pick a load you like the look of and get testing. as Slim says stop over thinking it . get some loads done and work out what your smokepole likes. if you have magnum primers and want to use those well by golly do so. if you have regular primers and the load calls for them well where is the issue?
Ive used both types in my .270 in the past and just use regular winchester large rifle now.

"The Right Primer for Better Reloads" was in the May/June 2012 RiflesShooter. I was not able to find it on-line.

Good primer on primers here.
www.chuckhawks.com/primers.htm

Also consider that it is the primer that starts the bullet moving then the powder. I read in one book that benchrest shooters prefer mild primers as it allows powder changes to have greater relative impact on the accuracy of a load.

MacD wrote:

Also consider that it is the primer that starts the bullet moving then the powder.

I was interrupted by SWMBO once to do a chore during reloading some .223. Came back and finished loading my rounds. At the range I had 3 misfires. When I got home and pulled the bullets, the powder had completely vaporized. COAL was unchanged. Maybe magnum primers would have moved the bullet.

Then again, I've seen BR shooters that only seated their bullets in a 1/10 of an inch. I imaging a pistol primer might move those bullets.

Lesson learned. Don't let SWMBO enter man-cave during reloading.

I ALWAYS look into the case mouth before seating a projectile and shake the cases when cleaning lube off them to listen for a non rattler!!!!!

Slim:
I have only seen one gun go kaboom. It was an eastern European surplus pistol. The guy firing it was using steel cased ammo that looked pretty old. Occasionally he would get a fired case stuck and have to manually eject it by putting his hand and the pistol between his knees and hauling hard on the slide. Every now and then a round would make a loud popping noise rather than a bang. Lots of smoke when this happened. Finally he had one go pop and the slide stuck. He did his knee pull and then fired the next round. The slide, barrel and return spring all seperated from the frame. We retrieved the barrel and it had bulged and split a liitle way forward of the chamber. A bullet was lodged just ahead of the split. We drove it out with a srewdriver and its point was totally mashed. We couldn't find the fired case. My theory was that the primer fired but the powder didn't ignite on the previous round. This pushed the bullet into the barrel but wasn't enough to cycle the action. His next round was fired into a plugged barrel. All this to say that a mild primer in an empty case may be an unexpected blessing if it leaves the bullet seated in the case. BTW the the guy never even got a powder burn. Of course he blamed the ammo.

ok i will try both primers and see which works best . ive just always went by the manual as to which to use and the manuals say both ,lol
that mole hill is climbable tho lol

If all the components are the same the difference in primers is just due to the testers preference. If any of the components change then match your choice of primer to your components.
Bullet make and type, case capacity, cartridge overall length, and powder charge and lot can make a big difference in the pressures generated and velocities recorded. It has been my experience that pressure and velocity do not necessarily correlate in any meaningful manner. Just using three different large rifle primers gave variations in velocities of over 100 fps! (none were magnum primers)

I had bought a book "Any Shot You Want" by A-Square years ago and remembered that they did a test on pressures of a rifle with changing only one component. In this scan of 4 pages, it shows the difference of 12,000psi between different brands of primers!!

Load was 66grs H4831 with 160gr Sierra Spitzer BT, same components used except for primers.

Under "Conclusions": first 3 sentances sum it up nicely.

And I consider any change of any recipe significant. Mutliply by 2000 if you are a hot or anywhere near MAX loader. There's SO many veriables involved I can only safely say there's only one Rule of Thumb for me: When you change anything? Back it way down and START over.

I am starting to believe everything including the phase of the moon makes some difference.

+1 on Stovie's comments. Another good reason not to pursue the ultimate velocity. Except my 308 all my guns like moderate loads or so it seems. I think the 308 would too except I insist on the heaviest bullet it will shoot for hunting level accuracy.

Interesting, the velocity difference as insignificant. I will be working with both standard and magnum primers in my 6.8. It will be interesting to see what I find.

my shotgun loading manual does these tests aswell and the results show the same thing.....