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Recoil project

Old 03-20-2006, 07:50 PM
  #1  
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Default Recoil project

hey for an upcoming science fair i was thinking of doing an experiment on felt recoil in slugs. i have decided id go with all remington slugs for the test at least to begin so that they are in a nut shell the same tho different types. im going to use regular rifled, high vel. rifled, and reduced rifled. but my question is does anyone really know a good way of testing the difference? What i have come up with so far is to take a piece of styrofoam and place it between my shoulder and the gun butt. will this work or do i need to change it? and if so either way what are different ways to do it and/or improve it? i think in the begining ill only stick to one brand but if i get it to work well and the shoulder can take it i may try federals or win or someothers. any comments or ideas very much appreciated!
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Old 03-22-2006, 01:28 PM
  #2  
Typical Buck
 
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Default RE: Recoil project

Not very scientific and I don't really think you will be able to tell from looking at styrofoam
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Old 03-22-2006, 06:59 PM
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Default RE: Recoil project

dvd is right, it's not very scientific. Recoil can actually be calculated using this mathematical formula.

CALCULATING FREE RECOIL
The most practical measurement for us is free recoil energy in foot-pounds. To find this you must know the weights of gun, bullet and charge and the velocity of the bullet. The three step calculations (taken from The NRA Firearms Fact Book) are:
1. I = (WB x VB + 4,000 x WC) / 225,400
I = Recoil Impulse
WB = weight bullet (grains)
VB = velocity bullet (fps)
WC = weight charge (grains)
4,000 = assumed velocity of charge in fps
225,400 = constant to adjust units

2.VG = 32.2 x I / WG
VG = velocity gun (fps)
32.2 = gravity
WG = weight gun (lbs)

3. EG = WG x VG squared / 64.4 (2g)
EG = free recoil energy (ft/lb)
VG = velocity of gun (fps)
64.4 = 2g (acceleration of gravity)
To make these calculations all you need are accurate scales (for both pounds and grains) and a chronograph.

If you do your experiment as you have described, you will have too many variables and you will not have very good control. Sorry to burst your bubble. But if you have accurate scales and a chronograph, you could do your experiment based around this formula. Just be sure to use the same gun every time and minimize your number of variables by cleaning your barrel after every shot, shooting at the same elevation every time, and make sure the weather is always the same (i.e. wind, barometric pressure).
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Old 03-22-2006, 07:05 PM
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Default RE: Recoil project

The judges will be impressed with the number cruntching too.
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Old 03-22-2006, 09:40 PM
  #5  
Nontypical Buck
 
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Default RE: Recoil project

Do you think a bow draw weight gauge would work? It probably could be rigged up somehow---???
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Old 03-22-2006, 09:52 PM
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Default RE: Recoil project

hey guys first off thanks for the advice. i refined my strategy a bit and made a rest from 2x6's andgot a box of potters type clay instead of stryofoam. for this year i was going for the idea of felt recoil. last year i did velocity with a chrony and all the things to go with it and found that what they put on the box of shells isnt always very true. i know there are some variable in that too but some still kind of amaze me. i am still working on ideas for my felt recoil test but if you have any other ideas...they would be helpful. my science teacher is amazed that every year since 3rd grade ive been able to come up with a hunting/gun related project. o well i guess ill keep her guessing for next year eh. lol thanks again
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Old 03-30-2006, 04:30 AM
  #7  
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Default RE: Recoil project

Doesn’t felt recoil have a lot to do with gun fit to the shoulder. How about the shape of the rifle? I have shot some lighter caliber rifles that kicked hard and some larger caliber rifles that I don’t hardly notice the kick. My BP inline with 100grains of pyro hardly kicks. My Kentucky long rifle with 70 grains pyro kicks like a mule and its much heavier!!
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Old 03-30-2006, 10:37 AM
  #8  
Fork Horn
 
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Default RE: Recoil project

Recoil energy and felt recoil are really not the same things. Yes, felt recoil has a lot to do with stock configuration and fit (inline vs. drop stock on KY. rifle). I once built a trap gun with almost a1" inch high rib and then matched the cheekpiece to be in line with the rib. With a good shooting stance more recoil was sent straight back to your shoulder and you were able to track birds better and shoot longer with less fatigue (I shot about 5,000 targets per year). In fact Mossberg had done this same thing with their Model 500 trap gun in the 80's.
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Old 03-30-2006, 03:07 PM
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Default RE: Recoil project

Put the rifle in a rest and put the butt against an object of a specific weight. Put the weight on something that will roll or slide. Fire the rifle and measure the amount it moved the object backwards. This may not tell you exactly how much recoil the weapon has, but it will give you a comparison between the different loads as long as the same weight object is used in each test.

This isn't real scientific since there are quite a few variables and things to take acount for like friction and stuff like that. However it should make a decent presentation for a highschool project.

You could also do the math shown above and estimate how far the object should move in theory and compare it to what it does in real life. You may have to take into acount for the weight of the rifle as well. Maybe even the rest depending on how much it restricts the movement of the rifle.

Paul
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Old 03-30-2006, 04:04 PM
  #10  
Fork Horn
 
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Default RE: Recoil project

Actually I just found out there is a way to measure felt recoil. Load force makes a system that connects to your PC and to a pressure switch on a block between your shoulder and the gunstock and will calculate the recoil when you fire, it's called Loadforce-250. All this for only $499.00 and you to can find out why a 3 1/2" mag w/heavi-shot kicks the crap out of you.
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