Magnum vs. Standard primers

[Devil Dog]

An older box of Winchester large rifle primers I just finished using up states that the primers are for "Standard or Magnum rifle loads". The newer boxes of Winchester large rifle primers I recently bought just say for "Standard rifle loads". What is the difference? Both are marked "WLR". Likewise, my Winchester large pistol primers say "standard or magnum" while the Winchester small pistol primers just say "standard". What gives?

Also, what is the rule for substituting Magnum large pistol primers in a load normally using standard primers? My normal .45 ACP target load is 4.8 gr. of W-231 under a 200 gr. lead SWC with the Winchster "standard or magnum" primers. I'd like to use up a box of 100 CCI 350 Magnum primers that I have had around forever and don't even know why I got them in the first place...

Thanks,

D.D.

 

[Grumulkin]

Substituting large rifle for large rifle magnum primers in medium to large rifle cases will make no appreciable difference in pressure though accuracy may be affected.

If you're using a conservative 45 ACP load (i.e., not right up at the maximum listed recommended load) I wouldn't think interchanging large pistol with large pistol magnum primers would make any difference in pressure either. I've done it with 44 Magnum loads with no problems.

I even tried large rifle magnum primers in 44 Magnum loads. With 44 Magnum loads with H110/Win. 296, I had to reduce the powder charge by 1.5 to 2 grain when using the large rifle magum primers.

 

[the_right_reverend]

good primer info from some one that would be considered the guru

http://www.jamescalhoon.com/primers_and_pressure.php

 

[MovedWest]

I've done all kind of tests with magnum and standard LP primers in my 44 magnums. From what I can gather the offset of the load is about 5%.

For instance if I'm building a load for a LPM primers that works with standard LP primers, I subtract 5% of the powder by weight and it gets me in the ballpark on velocities. I can't speak for the pressure, but velocity is comparable.

I've done most of my testing with 2400 and Green Dot. YMMV

-MW

 

[tango2echo]

Exactly what he said.

I've been using LPM for .45ACP with POWER PISTOL for about 1000 rds now because it was all I had. Reduce by 5% and I get the same FPS.

I usually only use LPM when I am loading H110 or 2400 (.357, .44, etc) and LRM when it is a large case full of slow powder. (.338WM, .300WM, etc) SD is usually lower with the magnums IME.

 

[W.E.G.]

Thanks for that link Rev.!

 

[ArchAngelCD]

Here is the link for primers available from Winchester. As you can see they no longer offer separate LP primers for standard and magnum use. They are combined as you mentioned but they are clearly marked for standard and magnum use. However, Winchester does have 2 large rifle offerings, WLR #8-1/2 Large Rifle and WLRM #8-1/2M Large Rifle Magnum primers. I don't recall even seeing a combined use LR primer like the LP primers.

I have used the WLP primers in standard loads without having to modify the charge at all when changing over from CCI primers but Winchester WLR/WLRM primers are a whole different case.

Welcome to the forum Devil Dog...