NFOA MEMBERS FORUM
General Categories => Hunting and Fishing => Topic started by: Burnsy87 on December 29, 2014, 08:56:14 AM
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I'm math dumb, so forgive me. I have a few AR's I don't necessarily want to use for deer - coyotes are another matter - but I'd just like to know how to calculate that number we need to hit.
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Quick google search this one has a calculator
http://www.pyramydair.com/article/What_is_Muzzle_Energy_August_2003/5 (http://www.pyramydair.com/article/What_is_Muzzle_Energy_August_2003/5)
I know it's for air guns but plug in bullet weight and velocity
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I don't know actual velocity out of different barrel lengths though.
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chrony is the right way or Google will get you close.
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Factory or reloaded ammo?
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I don't know actual velocity out of different barrel lengths though.
WAG time.
Use the velocity from your manual and guesstimate using loss of roughly 35 to 50 FPS for each inch of tube shorter. A chrony will be a lot more useful.
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First, set up a chrony @ 100 yards.
Second, shoot a round through the chrony's measuring area to obtain the bullet's velocity. [Should be No Biggie to cleanly hit through the chrony throat area with a .223 @ 100 yards.]
Third, calculate the kinetic energy.
Using the English system,
Square the velocity. [=velocity "squared"]
Multiply [velocity "squared"] by the bullet weight in grains/7000
Divide by 32
Result will be ft-lb of energy at 100 yards. (Must be at least 900 ft-lbs to be legal in NE for deer. Usta say "factory ammo only"; FWIW, no longer so says.)
Or just post your 100-yard velocity in ft./sec. right here on the Forum and we'll crank out the ME for you.
Important Rules:
1. Do Not Shoot the Chrony.
2. Do Not Loan Your Chrony to a Bad Shooter.
3. If You Do Loan Your Chrony, Get Some Kind of Tangible Cash Security First.
sfg
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First, set up a chrony @ 100 yards.
Second, shoot a round through the chrony's measuring area to obtain the bullet's velocity. [Should be No Biggie to cleanly hit through the chrony throat area with a .223 @ 100 yards.]
Third, calculate the kinetic energy.
Using the English system,
Square the velocity. [=velocity "squared"]
Multiply [velocity "squared"] by the bullet weight in grains/7000
Divide by 64
Result will be ft-lb of energy at 100 yards. (Must be at least 900 ft-lbs to be legal in NE for deer. Usta say "factory ammo only"; FWIW, no longer so says.)
Or just post your 100-yard velocity in ft./sec. right here on the Forum and we'll crank out the ME for you.
Important Rules:
1. Do Not Shoot the Chrony.
2. Do Not Loan Your Chrony to a Bad Shooter.
3. If You Do Loan Your Chrony, Get Some Kind of Tangible Security First.
sfg
Laffin big time here. Your drops will be all wrong as most if not all ballistics charts run off muzzle velocity measured 10 feet from the muzzle.
OP if you want shoot me a PM and if you want to come to lincoln I will take you out to Ike's and set up my Oehler and calculate drops and energy before you go home.
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From here: http://www.winchester.com/Products/rifle-ammunition/Performance/Super-X-rifle/Pages/X223R2.aspx (http://www.winchester.com/Products/rifle-ammunition/Performance/Super-X-rifle/Pages/X223R2.aspx)
Winchester 64gr. SuperX power point. Most commonly accepted ammo as being suitable and legal for deer in Nebraska.
RIFLE BALLISTICS
DISTANCE(YDS) VELOCITY(FPS) ENERGY(FT.LBS.) TRAJ.SHORT TRAJ.LONG
Muzzle 3020 1296
50 0.1-0.2
100 2656 1003 0 1.7
200 2320 765 -3.5 0
300 2009 574 -13.4 -8.2
400 1724 423 -32.1 -25.1
500 1473 308 -53.6
This should give you a general idea of what kind of muzzle velocity you'll need in order to get a certain muzzle energy farther downrange.
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You aren't gonna get 3020 w/64 gr bullet out of a short AR, that's the ballistics from winny w/24 inch tube.
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Exactly what I'm saying. I don't like long barrel AR's. I got a basic 16" and an SBR.
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you aren't going to get there with a 223 sbr. invest in a different caliber. an 8" 300blk or a short 6.8 spc will make the necessary power.
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300 Whisper is a good round. Seen good things lately at the 300 yard line out of the 6.8.
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Eh I don't have the time for reloading and I don't want to pay that much for ammo.. I shoot my firearms a lot, cheap plinkin ammo is high on my 'importance' list.
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Take a look at the 7.62 x 39 AR's. When you are just blasting use the cheap FMJ and for hunting use the Hornady SST loads.
John K
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My 16" 223 upper got 930-ish ft\lbs when i chronied it with 55gr hornady amax.
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I'm a TSX guy, got some 50 and 70 gr.. 70gr quotes 2800 out of a 20" barrel
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I'm a TSX guy, got some 50 and 70 gr.. 70gr quotes 2800 out of a 20" barrel
I forgot to mention my rounds are factory loaded, also the box says 3240fps. If you know your velocity and bulet weight you should be able to calculate it.
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55gr good enough for larger game?
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55gr good enough for larger game?
Its legal yes, but is it best? Prolly not. Spot placement is key. And no long shots.
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Fair enough. I just would prefer 70gr.
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Since the Ft/Lb @ 100 yards is generally a hunting requirement in NE. I am going to ask...how does the DNR decide?
For instance...you are hunting with your AR....stopped by DNR...you show them the box your ammo came from...how do they deside you have the proper ammo to make the foot/pounds?
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^ Yeah that's a good question
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I would say you wouldn't get picked up for this unless your have a mall cop dnr guy or they are stacking charges on you.....
If they wanted to question your loads they would have to do the same method as we are disscusing. Set a crono have you shoot through it and calculate it out. There are way to many variables just base things off of calculations of boxed ammo. Barrel material, rifling, and coatings all make a difference in velocity.
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If they wanted to question your loads they would have to do the same method as we are disscusing.
That is basically what I was referring to with my questions. The DNR sets a regulation, but doesn't specify the method of verification. Most likely you could be charged and would have the burden of proof in your defense. A classic case of too much law.
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That is basically what I was referring to with my questions. The DNR sets a regulation, but doesn't specify the method of verification. Most likely you could be charged and would have the burden of proof in your defense. A classic case of too much law.
That's a lot of speculation.
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That's a lot of speculation.
Can you show me how the DNR determines the ft/lb requirement is met in any given circumstance?
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I cannot. That's why Im not speculating.
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has anyone emailed or called them yet to find out? im pretty sure they will be open tomorrow.
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It looks like a job for "My Personal Radar".
http://mylabradar.com (http://mylabradar.com)
(http://mylabradar.com/images/radar.jpg)
Never have to set the chrono up, shoot at it (or in some cases actually shoot it), and then tear it down. Get the muzzle velocity at any distance up to 100 yards. Day, night, indoor, or outside.
Fly
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has anyone emailed or called them yet to find out? im pretty sure they will be open tomorrow.
Just called NG&P and spoke with the law enforcement division. They said they DO NOT travel with cornos and as far as the gentlemen knew it would be handled on a case by case bases. He said he has never had encounter with a officer questioning the FT/LB reg. He said most of the time the specification is used to insure that people are using the proper caliber.
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Just called NG&P and spoke with the law enforcement division. They said they DO NOT travel with cornos and as far as the gentlemen knew it would be handled on a case by case bases. He said he has never had encounter with a officer questioning the FT/LB reg. He said most of the time the specification is used to insure that people are using the proper caliber.
thanks. i was going to call, but forgot. i figured as much.
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Bringing back from the dead, sorry admin/mods.
Came across https://billstclair.com/energy.html (https://billstclair.com/energy.html) today. Can anybody find serious discrepancies with the formula?
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Bringing back from the dead, sorry admin/mods.
Came across https://billstclair.com/energy.html (https://billstclair.com/energy.html) today. Can anybody find serious discrepancies with the formula?
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Just screwing around. Took 200 fps off, though that's not accurate, I don't know what Black Hills uses for a barrel length for their printed FPS. But it gave me the required energy at 100, so I'm assuming it's a 24" barrel instead of 20" they use that I assumed.
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Agreed, most use 24" to test fps and calculate for Ft #'s I'd probably use a 62-79 gr. soft point to hunt med game. Should be no problem.
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Talked to Black Hills (through Facebook, of all things... blown away it worked, and they responded so quickly)
.223 is out of a 24" barrel
5.56 is out of a 20" barrel
According to that website, 5.56 62gr TSX is good to go. I still want to chrono though.
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Talked to Black Hills (through Facebook, of all things... blown away it worked, and they responded so quickly)
.223 is out of a 24" barrel
5.56 is out of a 20" barrel
According to that website, 5.56 62gr TSX is good to go. I still want to chrono though.
Interesting. Although I am still a neophyte with regard to the difference, I would not have thought they would have a 4" barrel difference. Can anybody with more knowledge explain that to me?
Thank you in advance.
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My best guess is the difference between military and civilian ammo specifications.
From what I have seen/read the standard length barrel is used to test most civilian/commercial ammo is 24 inches for rifles. This relates to the barrel length of most bolt action hunting rifles.
For military ammunition what is used is the barrel length of the standard service rifle which for years has been the M-16 with a 20 inch barrel. Most of the reloading manuals that list the 5.56 separate from the .223 also state that a AR-15 with a 20 inch barrel was used for testing.
When the military orders ammo, it will specify a bullet weight and velocity for the ammo along with a minimum accuracy level and the weapon it is going to be fired from. I have attached a couple of pages from military manuals that show this.
John K
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Your explanation certainly makes sense based on what I know from being around the military and friends who get to hunt. Thanks for the info.
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Black Hills Ammunition just got back to me, out of a 16" barrel, their 5.56 62gr TSX has ~916 ft/lbs at 100 yards. Plus I'll have a suppressor that should (theoretically) boost that number slightly. Same ammo out of a 20" should have 983 ft/lbs. at 100.
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Black Hills Ammunition just got back to me, out of a 16" barrel, their 5.56 62gr TSX has ~916 ft/lbs at 100 yards. Plus I'll have a suppressor that should (theoretically) boost that number slightly. Same ammo out of a 20" should have 983 ft/lbs. at 100.
Ok, good. Still no problem meeting Game and Parks minimum (Anything from 62-79gr will work). Let us know after you've had a chance to test it.
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Black Hills Ammunition just got back to me, out of a 16" barrel, their 5.56 62gr TSX has ~916 ft/lbs at 100 yards. Plus I'll have a suppressor that should (theoretically) boost that number slightly. Same ammo out of a 20" should have 983 ft/lbs. at 100.
Was there a velocity specified or did I miss that? I am about to work up a load with this 62gr TSX and I am shooting for 3000 fps which is a max load with TAC
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5.56 62gr TSX
16" Barrel: At 100 yards, 2,580 FPS, 916 ft/lbs
20" Barrel: At 100 yards, 2,673 FPS, 983 ft/lbs