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Old 3rd April 2015, 08:53 AM
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Brian.Samson Brian.Samson is offline
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Join Date: Jun 2009
Member of: Pontefract, Doncaster Airgun Range
Location: Doncaster
Posts: 2,335

Originally Posted by mustad View Post
lot to take in at this game lol,cant believe different pellets from same brand,head size, down to dies.
There's got to be at least 50 different dies used for JSB Exacts and the re-branded versions (AA Field etc), some of the dies are very very similar (you'd be hard pressed to see any difference on visual inspection)

Now you might think it doesn't make much difference, and in truth it doesn't make a massive difference on the face of it.

To give you an idea, the difference between a good die and a bad die might mean your group size increases by ½ MoA (at a guess)

To put that into perspective, ½ MoA is 5mm at 35 yards and about 8mm at 55yards.

If you're a hunter and you zero at 35 yards, even a bad die is going to put in a pretty decent group.
If you're a target shooter who's able to shoot a ½MoA group at 50 yards (7mm) which takes some doing! Then you'll notice the difference in grouping between a good die and a bad die quite easily.

If however you can't shoot sub MoA groups at 50 yards, then it'll be much harder to spot a good die from a bad die.

When you consider that most people don't have a 55 yard indoor range and a bench to rest their gun on, it's easy to think that a shot that lands outside a tight group was down to a wobble or a bit of wind - but it could have been down to the fact you're using a bad die.

If you also have access to a downrange chrono set up at 50-55 yards and a chrono at the muzzle, you can measure how efficient the die of pellet is.

A more efficient pellet will also theoretically take less wind (according to the ballistic calculation for wind drift).

All of that might sound like mumbo-jumbo and what does it really matter?

Well... if you can find a pellet that will reduce your group by ½MoA and is better in the wind, then you will get on average an extra half a kill of leeway for guessing the wind wrong.

I can prove that with some maths, and I can also give you a practical demonstration of that with my little wind training game

Of course that all relies on whether you believe 200+ years of exterior ballistic theory or not
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