kas suprantat angliskai B2 tuningas
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Hi Amsniper, I see you too are interested in the amazing B2. I published a tuning guide on another BBS some time ago, I've reproduced it here confident that it will be absolutely no use to you whatsoever. Do Not take anything in it seriously.
Part 1
I have solved the problem of bending barrels when super strong motorcycle springs are fitted. Cut two lengths of 25mm angle iron and position them so they clamp the barrel between them, them arc weld along the joints. There will be gaps between the iron and the barrel at both ends, this is a bad thing because moisture can get in here and cause rust, so hammer the gaps closed and weld the gaps shut.
The effect is to give your B2 a pleasingly angular "Stealth Bomber" appearance, with the added bonus that your rifle becomes almost invisible to Rabbits and Pigeons.
I've personally used this with springs up to GSXR600 and it works a treat in both .177 and .22, with a very flat trajectory out to 400 metres.
Part 2
Hi again B2 fans.
After last months succesfull reinforcement of the barrel and installation of the Suzuki GSXR600 spring, I have turned my attention to the ever present problem of dieselling.
As some of you may know from experience with cars, the highest performance engines use petrol rather than diesel, so this month I have converted my B2 to run on Super Unleaded. There were initially two aims, better performance and cleaner emissions, but an unexpected benefit arose during testing, more of which later.
First a bit of theory. Diesel engines work on a principal called compression ignition where the air is compressed to a point that its' temperature is high enough to ignite the fuel - this makes it ideal for a simple air rifle installation but the specific energy of diesel fuel is lower than more refined petroleum products. In order to convert the B2 to use petrol a spark ignition device must be fitted, I did this by drilling a hole from the top of the rifle into the transfer port, and tapping the hole to take a small 6mm motorcycle spark plug, the tip of the plug must JUST protrude into the transfer port. Now you need a method of generating a spark at the correct time, this caused me a lot of hard thought and I considered using a car electronic ingnition module, however the complexity of the system and the weight of the car battery were obviously going to cause problems in the field, so I hit upon a simple and elegant solution. I used the piezo crystal from a common electronic cigarette lighter ! This is so easy, place the crystal between a small block of steel that is fixed to the cylinder near the spark plug and another block that is free to slide and is wired to the spark plug. Upon firing the piston hits the end of the cylinder and the shock wave creates the spark in the piezo. Bingo - reliable ignition with no timing problems. I was pleased with this one. Fueling is currently taken care of by a model aircraft engine carburettor and a valve arrangement, I won't go into too much detail as this is the next upgrade
Next month - I fit fuel injection, and more about the "unexpected benefit"
Keep B2ing
Part 3
Well done for mentioning the safety aspect, naturally all my work is done in the safety of a fully equipped shed, complete with lights for working in the evening. No gases should be used in an air rifle, my rule is if I won't put it in my engine it can't go in my B2. I formulated this rule after blowing the engine in my car and the tip off my little finger in one week (Nitrous Oxide is not suitable for CO2 air pistols or Fiat Pandas).
Recently, I've been reading the other BBS quite a lot, and the general opinion is that the consistent 147ft/lbs I'm now getting is adequate for a clean kill on any quarry up to grey squirrel, so I've decided to concentrate on improving the accuracy on my B2.
Difficult, I hear you say, and you're correct - "the B2 is capable of astonishing accuracy straight out of the box, it rivals many so called FT rigs...." to quote a famous publication. However, as with any factory produced rifle no matter how good the quality control, there are a few rough edges that can be smoothed to give the performance that only a custom rifle can give. I'll start with a barrel crown job, to make the most of the Lotharee Walthong barrel.
First a bit of theory. The flight of the classsic Diabolo pellet is largely stabilised by the tail of the pellet, this needs to exit the barrel exactly square in order that there is no "wobble" in the pellet, which can cause a lower ballistic coefficient and hence alter the trajectory of the pellet. This is especially important when the pellet is travelling at the 3700fps (.22) easily achievable from a tuned B2. What is needed is a totally square end to the barrel, and I have devised a simple and effective way of achieveing this. I have a fully equipped workshop shed including an electric drill, (if you don't have your own they can be hired very reasonably) ,you will also need a good sized drill bit of 1/2 " or larger and some wooden packing pieces. The technique is simple but must be followed exactly:-
Lay the electric drill with drill bit fitted on a flat surface (a table will do, the lawn won't) and measure the distance between the point of the drill and the surface. The next task is to rest the barrel of your rifle on some blocks so that the centre line of the barrel is the same height - a little bit of mathematics can help here, measure the height to the top of the barrel, subtract the height to the bottom of the barrel, divide the difference by two and add it to the bottom of the barrel, this will give you the exact centre height, essential for accuracy. Next switch the drill on to a medium speed and simply slide it into the opening of the barrel for a few seconds. Job done, and a perfectly "Crowned" barrel.
Results:
Well, it was always going to be hard to improve on the country that invented gunpowder, but I think you'll agree this mod is worth the effort. On initial testing I am getting groups better than 3" at 25 Yards with only the occasional flyer !!!! Pretty remarkable for a springer, and measurably better than the already excellent accuracy of the standard gun.
Altogether a recommended modification if you are serious about your hunting or considering top flight competition.
Brian
Part 4
Hi B2 Fans,
I hope you've all had fun with the modifications in this series so far, I'm so glad that Banned put me in touch with Chinese engineering, I'll admit I was a bit stuck in a rut of British and German rifles before - how blinkered can you be ? As many of you have discovered, the B2 can be the equal of any production rifle with a few inexpensive modifications, as have been covered earlier.
It was great to see the B2 doing so well in the World Field Target Championships last weekend, especially as the B2 is primarily a high class hunting weapon, but I was upset at some of the protests from other factories, there was no contravention of the rules - I'll say this once to clarify THERE IS NOTHING IN THE FT OR HFT RULES THAT SAYS THE BARREL HAS TO BE STRAIGHT.
Now it's all out in the open I can reveal the secret behind the Chinese factory teams seemingly amazing rangefinding.
But first some theory.
The range finding of a target rifle is mainly concerned with the relationship between the "Sight Line" (the straight line the telescopic sight sees) and the "Trajectory" (the curved rainbow path the pellet travels). On a correctly adjusted conventional rifle the two "lines" will intersect at two points, typically 12 and 35 metres, and the sights will be "on" at these two distances. Of course the greater the distance between the "lines" the greater the inaccuracy at any given distance.
So much for the theory, what is the secret of the amazingly flat trajectory of the B2, well, there is none. That's right, the FT rules mean that the power has to be turned right down to 12Ft/Lbs so the trajectory is the same as any other manufacturer, this is when the Chinese thought a little differently. What if the scope line of sight could be brought closer to the pellet trajectory ? This would make rangefinding less important, as there would be less hold-under/hold-over required. Enter the Corrected Range Automatic Pellet Position barrel, basically a precision barrel that has its' centre line modified to be inline with the scope centre line. To simplify, the barrel is "bent" downwards so that the scope looks down the line of the end of the barrel and the pellet exits exactly on line with the scope sight line, genius. The results are amazing, you can be within 0.5 inches of scope zero from 0-55 yards, and for you hunters there is good news too, from 10-45 yards you are within the 1/16 inch kill zone required by all humane hunters nowadays.
Good news all round, except for manufacturers of PCP rifles whose air reservoirs preclude them from using the CRAPP barrel, no wonder the protested so loudly at the World Championships.
Keep B2ing
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