HW77 .177 transfer port size

[greenwayjames]

"I tested 3 to 4.2mm in .1mm steps and settled on 3.9, i know Wonky likes 3.9 also, JB likes 5/32 which is just a nats over 3.9, T20 uses 4mm, BTDT runs 4mm on his 77k....the list is long for rifles that all run very close to the same transfer port dia...now ask yourself why"

The list of many longtime professional "tuners" who kept to the original or even sleeved transfer ports is even longer..... now ask yourself why? from first hand experience I include in that list Cardew, Mike Wade of Power without Powder fame, Venom, Worcestershire Black Powder Supplies, Kestock and many more. They must have done a half decent job to stay in business as long as they did with many repeat customers.

The best piece of advice is.
"If you must experiment drill the TP to 4.2mm and tap to m5, get some 6mm long m5 grubscrews and have them drilled from 3 to 4mm in .1mm steps, use a little blue loctite to hold them in and seal the threads, you can now play with TP dia and see what works for you

A little heat and an allen key gets them out, run the tap back in to clean the threads and screw a new one in to resume testing"

[T 20]

The list of many longtime professional "tuners" who kept to the original or even sleeved transfer ports is even longer..... now ask yourself why? from first hand experience I include in that list Cardew, Mike Wade of Power without Powder fame, Venom, Worcestershire Black Powder Supplies, Kestock and many more. They must have done a half decent job to stay in business as long as they did with many repeat customers.

I thought Mike Wade just supplied his "Viper" tuning kits and didn't actually tune guns for anybody ?

If you look at Mike Wade's order form that came with Power Without Powder, he recommends drilling the transfer port out on the 77 for both his Max power and FT Viper tuning kits.




All the best Mick

[greenwayjames]

My mistake. I was thinking of his recommendations for the HW80 tune. He did tune some himself for a chosen few in addition to selling his 80 springs. He also made a regulated high power PCP for his own use I was lead to believe. Ahead of its time.

[T 20]

My mistake. I was thinking of his recommendations for the HW80 tune.

He recommended drilling the HW80 transfer ports out as well.





All the best Mick

[T 20]

And come to think of it Cardew wasn't a professional tuner either.

Though he did do a few experiments where he opened transfer ports up.




All the best Mick

[greenwayjames]

He recommended drilling the HW80 transfer ports out as well.





All the best Mick

Did he really. I no longer have a copy so I will take your word for it. Cardew used to tune quite a few rifles for shooters in addition to repairing/restoring antique pneumatics, Giffards etc. He charged for the work he did. Cant agree with you about ports having read his books.

The main point of my first post was to agree with the advice that whatever you do should be "undo-able"if it doesn't work out

[T 20]

Did he really?

Yes he did --- in both editions of Power Without Powder (there were two different editions) Mike recommended opening the HW80 transfer port out.

Cant agree with you about ports having read his books.

As good as Trigger to Muzzle is and how revolutionary it was when first released in 1976 you need to bare in mind that a lot has changed in 37 years.

In 1976 calculators were in their infancy --- 1977 being the first year they were deemed good enough to use them in O level exams.

Decent cheep chronographs were unheard of.

Digital scales were unheard of.

And all Weihrauchs had Leather seals fitted back then.


You would need to have followed Gerald Cardews later works in Airgun World to have read his transfer port and stroke experiments.

Most home tuners on here have equipment which Gerald Cardew could only have dreamed about in 1976.

The main point of my first post was to agree with the advice that whatever you do should be "undo-able"if it doesn't work out

Amen to that









All the best Mick

[TonyL]

Yes he did --- in both editions of Power Without Powder (there were two different editions) Mike recommended opening the HW80 transfer port out.

As good as Trigger to Muzzle is and how revolutionary it was when first released in 1976 you need to bare in mind that a lot has changed in 37 years.

In 1976 calculators were in their infancy --- 1977 being the first year they were deemed good enough to use them in O level exams.

Decent cheep chronographs were unheard of.

Digital scales were unheard of.

And all Weihrauchs had Leather seals fitted back then.


You would need to have followed Gerald Cardews later works in Airgun World to have read his transfer port and stroke experiments.

Most home tuners on here have equipment which Gerald Cardew could only have dreamed about in 1976.
All the best Mick

Yep, Mr Wade certainly advocated opening the TP up.

And, YES, as above re The Airgun from Trigger to Target.....Revolutonary and eye-opening in its day. I have read and re-read it many times in the past. And we can all be grateful for Mr Cardew's work and insight.
But times move and technology has moved with it, especially with the advent of the synthetic seal.

Jim Tyler and Dr Mike have dis-proved some of the Cardew work. For example, the reliance of the springer on a controlled burn in order to make power.

Not having a go at the book or theories. As I say, we can all be grateful for this insight. With every generation of new tuner, we now have a wealth of previous work and information to tap into to. Many of the basics are in place for the modern tuner to just tweak and, step by step, make small, incremental improvements. So we all owe much to Mr Cardew, Mr Bowkett, Messrs Hancock and Popes, Jim Maccari, Ken Turner etc. And, in AGW and right here on the BBS, the many expert tuners such as your good self, Mick, Bigtoe, Wonky Donky and many, many more.......

But the ones who I'd also loved to have really met are those earlier pioneers. The guys that came up with the original theories and ideas. How did they work out or guess at the bore and stroke dimensions, for example? I assume that, firstly, it was down to handling/size/weight to arrive at an aesthetically pleasing layout that was portable, dictating the outer cylinder diameter, thus the internal. Then lengthen the stroke to up the power.

I remember in one of John Milewski's excellent little write ups of an early 1900s rifle (can't remember the make/model right now), where the maker fitted an aluminium piston in the target version to reduce recoil.

Without digging books out, someone remind me of which was the earliest springer. Was it the Quackenbush design? And, I know they were a little later (post WW1?), but those Lincoln Jeffries rifles were beautiful, no?

[brucegill]

Trying to get another set to play with.

These grub screw.... Do you need to do anything else to the grub screw, other than drill them?

Cheers
B

[Snooper601]

Just make sure the gurb screw length is the same as the port length to save making any extra lost volume.

Cheers

John

[bigtoe01]

drill them from the back so the Allen key still works to get them in and out and make sure each one is sized to exact length to finish flush with each face both inner and outer.

[brucegill]

Just make sure the gurb screw length is the same as the port length to save making any extra lost volume.

Cheers

John

Thanks John

I was worried about the actual Allen key hole, would this not cause problems?

Cheers
B

[Snooper601]

As Tony says above, make them flush at both ends.
The slight lost volume due to the Allen recess is only slight and is like putting a pellet with a deeper skirt in the barrel, probably less than the 0.1mm size difference in the drilled holes, though it may be a bigger difference on a short transfer port.

Cheers

John

[greenwayjames]

There was a very early 20th century, pre first world war, trade magazine called Arms and Explosives? I read an article in an edition which detailed in several pages experiments carried out by BSA using the Lincoln Jeffries patent underlever rifles they were making at the time. They experimented with light and heavy pistons eventually settling on the heavy for best overall performance in their production air rifles.

"an early 1900s rifle (can't remember the make/model right now), where the maker fitted an aluminium piston in the target version to reduce recoil."

[bigtoe01]

the difference now is in an age of sharing, before 99% was all kept secret, so even though 99% has been done before it really is all new as before most was never released.

Ask Jb if he will share all his secrets....report back to us what he says

the gun trade is very secretive.....