The Shoot2hunt Podcast

[wy_will]

That would make sense to me if comparing small hole vs large with the same volume of gas. But does it apply in a bore where the bigger opening also has a larger volume of gas at said pressure? (didnt listen to podcast for context, probably changes if we're talking about muzzle pressure vs pressure exiting a suppressor with different sized bores..)

At an equal pressure, volume does not matter when comparing velocities. A larger volume will only mean that gasses will exit the barrel for a longer duration.

Granted, as pressure decreases, velocity will also decrease.

 

[wy_will]

For context. The claim was that with 2 rifles with the exact same weights and comparable ballistics but with a different bore diameter, the smaller diameter would have less recoil do to the gasses moving slower down the barrel.

The examples were a 6UM bs a 6.5PRC. Stating that it was easy to spot hits with a 6UM, but a comparable 6.5PRC was almost impossible to spot hits. Of course there are too many variables in this comparison to ever actually make them equal.

 

[wind gypsy]

At an equal pressure, volume does not matter when comparing velocities. A larger volume will only mean that gasses will exit the barrel for a longer duration.

Granted, as pressure decreases, velocity will also decrease.

Why wouldn't volume matter? More volume at same pressure = more energy doesn't it? At least from a recoil standpoint.

I can relate to this kid.

 

[huntnful]

Kinetic molecular theory and Graham's Law of Effusion were definitely not on my Rokslide bingo card for today.

Bro is just making up big words to make us feel inferior right now. Not gunna work on me pal, because I can’t even read.

 

[alexnelon]

Why wouldn't volume matter? More volume at same pressure = more energy doesn't it? At least from a recoil standpoint.

I can relate to Bobby.
View attachment 1056741

Volume doesn't affect velocity of the gas at the same pressure.

I think the big point is that Ryan and Jake don't understand physics well enough to explain why different guns have different levels of recoil, and everyone is more confused because of it.

Pressure and volume of gas affect recoil, gas velocity during effusion doesn't (much).

Comparing 6UM and 6.5PRC is a false equivalence. You can't use external ballistics as a baseline to explain differences in internal ballistics.

 

[Ryan Avery]

Volume doesn't affect velocity of the gas at the same pressure.

I think the big point is that Ryan and Jake don't understand physics well enough to explain why different guns have different levels of recoil, and everyone is more confused because of it.

Pressure and volume of gas affect recoil, gas velocity during effusion doesn't (much).

Comparing 6UM and 6.5PRC is a false equivalence. You can't use external ballistics as a baseline to explain differences in internal ballistics.

So what's the answer? I've made it clear I don't know why, but none of you nerds have explained it to my simple brain either, so that tells me no one knows....

 

[Firth]

I can see why they would think a smaller hole would produce less velocity. If you think of a tank of water with a hole in it under pressure, it will spray water if the hole is big enough, but as the hole gets smaller it will drop to a drip. Basically, the energy loss gets high enough that there isn't much potential energy from the pressure left to be velocity after the exit. I don't think that applies here though due to the relative sizes in holes.

My answer for gun barrels: I'd have guessed the same pressure would produce about the same velocity. Pressure is potential energy and it's getting converted to kinetic energy (velocity).

But I'm a civil engineer where everything is steady state, incompressible, and the temperature is constant, and I have no idea on the relative magnitude of those effects. Pretty big would be my guess though.

@Jordan Smith

He's a physicist, let's see if he can resist.

 

[alexnelon]

So what's the answer? I've made it clear I don't know why, but none of you nerds have explained it to my simple brain either, so that tells me no one knows....

It technically is rocket science, and I'm not a rocket scientist, I'm just a nerd, but basically;

Mass flow rate X Gas velocity + (area X pressure) = thrust (or close to that)

In rifle terms;
mass flow rate = Gas volume
area = barrel diameter
gas velocity and pressure mean the same thing in both aspects

a 20 inch 6.5mm barrel holds ~15% more volume than a 6mm. Which (loosely) equates to 15% more gas leaving the barrel with the same powder at the same pressure. But you have to burn more powder to get that pressure, which is how you get more gas.

The problem with comparing recoil between different cartridge diameters is you can't really have equal gas pressure AND equal gas volume unless you compare different powders and charge weights.

A 6UM at 62k PSI with N570 is actually closer in gas volume to a 6.5 creed at 62k with 42 grains of H4350, which I bet your shoulder has told you already.

 

[nm.otter]

I'll wait for DAS captures of the recoil impulses. If the other variables are controlled and they feel different, we should learn something useful.

Based on what I heard, my working hypothesis is that smaller hole = longer time to vent gases = spread out impulse.

 

[mt terry d]

Can someone give me a website for Foster Huntington?
Great guest.

 

[Wprinkle]

When you dorks are done dorkin, send me the cliff notes.. i engaged both brain cells reading that, imma need you to explain to me like you would a 5 year old that English is a second language. Pictures help lmao

Joking aside, physics and “feel” both point to the 6.5 saum improved necked down to 6 (6um) is the best return on investment cartridge speaking. Wonder how the 6.5 saum compares to other 6.5’s.. is it case/ chamber design?

 

[wyosam]

One thing is clear in this conversation. It must be about time for spring bear, because cabin fever is getting pretty intense.


Sent from my iPhone using Tapatalk

 

[wy_will]

So what's the answer? I've made it clear I don't know why, but none of you nerds have explained it to my simple brain either, so that tells me no one knows....

You are comparing a 115 grain to a 147 grain. We all know heavier bullet is more recoil.

Of course that is actually not always true, but I’m just giving you a simple answer for your brain to understand.

 

[WDO]

Can someone give me a website for Foster Huntington?
Great guest.

For the range cards and stuff

Sobchak Security LLC

Sobchak Security LLC

waltersobchaksecurity.com

I’ve read his articles for a few years on other topics. Interesting reads in my opinion.
Here’s his other. I get the newsletter/email that goes once a week or so.

https://arestlesstransplant.substack.com/

 

[mt terry d]

Thank you

 

[4th_point]

Sorry if I missed it.

What are the rifle parameters?
-Barrel lengths
-Chamberings - 6UM and 6.5 PRC?
-Overall weights
-Same stocks? Same scopes, mounts, butt pad?
-Same muzzle treatment - same can design?

What are the load details?
-Bullet type and weights
-Case capacity
-Powder charges, and what powder
-Muzzle velocities

 

[Bittereinder]

Dude talking about the way the tacticool guys speak had me cracking up. “You’re utilizing?”

Also, "knowledge transfer".