Uuuhh. I though muzzle velocity went down when you shorten the barrel
Not really, muzzle velocity would go up because you dont have the bullet being slowed down by the barrel drag. Longer barrels give better long range accuracy but the longer the barrel the slower the projectiles/rounds are. Thats why my rifle doesnt recomend using a .22s in it because the powder load out is so small theres a high chance of the bullet jamming in the barrel. Thing is though shorter barrels typically are not as accurate at long range the round will drop off. Think about this, how much more muzzle velocity could I get out of my old 12ga lc smith shotgun if I shortened the 36" barrel. Not that I would but I would see a increase but it would be pointless due to the barrel design.
Thats just like for instance the Pennsylvania Legislative Budget and Finance Committee did a report comparing a 150 grain .30-06 bullet, 50-caliber muzzleloading projectile, and a 12 caliber slug. Long story short the 12 caliber slug is more dangerous than the .30-06 and the .50 caliber muzzleloader.
They came to that conclusion because the 12 ga slug ricochet`s farther than the .30-06 and the .50 caliber muzzleloader. The 12ga slug ends up when shot at 0 elevation going 5,205' (thats feet), the .30-06 went 4,835', and the muzzle loader went 4,498'. People would expect the more streamlined .30-06 to bounce/skip further than a bulb shaped slug but the .30-06 small size reduces the ricochet where as the slug skips across the surface more losing less energy.
But yea not to get off topic of the question you asked, but muzzle velocity can be tailored based off barrel length. Same can be done through adjusting the powder load. For instance I can increase the fps and ft/lbs at the muzzle on my .44 caliber confederate navy revolver by adding alittle more powder to the chambers. BUT if you shorten the barrel too much though you will make the muzzle velocity go down.
