PDA

View Full Version : 4000day old post

mikthestick
March 14, 2012, 06:28 PM
Found this old post leads me to believe few people who shoot understand recoil. Too many who shoot think they understand and don't.

1. Recoil is usually measured in ft/lbs 10ft/lbs would hurt you like if I dropped 1lb on your shoulder from a height of 10 feet.
FREE RECOIL is the energy the weapon develops if it were balanced on strings and allowed to jump back when the gun goes off. This energy is about 15ft/lbs for a WW2 rifle or 30 ft/lbs for a 12 gauge shotgun.
There are at least 2 formulas I know which calculate the recoil speed I'll use the one for modern powder. A US M1 weighs about 9lbs fires a 150gr bullet at 2800ft/sec with about 50gr of propellent.

(150 x2800) + (4700 x 50)
_______________________ = 10.4ft/sec
9 x 7000

Someone posted this formula and called it free recoil.

FREE RECOIL is half the mass times the velocity squared

0.5 x (9/32.16) x 10.4 x 10.4 = 15.1ft/lbs

Now the bit people don#t seem to get. If i take a piece of brick weighing a pound and drop it on your shoulder from 15 feet I expect you would need a trip to a hospital. So why can hunters shoot 20 rounds in a day and enjoy it?
The answer is they hold the rifle firmly against their shoulder. British WW2 veterans are known to have said of the 303 Enfield. "Hold it right or it'l break your shoulder. It is you weight behind the rifle which does not allow it to accelerate to its full potential. So if your body only allowed the rifle to go at 2ft/sec (my guess) you have to absorb only 0.9ft/lbs. If anyone is stupid enough to hold an M1 1/4" away from their shoulder with their arms relaxed and fire it. I would expect they will get a painful rude awakening.

Hawg
March 14, 2012, 06:35 PM
British WW2 veterans are known to have said of the 303 Enfield. "Hold it right or it'l break your shoulder.

If that's true Brits during WWII must have been pretty wimpy, a 303 doesn't have much recoil.

KEYBEAR
March 14, 2012, 06:37 PM
After shooting Registered Trap for over 40 years I do understand Recoil .
The better shooters don,t hold the gun hard just to the shoulder .
Gun Fit is a lot of the answer .

I would shoot 300 rounds of 1.1/8 oz. 1200 fps all day . After the day was
over I had no thoughts about recoil no pain or soreness .

I shot some marathons and fired 5/600 rounds a day .

A trap gun will go 12 lb. or more .

mikthestick
March 14, 2012, 07:13 PM
I am not an ex-soldier and have not been trained to fire a rifle. I have known some WW2 veterans. I know some retired British soldiers and some serving. Let me assure you there are no wimpy British soldiers. I am not offended by your comment only amused for I must be the wimp.:o
20 years ago I was invited to a shoot supervised by the army. I was allowed to shoot the Enfield 303 followed by the German 8mm Mauser, a total of 10 rounds. I was afraid the recoil would hurt me. I put wooly hat under my jacket and held the rifle firmly to my shoulder. The next day I was not bruised but my shoulder felt like I had done something I did not normally do.
With hindsight the wooly hat may have kept the rifle away from my shoulder and created a space for the rifle to accelerate into, thus developing more energy negating the cushion effect of the hat.:o

MJN77
March 14, 2012, 07:34 PM
I own and shoot a K98 mauser, M1 Garand, two Mosin Nagants, an M1A, and have fired .303 Enfields. All of them have comparable recoil. None of them bother me unless I shoot a hundred rounds at a time. When I started hunting at 11 years old, my first rifle was a Remington 742 in 30-06.

Jo6pak
March 14, 2012, 07:57 PM
Good post, Mik.

The other part of felt recoil is the movement of your body to help absorb the recoil, and the fact that you are (normally) leaning into the rifle.

Since the impulse duration of a discharge is very short, the force of the recoil has very little time to overcome the inertia of the shoulder. It's more of a "shove" than a impact when the butt is firmly plaed against the shoulder.

Think of two scenarios.
A person shooting a .338 while standing and leaning into the gun
or
A person sitting with his back against a wall, and shooting the same rifle.

Hawg
March 14, 2012, 08:01 PM
My first deer rifle at the age of 12 was a bubba'd 98 Mauser in 30-06 with a solid steel recoil pad. My first shotgun at age 11 was a Winchester 1887 12 gauge with a solid steel and checkered recoil pad.:D Dunno if any of that has anything to do with it but most calibers I've fired do not to me have much recoil. I disdain rubber recoil pads for any but the heaviest calibers. I have two 30-06's that have them but the stocks came with thin rubber pads and would look funny without them. None of my other rifles or shotguns have pads.

MJN77
March 14, 2012, 08:07 PM
I agree. All my milsurp rifles, "sporting" rifles and shotguns are stock.

Mike Irwin
March 14, 2012, 08:22 PM
Hum...

The recoil must have kicked this out of the rifles forum and into the black powder forum...

Hawg
March 14, 2012, 08:38 PM
Musta did.:D

Bill Akins
March 14, 2012, 09:44 PM
Mike Irwin

Hum...

The recoil must have kicked this out of the rifles forum and into the black powder forum...

http://i607.photobucket.com/albums/tt154/malefeet1/ROFL.gif

.

March 15, 2012, 06:53 AM
Quote:
British WW2 veterans are known to have said of the 303 Enfield. "Hold it right or it'l break your shoulder.
If that's true Brits during WWII must have been pretty wimpy, a 303 doesn't have much recoil.

Spend some time behind a No5 loaded with Radway Green or SA 7.7, maybe this "tanker" LE well tickle your shoulder.
This fire snorter does have some kick to it.

The No4's aren't to bad in full dress. From the LOP on the No4's I think the average Brit war2 solider was about 5'7" and 150lbs. Even the "L" butt is way short for me.

Rifleman1776
March 15, 2012, 08:33 AM
Not yet discussed is "perceived" and "felt" recoil. Despite the mathematics, recoil can feel differently to different people. And the 'felt' or 'perceived' recoil can be affected by rifle design. I am primarily a traditional muzzle loader shooter. On my muzzle loading forum some people are currently complaining about the recoil from shooting a Brown Bess. I have a BB and simply do not feel much recoil at all. BTW, I am no a very large person.
FWIW, I do shoot modern. My cf rifle is a 30-06 Mod. 70. I can shoot it comfortably up to max charges with heavy (200 gr. or more) bullets. Then it gets very uncomfortable. ( for me) I have known big men who suffered with moderate charges and 150 gr. bullets. And others who wonder what my problem is with the max. charges and heavy bullets.

wogpotter
March 15, 2012, 09:04 AM
The recoil must have kicked this out of the rifles forum and into the black powder forum...
Not at all, the resurrected post is just so old the .303 in question is the old Mk1 round firing the 215 grainer powered by a 74 Gr compressed black powder charge!

Now those kicked like a mule back when we were fighting the Fuzzy-wuzzies.:)

mikthestick
March 15, 2012, 09:32 AM
jo6pak

With your shoulder against a wall it can't move. A recoiling gun moves back a bit as does your shoulder "Rolling with the punch" in normal shooting. The recoil is the same, the perceived recoil is less in the normal mode.
You will notice in the 303 pictures posted the but angles down. This tends to make the muzzle want to rise during recoil. If the stock was straight there would be almost no tendency for the muzzle to rise but the perceived recoil would be greater.

mikthestick
March 15, 2012, 09:41 AM
Keybear
If you understand recoil, you will understand that if your gun weighed 8lbs not 12lbs it would come back at you faster with more energy.

KEYBEAR
March 15, 2012, 10:10 AM
My last Trap Gun was 9lb. it was a soft shooter .
And yes the more the gun weights the less felt recoil the shooter feels but not less recoil in the gun . Fit is the answer and the only answer .

If LOP and pitch is right your not going to feel it as much . Also barrel location if your shooting a top single a O/U or a Mid single and don,t forget the unsingle ?

arcticap
March 15, 2012, 12:18 PM
Grasping the rifle butt is one way to prevent getting thumped when
shooting off the bench. It can also help to control any barrel torque.

http://thefiringline.com/forums/attachment.php?attachmentid=79792&stc=1&d=1331832079

http://thefiringline.com/forums/attachment.php?attachmentid=79793&stc=1&d=1331832114

mikthestick
March 15, 2012, 12:42 PM
Yes this is a BP forum So here is the recoil for the "Quiggley Sharps" 45-120-540 at 1495ft/sec. Weight = 12lbs? Hatchers notebook says to use 4700 in the formula for charge velocity. I got these numbers of the internet.
Typically the charge velocity are:

Black powder: 685.8 m/s (2250 ft/s)

Pistol and Shotgun powder: 1707 m/s (5600 ft/s)

Rifle powder: 1585 m/s (5200 ft/s)

BMG powder: 1433 m/s (4700 ft/s)

free Rrecoil is:
(1495 x 540)+(120 x 2250) =12.83ft/sec
12 x 7000
Free recoil = 0.5 x 12/32.16 x 12.83 x 12.83 = 30.71ft/lbs
If the rifle weighed 12.5lbs the number drops to 29.4ftl/bs