Another Webley pistol thread---Tuning

[mrto]

I'd like to see a Senior chambered for .455 Webley! That beautiful firearms build quality deserves something more than just three and a half wimpy foot pounds or so!

[gedfinn 2]

Hiya Guy & All,
As you know I am no longer intrested in pumping or cocking hard to cock guns,
I found these Pics of the Webley PCP/Co2 conversions on the Tempest, It uses either .
These are 2 of the activated piston designs I used, Both on this & The Bsa rifles
Ged.

[Shed tuner]

If anyone has a rough but more or less functional one, I'm happy to have a play / test, but as one has not presented itself to me yet....

Or if any owner can give us bore, stroke, tp volume, seal type, piston weight, spring spec, chrono results with a range of light / heavy / medium pellets....All that info will be a very good start in ascertaining scope for potential efficiency increases...

[Hsing-ee]

I think the easiest way to increase the power and efficiency of a Webley air-pistol is to sell it and buy an HW45, which is basically the same thing but done properly.

Maybe a machined-down HW45 to make it look like a Webley would be the ideal solution? Otherwise the CO2 conversion that that bloke used to make is the best way to deal with the Webley.

[ggggr]

A REALLY dog rough Premier Mk 2 is finding it's way to Mr Budd now. The top of the breech block is worn on this and allows the barrel catch to go too far forwards when cocking (but ok with the barrel in the locked position). Without being built up with alloy weld, I guess a little stop pin or screw needs to be put into the block.
The frame of this one had a hole and grub screw in the end of the cylinder, where I guess someone had tried to make a shoulder stock?
The screw hole for the rear sight had gone over sized so I tapped it 2ba and Phil made up a stud to go in and I used a knurled adjuster off a scope, tapped to 3ba.


My guess is a fraction of weight could be taken off the piston, which should help to reduce recoil. Trying to lengthen the stroke is probably not worth the trouble and could cause the back of the piston to hit the cocking link.
Keeping it simple, once a transfer port is sorted, maybe a top hat and better fitting guide.
If no more power can be got from the pistol without a monster spring, a gun that achieves standard power but shoots sweeter, with less recoil would be great.
I prefer the Tempest triggers as I can do them really good. I am not a fan of the Premier set up.

[Shed tuner]

Well, I had a quick play... personally I didn't think it was that rough, but I guess I'm not very fussy

First some stats...
horizontal part of port = 5mm long at 3.2mm dia. Plus another 3mm for the seal thinckness
vertical part of port = 14mm long at 3.1mm dia

man, that's about 22mm of 3.15mm port; total volume ~ 171mm2

stroke x bore = 60 x 20 = 18cc. So that's a horrible SCR of 110 !

Obviously the plan was to reduce the port volume, so I just filled it with liquid metal and drilled it back out to 2.6mm. tempted to go smaller, but then it just won't flow, so it's a balance. This reduced port volume to 126 and raised SCR 40% to 150

Weirdly, the entrance for the port into the comp tube wasn't aligned with the scalop at the end of the cylinder either. So i filled that too.

Also noticed the hard delrin piston "seal" wasn't a great fit the bore. So I made a new delrin nose about 1.5mm thicker, and cut an o-ring groove in it. (this will reduce stroke buy 1.5mm, but it's worth it to actually get a decent seal). Seems to seal better now, nice amount of drag when inserting the piston.

Finally did some slight tidying up of the breach seal, and of the receiver where the breach end of the barrel sits in it, so it seated more easily. Finally gave the plunger spring a slight stretch to increase the tension on the stirup and reassembled.

Shooting before and after was interesting. In it's original state, it felt a little slammy (not terrible, but you could just tell) with the short spring fitted, and gave bang on 2.0 FP with superdomes, LRGs and Hobbys.

Post my mods, it seems to be noticably softer to shoot, and is doing 2.7 FP with all three pellets. When I get a mo, I'll fit one of the longer springs and see what happens Better fitting spring guide is also a must - will sleave this one.

Quite pleased so far, that's a 35% energy increase with the same spring

[deejayuu]

They also watch that remain silent

[ggggr]

Well, I had a quick play... personally I didn't think it was that rough, but I guess I'm not very fussy

First some stats...
horizontal part of port = 5mm long at 3.2mm dia. Plus another 3mm for the seal thinckness
vertical part of port = 14mm long at 3.1mm dia

man, that's about 22mm of 3.15mm port; total volume ~ 171mm2

stroke x bore = 60 x 20 = 18cc. So that's a horrible SCR of 110 !

Obviously the plan was to reduce the port volume, so I just filled it with liquid metal and drilled it back out to 2.6mm. tempted to go smaller, but then it just won't flow, so it's a balance. This reduced port volume to 126 and raised SCR 40% to 150

Weirdly, the entrance for the port into the comp tube wasn't aligned with the scalop at the end of the cylinder either. So i filled that too.

Also noticed the hard delrin piston "seal" wasn't a great fit the bore. So I made a new delrin nose about 1.5mm thicker, and cut an o-ring groove in it. (this will reduce stroke buy 1.5mm, but it's worth it to actually get a decent seal). Seems to seal better now, nice amount of drag when inserting the piston.

Finally did some slight tidying up of the breach seal, and of the receiver where the breach end of the barrel sits in it, so it seated more easily. Finally gave the plunger spring a slight stretch to increase the tension on the stirup and reassembled.

Shooting before and after was interesting. In it's original state, it felt a little slammy (not terrible, but you could just tell) with the short spring fitted, and gave bang on 2.0 FP with superdomes, LRGs and Hobbys.

Post my mods, it seems to be noticably softer to shoot, and is doing 2.7 FP with all three pellets. When I get a mo, I'll fit one of the longer springs and see what happens Better fitting spring guide is also a must - will sleave this one.

Quite pleased so far, that's a 35% energy increase with the same spring

Thank you Mr Budd for having a play with this. As per my pm, I'll put up my "plinking findings". With the leather piston washer (plain leather, not a cup washer), the gun was "soft", and well down on power. I did not find it that accurate either. I tried the O ring head and the power was up (by the scientific method of listening to the pellets hit the stop). It was fairly accurate but threw out a couple of wild fliers (using Marksman pellets instead of my preferred Caledonians). The gun also started to grind on cocking. I have mentioned this before----that this can happen with modern "superlubes". A quick look at the cylinder showed witness marks and the crud was cleaned out and I used a bit of mineral oil (chainsaw oil) on the cylinder behind the piston. I managed to shoot 4 shots that a 5p piece would cover and then accuracy went a bit, which could be my crap arms getting tired. After a quick break to fit the standard washer, but with an O ring to pack under the screw head to reduce lost volume, I had another plink, but was shooting quicker. By the sound of the pellets hitting the backstop, I would guess the power was very similar (maybe a fraction more) than the O ring head. After the first 2 shots, I shot maybe a dozen shots 2 handed, that would have all hit a bottle cap, with one going high do to "pilot error". It has more power than when it was posted to Mr Budd and I think most of this is down to him reducing the transfer port size, although a bit could be that the grub screw that was at the end of the cylinder could have been leaking a bit as well even though i thread locked it.
So---can the old Webley pistols be tuned? I would say that this one is back to near standard power and for a rough old thing it is shooting well now. Maybe someone else could try the reduced transfer port trick?