Just for larks, how would you go about adding a fixed hop?

[Rogerborg]

The barrel is intact with no window.  It moves back and forth, so anything TDCish is out.  Significant parts are a circlip against which the spring pushes, the sleeve / nozzle on the right hand side here which nestles into the (revolver) cylinder, and a keying ridge on top.  I can't actually see any point to this at the moment since there's no hop, so it doesn't matter if it rotates.  I'd need to retain that to keep it orientated.

What I'm imagining is that I could remove the nozzle sleeve and cut a window in the barrel and s-hop it.  I.e. put a 6mm drill bit inside to fill the barrel and gloop some silicone in to fill the window, leaving a slight bulge on top, which would then push the silicone into the barrel when the nozzle sleeve is put back in place.  Obviously, it would need "tuned" by sizing the bulge on top.

Waste of time, or an idea whose time has come?

View attachment 90424

 

[Adolf Hamster]

i might be inclined to move more towards the WE ct25 style where the hop is a separate piece slightly further down the barrel.

part A07 is the actual hop with A09 being the grub screw adjustment through the outer barrel.

2 main downsides are getting the slot cut in the barrel, really needs milling, and the seal quality isn't going to be great although tbf that's probably a worthy trade for actually having some hop.

certainly with the WE as-is i didn't find it lacking in terms of being able to reliably yeet .32's at a meagre 0.6j, with the results being hilarious given the comically small nature of the gun.

another possibility, maybe simpler, is to drill an undersized hole for a solid circular nub (same idea as the ct25 but minus the tab/slot which prevents the nub falling into the barrel) which you can press through with enough friction to prevent it falling out.

edit: in both these case i'm guessing you'll have some ability to fit a tdc grub screw into the outer barrel for adjustability?

 

[Rogerborg]

i might be inclined to move more towards the WE ct25 style where the hop is a separate piece slightly further down the barrel.

I'd want to keep the hop as far back as possible, since (in my imagination) you'd want to spin the BB up at the start of its linear acceleration, rather than putting an obstruction in while it's already moving. This is for an HFC HG-132 4" barrel green gas revolver which is already super weak.  Also, there's not much barrel there to begin with.

2 main downsides are getting the slot cut in the barrel, really needs milling

Dremel, needle files, and a devil-may-care attitude will be my allies.

another possibility, maybe simpler, is to drill an undersized hole for a solid circular nub (same idea as the ct25 but minus the tab/slot which prevents the nub falling into the barrel) which you can press through with enough friction to prevent it falling out.

Oh, now I like that idea.  Simpler and safer to centre-punch and drill a hole than to cut a slot, and it could be gradually enlarged until I run out of nerve.  The actual rubbery bit I'd do with RTV silicon gasket maker.  Put a silicone-oiled 5.5mm drill bit into the bottom of the barrel.  Spooge RTV into the hole, and remove most but not all of the excess on the outside.  Ideally leaving something like this (not to scale, or connected to achievable reality)

View attachment 90430

edit: in both these case i'm guessing you'll have some ability to fit a tdc grub screw into the outer barrel for adjustability?

Sadly not.  The whole barrel moves forward to let the cylinder rotate, then back again to "seal" against the shellazines.  Any hop would have to be entirely self contained on the barrel itself.

Since we're doing nudey-pics, these are all the components that I have to work with, and where I reckon I could put a hole.  The mark in front of it is an indexing indentation for the plastic sleeve/nozzle.  As an alternative, I could dremel or file that all the way through into the barrel and spooge in there.

View attachment 90432

 

[concretesnail]

If the proud section on the black part stops the whole barrel assembly from rotating then an s/r hop style patch over a cut in window would-be fine. Then a grub screw into the assembly to apply pressure. 

 

[Rogerborg]

Then a grub screw into the assembly to apply pressure.

Probably not do-able.  It would have to be on the unit itself, and even an M3 x 3mm looks like it would project too far.  It'll have to be fixed, and hope for the best.

[UPDATE]

Oh, on disassembly, the barrel actually has a flat (badly) milled or filed or chewed along the top surface.  Here is is (top) beside a spare MP5K (?) AEG barrel.  I'll start by putting a matching flat and circlip notch into that, and doing an s-hop patch for the window.  If that results in spilled guts instead of glory then I can move on to wrecking the revolver barrel itself.

View attachment 90433

 

[Adolf Hamster]

I'd want to keep the hop as far back as possible, since (in my imagination) you'd want to spin the BB up at the start of its linear acceleration, rather than putting an obstruction in while it's already moving. This is for an HFC HG-132 4" barrel green gas revolver which is already super weak.  Also, there's not much barrel there to begin with.

it's not strictly necessary for it to be placed at the chamber, the main reason most designs to it that way is to have a method of keeping the bb from rolling out the barrel, but that doesn't apply here.

Oh, now I like that idea.  Simpler and safer to centre-punch and drill a hole than to cut a slot, and it could be gradually enlarged until I run out of nerve.  The actual rubbery bit I'd do with RTV silicon gasket maker.  Put a silicone-oiled 5.5mm drill bit into the bottom of the barrel.  Spooge RTV into the hole, and remove most but not all of the excess on the outside.  Ideally leaving something like this (not to scale, or connected to achievable reality)

View attachment 90430

the thing i'd say with that diagram is i can see the rtv peeling off the inside and changing the hop dynamics/blocking the barrel pretty much immediately

i'd go light with any centre dabbing lest it deform the barrel too, but drilling a ~3mm hole and stuffing a solid aeg nub into it or cut up section of o-ring is more where i'm thinking, nice tight fit so it stays in position, if anything it'll be wanting to be pushed out by the bb/gas pressure.

Sadly not.  The whole barrel moves forward to let the cylinder rotate, then back again to "seal" against the shellazines.  Any hop would have to be entirely self contained on the barrel itself.

any room to perhaps shorten the spring and add an external sleeve to the barrel for the purposes of mounting an adjustment?

 

[Rogerborg]

any room to perhaps shorten the spring and add an external sleeve to the barrel for the purposes of mounting an adjustment?

I don't think there's quite enough space for that, although ideally I'll want some sort of adjustment there.

For now, I've just gone with s-hopping the AEG barrel.  Can't find my RTV, but I did rustle up some Sugrutm.  Potatocam pics follow.  I'll see how this works out. I might want to take more material off the flat section and replace it with sugru to create more lovely rubbery integrity.

View attachment 90440View attachment 90441

 

[Adolf Hamster]

I don't think there's quite enough space for that, although ideally I'll want some sort of adjustment there.

yeah, not a lot of room to work with, only place i can think to put an adjustment would be on a sleeve between the circlip and current rubber seal, but there's not a lot of meat there to have both threads and room under for a nub of some description.

 

[Rogerborg]

but there's not a lot of meat there to have both threads and room under for a nub of some description.

M3 x 3mm is the smallest grub screw that I have, and it looks to be just a little too long.  Still, worse case I can just plug the hole so never say never.

 

[Rogerborg]

With 20-20 hindsight, this edge is too sharp, and will need ramped and redone. But otherwise I think the principle is sound, and by packing with slivers of electrical tape or similar on top I should be able to tune in some sort of hop effect.

View attachment 90457

 

[Adolf Hamster]

M3 x 3mm is the smallest grub screw that I have, and it looks to be just a little too long.  Still, worse case I can just plug the hole so never say never.

it'd have to be a fine thread, take a sliver of a bolt and cut a slot in for turning.

but that'd still need some more meat around the inner barrel to engage in, the wall thickness just isn't there otherwise.

 

[Rogerborg]

I'll try this version out first. The barrel can just be held in place while firing, so trial and error tuning should be viable.

 

[Rogerborg]

Well, rather to my surprise, that does actually appear to have an effect.  Even at 6m garage ranges, there looks to be an upwards trajectory, although not hugely consistent.  The BB nestles in the "hop" and needs some pressure to be pressed or blown through.

Sure, the power is down to 0.2J, i.e. essentially spitball energies - there's just not enough puff or air seal there to make it viable. But the principle seems sound enough. Who'd have guessed?

 

[Adolf Hamster]

Sure, the power is down to 0.2J, i.e. essentially spitball energies - there's just not enough puff or air seal there to make it viable. But the principle seems sound enough. Who'd have guessed?

wow, there was me thinking the ~0.6j i got out of the ct25 was a bit on the light side

 

[Rogerborg]

wow, there was me thinking the ~0.6j i got out of the ct25 was a bit on the light side

Per my review, it's a point-blank trinket only.  It's a wonder that it shoots at all when you consider that there's hard plastic interfacing with the brass cartridges front and rear, with no rubber seals, under very little pressure.  I'm seeing 0.3 - 0.5J out of it with the stock barrel.

Adding a hop isn't an attempt to make it skirmishable, it really is just out of interest to see if it can be bodged in.

Chances are I'll go back to the original barrel, pre-load the barrel spring, and grease the heck out of all the mating surfaces since I won't have to worry about contaminating a hop bucking. 

 

[Adolf Hamster]

Adding a hop isn't an attempt to make it skirmishable, it really is just out of interest to see if it can be bodged in.

fair enough, i can get the desire, i'm still wondering if retro-bodging a hop onto the We luger might have made it bearable to shoot.....

Chances are I'll go back to the original barrel, pre-load the barrel spring, and grease the heck out of all the mating surfaces since I won't have to worry about contaminating a hop bucking. 

one of those situations where running lighter ammo ironically ends up the order of the day

tbf, there's a lot of satisfaction to be had from getting hits with a gun like that, i bought the ct25 as a joke thinking "if it shoots 20 feet i'll be happy" only for it to turn out to have stolen some of tm's fairy dust from somewhere.....

 

[Rogerborg]

one of those situations where running lighter ammo ironically ends up the order of the day

Shouldn't really run 0.12g, but [looks around shiftily] they can't all be market stall yellow, right?

tbf, there's a lot of satisfaction to be had from getting hits with a gun like that

There really is. I ran it as tertiary on Sunday, and used it in a kill-house, hammer cocked in preference to rocking my Glock. Every point-blank hit with it was immensely satisfying even though most of them were trade-offs - which means the 6 shots isn't actually a problem.  Less can be more.

 

[Adolf Hamster]

Shouldn't really run 0.12g, but [looks around shiftily] they can't all be market stall yellow, right?

i wouldn't be the one to know, haven't even seen a .2 in years