Why do different powders giving the same velocity result in different recoil levels?

Status
Not open for further replies.
L

Lone_Gunman

Member
Joined
Dec 24, 2002
Messages
8,054
Location
United Socialist States of Obama
If the bullet weight and velocity are constant, why does recoil seem to differ for different powders? I made up some 45 ACP loads with 230g FMJ's using VV340 at 750 fps, and these seem to recoil more than W231 and Unique loads using the same bullet at the same velocity.
 
How does charge weight affect recoil? I would think recoil would be related to potential energy in the charge, and not the weight of the charge.

In other words, if VV340 and Win231 both drive a 230g bullet to the same 750 fps velocity, would they not have equal energy, and therefore have equal recoil?
 
"Why do different powders giving the same velocity result in different recoil levels? "

Variations in the time/pressure curve. Mathmatically, one half of the charge weight contibutes to the projectile weight.
 
The time/pressure curve could explain it. Would faster burning powders give a sharper rise in pressure, which the shooter would perceive as snappier recoil?

Also, would the absolute pressure be increased, or would it simply be a percieved increase because the rise in pressure is occuring over a shorter time?

Would the VV340 powder that I perceive has greater recoil have greater total pressure?
 
Last edited:
There are a lot of variables, but my experience mirrors yours with N340 in .45 ACP. It gives more recoil for the velocity than several other powders I tried, at least in that caliber. N320 is a better choice in .45 ACP. AA #2 will do almost anything N320 will in the .45 and is cheaper.
 
It sounds to me like if you put a force gauge on your pistol somehow, both loadings would show the same amount of total "recoil force" but a gauge would not mesure the 'snap' or how fast it recoiled which is what I think we perceive and call force when we shoot?
 
In other words, if VV340 and Win231 both drive a 230g bullet to the same 750 fps velocity, would they not have equal energy, and therefore have equal recoil?
Click to expand...


IMHO, they may have the same actual recoil, but the perceived or felt recoil my be different. I have found some powders tend to slap you with recoil while other powders that produce the same velocity with the same bullet in the same gun, tend to push.
 
How does charge weight affect recoil?
Click to expand...

When the charge burns, it expands, and uses some of it's energy to push the gas it is turning into out the barrel. It is not just pushing the bullet out, it is also pushing itself out.
 
The key to your question is the burn rate of the different powders.

A fast powder like Bullseye Hits it & Gets it.

Slower powders like Unique push more slowly and accelerate the bullet further up the barrel.

They may both produce the same velocity, but the slower powder don't seem to kick as much.

And as noted above, the weight of the "ejecta" includes the bullet, approximately half the powder charge weight + the primer component.

rc
 
A good place to read about this is on pistol competition forums such as http://www.brianenos.com/forums/index.php?act=idx .

Faster powder and heavier bullet usually equates to faster sight recovery and lighter perceived recoil. Slower burning powders continue the "push" longer making us perceive the recoil as heavier. 231 is a fairly fast powder.
 
Is there a chart comparing burn rate of various powders?

Also, there is a discrepency in what has been posted here:

rcmodel says:
"Slower powders like Unique push more slowly and accelerate the bullet further up the barrel. They may both produce the same velocity, but the slower powder don't seem to kick as much."


and Apiarian says:

"Slower burning powders continue the "push" longer making us perceive the recoil as heavier."


Aren't these two statements in opposition? Which is correct?
 
Faster powder and heavier bullet usually equates to faster sight recovery and lighter perceived recoil. Slower burning powders continue the "push" longer making us perceive the recoil as heavier. 231 is a fairly fast powder.
Click to expand...

+1

This is easy to test too. Try loads of a given velocity in .45 ACP and 230Gr FMJ, some with Clays or N310, against a slower powder like Power Pistol.
 
In my opinion, the faster powders recoil less. Shooting 1050 fps out of my CZ75 9mm, Clays felt softer then the HS6 loading;)
 
Did you chronograph the loads in question?
Do you KNOW your N340, W231, and Unique loads were all really doing 750 fps?
If you are depending on book data, you are flying blind trying to compare recoil; the literature is just not that accurate.

Felt recoil is a very subjective thing. I cannot tell the difference from powder to powder with equal bullet weight and equal ACTUAL velocity. I worked on it hard when shooting a lot of Trap back in the 1970s when the fad was to slow burning shotshell powders to give that "gradual acceleration" but it made no difference to my comfort so I went back to the traditional fast target load powders.

But a lot of people say they can tell a difference, kind of like The Princess And The Pea. But I am not sensitive enough to do it.
 
Fast powders can have less recoil sometimes. The amount (volume) of powder burned also contributes to recoil. There are so many variables it just has to be tried to find out for sure in any given application.
Did you chronograph the loads in question?.....If you are depending on book data, you are flying blind trying to compare recoil;
Click to expand...
Absolutely true
 
Did you chronograph the loads in question?
Do you KNOW your N340, W231, and Unique loads were all really doing 750 fps?
Click to expand...

Ah, yea, I chrono'd all of them. Thats why I said they were doing 750fps, how else could I determine that?
I would not have even asked the question if I wasn't sure I was shooting the same weight bullet at the same velocity.
 
Also why your shoulder will survive a 4 bore BP cartridge and not one loaded with smokeless.
 
We really should not compare shotguns, rifles, and pistols. Even revolvers and autoloader pistols have some differing characteristics.

The velocity of the slide will change somewhat with some powders and therefore change perceived recoil. I think this is one reason for the fast powder heavy bullet having a softer feel. I however have no proof of the slide velocity posit.
 
Well, my answer stays the same. I agree that N340 gave me me recoil than other powders in .45 ACP. I don't know why because it used similar charge weights to similar burn rate powders and still gave more recoil, noticeably more.

It is single based, and some double based powders seem to give more velocity for the recoil than single based powders. (More energy for the charge weight)

As posted earlier, there are a lot of variables. I certainly don't know the entire answer, but it is a fact that some pistol loadings give more felt recoil for the velocity than others. :)
 
A lot of people would say they knew it was going 750 fps because the manual or computer said so. Just trying to get your source clear.

I can tell the difference in recoil between bullets of different weight at the same power factor - momentum balance - but not between bullets of the same weight driven to the same velocity by different powders. But there is a guy on one of the boards who says Reloder 19 kicks less than other powders in his 7mm Magnum. Good for him. I am just not sensitive enough to FEEL the effects of Davis Mechanics.
 
Status
Not open for further replies.

Similar threads

L
  • Locked
What formulas will actually give me 800 fps in 45 ACP?
Replies
24
Views
1K
jfdavis58
J
L
  • Locked
Which VihtaVuori Powder do I want to try for 45 ACP?
Replies
6
Views
3K
Ol` Joe
O
L
  • Locked
Need help with a clean-burning 45 ACP load
2
Replies
28
Views
2K
ilbob
ilbob
M
  • Locked
What difference does the powder make?
Replies
7
Views
521
redneck2
redneck2
D
  • Locked
Precision Bullets???
Replies
4
Views
485
Walkalong
Walkalong
Back
Top