Hw55

[rockdrill]

I have just acquired a reasonable example of an HW55.

The breech seal appears to be leather and looks like it could do with replacing.

Before I go digging it out of its recess does anyone know if it will be the same size as the later synthetic versions? By that I mean will an HW35/80 breech seal fit?

[coburn]

Hi Rockdrill

I was tempted by that 55 as well. got 55's with both leather and synth breech seals so I'll let you know when I have a look at home later.

I suspect they are the same size but with the synth seal you need to shape it with a razor or scalpel for a flat fit in the 55's breech.

Also do a search on the American Vintage Airguns site there is loads of info for the 55 on there.

[rockdrill]

Thanks for the info coburn.

The rifle has cleaned up rather nicely, the rust has been largely removed with the old fine wire wool and oil trick, the stock will be stripped and oiled when I have time.

One other thing the rifle is chronoing at a very consistent 540fps average.

What is the expected output for an HW55, looking at it I would say this is a little on the slow side, I would guess around 600fps for a normal output?

[Prof51mtw]

I've just finished a tune on a 55T and it is running well at about 9 ftlbs (700 ft/s with Mosquitoes). Much more than that and the gun becomes quite harsh.
The breach seal for a HW95 will fit after it is has been shaved to fit the angled breech on the 55. To do this put the breech seal in BACKWARDS and pop a thin steel washer (thinner the better) over the seal so that the exposed side of the breach seal protrudes through the hole in the washer. Now shave the beach seal flush with the washer using a Stanley knife blade. Take the breach seal out and refit it the correct way round and you're all set!

Mike

[Garvin]

I've just finished a tune on a 55T and it is running well at about 9 ftlbs (700 ft/s with Mosquitoes). Much more than that and the gun becomes quite harsh.
The breach seal for a HW95 will fit after it is has been shaved to fit the angled breech on the 55. To do this put the breech seal in BACKWARDS and pop a thin steel washer (thinner the better) over the seal so that the exposed side of the breach seal protrudes through the hole in the washer. Now shave the beach seal flush with the washer using a Stanley knife blade. Take the breach seal out and refit it the correct way round and you're all set!

Mike

Am I right in thinking you fitted the larger HW50 spring Mike? As I understand it the original HW55 soft spring delivered around 6 ft/lbs.

Great tip on the breech seal BTW!

[Prof51mtw]

I fitted a 99S spring, less three coils, with a home-made Delrin spring guide. Fits a treat.

Mike

[coburn]

Looks like the synth seal is a direct replacement, but don't dismiss the leather seal too quickly. The 55 have a very secure lock up and the seal does not need to protrude much from the breech face.

On the subject of power my 55MM is fitted with the spring Chambers list for the 55 (part no MS094), however this is slightly more powerful than the original target mainspring. I spoke to Chambers at the time I ordered it and they told me they could not get the weaker spring.

Chambers also list a spring for the 50 (part no MS023) and this should be more powerful.

My 55MM runs at 675fps using Hobbies and 610fps with Superdome.

When my 55SM was fitted with the original Venom 55 spring it made 820fps with Hobby but was much harder to cock and harsher to shoot. Interestingly the Venom spring is shorter than the MS094 in the rifle but much stiffer.

I also note that the No1 Ox Mainspring is listed for the 55, god knows what that would do.

Venom adverstised the Venom 50/55 at 10 to 12ftlbs dependant on calibre. I suspect only the .22 HW50 regularly made over 11ftlbs.

In my 1980 edition of Airguns on Test the 55 was chronoed at 595fps with RWS Match whilst the .22 HW50 tested in the same mag did 537 with Kassnar pellets.

Most 55s on the American Forum chrono around the 680fps mark with Hobbies.

Hope this is of interest

[BSFNUT]

I have a venom tuned HW55T.

The last time I put it over the chrono it did 10 ft/lbs with premiers (7.9gr)

[rockdrill]

Thanks for the responses.

I have ordered a Macarri HW55 tune kit for mine so will see how it compares.

I don't want the rifle trying to make 'mega' power, but it would be nice to get it around the 600fps mark. From what I can see through the cocking slot, the original spring is looking a bit bent.

The consistency it is giving suggest the seals are in good order, so I will not mess with them for the time being.