Bolt thrust, easy extraction and case shape

[getitdone1]

How much greater will the bolt thrust of a very tapered case be compared to a nearly straight case?

One example of a nearly straight case would be the 45-70.

An example of a case with much taper is the .348 Winchester.

To what degree does a straight case hinder easy extraction? To what degree does a tapered case aid extraction?

What brought this to mind was comparing the 375 H&H, with taper to the 375 Ruger with little taper.

The Ruger also has higher pressure so I would think, on a hot day, it's extra pressure plus little taper might cause the casing to be more prone to stick in the chamber or at least be hard to extract.

Seems I recall that P.O. Ackley did a test for bolt thrust and found the backward force on bolt was not nearly as great as was thought. Can anyone recall this test and details?

Your thoughts?

Don

[Borregos]

There is a fairly recent thread on bolt thrust I think.

[harry]

Here we go again

[AJMD429]

Start here. . . viewtopic.php?f=1&t=51148

and viewtopic.php?f=1&t=51148

and viewtopic.php?f=1&t=51041

[Borregos]

Start here. . . viewtopic.php?f=1&t=51148

and viewtopic.php?f=1&t=51148

and viewtopic.php?f=1&t=51041

Glad you did that doc, my search powers are weak

[Nath]

Oh no....not again

I will start it off again then....there is no relation between peak pressure and the bolt being exerted to the same peak pressure.

The brass will flow at very low pressure. Somewhat low pressure compared to peak pressure even. Time is often overlooked or the distinct lack of it!
Tapered cases do stretch more due to the pressure flowing the brass forward, the bolt thrust difference is negligible and more influenced by any possible oils present on the case or chamber.

There done

N.

[Chuck 100 yd]

Bolt thrust ??? Oh no!!!

[AJMD429]

The only thing I'd add is that the revolvers that have been produced over the years with highly tapered cases have had lots of issues with cylinders locking up due to case set-back.