Highest velocity

[Larryjk]

When you are trying for extreme velocity, you will find quite a bit of variation between barrels. I am not saying between brands, but within the same make. Take 5 barrels from brand X and chamber them all the same and fire them across the chronograph. You will likely get quite a bit of variation. The tightness of the bore determines which are fastest, and the barrel makers do not want to get into the business of air gauging barrels to select out the tightest ones. Put moly on a bullet and velocity goes down because that bullet has less resistance as it passes through the barrel, the pressure goes down and the velocity follows the pressure. You have to add to the powder charge to maintain velocity if you use moly; just don't forget to go back if you quit using moly. On extreme velocity I am always hesitant to quote it unless I have seen the chronograph readings myself. I have completed a .22/243 Ackley Imp. for a fellow that is a speed freak and I won't mention his velocity until I see it on the chronograph.

[bulletpusher]

Yes, I said a smooth bore, and to be honest its not a sub-caliber so it really doesn't qualify but its a wonder to behold.

It's a 120mm on the M1 Abrams tank. Will punch thru multiple inches of armor at better than 3 miles, and get there in just a couple of seconds. Puts the muzzle velocity in the 5,000 fps plus range.

I also here that there are attempts at 10,000 fps in the works, but what do I know.

Oh yes, by the way the bore of the barrel is 120mm the projo is actually 2" in dia. about 24" long with vanes kinda like an arrow. It is the sabot round that the Army uses and the vanes burn off while in flight giving the round a golden low as it goes downrange.

Just for the fun of it
Bulletpusher