Thread: Anyone used 2206h/4895 for .308 subsonic load?

Originally Posted by Sharki

u obviously know what u doing - just be aware of low volume loads in bigger cases - "Flash Over" can happen or secondary explosive effect - I cant remember which one the blokes with the white coats and thick glasses decided on to eventually blame for a burst gun

Greetings @Sharki and all,
There was a very good article in Handloader decades back dealing with this which the writer called "Secondary Explosion Effect". At the time opinions varied as to whether it existed or not but the writer managed to reproduce at will. The problem seemed to be with slow powders in large cases of small calibre. From memory he was using something like a 6mm-06 and 4831 powder which may have been military surplus. His take on it was that the powder charge ignition stopped or was delayed sometime after the primer ignites allowing the projectile to be driven into the rifling a little before stopping. A rough throat from the hot shot cartridge could also have been a factor. The bulk of the charge then ignited behind the projectile which had almost become a barrel blockage. No problems were found with heavier charges.
A light load of 40 grains of 4895 was used in the .30-06 behind the standard 150 grain projectile as a light practise load and a 200 yard target load for years and I used 38 grains in the .308 for the same purpose without problems. Hodgdons marketed both 4831 and 4895 as milsurp powder from the late 1940's so they will have been aware of all this so we should not go below their loads for H4895/ AR2206H. We also should not use any loads not listed in pressure tested data offered by the powder and projectile companies.
Regards Grandpamac.