Bowkett supertune

På Bowketts fansida så presenteras idag innebörden av Bowketts "Supertune" och dessutom en hel del spännande bakgrundshistorik runt den klassiska SuperTen. Ordet går nu över till JB himself:

The FAC/Export Blueprint Tune differs from the non FAC one in as much as part of the regulator is replaced with another of my design. Approximately sixteen years ago when I was asked to assist in bringing BSA Guns UK Ltd into the world of PCPs the first model I worked on was the S10. The UK 12ft/lbs version had a different regulator from the Export/FAC version. After barely six months production it was decided by those in charge of production to use the 12ft/lbs regulator on all versions.

This meant that the high power S10s had a regulator pressure setting at about the maximum for its design when set at 28ft/lbs in .22” using a heavy pellet. At that setting the regulator is on the borderline of not working at all. Over the years I have carried out many hundreds of FAC Blueprints but I use a regulator which is capable of working at far higher pressures than required and usually set the velocity with 16g pellet at 910fps unless asked to set higher. Using heavier pellets will give more energy. It therefore is working in a relaxed manner which is better for both mechanisms and humans! From the feedback I get through owners of my FAC Blueprint Tuned rifles that decision, and others based on similar production ideology, to use and continue using an overstressed regulator killed off the export demand for the S10 before it even got going. It could have been a huge seller with its superb trigger and a barrel capable of unsurpassed accuracy in .22” calibre. Now out of production for several years the Super Ten is still much in demand but with the passage of time and curious hands there are quite a number of bodged up examples on the market – so beware!

The Blueprint Tune on all versions of the S10 is not just a quick service but includes hand/custom work that is outside the realm of production in addition to a number of modifications that for a variety of reasons were never included in factory rifles. These all vastly improve the performance and reliability. This is the reason I can have confidence in offering a guarantee on a Blueprint Tuned S10 providing it hasn’t been taken apart or abused in an out of the normal way.

All Blueprint Tuned rifles are tested for accuracy at 50 yards with a variety of easily available pellets. The target sheet supplied acts as a guide to steer the shooter in the right direction without having to buy many different tins of expensive pellets only to find they wont perform in their particular air rifle. BSA produce some fine .22” calibre barrels which, providing they have been machined with the choke on the muzzle end, are capable of consistent accuracy at both FAC and non-FAC power levels that cannot be beaten. I usually test with four or five different brands of pellets and it is a rare occasion when any of these give poor results. The shorter barrels can be the little more pellet fussy of the two but nothing to worry about.

The smaller calibre barrels are however a different kettle of fish. I usually test these with anything up to six types of pellets to find a light, medium and heavy pellet that gives good accuracy. More often than not only heavy pellets will work well restricting the choice for accuracy. This is not a problem for hunters, informal target shooters and plinkers but can be a real problem for anyone seriously considering taking up HFT or FT shooting with an air rifle dedicated to that task. The carbine barrels can be even more pellet fussy in .177”. The smaller calibre BSA barrels vary so much batch to batch but on rare occasions one can be found that produces exceptional accuracy with a lightweight (7.9g Crosman Accupell type) and medium weight (H&N Field Target Trophy) pellets in addition to the normal heavyweights. Recently I have been having a degree of success with JSB Exact in 4.53” head size as a medium weight option but this again is not always the case.

The cost of the Blueprint Tune includes all spares required unless someone has sawn the barrel in half or it needs a new trigger fitted to work correctly with safety. Pretty much everything else is included. Many new non-factory parts are fitted that I have developed over the years and make for each rifle on an individual basis. Starting at the top:-
The barrel is removed, the breech end is modified to improve flow and also to allow smooth pellet feeding into the rifling. The transfer port recess is cleaned up if it has been damaged by past incorrect assembly. The barrel can be threaded ½” UNF for a silencer if required but this is at extra cost. The muzzle end of the barrel is crowned correctly so that the fragile pellet leaves the rifling evenly around its circumference and without being damaged.
The bolt has all its sharp edges removed and is polished for smoother operation. The bolt nose is modified at the same time.

The buddy bottle valve assembly is removed, the valve seat refaced and the valve machined to work in the way I designed it and to the correct dimensions. The probe on the “cigar” was designed in such a way that the bottle O ring is protected by being fully enclosed at the point when the valve is opened. The bottle can then be screwed on further until metal to metal is felt and then backed off 1/8th turn. BSA modified the valve to suit the Spitfire, instead of making the Spit. to suit the standard bottle. It never got back to the way it should be after the Spitfire went out of production! The Blueprint Tune corrects this problem making changing bottles less of a chore.

The bottle O ring is replaced with a longlasting one of mine that I have been using for 15+ years. Lubrication should be with a drop of Abbey SM50 or Bisley Gun Lubricant both of which are a silicone/moly liquid mix that is good for both O ring and bottle/socket brass components. Other greases may cause damage when they migrate to where they are not supposed to.

The “cigar”. This was the name given to the regulator/valve/anti-bounce unit which I designed to be easily removed from the S10 by an owner if required. He could get it serviced by the factory or a distributor who would send him an exchange unit to fit. The same idea, but even more simple using one large caphead screw instead of four small, is also in the R10 where the regulator block complete can be removed without stripping the rifle down. I match the probe to the bottle or bottles.

I then machine and fit a different valve from the high to the low pressure side of the reg. The factory ones give problems. I have been fitting mine to blueprints since the early 2000s. The factory PTFE rings fitted to replace the original poor quality poly. ones work fine initially but as PTFE has no memory, are not elastic, they will close up in time giving flow problems. I finally got my modified valve in production with the late Mk1 and the Mk2 R10 long after the S10 and Hornet were obsolete.

The regulator piston is modified and fitted with back up rings made of a different material and to suit the individual honed cylinder they run in. The regulator pressure is set to match the rifle as an individual and as low as possible. This avoids problems when the S10 comes off the reg.

The exhaust valve seat is refaced, valve replaced where necessary and set to the correct dimensions. The valve stem recess machined and seal altered.

The anti-bounce unit is honed and set up to work correctly.

The trigger unit is set and slightly modified to give a better feel.

The hammer spring is replaced and balanced with specially made shims to exactly match the reg. pressure of your rifle and the spring guide itself modified so that the detent ball locates better in the bolt.

After the tune is completed but before velocity is finally set your S10 is shot for accuracy as previously described. Shot count after a Blueprint Tune varies from rifle to rifle but experience has shown that from a full fill of 232 bars in rifle form expect 240-250 good shots in 22”, 200-210 in .177” with carbine versions giving 170-180 and 100-110 respectively.

Cost for the 12 ft/lbs Blueprint Tune as from 1/4/2012 is £125, barrel threading £20, large ball handle bolt ( about 1¼”diameter with a band of knurling) £25, lightweight regulator body and bolt £85. All of these prices are subject to VAT at 20%. Return postage, if required is £23 Special Delivery service which is the only way I post air rifles/pistols. A popular modification over the last year or so has been fitting the S10 with a barrel between the length of the carbine and the rifle so giving better shot count than the short 10 ½” barrel versions but keeping it quite short with the threaded barrel ending flush with the 200cc buddy bottle. FAC Blueprint Tuned S10s are usually set at 900fps using a 16g pellet but can be higher/lower if required . The standard FAC Blueprint Tune is £150 +VAT including the special regulator. Phone for more details and prices of longer/shorter barrels.

 

Johan

20 mars 2012 20:11

Finns det någon som tunar FX bössor i Sverige?

http://www.skyddsjakt.n.nu

Johnny Ottosson

20 mars 2012 22:13

Inte som jag känner till.

Tror det är svårt att hitta behovet också..

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