View Full Version : Are different brand primers interchangeagle in the "recipe books"?
I want to start reloading soon in 45acp. I have done lots of reading. One source said NO and another said YES as long as you start with the minimum load. (and use the same primer for all of the loads). With some recipes, they dont say which brand primer is used.
For start loads they are interchangable. Some loads require magnum primers and most loads don't use magnum. But as far as brand is concerned, use starting load data and don't sweat it.
ETA: For 45 ACP, don't use magnum primers.
^^^^ what he said! As far as protocol goes, anytime you change or substitute a component, always drop back and work back up.
I know what you mean. I've read pretty much ever book I can get my hands on and there is more variation between each than I was expecting to find. A few are specific with the details and others are not, leaving out important things like OAL or brand details. Start low and work up. I also try to stick to one brand of primers.
The politically correct answer to your question is that you should work up any load after changing any component. However, I don't think any of us (unless we have access to pressure testing equipment) has a reliable way to detect the kind of pressure changes that might occur with a change in primer brand.
You asked about the .45 ACP cartridge. SAAMI maximum pressure for this round is about 21,000 psi. Suppose you had a load that developed 20,000 psi and you changed primers. Now let's suppose that the primer change had a big effect and raised pressures to 25,000 psi, well above SAAMI maximum. How would you know this? Some people would say "Look for primer flattening.". But primer flattening usually doesn't occur below 35,000 - 45,00 psi and is very dependent on the hardness of the primer cup. The kind of pressure signs that suggest impending doom, like blown primers or loose primers occur at much higher pressures than would be caused by changing primer brands. So I think we're stuck with not really knowing the answer to your question. I've loaded countless thousands of .45 ACP in mixed brass with many different kinds of bullets, powder and primers. I've generally kept away from absolute maximum loads and have never had a problem in a variety of revolvers and automatics.
If your loads are well off max, substituting a like primer for a like primer will have little affect (ie, standards cci for standard Fed). If your load is running the top end, it's wise to back off 5% when substituting, just in case, & work back up. Primer spark does vary from brand to brand, how much, only a pressure testing equip will tell you for sure, but it can matter.
I ran a test in 45acp using Wolf LP vs RP w/ 5.6gr of W231 & 230grLRN. The Wolf ran about 40-50fps higher vel. That tells me the primer is putting out a bit more energy than the RP.
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