How much of an accuracy difference can primers make?

[Felix]

If you haven't run across Dr. Bill Riehl's new website yet, I predict it's going to eventually turn into a great resource for serious reloaders. Right now the site is oriented primarily toward 1911-style pistols but posts like the following show it has potential for furthering the education of a lot of us who do match-quality reloading for competition.

Riehl, doctorate in chemical and materials engineering from the University of Dayton and username Feral, pontificates on primers and discusses his company's plan for manufacturing specialized or tuned primers because he feels "the next big step in accuracy will be done by developing primer intensities similar to powder burn rates." He goes on to talk about how he believes the .40 S&W requires a different primer composition from anything currently available to bring its accuracy potential up to .45 ACP levels. And his manufacturing company plans to do just that.

Link Removed

 

[jtg452]

Thanks for the link. I'm gonna have to keep an eye on his developments. I knew from my own experience that the .40 was a different kind of critter than any of the other semi auto rounds I have loaded (.32ACP, 9mm, .38 Super and .45ACP) but never really considered the primer as a variable (mostly since there hasn't been an option other than changing between Magnum or Standard small pistol primers).

 

[-06]

Would take a real serious comp. shooter to be concerned with any minor variations of primers. But perfectionist worry about real and imaginary variations in every aspect. Nature of the beast I suppose. If it concerns one then worry about it. An just a lead chunker now but still like to "chunk em" in the black.

 

[Punch]

To get maximum accuracy, you have to have maximum consistency in your loading. If the weapon does its part, a bullet leaving the barrel at the exact same velocity as the last bullet should hit in the exact same place as the last bullet (ignoring other variables). This can become an issue with bench rest rifles where you are trying to see how many bullets that you can put through the same hole at 100 yards. However, given the standard combat pistol and given the standard skill level of most CCW holders, the differences between one primer and another are not likely to be noticed.

 

[SC Tiger]

It seems to me that primers could be an issue if you are getting inconsistent ignition, resulting in differences in velocity. To prevent this you could switch to magnum primers but this can cause an increase in case pressure which could end very badly if you are pushing the envelope. I have used both interchangably (actually I made 25 rounds with magnum primers instead of standard as a mistake) with sub-maximum loads (.357 magnum - 17 grains of 2400 behind a 110 gr JHP bullet) and didn't notice a difference.