Radial and Axial cartridge case expansion explained (with lots of pictures)

[Edward Horton]

Yes its been covered before in great depth, just click on the link below

FEA Analysis of a Remington Model 7 action in 243 Winchester Caliber

The alternate title of this posting is called Stretching things to their limits, or why things break



A 10-32 Grade 8 socket head cap screw being pulled to failure.
The first view is the mesh and the second is the outline.
The mesh detail was removed during the axial loading to failure.
The contours are of effective stress. The failure stress is reached in the next to last view.

Cartridge cases are just like lug nuts.











The factory loaded .303 Winchester case below stretched .009 on its first firing, and gauges never lie.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[Edward Horton]

Did I tell you I shoot Winchester cases in my .243.



Did I tell you my new .243 has a removable bolt head (just remove the pin)



My .243 also has adjustable head space (just loosen the nut)



And I'm still using these same case today and they have never had a case head separation.



Kinda gives new meaning to axial and radial case expansion and the effects of chamber size, head space and chamber finish.

Rifle Chamber Finish & Friction Effects
on Bolt Load and Case Head Thinning.
FEA Calculations done with LS-DYNA
Rifle Chamber Finish & Friction Effects on Bolt Load and Case Head Thinning Calculations done with LS-DYNA

Don't ya just hate excessive compulsive bullet head gun nuts This is no "stretch" of the imagination radially or axially.

[ireload2]

"For a very rough chamber with a 0.55 Coefficient of Friction the movie shows the case stretching and thinning where case head separations usually occurs."

About half way down the page

[Edward Horton]

And look what he has to say in *red just below 0.55 Coefficient of Friction level.

[Edward Horton]

Got a nice email tonight from another forum, below is a PM from the Savage Shooters forum from another happy camper.

Note: How to measure head gap clearance (head space) with a fired primer and a new or fully resized case.







Close the bolt and then measure the case length.



The amount the primer protrudes is your head gap clearance or the "air gap" between the case and the bolt face.

[Badger]

Thread Closed !

Didn't another moderator just close a similar out-of-control thread just like this one?

Why the F$$$ is it being started over again accomplishing nothing accept seeding cannon fodder for more angst and anxiety !!!

I'm fed up and at the end of my rope with this scientific techno-babel drivel that has a unique audience of believers consisting of exactly one person, who endlessly promotes it all over the freakin forums ...

Geezzz... what does it take to get the message? My in-box is full of complaints from some pretty competent technical folks (including a metallurgist with a PhD physics), that many of the conclusions in these threads are based upon faulty data, scrounged Internet pics and extracts from selected articles, documents and manuals that simply create false generalizations. The content is more like Scientology then science! Not only that, but most of the time the post"creep" away from members original questions is so bad, it barely resembles what they were trying to find out in the first place, with the thread always seeming to morph into some bizarre argument about head spacing or condom lubricants, loaded with pics of Koala bears with arrows shoved up their a$$.

If I see one more self serving thread like this Ed, you might as well log off and keep going ....