Bowkett FWB piston

[Garvin]

My .22 cal Bowkett-tuned FWB Sport was running a little hot so I opened it up today and removed a coil from the spring and one of the preload washers.

The rifle is one JB modified in the 1980s and has a screw down breech lock and barrel shortened at the breech. The cylinder is from a 124 but the barrel is a .22.

Some of you might be interested to see the piston seal mod. It has an O ring sset in a stiff red plastic washer screwed into the end of the piston. The other end of the piston has been rounded at its edge and highly polished. The spring guide is floating as pictured.

The gun shoots very sweetly with very little felt recoil.

[Ideot Savant]

Floating spring guide? Whats that?
The current fashion would be to button the piston and fit a parachute seal, its interesting to see what was done many years ago when tuning air rifles...have we really improved them, thats what I'd like to know.

[Paddy_SP]

Very interesting - thanks for that!

[Garvin]

Floating spring guide? Whats that?
The current fashion would be to button the piston and fit a parachute seal, its interesting to see what was done many years ago when tuning air rifles...have we really improved them, thats what I'd like to know.

Floating as opposed to fixed to the rear block as the original one was. Looking at the slight wear points on the piston I'd say buttoning would have been even better but it's pretty good as is. The transfer port has also been opened up a little. There's virtually no spring preload now and yet power is right up near the limit.

Very interesting - thanks for that!

Cheers Paddy.

[Powderfinger]

I have one of these Bowkett 127s and as you say it really is a sweet shooter. But after 25 years of service it is now down on power and I face the dilemma as to what to do with it: Should I replace the Bowkett seals with a standard seal or is it still possible to obtain or make the Bowkett seals? John Bowkett really is a terrific gunsmith and was years ahead of his time.

[Garvin]

I have one of these Bowkett 127s and as you say it really is a sweet shooter. But after 25 years of service it is now down on power and I face the dilemma as to what to do with it: Should I replace the Bowkett seals with a standard seal or is it still possible to obtain or make the Bowkett seals? John Bowkett really is a terrific gunsmith and was years ahead of his time.

If your seal is like mine it should be simple enough to replace the O ring - assuming it's a size and type available off the shelf. Far as I can work out the O ring is the only part that would wear.

[petec]

Thanks for that Garv, it also looks like a piston liner has also been added. I have both a 124 and 127, and the 127 in particular, with a Maccari kit, is a joy to shoot

Can you tell me what the transfer port is opened up to on yours, and also what the barrel length is? I have read the article in the link below, but was a bit reluctant to try any mods as I'm afraid to modify mine in anyway unless it's a genuine improvement on what are great little rifles.


Pete

http://www.reviewcentre.com/review182535.html

[Garvin]

Thanks for that Garv, it also looks like a piston liner has also been added. I have both a 124 and 127, and the 127 in particular, with a Maccari kit, is a joy to shoot

Can you tell me what the transfer port is opened up to on yours, and also what the barrel length is? I have read the article in the link below, but was a bit reluctant to try any mods as I'm afraid to modify mine in anyway unless it's a genuine improvement on what are great little rifles.


Pete

http://www.reviewcentre.com/review182535.html

OK Pete, here's a rough idea of the FWB Bowkett transfer port diameters, subject to it being impossible to measure accurately while holding the cocked barrel plus a torch and sticking digital calipers between the breech jaws.....

The port on my 124 Bowkett is about 4mm, the 127 Bowkett is about 4.35mm and a factory standard 127 is around 3mm.

I couldn't see properly what, if anything, JB did to the inside edges of the port in the cylinder when I had the 127 apart.

The barrels on both Bowketts have been shortened to about 13 inches including the breech block.

HTH

Pics of the barrel lock:

[petec]

Thanks Garvin, that's interesting stuff and seems to be in line with what the guy in the link is saying.

Reg'ds

Pete

[Powderfinger]

Lots of interesting pics and specs here. I suspect mine will need a new (shortened) spring and the piston O-ring. I'll have to get it in a sash cramp.

[sbd]

...is still in the land of the working albeit PCP's seem his thing nowadays, will he still work on his older stuff?

[lightning22]

...is still in the land of the working albeit PCP's seem his thing nowadays, will he still work on his older stuff?

I think he's strictly PCP these days unfortunately.

[Garvin]

And now, because I'm becoming a dab hand at opening up these FWBs (), here's a pic of a Welham Mastersport piston, with what looks like two brass rings brazed to the back end of the piston and turned to fit the cylinder perfectly. I'm guessing this was some sort of lazaglide alternative, with the rear of the piston riding on a softer material. Can anyone can explain the thinking behind this?

The piston head looks like a bog standard FWB one.

[Ideot Savant]

Maximum friction between materials is when they are both the same material
Put grease between and its a different matter of course.

[jonnyone]

Isnt it interesting opening up old modified springers. You wouldnt do it back then for fear of disturbing all the lubes and costly work done to them!
Nowadays though with all the hard work these guns have seen and the fact they are probably down on power and running a bit dry of lube- well, its open season!!!

Its funny you posted some pics of the innards of your "Sports". I have an Anscuhtz 335 with a Bowkett piston head conversion that was exactly like yours (I think he was a fan and advocate of the BSA piston head arrangements). Unfortunately I am not and I found with my 335 that its would never settle down and run consistently and would diesel quite violently at times. I would imagine that others have different story and have had good experiences.

Also, my HW80 piston is presently with Dave (aka Bonnie and Clyde) being buttoned. It previously had brass bearing surfaces brazed onto the rear of the piston exactly like yours. In my case the work was carried out by T R Robb. Unfortunately (and thru Dave's expert eye and experience) I have found that the work was carried out less than perfectly.

Its all interesting isnt it?
Dave