BSA BSA Spitfire SF

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JamieUK

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Nov 14, 2017
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Suffolk, United Kingdom
Decided to air the old BSA spitty today, one from the collection that hasn't left the rack for over 4 years now.....

20250327_145012.jpg


.....and as soon as I started shooting, had a bit of a face palm moment questioning why I'd left it sooooo long.

Yeah I know this should really be in the PCP section, but there is no doubting these unusual rifles are 'traditional'.

Being a springer man, it really messes with your senses breaking the breech open, and setting the hammer with just the slightest of force. Once you've locked the barrel and settled in for the shot, the springer feeling kicks in again, until...you let the trigger off and......almost nothing....just a quiet pop! It really takes some getting used too!

I rebuilt this one about 4 years ago, and did some slight mods to the valve (increased poppet size to reduce flow through throat) and now its returning around 55 usuable shots at 11fpe before there is a notable drop.....quite impressive from its tiny little 50cc ish cylinder.

If you ever get the chance to own or try one....go for it. These BSA barrels are superb, the faux 2 stage trigger can be made light and crisp, and the overall shooting experience is a refreshing break from the norm.....
 
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Great guns and crazy accurate. Glad you got yours sorted. I had a Spitfire and Firebird. Firebird was still holding air but sold it to a friend in FL who is a big BSA collector. Sold him the Spitfire action to him as well but put its barrel on my BSA Lightning and it's my most accurate spring gun.

Would love to pick your brains in the reseal.
 
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xsarfc9x said:
Great guns and crazy accurate. Glad you got yours sorted. I had a Spitfire and Firebird. Firebird was still holding air but sold it to a friend in FL who is a big BSA collector. Sold him the Spitfire action to him as well but put its barrel on my BSA Lightning and it's my most accurate spring gun.

Would love to pick your brains in the reseal.
Click to expand...

Maybe some of the best (most accurate and least fussy) barrels ever made. I've kept back a full length barrel like you, for a future project 🙂

It's been a while since the rebuild (and I've slept alot 😂 ) but I took plenty of photos so would be happy to go through it over pm. Its been said you need special jig for these, but its not the case👍
 
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Smart move on keeping the barrel.
Photos would be great.


I have the parts diagram and it doesn't look overly complicated but I guess there was a balancing act with the rod section and the Teflon seal and getting it adjusted right. Clever design for fitting something into a spring gun body.


On the old BSAOG and other forums ppl always said you need the "special jig" and that put me off having a go.
 
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Good afternoon gents. I am new member to AN and this is my first chat. I am the big BSA collector in Florida and huge fan of John Bowkett’s Spitfires, Firebirds and Techstar’s. I chat with John couple times a year for his advise but unfortunately he is aging out and not doing any repairs, service work or customizing any more. I got to visit Mark Knibbs September last year which was incredible and hopefully going back later this year to pick thru the huge amount of BSA parts he has stored away. I was also hoping to meet up with John in Birmingham but he was just not taking visitors. I have three Spitfires, two Firebirds and a Techstar which is also a fantastic accurate rifle. Like all the others that own these great guns keeping them sealed without leaks is a mission, so any advice or help that we could share would be greatly appreciated especially resealing and servicing them. I have a whole cylinder from xsarfc9x to practice on but I’m trying to build the confidence to strip down and work out its complicated internals. I also have many ongoing springer rebuilds which I enjoy doing and easy😉
Looking forward to many chats and meeting my fellow BSA collectors.
 
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Just one thing John did say to me about 6 months ago. In all his articles or writings he mentions special tooling and jigs for service these guns. He wrote this to protect himself from amateur gun smith’s taking them apart and hurting themselves if still under pressure. He nearly did to himself many years ago, but actually not needed if you know what you are doing. He is willing to email me the sequence of repair when I’m ready to start so I’m must take advantage of this before he is just unable to.
 
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Hi there,

Yes John told me he had an accident, best kept off forum 😚

I have just sent a lengthy pm to your friend with photos and strip down guide....perhaps he could share it with you 👍

Any questions, just shout 🙂

A serious note about the spitty action/ valve stem (that runs full length through the action).

If you were to fill and test the cylinder was sealing/ test the valve seal (by tapping the anvil) WITHOUT the anti bounce device fitted, OR forks screwed into the cylinder, and either the anvil, or poppet were to be poorly fitted/ come loose.....you could basically end up with an extremely high pressure spear gun in your hands. Not good......so go carefull....
 
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Thank you for the note and heads up. Before I do anything I would like to gather up all the info, schematics, drawings and what emails I can get from John to clearly understand and plan what I’m about to do. With your photos and strip down guide plus another gentleman I‘ve spoken to who recently resealed a Firebird I should be ready to do the reseal and service. It’s like they say, the more you do the easier it gets and the better you become
 
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Once you've done it, you'll wonder what all the fuss was about 👍

As far as I know, these unusual rifles must rank as one of the most efficient pcps built.

Following some online calcs (if I'm interpreting them correctly) I get this....

From a 130b fill (pressure relief valve setting), dropping off at 60b (going on dive bottle gauge), at an average of 11.2fpe (keeping within a 20 fps ES) my full length .22 barrelled spitty did 46 shots.

So......

Pressure drop- 70b

Reservoir vol in CI 13.1x70b=917ci

Reservoir vol in CI/ air used in bar-cc- 70bx50cc=3500 bar-cc

16.4cc per CI, so vol in standard CI- 3500/16.4= 213.4ci

Efficiency......

46shots at 11.2fpe gives a total FPE of 515.2.

515/213.4ci= 2.41 fpe per CI.

Would appreciate it if someone else familiar with these cals would go over this to confirm, hopefully its sound, but either way.....its not hard to see and compare to others, that 46 shots from a 50cc reservoir/ 70b range is very impressive 👍
 
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Right, need to make a correction here.....!

John Bowkett has stated the cylinder volume on these is 50cc, but....I've just measured a spare cylinder I have, and with parts in place (valve seat/ inlet body), and allowing for the 4mm valve stem, it actually comes out at 62cc (100mmx27mm, plus a 20x20mm void, minus a 100x4mm stem)

Still small, but does increase the CI to 264, bar-cc to 4340, and reduces efficiency to 1.95fpe per CI.

Still very efficient, but....the 50cc volume thats been spread across forums fr years.....myth busted.
 
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Good morning Jamie. Thank you for all this info and I have put my first Spitfire thru a test shoot and do have some good readings. i will send photos little later today plus the readings. I am very pleased and thankful to have met you in this chat, my Spitfire SF is my very favorite gun and looking forward to having all of them in fine working condition. Regards Colin
 
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