Help me understand twist rates

[Herb]

Thanks, Notchy Bob. Yes, my last Bridger Hawken was built with an Oregon Barrel Company barrel. According to The Gun Works catalog (info@the gunworks.com), "Oregon Barrel Company is a specialty barrel making company." Look them up on their web site. They custom make a barrel to your specs, and they are good. Now that I have my chronograph back, I'll be doing some more test shooting after I cast some .526 balls.

 

[nkbj]

Hi joesmoe3,
Uncle Sam compiled the tests' data in the 1850's showing that even the absence or presence of lube grooves (lubed versus paper patched) affected how a hollow based bullet flew going down range. The lube grooves lend greater stability through the slight addition of rearward drag. The shape, the depth of the hollow base, how nose heavy the projectile is... all of it matters. The British found a more rapid 48" twist to provide better accuracy for their slick sided paper patched minies.
To me some of the really interesting stuff got into how the faster the twist was and the more rifling grooves there were would make the minies want to go sideways. It's actually aerodynamic forces trying to make the minie pursue a spiral path but gravity flattens the curve to produce lateral movement. More and deeper rifling marks on the minie works like mud grip tires when at long ranges the forward momentum slows and the spin remains. Those guys were some awesome shooters to do it well enough to be able to develop data worth interpretation.

All that caught my attention because I remembered what my grandfather told me about things he was taught by German officers in sniper training for WWI.

 

[Rifleman1776]

The .50 with a 1:48" twist is about near as you can get for a perfect all-around rifle. Peruse some large museums and you will maybe not even find an old original that has anything but a 1:48" twist. The .54 with a slow twist will require heavy powder charges to get any kind of accuracy. Plus, there is the consideration of almost no recoil with the .50 and lesser powder charges compared to the shoulder busting large .54 with heavy (90 to 120 gr.) charges required. Personally, I consider this decision to be a no-brainer, hands down, choice of the .50 unless your exclusive use is for moose and griz. Then the bigger bore would be best.