Bolt Thrust Pressure

[Bryan Austin]

My Dear Bryan

Firstly, you are now my Ballistic Sciences hero.

Second, would you please be so good as to describe what we are watching in slo-mo? I clearly see the rim of a shell,apparently in a test barrel,
some sort of flame, and then the large rectangular thingy is moving... towards the test barrel?

thanks very much, please keep up the good work!!

your admirer
prof marvel

LOL, Thanks!!!

What we are looking at is/are tests checking to see at what pressure the case will thrust back out of the chamber. John Kort did some tests in his rifle as aforementioned and determined that the case did not thrust aft and contact the bolt with his particular load. The load is advertised at 11,000 psi but my tests recorded much less.

I am using a 20" MGM barrel that I have attached to a death trap.....I mean.....a stand that I built for testing chamber pressures with the Pressurtrace II strain gauge system. The barrel is 1 1/4" diameter that a stick of dyn-o-mite couldn't damage...but will only record pressures above 6,000psi.

I purposely set the barrel far forward of the blast plate so we can see if and when the case moves. I also have to remove the firing pin and use a punch and hammer to ignite the primer. If enough pressure is created, eventually, the case will thrust aft into the blast plate and well as kick the punch out of the firing pin housing.

In my previous post I included a link to the 44-40 website where I have added some detailed information with more photos. It just takes too much effort to post it all on the forums so I try to be brief and then link to the info!

[Bryan Austin]

Today I tested 6.4gr of trailboss. Forgive me for not posting here, I am tired so I will just post a link to the videos and photos. Scroll to the bottom of the page at the following link: https://sites.google.com/view/44winchester/handloading/bolt-thrust-pressure