Tuning HW35 Tuning

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JamieUK said:
Some of the early 35's suffered from poor brazing (cylinder plug to main tube) here.....

.....which creates a huge amount of lost volume, or in other words horribly low compression ratio (on a rifle that already has a very low comp ratio). Im not saying this IS causing your results, but if yours is suffering from this you'll struggle to make 7-8ish fpe no matter what tuning is done.

If it does have this issue it can be resolved by thoroughly degreasing the cylinder, bunging up the TP, squirting a thin loctite around the join, and then holding it under either compression or vacuum (with the piston) so the air in the void is replaced by the loctite. It doesn't need de brazing as per my pic, that's just an example from a 25mm conversion I did on a leaky 35 a while back. All the best.....
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Fascinating post! Long story short, last week I acquired a 1980-vintage, leather-sealed HW 35 which struggles to make 6 FPE with a fresh breech seal, reconditioned piston seal, and any of three different springs.

It's a beautiful rifle and I'm not particularly a "power guy," but yeah - I need my HW 35 to shoot harder than my old R7! I'll be giving this a look.
 
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MDriskill said:
Fascinating post! Long story short, last week I acquired a 1980-vintage, leather-sealed HW 35 which struggles to make 6 FPE with a fresh breech seal, reconditioned piston seal, and any of three different springs.

It's a beautiful rifle and I'm not particularly a "power guy," but yeah - I need my HW 35 to shoot harder than my old R7! I'll be giving this a look.
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Very keen to know your findings Wonder if it has porosity in the tube ?
 
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FWB127 said:
Very keen to know your findings Wonder if it has porosity in the tube ?
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Since my last post I've taken this HW 35 apart. There are no other obvious internal problems that I can see. The chamber and piston seal look as new and seal up tightly.

I have history with this rifle! I first bought it in 1988 (!! - no interwebs then; we airgun geeks just snail-mailed photocopied sale lists around to each other). It was in a batch of NEW rifles with water damage from a flooded shop. I also got my first Diana 27 from that batch. I had to re-finish both stocks, but metal was fine (still have the 27, great shooter, never done squat to it but an occasional squirt of oil).

I got the 35 for a lifelong friend who is not an "airgun guy" but just wanted a plinker. The power was quite low - it barely does 6 FPE - even after I went through it with Maccari lubes and three different springs in 2001. I was frustrated but he didn't care - accurate, great trigger, smooth shooter, and enough zip for his small back yard. Later I helped him fit a Burris 6x AO Mini scope on it.

So, lo these many years later, my friend has some serious health issues. He can't use it any more, and being the sort of person that won't take your money for anything...he just GAVE me the gun and scope a couple weeks ago. I will definitely be hanging on to it for the duration, and want to do the best I can with it.
 
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MDriskill said:
Since my last post I've taken this HW 35 apart. There are no other obvious internal problems that I can see. The chamber and piston seal look as new and seal up tightly.

I have history with this rifle! I first bought it in 1988 (!! - no interwebs then; we airgun geeks just snail-mailed photocopied sale lists around to each other). It was in a batch of NEW rifles with water damage from a flooded shop. I also got my first Diana 27 from that batch. I had to re-finish both stocks, but metal was fine (still have the 27, great shooter, never done squat to it but an occasional squirt of oil).

I got the 35 for a lifelong friend who is not an "airgun guy" but just wanted a plinker. The power was quite low - it barely does 6 FPE - even after I went through it with Maccari lubes and three different springs in 2001. I was frustrated but he didn't care - accurate, great trigger, smooth shooter, and enough zip for his small back yard. Later I helped him fit a Burris 6x AO Mini scope on it.

So, lo these many years later, my friend has some serious health issues. He can't use it any more, and being the sort of person that won't take your money for anything...he just GAVE me the gun and scope a couple weeks ago. I will definitely be hanging on to it for the duration, and want to do the best I can with it.
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Pressure test the tube. Plug the port and draw the piston back and tie it fixed. If it leaks down fast it’s leaking at the internal weld. Pending your piston seal is good. I’ve resealed a few Webley guns that thread the forks on with retaining compound.
The vacume created draws the 680 in the open areas and seals them up.
 
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A.G.R said:
Pressure test the tube. Plug the port and draw the piston back and tie it fixed. If it leaks down fast it’s leaking at the internal weld. Pending your piston seal is good. I’ve resealed a few Webley guns that thread the forks on with retaining compound.
The vacume created draws the 680 in the open areas and seals them up.
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Thanks! I did that briefly a couple of days ago. That big old chunk of leather still looks new, and seals pretty tightly - piston didn't move even when I pushed down hard on it.

IMG_5924.jpeg
 
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MDriskill said:
Thanks! I did that briefly a couple of days ago. That big old chunk of leather still looks new, and seals pretty tightly - piston didn't move even when I pushed down hard on it.

View attachment 510950
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Not just a quick push. The extreme pressure when shooting will only show the issue if your getting lower than normal velocities. Tie it and see if it holds air for 1 hr

Pending your spring has the potential for bigger power and breech seal is good ,only area that’s got a leak ,or loss trap

if your only getting 6 lbs and you know your seal is good, there is a braze leak.
 
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Motorhead said:
Leather seal needs to be running slightly wet to slide freely as well seal at its best.

On the Comp tube walls Silicone oil works great ... Tho have a MOLY lube on rear of piston where it meets tube metal on metal ;) what ratio do you recommend for this mixture

Tho ideal lube is 80-90 wt Silicone and Neetfoot oil blended.
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Most things work neatsfoot oil synthetic motor oil , bla, bla, ...

One thing I do think is what ever you sokak / condition with remember it and stick with it . Make a dropper bottle full for periodic maintenance drops .

What runs in to issues is mixing oils or what ever on the seal that don't jive or mix together well and will gum up the works . ( Can also scratch the tube wall )

Leather seals ain't easy to come by today
You'll get it going and learning something fun ..
 
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