THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
NEXT EVENT :- May 17/18, 2025.........BOING!!
yeah, the airsporter benefits from a sleave down too.. never looked at a merc port ?
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
Hi Mick
What is the scope you have on the Ratter?
Cheers
Matty
Opportunity is missed by most people, because it is dressed in overalls and looks like work.
Probably wise to keep the full skirt. Mine had started scraping out grooves in the cylinder before I got it.
Dont know if it is the original piston as the gun doesn't have the Maxigrip, and other parts had been switched on the gun too.
Its better now with a deburr and proper lubrication, but the full circumference piston would be best.
Too many airguns!
No idea on the Airsporter yet, Tone, but what I can give you are the standard Mercury dimensions :-
Cylinder Bore X Stroke = 28mm X 65mm (1.1" X 2-9/16")
Available compression cylinder = 28mm X 95mm
Piston weight = 320grams
Transfer Port = 3mm X 11.2mm
Available Spring room when cocked = 110mm
The only difference on my rat gun are the stroke at 70mm and a piston weight of 314 grams.
The spring I removed was a 33 coil Spring with 3.1mm wire.
Another problem which showed up was the fact that the end wall of the cylinder has a hemispherical section machined from the centre of it.
I don't know if this is supposed to be there or is a machining cock up at the factory, whichever it is it creates a little more work as I'll have to make a P38 casting of the cylinder end wall and machine the piston head to match.
That's about as far as I'm going to get today while I stare at the piston and think about the job, but I have a good idea which way this is going to go --- new piston.
All the best Mick
Last edited by T 20; 04-06-2022 at 07:25 AM. Reason: Compression cylinder
Hi Matty --- long time no see.
The scope is a Kassner 4 X 40 PA with TV screen view and is basically scrap, I got it for free as the crosshairs had snapped.
I took the scope apart and soldered the thinnest wire I could find in there as new crosshairs.
Unfortunately the wire wasn't thin enough, so now when you look through the scope it's like looking at a pair of crossed fence posts --- looks a bit like the Klan are in town.
I know this doesn't sound too good but at short range in low light conditions when ratting my homemade crosshairs work well.
All the best Mick
Excellent information as always, Maestro.
Maybe nice to post those vital stats in Brucie's Bore, Stroke & SCR thread, if you don't mind?
Nicely enough dimensioned TP, methinks?
Hemispherical section in the cylinder end (head?) - does it think it's an internal combustion engine? Maybe this was where the term "dieseling" originated from?
Hope you get that addressed. Correcting that lost volume should improve efficiency no end.
THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
NEXT EVENT :- May 17/18, 2025.........BOING!!
THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
NEXT EVENT :- May 17/18, 2025.........BOING!!
Reminds me of the nasty, knackered looking scope atop my equally cosmetically challenged Supersport, Mick. And that's another ratty looking potentially ace little ratter......The stock is truly distasteful after being "customised" by some previous owner. But it's actually really ergonomic and handles well. On the scope, the windage turret has some nasty cover hammered on. And the elevation turret is hanging off. But it adjusts okay. Sight picture is excellent and I really like the simple single post (German sniper?) reticle. The quintessential barn / ratting gun.
THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
NEXT EVENT :- May 17/18, 2025.........BOING!!
Well after looking at the Mercury piston for a while, measuring a few dimensions and calculating some weights I've decided that I'm definitely going to have to make a new piston --- again.
There's some very weird designing went into the Mercury and Airsporter pistons which doesn't make much sense.
The distance from the front of the piston cocking lever slot to the front of the piston head is 37mm --- on a HW95 this measurement is 17mm, the weight of this 37mm of piston head is about 90grams and would be difficult to shed any significant weight from.
So it looks like it would be quicker and easier for me to machine a completely new lightweight piston body to screw the original BSA latch rod into rather than try to lighten the original Mercury piston.
All the best Mick
On a Mk4 Airsporter it's 20mm long plus the loading tap so less efficient but it makes the power with a little love .
Cheers, crowbar.
Good luck with the piston build, Mick. Obviously this is going to be more involved than first envisaged but will prove an interesting journey.
THE BOINGER BASH AT QUIGLEY HOLLOW. MAKING GREAT MEMORIES SINCE 15th JUNE, 2013.
NEXT EVENT :- May 17/18, 2025.........BOING!!