dug out some guns...
We have ended up with a total of four of these old HW50's with the old screw in end block

The chrono had a low battery, but I managed to get some shots measured.
Here are the numbers, all shot with 7,9grs JSB express:

Dads synthetic sealed HW50, with a setup I did some years back (cant remember, but it might be a Vortek seal and a JM/ARH E3200 spring):
715-717-733

My synthetic sealed "new" HW50, with JM piston seal and JM/ARH E3200 spring, close to max preload and a heavy steel tophat:
698-693-688

My leather sealed old rusted HW50s, with an unorigial leather seal that gives a little extra stroke and a spring I really cant remember:
720-716-716

Dads leather sealed HW50, with original seal and spring. I suspect the breech seal is leaking, it looked quite bad:
672-

...and then the battery was gone, so thats it for now.

We have two HW55's in the family as well, these might be interesting to run over the chronograph for comparison.

[evert]

Recently sold my HW50S which was tuned to two specs depending upon innards; one set for Bell Target work at around 6.5fpe and the other as a "full power" setup at around 10.5-10.9fpe.

One can play tunes with the setups depending upon whether one wants an easy cocking subjectively smooth firing cycle or an better MV consistency.

Eg/ a 24 coil 3.15mm wire 20.2O/D spring with oal 200mm and a PL of 38mm gave 10.9 fpe with 9.8 fps pk-pk MV variation, and
a 28 coil 2.85mm wire 19.6O/D spring with oal 209mm and a PL of 37mm gave 5.6 fpe with 15.2 fps pk-pk

Spring stiffness is of the essence since it determines the energy released for a given stroke and PL and also the PL force resisting bounce so one pays one's money and takes one's choice!

In the end it comes down to what one feels happy with for the shooting type being undertaken! If it was easy . . . . . . !

The same principles apply to any springer; best though that one can measure what one needs to and assesses why it feels as it does! In the final analysis it's performance, shooter and gun combination which matters!

Happy airgunning!

atvb
David

Thanks! What kind of seal do you use in these guns?

[TopDog]

Thanks! What kind of seal do you use in these guns?

I bought mine about 9 years ago (just re-sold it though due to just taking up cabinet space!) and it's SN gives it a date of 2010 so was almost new then!

I found that the seal which was fitted upon recent needed re-sizing but I was not too happy with it so changed it for a standard HW one (26mm).

I also did not like the guide arrangements so replaced all those with my own favoured setup at that time. I have attached a drawing of the innards (I prepare these for all models I work on and note differences if noticed between different examples of the same model). I just added a couple of pics showing it with a cocking grip (to save hands on foresight dovetail) when used without open sights. Hope this helps a bit!

The file can be downloaded from:-

http://freepdfhosting.com/b6f616ff8a.pdf

If there is any trouble with downloading since I gather some rules have changed, I can e-mail it directly to you!

Happy airgunning.

atvb
David

[HW777]

It is straight! Is yours synthetic sealed?

It has a leather seal but was planing to convert to synthetic, not sure that's such a good idea now without reducing the size to the transfer port, plus it being angled it's not a straight forward job.

[evert]

I bought mine about 9 years ago (just re-sold it though due to just taking up cabinet space!) and it's SN gives it a date of 2010 so was almost new then!

I found that the seal which was fitted upon recent needed re-sizing but I was not too happy with it so changed it for a standard HW one (26mm).

I also did not like the guide arrangements so replaced all those with my own favoured setup at that time. I have attached a drawing of the innards (I prepare these for all models I work on and note differences if noticed between different examples of the same model). I just added a couple of pics showing it with a cocking grip (to save hands on foresight dovetail) when used without open sights. Hope this helps a bit!

The file can be downloaded from:-

http://freepdfhosting.com/b6f616ff8a.pdf

If there is any trouble with downloading since I gather some rules have changed, I can e-mail it directly to you!

Happy airgunning.

atvb
David

OK, the gun you are working with is not the same as the ones I am working on. The New HW50/Hw99 is a quite different gun from the old HW50, so the powerplant is not the same.

[evert]

It has a leather seal but was planing to convert to synthetic, not sure that's such a good idea now without reducing the size to the transfer port, plus it being angled it's not a straight forward job.

I'll check my leather sealed gun when it is apart. The transfer port og my leather sealed gun is not overly large, but the gun has not been very pleasant to shoot when I converted it to synthetic. Som I'm back to leather seal in this one.