recoil vs case head diameter

[Hanic]

Greetings all,

At the risk of exposing too much ignorance, I am asking about the effect of case head diameter on recoil,at the same operating pressure). I have read on several occasions that a major shortcoming of short magnum cartridges was "higher than expected recoil". This was invariably blamed on the larger case head diameter. I always gave these writers 1 or 2 black marks for sustaining and spreading incorrect info. It has been my belief that head diameter didn't effect recoil because its the mass of the bullet and the powder charge being pushed down the barrel that produced an equal and opposite reaction on the mass of the rifle, which imparted an appropriate,rifle) velocity and produced the kinetic energy felt as recoil. Writers of the said articles say or imply that the effect of chamber pressure on the increased area of the larger head cause much more force and recoil. If that were true, the typical operating pressure of 50,000 psi pushing on the typical head area difference of the standard head size,308, 6mm, 270 etc) vs the smaller head size of a 223,about 0.25 sq inches) would be 12500 lbs of force, quite allot for a shooter to handle.

Lately I'm seeing the above explanation a lttle more frequently, so I'm posting this to be sure I'm not missing something. I'm looking for someone to show me where my thinking is wrong, if that's the case. Thanks, Hanic

 

[AlNyhus]

It sounds like they're confusing recoil with bolt thrust.

The larger the case head, the higher the bolt thrust at identical chamber pressures.

But increased bolt thrust doesn't always give you increased felt recoil.

Dan Lilja has a great explanation of this along with an easy way to calculate this on his web site. Here's a link:
Bolt thrust

 

[TRECustom]

My experience is very simple. A maximum load with a 500gr bullet in a .460 Wby kicks a lot harder than a maximum load with a 350gr bullet in the same rifle. I believe that it's the bullet weight that makes the difference. I normally push my rifles until I get high pressure signs. Across the board, as I load heavier bullets in any rifle, the felt recoil goes up.

ALNyhus makes sense about bolt thrust going up as base diameter goes up, but the hypothesis that the short magnums with the bigger case diameters kick harder than the older magnums of similar performance that have smaller diameter, longer cases doesn't seem logical to me.

Hanic, I gave up worrying about exposing my ignorance a long time ago. In fact, I may have just done it again. Interesting thread.

Thanks, Tom