relationship of load density with failure to ignite powder

[George63]

OK - here is one for this season since most of the failure to ignite inconstancies happen in cold conditions

this is what I am finding: a powder that is faster ( so should ignite easier ) is showing slow ignition / ignition failures with the same primers vs. a slower powder with a higher density charge

ie:

2 different years, both times around 20 F

338 LM 87 gr R22 win magnum primer slow or no ignition -- when 95 gr R 25 / same primer is fine

338 LM 85 gr H4831 SC CCI mil primer - no ignition ( scorched powder ) --- when 102 gr of R33 / same primer is fine

any one else concur that when you are around 100% case fill, the failure to ignite the powder problems are less

I think if I could find the hotter Fed magnum primers it might be a cure

the 338 LM is apparently at the edge of being able to use a LR primer

I am understanding why the 50 BMG needs that big ass primer, especially with the common load of slow ball powder

 

[BuzzBoss915]

My casual rule of thumb is anything over about 75 grains of "relatively" slow burning powder requires a magnum primer.... except maybe the winchester 8 1/2, but probably not at those themperatures? So, I would say you are looking for trouble.

They say R22 is particularly temp. sensitive? Don't know, I only have one application and it's only 56 grains? BB