Author Topic: Re: The magic numbers = 12ftlb  (Read 5829 times)

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Offline foxabilo

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Re: The magic numbers = 12ftlb
« Reply #10 on: January 22, 2012, 01:40:53 AM »
that's near enough what i said and was getting at ;)  :P ;D http://planetairgun.com/index.php?topic=686.msg5339#msg5339

Ohhh yea sorry to paraphrase your post, You musta done maths and physics too! but you got the mass with springers mixed up with C02, i.e there exactly opposite to what you said. Springers loose KE with heavy pellets C02/pcp gain it, not the other way around, you said to use light pellets in springers , I think you meant heavy :)

Fox

« Last Edit: January 22, 2012, 01:46:36 AM by foxabilo »

Offline sme4969

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Re: The magic numbers = 12ftlb
« Reply #11 on: January 22, 2012, 07:51:09 PM »
that's near enough what i said and was getting at ;)  :P ;D http://planetairgun.com/index.php?topic=686.msg5339#msg5339

Ohhh yea sorry to paraphrase your post, You musta done maths and physics too! but you got the mass with springers mixed up with C02, i.e there exactly opposite to what you said. Springers loose KE with heavy pellets C02/pcp gain it, not the other way around, you said to use light pellets in springers , I think you meant heavy :)

Fox
i think you'll find i got it correct ;);):)

Muzzle energy tells the whole story!
Muzzle energy, however, is the combination of both velocity and the weight of the projectile. Because we know the general span of pellet weights for each caliber, muzzle energy clues us into BOTH pellet weight and velocity at the same time. Knowing the performance of the various powerplants (i.e., spring guns favour light pellets, PCPs and CO2 guns like heavy pellets) allows us to quickly determine the gun's performance range with all types of ammunition.this is becuase a springer has to work harder to push a heavier pellet than a ligheter one ;)
« Last Edit: January 22, 2012, 07:57:39 PM by sme4969 »
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Offline Ieazo

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Re: The magic numbers = 12ftlb
« Reply #12 on: January 22, 2012, 07:52:17 PM »
Heavier pellets in pcp and lighter pellets in springers as a general rule of thumb for best results.
Springers:- SMK VXS19 - 18 GRT3 trigger & HW97k V-Glide
PCP's:- Uncle Barry's Daystate Mk3 (FAC), BSA Superten & AA S510
FAC :- Anschutz 1417 .22LR, CZ 452 .17HMR & Tikka T3 .223 1:8
Shotguns:- 12 Gauge Bettinsoli Xtrail O/U & Beretta A302 Semi-Auto

Offline Wildman

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Re: Re: The magic numbers = 12ftlb
« Reply #13 on: August 08, 2012, 08:13:56 PM »
Just to correct some mathematical and physics and general errors in some of the replys in this section,

Look I dont want to come off as some smarty pants maths dude.... but erm.. thats what I am, so here goes


An Air gun taken as a perfect system with no friction recoil energy loss or anything will output the same KE /ft/lb no matter what grain pellet you put in it. F=MA the F being the result, A is the acceleration which would be how much gas/spring power you have.
(technically A= is a time function and has to be integrated  as a large group of changing values under one umbrella, as the gas expands for a set time and the spring expands for a set time, but for arguments sake lets say these events are instant)
OK

So in a perfect world 10ft/lb with 10grs would give a certain speed and 10fl/lb with 20 grains would be half the speed but carry the same KE.

But its not a perfect world, a C02/Pressure air gun will typically deliver the same energy output to any weight of pellet, so a fat boy 20 grain would kick ass and may be over the limit, hard to do with c02 unless you tune them.

Sringers have a different reaction as they recoil they build up gass pressure and the mass of the pellet has a direct relationship to the "echo" wave sent back to the piston as it moves, so a heavy pellet in a springer will result in a lower FPS and therefore a lower ft/lb rating , a lighter pellet will effect the spring less and give you a faster FPS giving a higher ft/lb reading.


e.g my tuned c02 78 gives 11.26ftlb with 14.66 grains thats calculated by the chrono v4. with a 19.2 grain Riono @ 530 fps, its 11.98 Ft/lb.. (wheeew) lucky huh! , PCP/C02 will go up in power as grain gets larger, Springers will go down in power. just to add to the confusion this is all @ 14 centigrade, as the temp goes down c02 power goes down and as it goes up so the power goes up. @40c a UK tunned c02 with a heavy pellet (20 grain) will almost always be over 12ft/lb

Untunned the UK C02 might actually knock a bottle over @40c

Ta for listerning

I await the onslaught
sometimes its nice to have a smart arse amoung us, hee hee
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Offline 21grains

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Re: The magic numbers = 12ftlb
« Reply #14 on: November 19, 2015, 02:53:22 PM »
What about Head size..... 5,52 Cuda's are faster (more flb) than 5,53 Cuda's of the same Weight in My M-Rod PCP. What Head Size does the Man use to test Your Gun at the Police Station.....Very Ambiguous, PCP Vs Springer. Do they test your Gun with every Pellet in every Weight and in every Head Size,till They get You???.....Franky

Offline Gambo

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Re: The magic numbers = 12ftlb
« Reply #15 on: November 19, 2015, 03:01:10 PM »
Nope, they can test your airgun with whatever pellets they choose.

As you say, it's a very open ended grey area, just as much of the laws in this country are. Maybe I'm being sceptical here, but I believe a lot of laws are purposely like that, to allow 'flexibility' on the side of the prosecutor. :(

Offline 21grains

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Re: The magic numbers = 12ftlb
« Reply #16 on: November 19, 2015, 11:41:00 PM »
So There plain is to make it ease'er for the Man to get You and Fine You to Pad There Lauder and Life Style. Thank God for the 2nd Amendment in the USofA. I Pray every Nite for You Guy's & Gal's in the UK.....Respectfully Franky

Offline Gambo

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Re: The magic numbers = 12ftlb
« Reply #17 on: November 20, 2015, 02:00:43 PM »
Thank you Sir. ;)

Offline 21grains

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Re: The magic numbers = 12ftlb
« Reply #18 on: January 20, 2016, 08:02:26 PM »
Is it the Magic Number's, or the Tragic Number's better Said.....Franky

Offline seagate

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Re: The magic numbers = 12ftlb
« Reply #19 on: January 20, 2016, 09:24:50 PM »

   

  ::) Don't hold back, say what you mean. 



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