BSA Improved Model

[edbear2]

I too wondered what the thought processes were, not just for the three ring piston but the perforated one too.

You might not have one made by whoever made the one pictured in this thread ( maybe one person made a few maybe a few people have made them as the drawing is out there) but its eminently doable if you have a lathe & want one.

Drilling pistons is the simplist way to reduce mass with all that entails, I wish I had checked the transfer port sizes on those guns back then, as may have told a tale too.

Tons about the effects of piston weight on various threads, and the effect that making the piston lighter has.

ATB, ED

[trajectory]

Drilling pistons is the simplist way to reduce mass with all that entails, I wish I had checked the transfer port sizes on those guns back then, as may have told a tale too.

Tons about the effects of piston weight on various threads, and the effect that making the piston lighter has.

ATB, ED

I suppose I was really wondering if they set out & drilled a couple first & tried it like that, increasing the number gradually or did the lot at once. I know there's no way of knowing but it's just curiosity on my part. I also wondered if they looked at the interaction of spring & pellet weight. If the transfer port diameter was non standard then it might well be they had a look at these other variables too.

Simple little machines but there's a lot of potential for fiddling & tweaking in them if you are that way inclined.

[jirushi]

Thank you gents for the interesting comments.

@Lakey, I am fine to swap a standard piston for this one with the still intact but carefully removed rings, as I think you would appreciate it more than me. I will send you a pm.

This morning, I finally started making a spring for the rear sight.
With the great tip to use a tape measure.
I have cut out the rough shape (easily done with a cheap pair of scissors, and a Stanley knife) and will finetune with file/Dremel.
It's now in vinegar to make it easier to remove the paint. Then I will try cold blueing.

Thanks to VAGF. I put this photo on my phone and zoomed out until the width of the spring was the same as the width of the rear sight. Then I put a piece of paper on the photo on my phone, with the screen as bright as possible, and drew the contours of the spring on the paper.






The stock is starting to look nice. This is after 6 layers of CCL oil.

[Airjet]

The brass rings with the chamfered ends do remind me of steam engine piston rings, - perhaps who ever designed them was more familiar with steam engine practice??

[T 20]

Ah, Louis

When I suggested using the spring out of a tape measure I meant the clock Spring inside the case which you can't normally see.
The clock Spring is just blued steel and wouldn't need cleaning, but no matter using the actual tape should do the job.



All the best Mick

[jirushi]

Ah, Louis

When I suggested using the spring out of a tape measure I meant the clock Spring inside the case which you can't normally see.
The clock Spring is just blued steel and wouldn't need cleaning, but no matter using the actual tape should do the job.



All the best Mick

Ah I see! Yes that would save some work.
I will make a few of these rear sight springs. It's actually fun to do.
Cheers

[edbear2]

Ah I see! Yes that would save some work.
I will make a few of these rear sight springs. It's actually fun to do.
Cheers

Hiya,

Have a look for a punch kit (the link is to a cheap knock off copy of a Roper Whitney but still OK for light work) but I have no idea what is available where you are, but they pop up used at various places.

A handy thing to have for all sorts of jobs, and it will make the spring job easier if you are doing a batch.

Just make one carefully out of say 1mm or so steel as a pattern, then you can start on the thin ones by punching the hole, inserting a dowel as a guide, the using the pattern to scribe round.

Then all your batch will be more accurate in relation to each other

https://www.zoro.co.uk/shop/hand-too...0aAjk1EALw_wcB

ATB, ED