Appalling chrono results from my 44 mag loads! Disgusting!

[gamestalker]

In post #17 you said even with a firm crimp your bullets will creep up until they reach the bottom edge of the canelure. This is why I said to crimp at the bottom edge of the canelure, it will stop them from moving. This is an especially important crimping step for full tilt magnum cartridges.

GS

 

[RealGun]

How does a bullet get subjected to enough inertia to make it start to come out of the case? It is easier for me to visualize the possibility of it sinking deeper, when preceding rounds are fired.

 

[Walkalong]

During the recoil, while the case moves rearward with the gun, the heavy bullet wants to stay still. It's the old an object at rest thing.

 

[jack44]

My hunting load is 18gr. of 2400 and a BTB300gr. Good shooter.

 

[RealGun]

Walkalong - During the recoil, while the case moves rearward with the gun, the heavy bullet wants to stay still. It's the old an object at rest thing.

Got it. I was stuck on the "object in motion" part. But there must be some of that too, considering how one's hand and wrist can feel.

It sounds like, if there is any bullet creep, the crimp isn't right. Declaring the obvious, I guess.

 

[jmr40]

Did you use the same chamber for every shot? 6 different chambers will give 6 different readings.

 

[Walkalong]

I was stuck on the "object in motion" part.

Once it gets moving, yes, but it has to get started first.

if there is any bullet creep, the crimp isn't right. Declaring the obvious, I guess.

For most applications neck tension does the work, but in heavy recoiling calibers, especially with heavy for the caliber bullets, a quality crimp into a proper cannelure or a good crimp groove on a lead bullet is a must to help the neck tension. Over crimping hurts neck tension and can make bullet creep worse, but together, good neck tension and a quality crimp do the job.

 

[murf]

remember the tablecloth trick? pulling the cloth out from under the dishes on the table and the dishes don't move? well, in your scenario, the bullet would be the dishes and the case would be the tablecloth and the gun (with the quick and heavy recoil) would be the person yanking the cloth.

murf

 

[rondog]

Ever use a "hammer type" inertia bullet puller? Kinda the same principle. Heavy recoil and heavy, uncrimped bullets, they can get "knocked out" of the cases a little bit, enough to bind up the cylinder and make you talk ugly.

 

[zxcvbob]

How does a bullet get subjected to enough inertia to make it start to come out of the case? It is easier for me to visualize the possibility of it sinking deeper, when preceding rounds are fired.

You're forgetting about the rims on the cartridges still in the cylinder. When you fire the gun, the recoil causes the cylinder to whack the other 5 cases -- hard -- by the rims.