Author Topic: Recoil calculator (Read 1512 times)

smylee grouch · « **on:** March 01, 2024, 06:41:44 PM »

There is a formula for calculating ft.pounds of recoil in CF rifles using dupont IMR powders. Calculated using bullet weight, powder charge weight and gun weight. I,m curious if such a formula exists for black powder .

ClaMar · « **Reply #1 on:** March 01, 2024, 07:21:34 PM »

Smylee,

If I remember correctly, that formula assumes either 4000 or 4500 fps powder velocity.

It would probably be reasonably close to use 2000 or 2500 fps powder velocity for black powder.

Clarence

Scota4570 · « **Reply #2 on:** March 01, 2024, 07:41:25 PM »

Based on intuition, it should be the same. The weight of powder matters because it is expelled and contributes to recoil. How much is actually gas should not matter.

https://shooterscalculator.com/recoil-calculator.php

The calculator gives higher recoil numbers for BP loadings than smokeless. When I tried common 45-70 loadings and added the powder weight difference between smokeless and BP to the bullet the recoil was still higher with BP. That indicates to me that the formula weights powder more than bullet for generating recoil.

I have noticed that given the same weight of bullet and velocity, a fast acceleration (smokeless) vs a slow acceleration (coarse BP) the recoil feels softer with coarse BP. I think that has to do with recoil velocity. A semi auto shotgun seems to shoot softer, maybe for the same reason.

The actual recoil formula is in Hatchers notebook.

smylee grouch · « **Reply #3 on:** March 01, 2024, 08:01:02 PM »

I assuming that black powder burns faster as it is more of a flash burn where as smokeless is what i,m told is progressive burning. ? $:-\$ ?

Eric Kettenburg · « **Reply #4 on:** March 01, 2024, 08:04:32 PM »

Just to be a smart arse:

Step 1: load rifle.

Step 2: fire rifle.

Step 3: repeat, make note of shoulder feeling.

smylee grouch · « **Reply #5 on:** March 01, 2024, 08:29:19 PM »

The amount of recoil encountered will not dictate the charge used for hunting. The most accurate load will be used regardless. I find it interesting that my 62 will be very close in recoil to my 66 with the same powder charge ( 110 ) by using this formula, I assume because the velocity will be aprox. 200 fps faster. When the weather starts co operating I can get out to test and work up loads. A lot if not most people don't care about the numbers. Some are more curious.

Daryl · « **Reply #6 on:** March 01, 2024, 08:39:49 PM »

Black powder loads usually create MORE recoil than a smokeless load producing the same velocity. This was evident in a 12 bore SxS I worked with.
The black powder load produced what felt like twice the recoil of the smokeless load. So, the formulae is not transferable between the powder types.
I was shooting round ball with a 7 dram charge. The equivalent velocity in smokeless powder was a pussycat to shoot. The BP load just about turned
me around first shot. Braces, it only turned me slightly sideways. With smokeless loads, I was easily able to make fast right and lefts on a plate at 100
meters. With the BP loads, no way. The gun was light 7 1/2 pounds, which exacerbated the recoil of the black powder loads.

Eric Krewson · « **Reply #7 on:** March 02, 2024, 06:14:47 PM »

My internal recoil calculator tells me if I load my standard turkey load of 100gr of 1F, 1 1/2 oz of shot and the oil soaked 1/2" fiber wad I use in the Skychief load, I better have this on if I am shooting multiple pattern test shots in the yard. My recoil calculator will be off the charts and a black and blue shoulder will result without the thick recoil pad. Strangely, I don't feel a thing when I am shooting at a turkey.

axelp · « **Reply #8 on:** March 05, 2024, 06:13:30 PM »

As a kid, the first thing my pops did after teaching me to shoot a .22 rifle, was to have me go out bunny hunting with his 12 gauge shotgun. From that day forward my "recoil calculator" was the felt recoil of a 12 gauge using high base shells. It was not scientific, but it told the story.

K

Daryl · « **Reply #9 on:** March 05, 2024, 07:45:24 PM »

Quote from: Eric Krewson on March 02, 2024, 06:14:47 PM

My internal recoil calculator tells me if I load my standard turkey load of 100gr of 1F, 1 1/2 oz of shot and the oil soaked 1/2" fiber wad I use in the Skychief load, I better have this on if I am shooting multiple pattern test shots in the yard. My recoil calculator will be off the charts and a black and blue shoulder will result without the thick recoil pad. Strangely, I don't feel a thing when I am shooting at a turkey.

I've had and have used one identical to that one. Bought it in the late 70's, but shot an elephant rifle too many times without it and ended up tearing the cartilage fore and aft in my right shoulder.
My .69 Sporting Rifle is a pussycat in comparison. The pad is still in my truck, for use with elephant rifles. Mine is the 3/8" thick one. Taylor has a thicker one.

PAhunter · « **Reply #10 on:** April 12, 2024, 01:52:17 AM »

My recoil caculator.....ir it hurts my shoulder its good.

Eric Krewson · « **Reply #11 on:** April 12, 2024, 02:01:59 AM »

My pad is a full inch thick, I have one of the 3/8" ones as well.

alacran · « **Reply #12 on:** April 12, 2024, 02:27:53 PM »

Daryl, out of curiosity, how many elephants have you shot?

Daryl · « **Reply #13 on:** April 12, 2024, 08:07:46 PM »

Only 6, in my dreams. The smallest was 110 pounds per side.

hanshi · « **Reply #14 on:** April 12, 2024, 09:20:07 PM »

Never thought much of a small bruise or two, got a few over the years too. The only "TRUE" hurt was from my much esteemed .338 Win mag and my handloads. All others, 45/70 to .375 H&H were mere kitty cats. Recoil rarely registered on my brain even when I found some fine bruises in the evening.

The most vicious recoil is found in the range where one gets a "gun headache". Shooting a bad boy off hand can produce very noticeable recoil but when fired off a bench gives a GUN HEADACHE! A .62 prb is the biggest projectile I've fired and even with heavy powder charges no painful recoil. I don't care to go to anything bigger as I have no use for such.

WKevinD · « **Reply #15 on:** April 12, 2024, 10:14:46 PM »

My recoil calculator turns off when facing game. My sound detector also goes to low.
Bear hunting with a .75 loaded with a .735 ball and 95 grains of ffg produced no noticeable recoil and a low barely perceptible boom but produce a entry and exit hole on the bear at 25 yards.

It all turns back on when facing paper.

Kevin

Bill Raby · « **Reply #16 on:** April 13, 2024, 02:32:15 AM »

My 4 bore shoots a 4 ounce ball and I have used powder charges up to 500 grains. Recoil knocks me back 5 or 6 feet. I have never gotten a bruise or any injury. The stock design makes a big difference in how recoil feels. Lots of practice with high recoil guns makes a much bigger difference. It is something that takes time to learn.

Hawg · « **Reply #17 on:** April 13, 2024, 05:29:57 AM »

Quote from: Bill Raby on April 13, 2024, 02:32:15 AM

Lots of practice with high recoil guns makes a much bigger difference. It is something that takes time to learn.

I got my first 12 gauge at 11. That's probably why I'm not recoil sensitive now. To me bp is more of a hard push than a kick. The hardest I've been kicked with bp is a .690 round ball in front of 100 grains of powder in a 5 1/2 pound 12 gauge. It was a thumper but not unpleasant.

Daryl · « **Reply #18 on:** April 13, 2024, 09:27:16 PM »

Piece of cake, not a scratch. Of course this was 25gr. short of my normal hunting load.

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Author Topic: Recoil calculator (Read 1512 times)