Bullets pushed in !!

[SandRoad]

Well I might have to reverse myself on that. I knew pressures would rise a bit but I didn't realise that it was quite on that order. Glad to have learned something.

When I ran the numbers I was also VERY surprised. As I said, the numbers are from a model and are not exact, but just the magnitude of the numbers really surprised me. Even if the model is off by say 100%, the calculated 200 to 300% above design pressure is still really high.

Also, the maximum pressures are generated when the bullet has travelled about 1/8" from where it is seated in the case. At the standard pressure and OAL, the max pressure is generated after about 1/4" of travel.

Short, straight wall cartridges are most affected by bullet setback.

In this example, a 9mm with a 125gr RN bullet, the interior case volume was reduced from 0.514 to 0.287 cm3, a 44% reduction. Obviously setting a bullet back in a longer case straight wall case or in a bottleneck case will have substantially less effect because the PERCENTAGE decrease in case volume is less.

I prefer posting with solid information, and not just speculation. I hope this has helped.

 

[smokingunns]

If you're not sure and don't want to risk damaging your gun as per the other posts, give them to someone that reloads who also has a bullet removal tool....they can reload this.

You're probably doing them a favour with the cost of FMJ bullets these days