flattening primers

Leica Amplus 6


Well-Known Member
hello all some advice needed

i have recently changed my rifle and have been trying some loads to see what she likes.

during my trialing of powders loads etc i found that H414 powder was flatening the primers. i started low and worked my way up and found the primers were flattening at 1gr under max load so i stopped there.

i did the same with VARGET and found no probs at max and even slightly over max. i have checked the CUP pressures on the HOGDONS site and they are about the same for both at max loads

i am using once fired REM brass CCI 200 primer cases neck sized and trimmed. should the primers be flattening below max loads.

i look forward to the replies........neil


Well-Known Member
Flattened primers

There are many possible reasons for flattened primers, only one of which is too much pressure.

Yes. a flattened primer is a reliable hint to back off, however other factors may come into play.

A damp or lubricated chamber, sizing wax or lubricant left on the cases, oversize chamber, tight headspace in some circumstances, undersized brass, loose or worn primer pockets etc.

All of these and others will allow the case too much mobility in the chamber and may result in flattened primers.

The real questions is are you seeking to maximise your load or have you found a load that is precise and powerful enough for your requirements with the charge below primer flattening level?

Incidentally, IMHO, powder manufacturers pressure information will always err on the high side for product liability and legal reasons.


Well-Known Member
thanks charadam

i have found my load that suits the rifle and is below the max loads this primer flattening just go me wondering ....neil


Site Staff
Primer flattening is a recognised presure sign, and as stated not the only reason. However in this case as you worked up to this load and a different powder produced different results, I would go with too much pressure.



Well-Known Member
under pressure

Is the varget and H414 going into the same brass?

I have to say i would say if they are that it is a symptom of pressure.

Leica Amplus 6