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welcome to you

My English is not good so I am writing through the translator

My question is about the Ruger Mark 4 pistol
Is there a difference between the 4.4 inch and 5.5 inch long barrel in projectile velocity or bullet velocity at launch? What is the difference between the two in feet per second?

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So basically, the longer the barrel, the higher the velocity.

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That is generally correct with the exception being excessively long barrels. A barrel can be too long causing the velocity to decease because of excessive powder burn driving the bullet through the barrel. I have no idea how long that might have to be.
 

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Once the powder in the cartridge has been fully consumed, the projectile has reached maximum velocity and additional barrel length just produces friction. Barrel length should be chosen with this in mind.
 

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Corndog said:
Once the powder in the cartridge has been fully consumed, the projectile has reached maximum velocity and additional barrel length just produces friction.
True for long barrel (longer than about 20") rifles, but this doesn't apply to pistol length barrels. Powder will still be burning as the case is ejected from any semi-auto pistol.
 

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True for long barrel (longer than about 20") rifles, but this doesn't apply to pistol length barrels. Powder will still be burning as the case is ejected from any semi-auto pistol.
I don't follow your logic. Almost all pistol barrels are too short to maximize velocity. Yes, the action type of ANY firearm effects velocity. We kind of tossed an orange in with my apples.
 

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A few years ago, I did some 22 LR chronograph testing just to satisfy myself. I used several different brands, bullet weights, standard velocity, high velocity and hyper velocity.

Standard velocity cartridges with 40gr bullets are rated at 1080 fps from a 24" barrel and I found that to be true in my own guns.

High velocity 22 LRs come in several different bullet weights so muzzle velocity varies quite a bit. In all, I found 20" to be the optimum rifle barrel length for high velocity cartridges. I had three rifles with 20" barrels .... a Henry lever gun and a Savage Bolt action, which both chronographed virtually identical with the same ammo. I also have a 20" bull barrel on one of my 10/22s but it only likes match grade standard velocity ammo.

Yes, I got a token increase in velocity from my 24" rifles and even a few more fps from my 25" Remington .... but not enough to warrant an unwieldy long barrel. My CZ 452-2E bolt action rifle produced the highest velocity of all my rifles in its 24.8" barrel, which has about .001" tighter bore than my other rifles. This obviously has an influence on velocity. My CZ is also my most accurate rifle.

Because CCI Minimags are so popular, I tested them in all my rifles, pistols, and revolvers. The factory rated velocity was 1255 fps from a 24" barrel and I found the lowest rifle velocity was from my 18.5" Ruger 10/22 at 1200 fps. My 20" Savage clocked in at 1220 fps and my Marlin 39A's 24" barrel chronographed at 1260 fps. The CZ squeezed a few more fps at 1270 fps. According to QuickLOAD, the powder in a 22 LR cartridge typically burns up in about 10" of bullet travel but because there is still considerable pressure in the bore, it will continue to drive a bullet faster until about 25" of bullet travel (26"' barrel). I have no way to actually test for a total burn but the factory velocity statistics seem to be quite accurate.

When I tested my handguns, I found velocity was much lower and more dependent on barrel length. My Ruger MK II with a 10" barrel delivered the fastest velocity with all brands and types of 22 LR ammo. CCI Mini-Mags delivered 1155 fps .... right at the speed of sound. All my other pistols and revolvers delivered sub-sonic velocities with CCI Mini-Mags and all other brands/types of high velocity 22 LR ammo. That said, CCI Stingers (rated at 1600 fps in a 24" rifle) delivered 1180 fps from my 4 5/8" Single-Six revolver and 1195 fps from my 4 1/2" Ruger Standard pistol, both over the speed of sound.

Back to CCI Mini-Mags ....my SR-22 pistol with its 3 1/2" barrel hit 870 fps. My 4 5/8" Single-Six clocked right at 1000 fps whereas my 5 1/2" Ruger Single-Six chronoed at 1050 fps. My 6 1/2" Bisley Single-Six came in at 1090 fps. I have a Colt Frontier with a 7 1/2" barrel and it produced 1125 fps.

My Ruger Standard 4 1/2" barrel came in at 950 fps, Kimber 1911 conversion kit with a 5" barrel chronographed the 22 LR CCI Mini-Mags at 1010 fps, and my Ruger slabside MK III with a 6 7/8" barrel clocked at 1120 fps.

As you can see, the velocity difference per inch of barrel was more pronounced with shorter handgun barrels and as barrels longer than 18" were tested, there was less difference per inch.
 

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I don't follow your logic. Almost all pistol barrels are too short to maximize velocity. Yes, the action type of ANY firearm effects velocity. We kind of tossed an orange in with my apples.
You stated "additional barrel length just produces friction" (implying lower muzzle velocity), which is not the case in barrels as short as handguns have. I probably should have said "Powder will still be burning as the bullet leaves a shorter barrel's muzzle", instead of specifying semi-auto. My word choice was because the OP was asking about Mark 4 pistols.

Incomplete powder burn in shorter barrels will still be the case - regardless of action type.
Sorry for any confusion my reply may have caused.
 

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Once the powder in the cartridge has been fully consumed, the projectile has reached maximum velocity and additional barrel length just produces friction. Barrel length should be chosen with this in mind.
Nope.
Not so.
Ain't the case.

The bullet will continue to accelerate even after all of the propellant is consumed due to the gas pressure in the barrel behind the bullet.

In theory, of course, the farther the bullet moves down the barrel, and as gas leaks out at the breech, the gas per unit volume pushing on the bullet decreases. At some point the bullet stops accelerating, and will begin to slow down, and will eventually stop.

Unless your barrel is very VERY long, this won't be a problem :)
 

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Nope.
Not so.
Ain't the case.

The bullet will continue to accelerate even after all of the propellant is consumed due to the gas pressure in the barrel behind the bullet.

In theory, of course, the farther the bullet moves down the barrel, the gas per unit volume decreases. At some point the bullet stops accelerating, and will begin to slow down.

Unless your barrel is very VERY long, this won't be a problem :)
The gas pressure peaks when or before the powder is consumed. Acceleration then starts to diminish. Acceleration is the square of velocity. Physics can not be denied.

Educate me, my ears are wide open here.
 

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crstrode, You're right .... I know bullets from a high velocity 22 LR cartridge will continue to accelerate in a barrel at least 25 inches long ... maybe longer. My above tests proved it. Velocity gain after about 24" is in single digits, but it's still a gain.

Once a lead bullet has been sized to the bore and engraved by the rifling in the first few inches of bullet travel, it takes very little pressure to keep it moving so bore friction is minimal .... much less than you would think.
 

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The powder can be burnt but the resulting gas is still expanding. A turbo charger is a prime example. The "propellant" is consume but expanding gases spin the impeller.
 
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Corndog, crstrode is right. Think of it this way .... peak pressure (AKA chamber pressure) peaks after the bullet has traveled a mere 1/2", but that doesn't mean the powder is burned up. From that point on, the driving pressure from burning powder will continue to drop but in the meantime, it will accelerate the bullet. Just an FYI .... powder burns at a whopping velocity of 6000 fps so it continues to accelerate the bullet until pressure equalizes in the bore. Point being .... the bullet will never decelerate in a barrel shorter than 25".
 
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The gas pressure peaks when or before the powder is consumed. Acceleration then starts to diminish. Acceleration is the square of velocity. Physics can not be denied.

Educate me, my ears are wide open here.
crstrode, You're right .... I know bullets from a high velocity 22 LR cartridge will continue to accelerate in a barrel at least 25 inches long ... maybe longer. My above tests proved it. Velocity gain after about 24" is in single digits, but it's still a gain.

Once a lead bullet has been sized to the bore and engraved by the rifling in the first few inches of bullet travel, it takes very little pressure to keep it moving so bore friction is minimal .... much less than you would think.
Yes and yes

But as said and I’ll use my words. As long as there is sufficient positive pressure behind the projectile the projectile will continue to speed up. This is also basic physics. Both of you are exactly right from each other perspective of view.

Bottom line is the bullet will continue to speed of in a barrel of approximately 24-26 inches at which point the pressure behind the bullet will not continue to push the bullet faster.


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I understand that @Iowegan, and we (I) may be discussing terminology more than physics. Acceleration is the rate of change of velocity. I went back to my post #5, and realize I should have used acceleration instead of velocity. The difference will be mere inches of barrel length.

The physics of what happens when a round is touched off is pretty complicated. In addition to friction, barrel length produces a pressure increase in front of the bullet.

Pretty cool stuff.
 

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One of the missing links in our discussion is "time". Sometimes "time" is counterintuitive but because slow burning powder takes longer to burn up, it keeps pushing the bullet for a longer period of time, thus it creates a higher muzzle velocity .... no different than a magnum revolver cartridge. 22 LR cartridges are loaded with slow burning powder that typically take at least 10 inches of bullet travel to burn up. 22 Magnums take about 15" of bullet travel to burn up so they develop an even higher velocity without exceeding the max chamber pressure (24k psi for all 22 cal rimfire cartridges).

I agree .... the physics of what happens when a round is fired is pretty complicated. Bullet weight, bore friction, powder burn rate, powder charge weight, powder burn velocity, time, and probably a few more factors are involved with determining muzzle velocity with different barrel lengths.
 
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