Webley Tomahawk heavy recoil

[Shed tuner]

pistons shouldn't slide down on their own.. they should need a few pounds of force minimum.if you can shove it in with one finger, it'll be fine.

[Mark A]

Thanks shed tuner. I think it does need sizing a little as it takes a fair bit of force to push the piston down and the power is down to 10ft/lb. It did feel to have a little less recoil, but still way too much, so I am going to give the transfer port a go. Do I need to use a pillar drill, or will a battery driver be ok? I got a 2.90mm long series cobalt drill bit and a 3mm twisted hand reamer.

[Shed tuner]

just noticed my typo.. but I'm sure from the rest of the line you got the message ! Yes, if it needs a good shove, then a little sizing makes sense... However, make sure you size it so it's still too stiff... reason being freshly sized seals wear in very quickly, so if you size to perfection, it'll be too loose within 50 shots. Also, tighter seals do generally dampen recoil a bit, so you probably want it on the tight side anyways.

As you are going to hand ream the final cut (which is definitely the best approach), hand held drill is just fine - and probably less awkward than trying to get that under a pillar drill ! just make sure it's as true as possible, checking from multiple angles.. and go very steady - low force, low speed

When you are reaming, you don't need any significant force shoving it in, just turn it and let it feed with gravity

[Mark A]

I drilled and reamed the transfer port to 3mm today and WOW what a difference. Its still got a bit of kick to it, but its definitely a lot better and more of a snappy nudge backwards. I'm almost tempted to go to 3.1-3.2, but think I'll let it run in and see what the accuracy is like.

I would love to get the piston lightened and glided at some point if anyone knows someone that can do that sort of work. I gave the piston skirt a light rub with 1200 grit and brushed moly powder into the cylinder where the skirt rubs and it feels smoother, but its still nowhere near the smoothness of my old Sidewinder.

Thanks for all the help

[Shed tuner]

I drilled and reamed the transfer port to 3mm today and WOW what a difference. Its still got a bit of kick to it, but its definitely a lot better and more of a snappy nudge backwards. I'm almost tempted to go to 3.1-3.2, but think I'll let it run in and see what the accuracy is like.

I would love to get the piston lightened and glided at some point if anyone knows someone that can do that sort of work. I gave the piston skirt a light rub with 1200 grit and brushed moly powder into the cylinder where the skirt rubs and it feels smoother, but its still nowhere near the smoothness of my old Sidewinder.

Thanks for all the help

Good result. Yeah, shoot it a bit with the 3.0 port before you go further... and let the new seal settle in. I do think a little more will help, but it's diminishing returns...

[TonyL]

Great to hear how well that has worked, Mark.

Jon, Shed tuner, really knows his stuff and following his recommendations is always a good idea.

Personally, unless there was excessive clearance between the piston and cylinder, I don't think there's much to gain from gliding. Moly treating is good. Just add a tiny smear of high moly content paste around the rear bearing part of the piston and done. Piston lightening might pay dividends (depends how heavy it is currently), but may then need balancing with the spring used - rate, force, preload etc. - and the gun's pellet preference might alter, too.

Now you're at a happy place, further mods go into the realms of diminishing returns for extra effort / spend.

As Jon says, enjoy for now. Let it all settle and see how you and the gun feel in another couple of thousand shots or so.

For gliding / lightening work, maybe approach NickG on here or Nick Simmons or Paul Short elsewhere if you want to follow that route.

[Mach 1.5]

For someone like Nick Simmons and the others then gliding the piston the Tommy is straight forward as the groove for the front O ring is already present on the short stroke nose. Mach 1.5

[ToniD]

I drilled and reamed the transfer port to 3mm today and WOW what a difference. Its still got a bit of kick to it, but its definitely a lot better and more of a snappy nudge backwards. I'm almost tempted to go to 3.1-3.2, but think I'll let it run in and see what the accuracy is like.

I would love to get the piston lightened and glided at some point if anyone knows someone that can do that sort of work. I gave the piston skirt a light rub with 1200 grit and brushed moly powder into the cylinder where the skirt rubs and it feels smoother, but its still nowhere near the smoothness of my old Sidewinder.

Thanks for all the help

I think there is a place in Preston called LSD, Liquid Steel Designs. I believe he does that among other things.

[Mark A]

Oh nice, I'll look into that company, thanks.

I found an image online of the Venom glided piston and it looks like they mirror the trigger sear slot on the top of the piston and then add a large piece of delrin as well as the band at the front Mach 1.5 mentioned.

[Brano]

Oh nice, I'll look into that company, thanks.

I found an image online of the Venom glided piston and it looks like they mirror the trigger sear slot on the top of the piston and then add a large piece of delrin as well as the band at the front Mach 1.5 mentioned.

I think the photo is of a 6mm reduced piston. A new slot is milled further forward as there's not much meat left after 6mm has been removed.