Primers Large Pistol VS Large Mag Pistol

[maxarma]

New to the site all wondering about the do and don'ts on substituting Large Mag Pistol primers on loads for the 45 ACP.... I currently use a 5.6 gr. of Unique on a 185Gr. LSWC powering it with Win LPP... I have discovered this load works exceptionately well in my Taurus PT145... shooting 1 inch group at 20 yards. Any input would be greatly considered... I sure don't want to overpressure the chamber with large Mag Pistol primers... The reason I ask is Winchester large pistol primers say can use as mags... I came across Federal Gold MAg Match primers and I picked them up knowing how hard it is to get primers right now...

Chris

[versifier]

Welcome to Gunloads.

That's a relatively mild charge of Unique, but if you go back to the starting load and work back up, that would be safest. Standard procedure says reduce charge by 10% when changing any component and work back up, but if it were me, I would start from scratch because I have never used LPM primers in my loading and I would want to start with a clean slate, just in case a minimum charge happened to be the most accurate with the new combination. Often we miss important things by taking shortcuts, even when it is perfectly safe to do so. There is no problem with such a substitution, though it might have a noticable effect on the accuracy, and that effect might be positive or negative. Do you have a chrono or access to one? Data on velocity and accuracy changes would be great for folks forced by the current situation to make changes in their primers.

[maxarma]

Welcome to Gunloads.

That's a relatively mild charge of Unique, but if you go back to the starting load and work back up, that would be safest. Standard procedure says reduce charge by 10% when changing any component and work back up, but if it were me, I would start from scratch because I have never used LPM primers in my loading and I would want to start with a clean slate, just in case a minimum charge happened to be the most accurate with the new combination. Often we miss important things by taking shortcuts, even when it is perfectly safe to do so. There is no problem with such a substitution, though it might have a noticable effect on the accuracy, and that effect might be positive or negative. Do you have a chrono or access to one? Data on velocity and accuracy changes would be great for folks forced by the current situation to make changes in their primers.

no access at this time to a chrono but will work on it.. love the current load I have making a 1 inch group....

[The Keymaster]

This one is right up my alley. I have exchanged several emails with Federal relative to magnum vs standard primers. This came about when I noticed that the published specs on many of their factory 9mm loads included a #200 magnum primer. According to Federal, the only difference between the magnum and standard primers is the thickness. I was told that one can safely substitute Federal magnum primers for Federal standard primers. Just for further clarification, the reason Federal uses #200 primers in their 9mm ammunition is for use in machine guns.

[k-g]

I don't think Winchester has specific "Mag" primers, and they rate theirs "for standard or magnum loads";
BUT changing brand means that you have to go back to starting loads again and work up.
LEE has a warning about primers regarding the use of their Auto Prime tools, as they are not equal from brand to brand.

www.leeprecision.com

[k-g]

http://www.castingstuff.com/primer_t..._reference.htm