Projectile material vs Pressure

[1shot]

Regarding the reloading of shotshells:

Could someone please explain to me why 1oz of lead would create a different pressure to 1oz of steel?
All of my reloading manuals simply say "Don't do it", but whats the difference? All I see is that the higher velocity of steel loads require a slower powder to keep the pressure down during acceleration..

Cheers!


1Shot

 

[Ganderite]

I don't know the answer to your question. I used to work in ammo R & D and can say that many facts are counter-intuitive - but the pressure guns don't lie.

The guys who write loading manuals get to test every combination you could think of. Testing not only proves what works but what does not.

I can say, with some authority, that shotshells have many more variables than rifle and pistol. Things like wad and primer take on special significance.

If they say "don't" then I would take that to the bank.

 

[Veovius]

Absolutely Zero experience reloading, but here's a theory :

Maybe the lead moves down the barrel slower, giving the powder more time to burn in a smaller volume, compared to the faster-moving steel?

 

[ben hunchak]

One oz. of steel takes up more internal capacity then lead, when you add the extra thick wad required for steel, and the fact that steel does not "compact" at all on ignition, you are asking for high pressures...they are very diff. and require very diff. charges/wads/powders........the shot column length of 1oz. of steel may be twice as long(inside shell) as 1 oz. of lead.....THIS IS VERY MUCH A SAFETY ISSUE!!!

 

[1shot]

Ok Ben, that makes perfect sense what you're saying about the wad taking up the slack on acceleration.

Thats what makes this forum worth reading.

 

[SandRoad]

Absolutely Zero experience reloading, but here's a theory :

Maybe the lead moves down the barrel slower, giving the powder more time to burn in a smaller volume, compared to the faster-moving steel?

OK, so which weighs more, a pound of lead or a pound of feathers?

I agree with ben, there is less internal volume when steel is used so pressures will be higher. No different than in metallic loading (especially handgun) if you seat a bullet deeper, the pressure can rise considerably.