BSA Improved Model

[jirushi]

That's a very interesting find.

Your photo is very good & shows the three split ring washers very well. Below the washers there are, on my screen at any rate, what looks to me to be two further brass coloured rings. Are they really thin rings or grooves around the piston that have picked up a coloured reflection or something like that. I'd be interested to know what they are please.
Looks a great find & I am sure will be of interest to fans of older BSA air rifles. Just makes you wonder how many others there might be that nobody realises they have...

If you have a UV light I wonder if that might help reveal the full serial number?

Thank you trajectory.
Great idea to use a UV light. I don't have one at home but will see if there is one at the vet practice where I work.
Below the three split washers, there are two grooves in the steel piston head.
They must have indeed picked up a coloured reflection.
To be honest I thought this rifle wasn't anything special, and it probably still isn't as the condition isn't great, but I like it anyway and hope to turn it into a good and accurate shooter.
Something that will help, is to put a little bag of lead shot in the recess in the stock, under the steel buttplate. BSA were fantastic to think of these things!
The gun is now a bit front heavy for me.

[trajectory]

jirushi thank you for explaining about the rings behind the three main phosphor bronze (?) ones. I thought it was most likely a reflection. As you said the leather seal looks a bit worn & chewed & a replacement should help things along. You also mentioned the friction between the three rings & the cylinder wall being a bit high & depending how tight they are it will sap some power. A moderately heavy oil might help, but then theres diesling to consider if too much gets picked up by the leather piston washer. You also mentioned that the rings don't close up that well & depending how well they do, as you say, will also cause losses, in theory if the gaps line up the air path will have less resistance & it will be a bit worse than if the gaps don't line up. Maybe it's more theoretical than actual compared to the losses of a poor fitting main seal.......?

With examples I have shot pellet seating doesnt seem to make much difference in accuracy, the main thing to me seems to be to make sure the pellet skirt is below the level of the tap so it does not get cut or damaged when the tap is closed. Pushing it all the way down should make things more consistent but in reality I've not noticed much difference between seating a pellet part way or all the way to the bottom of the tap.

I think it's an interesting example, have you any idea of its history?

[jirushi]

Thank you trajectory for your advice on pellet seating.

I will test the gun in the following days, with a few setups:
- new 28 mm leather cup type piston seal
- a number of springs (Protek advised a Meteor spring, which I have. I have also picked up another spring from a Diana. And then I will order an Airsporter spring)
- with and without the piston rings. Hopefully they will come off easily (without damaging them); otherwise I might have to leave them on.
- I will try to make/have made a spring guide to slide over the original one, as the springs mentioned above all have a loose fit over the spring guide

About the history of this gun: I bought it from someone who found it in a gunshop not long ago. That's all I know unfortunately.
The trigger block has more wear to the metal, and had a different/more faded finish than the rest of the gun. I wonder if it was on this gun originally...
It will never be a collector's piece, but hopefully it will turn into a good shooter.

Cheers

[trajectory]

On an improved model B I used an Airsporter spring cut to give about 1.5" pre load. The end was ground & polished up, might give you a starting point?


Cylinder/barrel & trigger block might be an original pairing despite how they seem to have aged differently; if the steel composition isn't the same perhaps it might account for the different look?

It might never look mint but It looks like one to hang on to

[jirushi]

On an improved model B I used an Airsporter spring cut to give about 1.5" pre load. The end was ground & polished up, might give you a starting point?


Cylinder/barrel & trigger block might be an original pairing despite how they seem to have aged differently; if the steel composition isn't the same perhaps it might account for the different look?

It might never look mint but It looks like one to hang on to

That's great to know, thank you.
Does your Improved Model B have an old leather seal, or a replacement? I have a feeling that the shallow cup ones from Protek will work best.
Good point on the possibility of different metals giving different looks.
Here is how it looked when I bought it:
(very dark stock, due to all those years of oiling and dirt, I suppose. And faded finish on the trigger block)

[trajectory]

That's great to know, thank you.
Does your Improved Model B have an old leather seal, or a replacement? I have a feeling that the shallow cup ones from Protek will work best.
Good point on the possibility of different metals giving different looks.
Here is how it looked when I bought it:
(very dark stock, due to all those years of oiling and dirt, I suppose. And faded finish on the trigger block)

Hi, the piston washer on that model B might be an original one. It looked intact & was supple so I didnt replace it & it seems to work pretty well. I tend to make them if I need them. It's a bit of fun if you have the time & the bought ones sometimes need conditioning & fitting so I end up fiddling with them anyway. Your woodwork looks to have cleaned up well. Some stocks have marks & large patches which are almost black in colour & are really deeply ingrained. They can be got out but it's often a long job to do so. Yours looks to be pretty good.

[jirushi]

Hi, the piston washer on that model B might be an original one. It looked intact & was supple so I didnt replace it & it seems to work pretty well. I tend to make them if I need them. It's a bit of fun if you have the time & the bought ones sometimes need conditioning & fitting so I end up fiddling with them anyway. Your woodwork looks to have cleaned up well. Some stocks have marks & large patches which are almost black in colour & are really deeply ingrained. They can be got out but it's often a long job to do so. Yours looks to be pretty good.

Thank you trajectory.
One side of my stock is a bit darker than the other; I must have worked less hard on the darker side! It was a lot of rubbing with the steelwool. In any case it's better than how it was. Making leather piston seals is something I should learn. For now I will order one from Protek.

Does someone know how to get the phosphor bronze piston rings off correctly?
I have tried putting a small tool in the gap of the rings, but this way I will deform the rings, if I pull them out. Perhaps that's the only way.
I would rather have a good leather seal and no rings, than both (as I have seen that air leaks past the rings anyway).