BSA Stutzen tuning

[mrgeoff]

I recently picked up a BSA Stutzen RB2. Its a lovely rifle, but has a bit of a kick.

After a bit of on-line research, I find its a bigger project to tune than normal, and could do with the O ring seal replacing with a normal type seal for best manners that will also lower cocking effort and trigger weight due to a lower pre-load spring being required, plus the rail removal can be a bit of a mare in the wrong hands (mine!)

Question is:
It will cost me £100 to get this tuned, o-ring removed and a normal type of seal attached, new spring, guide, transfer port modded. So will this add value to the rifle, or detract from its current value?
I dont want to turn a good collectors piece, into a piece of junk!

If it makes it a well mannered rifle, I will probably use it more than leaving it alone...



Thanks!

[look no hands]

I recently picked up a BSA Stutzen RB2. Its a lovely rifle, but has a bit of a kick.

After a bit of on-line research, I find its a bigger project to tune than normal, and could do with the O ring seal replacing with a normal type seal for best manners that will also lower cocking effort and trigger weight due to a lower pre-load spring being required, plus the rail removal can be a bit of a mare in the wrong hands (mine!)

Question is:
It will cost me £100 to get this tuned, o-ring removed and a normal type of seal attached, new spring, guide, transfer port modded. So will this add value to the rifle, or detract from its current value?
I dont want to turn a good collectors piece, into a piece of junk!

If it makes it a well mannered rifle, I will probably use it more than leaving it alone...



Thanks!

For starters the RB2 doesn't have the O ring head like the models that preceded it, it has the parachute style that is also fitted to the Superstar/sport, if I remember correctly the Stutzen had the adjustable transfer port screw, which if it's fitted then you can wind out the grub screw and then be able to fit a softer spring, either get Tinbum to make you a tuning kit or contact Welsh Willy for the same, tuning it won't really add much value to it, from memory the trigger on the RB2 Stutzen was pretty nice.

Pete

[Shed tuner]

As the man said, it's a solid type seal, not an o-ring.

I did the most basic tune on my normal RB2, and it shoots much better:
http://www.airgunbbs.com/showthread....d-me-for-years

Fitting piston sleeve and a tight fitting guide and top hat from TinBum is a good idea too...

[mrgeoff]

Ah, good news about the piston seal, that makes things easier, and im not so worried about the tune as I wont be fundimentally changing the rifle by tuning.

So if its got a grub screw in the breech, back it off regardless, then sort the spring to suit?

The linked thread mentioned shaving 30g off the piston, is this a good idea to do as well? (this would be done blind, with no knowledge of why im doing it!)


Cheers - Geoff.

[Artfull-Bodger]

If the piston is similar to the mercury one it's a right old lump, I lightened mine originally and increased the stroke on my Mercury by making a new piston head to take a Diana seal taking it to 39cc, in the end I made a custom piston that weighed 220g as the factory one is basically rubbish, folded steel sheet.

[PCPShooter]

Steve at V Mach will tune it for not much more than a ton, it'll be worth it on that rare rifle
That way, with Steves paperwork you'll actually add value as opposed to most tunes, which deduct value - just a thought -

[yorkieRM]

Some years ago I tuned an old friends Superstar RB2. One of the modifications made, and to me the most beneficial, was the improvement of the sealing o-ring on the rotary breech itself.

The standard o-ring seal is of a relatively small section diameter, so, I made up a jig, and machined a larger groove into the breech, so it accepted a thicker diameter o-ring. Messed the first one up so had to buy another, but ultimately managed to get the breech to seal completely airtight. Standard superstar parachute type piston seal, and custom polyurethane breech seal instead of rubber o-ring it was so good that we were able to de-cock the rifle with the breech in the open position and the piston would sit on a cushion of air in front of it...held like that over night without moving.

You can buy a thicker section o-ring which can be forced on, and then the whole lot back into the cylinder...but this makes the breech very stiff to open, and very very hard to remove again. Machining the groove open slightly works wonders.

Added plastic spring guides and top hat, new spring with a few coils lopped off to bring the power down and reduce the cocking effort and it was a joy to shoot. For me my best ever tune up I was very happy with the outcome.

So much so that I have spent some time searching for exactly the right one to do for myself...and finally a few months ago I got an Airsporter RB2 (without that IMHO horrible BSA maxigrip scoperail) in .22 from this very site, which now sits in the cupboard awaiting the same treatment.

Not an easy mod doing the breach seal, but well worth the effort.

yorkierm

[look no hands]

Ah, good news about the piston seal, that makes things easier, and im not so worried about the tune as I wont be fundimentally changing the rifle by tuning.

So if its got a grub screw in the breech, back it off regardless, then sort the spring to suit?

The linked thread mentioned shaving 30g off the piston, is this a good idea to do as well? (this would be done blind, with no knowledge of why im doing it!)


Cheers - Geoff.

The grub screw was added as a port restricter mainly for the .25 calibre so you could adjust it's power with out taking the spring out, if you cock the gun (so the piston isn't resting against the rotary breech) and then pull out the small black breech block lever (mind the small flat spring that holds the lever in place) you should be able to revolve the block in the cylinder with the aid of a screwdriver, if it has a port restricter then it will be on the underside of the block, undo the grub screw until the end it flush with the block and then revolve the block back again and push the black lever with it's flat retaining spring back in, now in theory if the grub screw was screwed in the rifle should now be more powerful (but it may not be), if it is more powerful, then you can fit a less powerful spring which should in theory reduce recoil.

Pete