Do you rework a load when changing primers?

Pistol ammo for the range, no. Pistol ammo where accuracy and/or velocity is needed, yes.
Rifle ammo, yes I start low and work up.

No.

If they are the same type of primer no. Meaning if I go from Winchester standard to CCI standard I don't change anything.
If I go from a standard to a magnum primer then yes, I back off a 2 tenths of a grain of powder if I'm trying to keep them the same.

Scout21 said:

Say you have a load worked up and you run out of your chosen primers. Do you rework the load if you can't find identical replacements? I know you're supposed to start at minimum when changing any components, but I'm curious if others follow this rule when it comes to primers.

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I may be able to answer this for you.
This is what I’ve learned shooting long range.
With any component change a node can and most likely will shift slightly or aggressively, when shooting at only 100 yards you may not notice however when distance increases the difference becomes quite clear.
Testing primers is a better or worse side by side comparison best accomplished by loading a few rounds of each primer at small incremental charge weights on each side of the original node, shoot the groups at the greatest distance you are comfortable with and note the changes.
Some guys load their ideal charge weight useing several different primers to look for a winner. As below vvv

If I'm anywhere near the red line...YES! If it's a mid-range load for casual plinking in an iron sighted military bolt gun...no. If it's a finely tuned match load...YES! If it's a hunting load that is a grain or 2 below max...no, but I will test accuracy and POI and observe brass for any pressure signs.

Well, I shoot it first and see if I need to take further action.

So, none of the above.

Scout21 said:

Say you have a load worked up and you run out of your chosen primers. Do you rework the load if you can't find identical replacements? I know that for safety reasons you're supposed to start at minimum when changing any components, but I'm curious if others follow this rule when it comes to primers.

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Depends. I always drop back one regular ladder step and sometimes that means going back up closer to the minimum load. The industry does a pretty good job of keeping things like primer pressure and brisance, cup thickness and tensile strength, to a tight standard but there’s only so much they can do. They are making explosives after all. There’s a lot of voodoo mixed in with the chemistry.

Blasting ammo and such... no. Most of my pistol cartridges, no, because the majority of them are not near max data. I also use powders that are not necessarily sensitive to primers... like Unique and IMR4227 (although there are many that say IMR4227 needs a Magnum primer, I am not one of those.)

Rifle cartridges loaded for accuracy... yes. Back Home, Years Ago, I never paid much attention to the primer... a primer was a primer. I had settled on CCI, anyway, as my primary stash, but these days you have to run what you can find. It wasn't until recently that a few of my test loads showed minor to significant accuracy and POI changes... based almost completely on the primer used, so now I know I may have to rework the load slightly with a different primer.

Seldom, if ever. Unless I use a mag primer, which is seldom.

I voted no. I also don't have any loads that are anywhere near a maximum load. If I were at the upper end of pressures, my answer would be different.

Same size same "power" different manufacturer? No. Different power (standard vs. Magnum) pistol vs rifle? Yes. Normal "Reloading 101"; any time a component is changed do another load work up...

I always confirm my nodes again any time I change lots of components, let alone changing brands. Usually, nothing changes, or very little. Sometimes, I’m very glad I redefine the nodes.

Glad this topic came up ! I'm getting low on CCI 200 LRP that I use in .308, and I'm going to have to break into a brick of CCI#34 that I've had stashed for a while. My most accurate load to date is 42.8 gr of IMR 4064 pushing a 168 gr hpbt. Nowhere near the max.
The #34 is described as a magnum primer. Should I be OK to stay @ 42.8 grains and just see how accuracy is affected, or should I back the powder down a little ?

Anytime I change primers I reduce the load a little and retune.

45 long said:

Glad this topic came up ! I'm getting low on CCI 200 LRP that I use in .308, and I'm going to have to break into a brick of CCI#34 that I've had stashed for a while. My most accurate load to date is 42.8 gr of IMR 4064 pushing a 168 gr hpbt. Nowhere near the max.
The #34 is described as a magnum primer. Should I be OK to stay @ 42.8 grains and just see how accuracy is affected, or should I back the powder down a little ?

Click to expand...

Just test a bit on each side of that original charge, you should be fine.

No

As already stated ; IF YOU'RE NEAR MAX LOAD IT WOULD BE ADVISABLE !.

Very BAD things can jump out and BITE You should you be on the verge of blowing primers and You change to a Hotter primer .

Very few people ever consider PRESSURE variants ; What's Funny is ALL Shotshell Reloaders DO !!!!!!!!.

In all my reading about reloading I have never read of a single incident of a gun blowing up because someone changed their brand of primers. I think it would be helpful to the OP if we could provide some examples of this happening.

My long range stuff, yes... except I have 10 lifetimes of primers for those, so in reality that will never happen. Everything else... I'll load and shoot a few to verify. Back in the obama years, i did a lot of primer testing and found that it made such a statistically insignifant difference, wasn't worth wasting time on for your average handloader. Maybe somebody loading match ammo, or benchrest ammo and measuring group variations in .1 or .01 increments... maybe it would be a factor. The best answer to your question is to buy primers in 5K cases when times are flush, and always make sure you have an unopened case in the closet. And that suggestion is for average loaders. If you are a high volume shooter, adjust accordingly.

Primers are a fairly simple device. I am really not sure how someone could make one wrong.

I've done this many times. Assuming I'm not going to/from a magnum primer:
With pistol rds I just chono them to make sure the velocity and ES hasn't changed much.
With rifle rds, of course I chrono and check group size and POI.
I have seen slight changes in group size with some rifle rds when changing primer brands, but it's never been more than a 1 moa change and I can usually adjust my charge enough to get it back.

Scout21 said:

Say you have a load worked up and you run out of your chosen primers. Do you rework the load if you can't find identical replacements? I know that for safety reasons you're supposed to start at minimum when changing any components, but I'm curious if others follow this rule when it comes to primers.

Click to expand...

Rifle plinking loads, no. Its blaster ammo, and its not warm, if the group grows a 1/4" I dont care
Pistol loads, no. Im not a good enough shot to notice and my loads arent overly warm
Rifle loads where accuracy is expected, yes. Mostly for ammo Im shooting where I expect good groups at 500 or more.

If I had a place to test them in my yard any time I would certainly load an experimental batch to pass over chronograph. But if it’s just brand or match related, and not LRP to LRMP, I would probably cautiously load in situ

Scout21 said:

Say you have a load worked up and you run out of your chosen primers. Do you rework the load if you can't find identical replacements? I know that for safety reasons you're supposed to start at minimum when changing any components, but I'm curious if others follow this rule when it comes to primers.

Click to expand...

For plinking/general shooting loads? No, as I haven't seen enough differences to worry. If for precision loads, long distance or hunting, yes.