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# Bullet weight and Recoil

Discussion in 'Caliber Corner' started by vefrancis, Feb 3, 2012.

1. ### vefrancis

1
0
Jan 26, 2012
With factory ammo does the bullet weight have any correlation with the amount of recoil? Example: Does a 155 grain winchester ranger have less recoil than a 180gr winchester ranger?

2. ### JBP55

9,639
250
Mar 4, 2007
Louisiana
Just the opposite. In the same type ammunition the heavier round is slightly softer shooting and will impact slightly higher on target compared to the lighter round.

3. ### DannyRModeratorMillennium Member

19,827
195
Dec 17, 1998
Roanoke, Virginia
The two variables are bullet weight and muzzle velocity.

4. ### 3/4Flap

Uh...

Normally the heavier bullet generates heavier recoil. This is of course not always true as what DannyR said is also true.

In other words, it is possible that either BULLET weight may generate heavier or lighter recoil, based on the velocity of the bullet.

Basically, with two cartridges generating similar pressures, the heavier bullet load will kick more.

And...

Powder weight also contributes to recoil. This is more noticeable in heavy kicking rifles due to the quantity used {may not even be noticed in pistols}. Powder forms part of the projectile mass of the load until it is burned.

5. ### frontier2011Give Me Brass

262
0
Sep 26, 2011
East Coast
Thats weird. The 180gr 'kick' a lot more than a 165 gr in my glock.

Does the 180 gr and the 165 gr have the same amount of gun powder?

Last edited: Feb 3, 2012
6. ### NucPhysics

134
0
Apr 19, 2009
DannyR is correct, it is both mass of bullet (m) and muzzle velocity (v),

The law is called the conservation of momentum:

m x v = m x v

The momentum in one direction is equal and opposite to the momentum in the opposite direction.

Thus, the heavier/faster the bullet, the more the recoil.

I am a Physicist and I approve of this equation.

7. ### 3/4Flap

In general, your experience is correct.

8. ### 3/4Flap

Don't forget priming compound, powder and mass of the gun itself that absorbs some of the energy causing differences in felt recoil.

i.e. a G29 kicks more with the same loads as does a G20.

I know...gun for gun.

Just flipping you you-know-what.

9. ### NucPhysics

134
0
Apr 19, 2009
3/4Flap,

You are exactly correct, it depends on the gun as the gun needs to be the same. A heavier gun has more inertia (resistance to move) and thus would dampen the felt recoil.

As far as powder charge, primer, crimp, bullet setback, and whatnot, they are irrelavant as the resultant muzzle velocity has already incorporated that into the mechanics.

One thing that isn't accounted for in "felt recoil" is the height of the barrel. Even though the recoil is the same with a higher barrel axis, bore axis, the more torque may make it feel as though there is more recoil even though there isn't. It's merely perception thing.

10. ### 3/4Flap

Wait...

Take a .45-70 rifle shooting a 500 grain bullet at 1150 fps using two loads.

One uses 70 grains of Black Powder to accomplish this.

The other uses 22 grains of smokeless.

Recoil energy is greater with the black powder by any measurement, so what is the cause?

11. ### Pierre!NRA Life Member

3,998
168
Jun 20, 2003
Lovin Sparks Nv!
Then there is the slide speed...

This seems to affect the transfer of recoil feeling, as well as changing the timing of the event.

My personal experience is:
220gr or 200gr bullets shoot *softer* but also have a slow slide speed - more of a push feeling
180gr seem to be a nice blend of slide speed and manageable recoil
165gr have a *snap* to the recoil, but you are back on target quickly!

When it doubt, try it out... Not easy to find 220gr loads for .40, but you should be able to find 200gr and 180gr pretty easily.

Let us know what you find out!

Patrick

12. ### JBP55

9,639
250
Mar 4, 2007
Louisiana

HST 180gr. 1010 FPS 408 energy. 180X1010=181,800
HST 165gr. 1130 FPS 468 energy. 165X1130=186,450
Do the math and get back with us.

13. ### barthsix barrels

6,544
569
Oct 7, 2011
The Free Zone
It's a combination of weight and velocity.
40 doesn't have +P or +P+ ratings.
But ammo is loaded a little differently depending on the manufacturer.
Most 180s are sub sonic and relativity soft shooting.
The 135/155s are usually loaded hot.
165 can be hot or cold - it depends...

Example:
Federal Hydra-Shok 165
980 fps 352 E

Speer GDHP 165
1150 fps 484 E

Guess which one kicks harder - LOL!

Last edited: Feb 3, 2012
14. ### ron59Bustin Caps

6,927
21
Jan 3, 2009
Smyrna, GA
I'm not buying any of this.

I'm a competition shooter and reloader. USPSA 'B' shooter and missed Expert in IDPA by less than a half-second last year, I expect to easily make it this year.

In "the games" (IDPA/USPSA), they compare bullet weights by using a computation called Power Factor. That is bullet weight times velocity.

They will usually then declare a minimum Power Factor that can be made, such as 125,000 (often called 125PF). For example, a 115gr 9mm bullet traveling 1150fps has a power factor of 132,250 (or abbreviated 132PF). That's pretty close to WWB 115gr 9mm FMJ bullet.

I shoot 147gr bullets, loaded to a similar PF. I load them to achieve velocity of around 915fps for a PF of 134PF.

The result? The 147gr round has a MUCH softer recoil than the 115gr bullet.

I have done this "test" with multiple friends, all who have done it have agreed with me. Take a magazine and load it with 10 rounds, 5 of 115gr WWB and 5 of my 147gr reload. Alternate them so you'll fire one first, then the other. The "softness" of the 147gr will put a smile on your face.

Some people's reaction is "you're comparing a HOT 115gr to a SOFT 147gr round". And I would disagree with that. The 115gr WWB round is by no means hot. And there is no way a 147grainer at 915fps could be considered soft. I think Speer Gold Dot 147grain bullets only reach 950fps or so out of a G17 sized gun (the size these comparisons and measurements were made through). 915fps is not *that* far off of 915fps.... not considering when I COULD load it way down to 850fps and still (almost) make minimum power factor.

I would suspect that these same results would be seen for any round, whether it is .40 or .45ACP.

I have converted several of my gaming reloading friends to shooting 147gr bullets just because of this. It is not hearsay, it is not myth, but fact. I have a chrono and chrono all my loads, as well as some factory loads for comparison sake.

Talk about pressures, talk about barrels, etc has no bearing. As long as your pressures are safe and you use the same barrel to compare, those points are moot. So are pretty much any other piece of "evidence" listed above.

Use ONE gun (the same gun). Take a lighter round and a heavier round of the same PF and shoot them through it, alternating as I described above. Money says the heavier round will feel softer.

Last edited: Feb 3, 2012
15. ### JBP55

9,639
250
Mar 4, 2007
Louisiana
My three posts are in agreement with ron59 and if you shoot the different weight rounds you will understand.

16. ### ron59Bustin Caps

6,927
21
Jan 3, 2009
Smyrna, GA
This is key. Not talking about pressure, or anything else. But true objective research.

1) It is important that the two rounds have fairly close Power Factor. That is the only method I've ever seen to try and compare the "power" of two different rounds. There's a reason why the gaming organizations use that computation, it works.

2) It is possible to bias the results by not following #1. I made the assumption that most typical factory 115gr ammo was loaded similarly. It is not. When I did my test using my ammo vs some Federal Champion my one shooting buddy had, I was surprised to see that I could not tell ANY difference between the two loads. I literally could not tell the difference between his 115gr load and my 147gr load.

I then chronographed the Fed Champion ammo. VERY WEAK AMMO. It barely was getting 125PF, quite a difference from the 132-133PF from the WWB. And thus the difference. I never did any accuracy tests with that ammo, but I know if you try and slow down a 147gr bullet too much (trying to achieve maximum softness), it *will* affect bullet accuracy. Which is why I run mine at 915-920fps. I suspect those Fed Champions *might* not be as accurate as the WWB.

Last edited: Feb 3, 2012

262
0
Sep 26, 2011
East Coast
ne1??

18. ### 3/4Flap

Look, what you guys are describing is as I said; velocity is a factor as well as bullet weight.

If you are shooting low velocity rounds like common service pistol rounds, the recoil is so similar between different loads it is relatively "the same", with different shooters often judging different rounds opposite as per felt recoil.

In rifles where the recoil is better "felt", heavier bullets in loads generating similar breech pressures generally generate heavier recoil.

felt recoil is an interesting phenomenon. I always felt my .357 SIG 226 kicked less than my 9x19. One pistol had the solid slide, the other the folded slide, but still...

Step up to the .44 Mag and you see in handguns the GENERAL rule-of-thumb applying.

Also, NucPhysics, my question was at face value.

Last edited: Feb 3, 2012
19. ### abq87120

775
6
Nov 2, 2007
Prescott, AZ
My G23 shoots 180g imperceptably softer than the 165g.

20. ### NucPhysics

134
0
Apr 19, 2009
We're starting to talk two different concepts: actual recoil and perceived recoil.

Actual recoil is what many here have already said is based on muzzle velocity and bullet weight which is what I thought the original question was asking. It's a straight forward physics concept - however, as long as everything else is all equal.

Perceived recoil is something many others here are bringing up and with many good points as well. The actuation of the slide, the slide slamming back on the RSA, the speed of the reaction, etc, etc. All good points. All effect the perception of recoil and how we will all perceive it differently.

An analogy of actual/perception is lifting a 200 lb weight over your head vs. a 20 lb weight 10 times. One is definitely easier but the ultimate work is the same (Work = force x distance). The first feels like more work, as it does to me, but the work is technically the same when calculated. Also, Temperatures can feel differently based on humidity or wind but actual temperature is still the same regardless of how of we perceive it.

Sorry I oversimplified earlier to actual recoil, but many of you have had good points on how and under different conditions recoil can be perceived differently, and there is no legitimate argument against different perceptions.