the longer the barrel the higher the velocity and the more accurcy you can achieve. but you can only build so much pressure in a case. so from this point on the bullet will be slowing down, so how do you know when you have reached the point of max velocity/accurcy. thanks dave

Basicly if the pressure in the barrel times the cross sectional area of the bullet is greater than the friction force of the barrel to bullet there will be acceleration or an increase in velocity. If the pressure X area product is less than the friction force the bullet will slow down.

How do you know +++++? You might start with a 22 hornet 40" barrel , a chronograph and a hack saw. roger

quote:

Basicly if the pressure in the barrel times the cross sectional area of the bullet is greater than the friction force of the barrel to bullet there will be acceleration or an increase in velocity. If the pressure X area product is less than the friction force the bullet will slow down.

This may only be true if the product of the coefficient of friction and acceleration is less than the exponent of the decelleration of the bullet at any given time in the barrel.

There are times when the integral from point 0 to the end point of the barrel may also be so great that the inverse of said product will become parablic in nature and a negative effect may be noticed.

I learned all this from Hotcore and Alf

sorry about that Roger
seriously now......

quote:

Originally posted by dep:
the longer the barrel the higher the velocity and the more accurcy you can achieve.

No.....not true at all!

quote:

but you can only build so much pressure in a case. so from this point on the bullet will be slowing down, so how do you know when you have reached the point of max velocity/accurcy. thanks dave

Accuracy has nothing to do with barrel length with the possible exception of extremely short barrels of four inches and less.

Your question of what length of barrel does a bullet start to slow down is largely dependent of what combustion chamber we are working with. The Navy used barrels of quite long lengths for the 16" shells.....and that projectile had quite a combustion chamber.

If you look to merely 26" of barrel we see that the increase in velocity is already starting to recede with normal chambers like the 300 magnums and if we look at the .223 we notice that velocity gains past 26" are almost nonexistent.

Frankly I have no idea where the velocity starts to recede but for sure past 30" with any of todays cartridges (not counting the BMG .50) is very much in the marginal returns category and possibly negative for such rounds as the .22 hornet.

I once chronographed a 12 Ga slug while cutting down a barrel from 26" to 19" and actually found an increase at the shorter length.....go figure!!!

I think it's safe to say that if one is looking for maximum velocities from a length of barrel he's in the neighborhood around the 30" range depending on how large the cartridge and what bullet diameter! But there will be no increase in accuracy past 16" of barrel and even a lot shorter.....

many moons ago the guys at remmington said that they they got max velocity out of 22lr at 19.6" barrel length. it decreased after than. I believe the same max length thing holds true for sex

quote:

Originally posted by vapodog:
...I learned all this from Hotcore and Alf

I've been thinking my memory was slipping a bit, but... that does have a familiar ring to it.

I remember Coefficient of Friction(good stuff to learn), but I don't remember the "exponent of the decelleration" being involuntary involved unless the twist is 1:4.63901", otherwise it must be conscripted.

Of course it is all compensated for by that inverse-in-reverse hyperabolical logarithmic strain gauge attachment on a frozen carcus (M43) when the caliber is under 23.

I feel sure alf can copy some stuff out of his books on it and try to tie it into killing humans.
-----

Hey Dave, It is best not to even concern yourself with Velocity and focus on Accuracy. Stay with the recommendations in the Powder and Bullet Manuals from the folks you buy the Powder and Bullets from. And ALWAYS watch all the Pressure Indication Signs you can.

Look for the best Harmonic(not Harmonica) and then Fine Tune the Final Load with Seating Depth Adjustments.

Long barrels do not necessarily equate to accuracy because of their tendancy to vibrate more than the same diameter short barrel.

quote:

Originally posted by vapodog:
I learned all this from Hotcore and Alf

Now that's a pair to draw to. roger

Are we having fun here or what?????

It isn't too bad when y'all are just syskatorious, but when you all get flablungent it is very difficult for some folks to handle.

quote:

Originally posted by Hot Core:
It isn't too bad when y'all are just syskatorious, but when you all get flablungent it is very difficult for some folks to handle.

I looked up those two words to broaden my vocabulry and found they are errexistoriant.

I'll think about you next week when I'm fishing in Alaska. I'm really getting too old to fight more than a couple of those big Halibut each day! roger EYHO

quote:

Originally posted by vapodog:

quote:

Basicly if the pressure in the barrel times the cross sectional area of the bullet is greater than the friction force of the barrel to bullet there will be acceleration or an increase in velocity. If the pressure X area product is less than the friction force the bullet will slow down.

This may only be true if the product of the coefficient of friction and acceleration is less than the exponent of the decelleration of the bullet at any given time in the barrel.

There are times when the integral from point 0 to the end point of the barrel may also be so great that the inverse of said product will become parablic in nature and a negative effect may be noticed.

I learned all this from Hotcore and Alf

-----keep them down, keep them urban, keep them democrat![in otherwords they do not have a idea of what the real world is like]!!

quote:

Originally posted by bartsche:

quote:

Originally posted by Hot Core:
It isn't too bad when y'all are just syskatorious, but when you all get flablungent it is very difficult for some folks to handle.

I looked up those two words to broaden my vocabulry and found they are errexistoriant. ...

For those of you who do not have access to the 13th Edition of Funk & Wagnals Interior/Exterior Ballistics and Colloquialisms "errexistoriant" by definition means = Precisely well said, could not be said better if thought about for a millenium, said with profound insight and wisdom, good choice of words too.

Best of luck on the Halibut. Do you need to borrow the Kayak? I discovered Thursday that a large Bass will darn near get it up on plane(with a LOT of weight on board.

quote:

Originally posted by dep:
...how do you know when you have reached the point of max ... accuracy.

If you Benchmark the rifle with Match Grade Bullets, fully Prepped Cases, using the never improved upon Creighton Audette Method, and then Fine Tune the Final Load with Seating Depth Adjustments, and call the Fliers, you will be able to achieve the best possible accuracy.

Or if you consider yourself very lucky, you can use a Randomly Picked Load, mixed brands of Cases, without any Case Prep and go with it. I strongly encourage the Random Method when folks shoot against me to see who buys the BBQ for Supper.