Clark
Member
CAUTION: The following post includes loading data beyond currently
published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the
writer, The High Road, nor the staff of THR assume any liability for any
damage or injury resulting from use of this information.
I necked down .308 brass to 243 and did not ream the donut or turn the necks. The load, 40 gr IMR4895 100 gr, was ~60k psi , but for bullet pinch.
The three rounds have the same charge, and took allot of force [~100 pounds] to close the bolt.
This bullet pinch causes pressure spikes faster than more powder, faster powder, heavier bullets, or deeper seating depth. A little bullet pinch makes big pressure changes.
I think that bullet pinch can be a problem with 9x19mm as well.
I was working up a Power Pistol overload with 158 gr XTP 1.169", and it
was ok with 8 gr, but the primer always fell out at 8.5 gr.
Because the powder was being severely compressed, I decided to correct
for bullet pinch.
I double compressed the powder charge [to prevent bullet squish] and
resized the loaded ammo with a 9mm sizing die with the decapping stem
removed.
I was then able to load up to 11 gr, and there we no more pressure
problems. This is stout load as the Alliant max load for 357 mag is 8 gr
and has a 1.59" OAL.
I am concluding that bullet pinch was what caused the pressure problems
at 8.5 gr.
published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the
writer, The High Road, nor the staff of THR assume any liability for any
damage or injury resulting from use of this information.
I necked down .308 brass to 243 and did not ream the donut or turn the necks. The load, 40 gr IMR4895 100 gr, was ~60k psi , but for bullet pinch.
The three rounds have the same charge, and took allot of force [~100 pounds] to close the bolt.
This bullet pinch causes pressure spikes faster than more powder, faster powder, heavier bullets, or deeper seating depth. A little bullet pinch makes big pressure changes.
I think that bullet pinch can be a problem with 9x19mm as well.
I was working up a Power Pistol overload with 158 gr XTP 1.169", and it
was ok with 8 gr, but the primer always fell out at 8.5 gr.
Because the powder was being severely compressed, I decided to correct
for bullet pinch.
I double compressed the powder charge [to prevent bullet squish] and
resized the loaded ammo with a 9mm sizing die with the decapping stem
removed.
I was then able to load up to 11 gr, and there we no more pressure
problems. This is stout load as the Alliant max load for 357 mag is 8 gr
and has a 1.59" OAL.
I am concluding that bullet pinch was what caused the pressure problems
at 8.5 gr.