Home Forums Reloading Big Game Rifles How much powder is a magnum primer worth?

Close to getting a load finalized for my tikka 6.5x55. Using ramshot magnum, and 140 grain interlocks. During load work up, I never got pressure signs before running out of powder space and while it was accurate I wanted to experiment and try magnum primers. Switching from standard large rifle (federal) to magnum large rifle (cci), I started by dropping down 3 full grains of powder and working up from there. The starting load flattened the primers (very flat). Remember that I saw no pressure signs with the standard federal primers and an additional 3 grains of powder. Does this make sense? It surprised the heck out of me.

The best way to tell if you have higher pressure with one load than another is with a chronograph.

The magnum primers could just be softer.

I did have that thought also as the loads with magnum primers actually impacted lower on the target. Don't federal primers have a reputation as having softer cups than CCI though?

GUhunter,

Despite what many handloaders believe, primer flatness is practically worthless as a pressure indicator, for a couple of reasons.

Mule Deer,

I hoped you might chime in. Your posts led me to using Ramshot Magnum in this cartridge in the first place.

So how did the load shoot?

Measured at .668 for 3 shots which is pretty well in line with its preferred charge with the standard primers.

My reasoning for further experimentation (other than I can't help but tinker) is that, because I ran out of powder space before seeing anything concerning as far as pressure, I felt I was leaving some velocity on the table. I know an extra little bit of velocity matters little in the real world, but I'm just trying to look at all possibilities.

Isn't Ramshot Magnum a ball powder?

I would of started with a magnum primer.

As for the POI shift, they are very common with a change in primers. It can have more to do with a shift in harmonics then a change in velocity.

I often play with primers to optimize accuracy, not velocity.

Yes, a ball powder. Perhaps I should have started with a magnum primer but I've read and heard many times that it is less necessary than many would lead you to believe, even in a cold Wyoming winter.

I truly expected to see pressure before I ran out of powder space with this combo but since I didn't, I reasoned that I might be able to get a bit more out of it by going to a magnum primer. Accuracy has been plenty good and easy to obtain with this combo and I don't particularly need it to do better in that department than it's already done.

Exactly. Even if you compare primers of the same type out of the same lot, you can't derive much pressure information.

Also note that different types of primers have different thicknesses of metal.

A chronograph is your friend.

I have gone for velocity in a Swift.
Worked too! smoked the tube in 1500 rounds.
Launched a 52 SMK @ 4050. H-380 max + and mag primer.
Speer load.