Originally Posted by
simgre
Dropping your load to around half of where it should be will probably give you incomplete obturation, fluctuating pressure and erratic performance. Potentially this could lead to a barrel obstruction and an explosion then likely.
I’d say the advice give so far has been good. There are some lovely, light and accurate recipes out there fir 100 yds with a .303. But none of them are with the components you want “to keep it simple” with.
Reducing powder is often more dangerous than increasing it.
Halving the charge is likely to lead to an explosion in the chamber with far greater pressure then normal and cause the brass to flow back at best and complete destruction at the worst.
I have seen this happen on three occasions with 223 cases where it is hard to over charge with the most common powders but they can be easily undercharged. Each time the chamber detonation as some would call it or secondary explosive effect (S.E.E.), I prefer pressure spike, was caused by reducing the powder deliberately (one instance) or not noticing 'bridging' in a Dillon powder measure (the other two instances). I still have some of the parts of one of these here where I keep them just for show after having to rebuild the rifle.
I have been told Hodgdons did a lot of research into this and found that a reduced load could leave the primer flash hole exposed, the pressure from the primer igniting could push the bullet out of the case where it would lodge in the rifling. The powder then ignites and the pressure would have to build up more (often to dangerous levels) in order to start the bullet moving again now that it is stuck in the rifling with the accompanying extra friction. They couldn't get the powder to detonate from the flash of the primer firing across the total surface of the powder in a half filled case.
ETA:
My 'light load' in .303 is not much lighter, certainly not light enough to be called a reduced load. It is 36.2gn R7 with 174gn FMJ or SMK bullet. Felt recoil is much nicer and although I haven't chronoed them yet the come ups are slightly greater than the older surplus or S&B 303Ball. Makes it a pain as I have to remember the come-ups whereas with surplus ammo the old sights are pretty much already calibrated.
Last edited by sarge4318; 10-05-2020 at 11:36 AM.
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