What's up with my velocity?

Woah guys. Accuracy and velocity are two different species. Somewhere along the line I got confused about what was being said here. So 16" is best for accuracy (as proposed by some) AND yields max velocity?

I think what grouse man said about gas pressure would be right to a certain degree. After while, the friction from the barrel would negate the remaining gas pressure force. But perhaps that would stretch the max. efficency length a couple of inches for velocity? Somehow I got the idea that 18" was what the mfg's use to test their loads and compile ballistics.

As for accuracy, that's a whole 'nother can o worms I guess.
 
Maybe we should E-mail myth busters, and see if they can check it out, for both accuracy, and velocity in a short barreled .22 vs Long barreled .22. :D

Mind you they would prob' screw it up somehow. :rolleyes: :D
 
To do it right you'd need to have a chrony, a way to standardize for atmospheric conditions and the willingness to start with say a 26-30" barrel and a scoped action as you cut it back 1" at a time and check on the results after each trim. Accuracy testing needs to be done over a period of time with each length to account for conditions (including fouling).

When you get down to 14" you can stop... :D

So who volunteers to have a custom long barrel made that they're going to turn into little bits? Plus do all the recording of data and all the work of testing? You can't use different barrels as then the variations in interior finish/dimensions may have a significant effect.

It'd probably be easiest on something like a 10/22 with an easily removable barrel.

I'll volunteer to collate and present the data in a meaningful manner, hell I'll even do all the cutting, and testing if someone else provides the rifle and barrel.

:) So who's up for it?
 
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Don't most 10/22 owners replace their barrels anyway? :D

You could do the same test without cutting the barrels only you would have to work up an average with both test rifles...which is prob' a better easier to go as having to re crown a barrel every inch cut would suck. :D
 
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Be easy to do - anyone got a rusty Cooey or similar to sacrifice?
Don't need to recrown for velocity tests. Just deburr.

Here is exactly what you are talking about but with .17 HMR.
http://www.bullberry.com/HMRdata.html
Best speed at 19".

I found reference to this place:
http://www.soundtechsilencers.com/
Shorter rifle barrels tend to be inherently more accurate than longer ones because they are inherently stiffer. They vibrate at a much higher frequency, and they vibrate much less at the muzzle during the critical moment of bullet departure. We have conducted barrel-cutting experiments to find the optimal rifle barrel lengths for the most common calibers. For instance, in .22 LR one gains little or nothing by having a barrel much longer than 8 to 10”. A good many rimfire rifle barrels are cut to 16”, just to comply with federal law regarding minimum rifle length. A 6” barrel will give us a velocity of 1,042 fps with Rem Hi Vel and 1,000 fps with Rem St. Vel. A maximum velocity of 1,180 and 1,120 fps occurs in a 14” barrel (with most rimfire chambers) after which friction reduces both velocity and accuracy.
 
What effect does a heavy barrel have if it is longer?

As some of the older rifles I have seen have pretty solid thick barrels.
 
The people that are using short barreled Anschutz rifles are talking about milli-seconds of time the bullet is traveling down the barrel from the time they squeeze the trigger. Some feel less human error with less barrel time.:rolleyes:
Smallbore shooting is a game in which there are many perfect scores fired and the match winner in declared by the highest X count. Drop a few points and your name ends up halfway down the second page:(
 
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