Canadian Bushman
Changing primers can skyrocket your pressures!!! The NRA has recorded changes as high as 13,000psi. Pistol ammo is the worst. But the dynamics going on in the cartridge case of the shot are very complex and beyond us mere mortals to predict. That being said, some guide lines from the experts:
1) Different primers can and do change the load.
2) Changing from a magnum primer to a regular primer of the same BRAND and TYPE will lead to lower pressure most of the time and the same pressure some of the time.
3) Changing from a regular to a magnum primer of the same BRAND and TYPE will RAISE PRESSURE! This is a done deal. It always goes up.
4) Different Brands have different characteristics. Different amounts of initiators and fuel. So it stands to reason there would be a change in load performance. Example; I have a load for 30/06- 180gr Seirra SpBT+ 56.5gr IMR4350+ Rem 9 1/2 LRM primer+ WW case. SD= <20fps. Change the primer to Federal #210, a primer that has always delivered VERY low SD, and this load goes to 30fps SD. Alot? No. But without trying you won't know. Why? Don't have a clue.
5) IN MY EXPERIENCE, the standard LR primers give similar pressure and velocity across the brands. But you will find a specific load likes a certain primer. There is a HUGE difference in Magnum LR primers. Federal is King of the Hill, the Remington #9 1/2 is pretty close. Both of these are pretty hot numbers. All the rest fall into the last category of hotter-but-not-by-much. Some don't show much difference than standard LR primers but I do not use any of them as the Federal & Remington #'s suit my needs.
Hope this helps. The Match versions are held to closer manufacturing tolerances and I feel they are worth it for everything but practice (cheaper) loads. No performance difference but somebody is checking everything twice or thrice and you are less likely to have a bad (out of spec) one.
Hope this helps. Change your powder around first in a new load then try different primers to dial it in. Primers are the next to the last thing I play with. Seating depth is the final resolution.
Just sayin'.