Shortening my 223 Barrel
- Thread starter ADAM25
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Jack Roberts
Moderator - Deceased
On average, the shorter barrel will be more accurate because it will be stiffer.
Jack
Jack
OneInTheBoiler
New member
Can you explain that one Jack ? I have a very hard time understanding that concept.
Jack Roberts
Moderator - Deceased
Given two pieces of steel the same diameter, shorter will always be stiffer. It is easy to visualize if you carry it to extremes. Take a rod 1/4" in diameter, one piece a foot long, the other 3 feet long. The foot long piece you can not bend noticeably, the 3 foot one bends pretty easily.
Jack
Jack
Jay Johnson
New member
Quote:
Can you explain that one Jack ? I have a very hard time understanding that concept.
Take a piece of 5/8 inch wood that is four feet long do you think you could bend it with your hands? Now take a piece of 5/8 inch wood six inches long now can you bend it with you hands?
Can you explain that one Jack ? I have a very hard time understanding that concept.
Take a piece of 5/8 inch wood that is four feet long do you think you could bend it with your hands? Now take a piece of 5/8 inch wood six inches long now can you bend it with you hands?
Yes, but all barrels have resonance. Short or long. Finding the length where the resonance is damped is the key. Unfortunately, the resonant frequency changes with bullet weights and velocities and even slightly with temperature. For instance, a .22 regular velocity will have a dampening harmonic right around 16" where a high velocity .22 through the same diameter barrel dampens out at closer to 18".
If you cut your barrel it could be more accurate, it could be less accurate. Whatever length you cut it to, you will probably still be able to develop a load that is accurate. Odds are, it will not be the same load that you are getting your best accuracy with now.
As ugly as those BOSS systems and those stupid donuts are, they do work.
If you cut your barrel it could be more accurate, it could be less accurate. Whatever length you cut it to, you will probably still be able to develop a load that is accurate. Odds are, it will not be the same load that you are getting your best accuracy with now.
As ugly as those BOSS systems and those stupid donuts are, they do work.
The shorter barrel fo the same diameter has less vibration and therefore less angle of flex as the bullet is traveling through the bore. with proper shooting techniques, the shorter barrel would be more accurate.
The reason for the longer barrels of older days was the sighting system. Iron sights. The longer the sight radias the more accurate someone could hold it. With scoped systems, that point is now mute.
The reason for the longer barrels of older days was the sighting system. Iron sights. The longer the sight radias the more accurate someone could hold it. With scoped systems, that point is now mute.
NM Leon
New member
Longer barrels also allow for slower burning powders, which in turn allows for higher velocities while staying within a safe pressure limit, though off the top of my head I don't think that would apply in the case of a .223 at the lengths you are talking about.
Kelbro is right that changing the length of a barrel will will change the harmonic response, but a shorter/stiffer barrel will require a lot stronger harmonic wave to flex it, and so it is usually more accurate as Jack pointed out.
As with most things concerning firearms/ballistics, when you gain in one area you lose in another. Finding the balance point that best suits your purposes is the thing that makes it so interesting.
Kelbro is right that changing the length of a barrel will will change the harmonic response, but a shorter/stiffer barrel will require a lot stronger harmonic wave to flex it, and so it is usually more accurate as Jack pointed out.
As with most things concerning firearms/ballistics, when you gain in one area you lose in another. Finding the balance point that best suits your purposes is the thing that makes it so interesting.
BuzzBee can you explain your theory on that. It is my understanding that bullet stabilization is created by RPM rather than speed. A bullet traveling at 3000 fps from a 1/10 twist barrel will make a complete turn in 10 inches of travel. a bullet traveling at 3600 fps in a 1/10 barel will still only make one complete turn in 10 inches of travel.
sleddogg
New member
ADAM25 - sounds like you have the heavy rifle blues. I don't know what your finances are, but I'd just sell the boat anchor and buy a lightweight callin' gun. /ubbthreads/images/graemlins/wink.gif
You may cut that barrel, and get better accuracy or worse. If you are intent on keeping the rifle, look into fluting it also, as that will also knock some heft off the gun.
Any off the shelf gun will give you plenty enough accuracy to kill predators at calling range right out of the box.
You may cut that barrel, and get better accuracy or worse. If you are intent on keeping the rifle, look into fluting it also, as that will also knock some heft off the gun.
Any off the shelf gun will give you plenty enough accuracy to kill predators at calling range right out of the box.
NM Leon
New member
RPM is a function of time as well as distance (in the case of a barrel/twist).
Take a 1:12 twist just to make the math easier. In every foot the bullet makes one revolution. At 3000fps that's 180,000 RPM (3000 feet per second X 60 seconds in a minute). At 3600fps it's 216,000 RPM. It still only makes one revolution per foot, but it travels more feet per minute.
That's why (in general) a 22-250 will stabilize a little heavier bullet than a .223 with the same twist rate. For instance, a 1:12 barrel will usually shoot 55-60gr bullets just fine in a 22-250, but 55-60gr can be pretty marginal in a 1:12 barrelled .223.
Take a 1:12 twist just to make the math easier. In every foot the bullet makes one revolution. At 3000fps that's 180,000 RPM (3000 feet per second X 60 seconds in a minute). At 3600fps it's 216,000 RPM. It still only makes one revolution per foot, but it travels more feet per minute.
That's why (in general) a 22-250 will stabilize a little heavier bullet than a .223 with the same twist rate. For instance, a 1:12 barrel will usually shoot 55-60gr bullets just fine in a 22-250, but 55-60gr can be pretty marginal in a 1:12 barrelled .223.
Dogwood Creek
New member
I have shortened 2 mod 12 Savages from 26" to 22". Purely for the sake of portability. Both are super shooters. One is a .223, the other is a 22-250. I haven't put the .223 over the screens yet, but I have the 22-250. It is currently clocking 52gr A-Max at 3680 with 36gr of H4895. Not a real barn burner, but real world numbers. Velocity is what we all like to have lots of, but zeroed properly, 3680 will do all I need to 300yds. I was lucky and lost no grouping ability after the crop job. We did however, put a bunch of time and effort into the crown. Both of these rifles make perfect little starbursts on the muzzle when fired.(The powder residue left from firing leaves a nice even and equal star-like pattern on the crown.)I got what I was looking for. A lighter, less muzzel heavy rifle and no loss of accuracy. You must know going in, that you can't put it back on if you aren't happy with a crop job. If it is feasable, do it in 2 steps. I would be hesitant to go clear to 20" the first time. Just my thoughts,R.J.
clayman90
New member
I had a Win 70 Varmint in 22-250 shortened from 26 to 21 inches, it was a good shooter to start with and if anything got a little better, probably from the re-crowning. I was just looking for handiness, portability. 5 inches really didn't make it that much lighter but so much handier.
If it was me I wouldn't hesitate to do it.
There is a benchrest theory about optimum accuracy being around 21.75 inches.
If it was me I wouldn't hesitate to do it.
There is a benchrest theory about optimum accuracy being around 21.75 inches.
BuzzBee
New member
Ragcajn,
It’s not a theory, it’s simply physics. Nmleon did a good job explaining it , i couldn't have done it better.
Gunsmiths and gun manufactures generally use the Greenhill Formula to determine the optimal twist for a given bullet. The formula is T=150(d/r) "d" is the bullet diameter. "r" is the bullet length to diameter ratio (length of bullet divided by diameter), but when velocity exceed 2800 fps you substitute the value 150 for 180 and why? Because the stability factor increase with the velocity.
It’s not a theory, it’s simply physics. Nmleon did a good job explaining it , i couldn't have done it better.
Gunsmiths and gun manufactures generally use the Greenhill Formula to determine the optimal twist for a given bullet. The formula is T=150(d/r) "d" is the bullet diameter. "r" is the bullet length to diameter ratio (length of bullet divided by diameter), but when velocity exceed 2800 fps you substitute the value 150 for 180 and why? Because the stability factor increase with the velocity.
Dogwood Creek
New member
Babys for breakfast!?!
OneInTheBoiler
New member
So the days of the Ol'Timers saying " The longer the barrel, the more accurute is BS". It makes sense the way you all explain it now. I have always heard with gun's the longer the better.