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Shot string plot for FAC Falcon FN19

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Re: Shot string plot for FAC Falcon FN19

Postby 247sniper » Fri Jul 11, 2014 11:08 pm

247sniper wrote:
Shootist wrote:
247sniper wrote:Can you post pictures of the groups with a know reference of an inch or half inch and I can fully analysis the group sizes etc?

Steve.


Too late. The prime purpose of the exercise today was this velocity check. The few targets were also trashed with another rifle checking different pellets.



No probs mate..... Do them again ! :grin:



A good excuse to get our again! :thup:
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Re: Shot string plot for FAC Falcon FN19

Postby leadpig » Fri Jul 11, 2014 11:54 pm

247sniper wrote:
leadpig wrote:agreed i would drop it to around 18/22 fpe and try it again :)



What ?

first post suggested a tiny sweet spot, no mention of 55 yard targets or that the first 25 shots were on target.
a slight drop in fpe can dramatically increase performance and shot count in unregulated guns ;)
Sidebyside wrote:Leadpig is probably right,( though I hate to admit that :mad: ;) ) .


Fenrir wrote:It is often better to let people think you are a bit simple rather than removing all doubt.
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Re: Shot string plot for FAC Falcon FN19

Postby Keef » Sat Jul 12, 2014 9:31 am

247sniper wrote:Like I suggested? ;)


No, what you suggested was to use different fill levels.

What I suggested was to use the same fill level, that would hopefully produce a similar spread of MVs, to check just what difference the fluctuating MV had on point of impact.

A different fill level would change where the "flat" portion on the graph began.

For instance if I fill my unregulated Daystate Huntsman to 190 bar the chrono shows a starting velocity that then climbs over a number of shots to that point where the velocity evens out level if it was plotted on a graph.

If I fill it to 170 bar then the first shot is at the start of that flat area on the graph and I will get 50 shots plus/minus 4fps. After that velocity starts to drop.

What I wanted from Shootist was a real world indication of how the impact point changed when using his current fill pressure and valve opening setting with it's current fluctuations in MV.

Ideally the test should be done bench rested on a sheltered range in calm conditions to eliminate wind effects and Shootist has access to that on his club 50 yard range. (Not withstanding the wind :) )
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Re: Shot string plot for FAC Falcon FN19

Postby Shootist » Sat Jul 12, 2014 9:44 am

This time of year might be good to remove the night sight, which is hardly the best bench rest scope in the world, and give it a go with a more appropriate scope to see the results. Part of the trouble is that the rifle is probably not bench rest accurate, but is more 'minute of bunny bonce'. The point of impact will therefore change somewhat due to pellet variations (I can't be arsed to sort them), and the nut behind the butt. Sounds like a worthy project though.
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Re: Shot string plot for FAC Falcon FN19

Postby Keef » Sat Jul 12, 2014 10:22 am

The first pre charged that I bought was an FN19 and I used it for field target.

It was good for up to 40/45 yards and that was over the knee in all sorts of weather so don't under rate your rifle.

In any case you need to test it with the pellets you will be using against rabbits so that variations in weight and size are in included in the test. This will give you an accurate answer as to what your rifle is capable of even with the MV variations.
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Re: Shot string plot for FAC Falcon FN19

Postby Shootist » Sun Jul 20, 2014 7:48 pm

Good news. I bought some Air Arms Field Heavy. They weigh 18 grains as opposed to the 15 grains of the ordinary AA. The group size halved. I didn't have the chrono handy, and I suppose there would be a bit of a velocity drop, but it's looking very good.
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