Small rifle primer vs Small rifle magnum primer

[AL45]

I have read many threads on this, but the answers always seem to vary. I have twice as many small rifle magnum primers as I do small rifle primers. The only thing I use these primers for are .223 and .454 casull. I bought the first 1000 magnum primers to use with H110 loads in the .454 casull. I mistakenly purchased the second 1000 magnum primers. My question is this. Is there a problem with using the magnum primers with any powder in .223 or .454 loads as long as I'm not at maximum powder charge? Thanks.

[mehavey]

Is there a problem...as I'm not at maximum powder charge?

For all intents & purposes, none.

[Shadow9mm]

Short answer, yes it should be fine.

Long answer, make sure you work the loads up from start. As i understand is magnum primers are generally used with ball powders, large case volumes, and in very cold conditions to ensure good ignition.

[Nathan]

Small rifle primers seem to be for all those small to medium cases running 35000-50000psi pressure. Small rifle magnums are helpful with medium size cases running up to 65000psi.

Generally speaking 223/556 is kind of on the border with light loads and definitely magnum with most common loads…especially with cfe 223 or TAC.

[lll Otto lll]

SR magnums can actually be beneficial with certain powders in 5.56. Varget comes to mind. Also with ball powders in very cold weather.
To answer your question, interchanging standard and magnum primers isn’t going to blow your gun up.

[reddog81]

Make sure your .454 sets them off before loading up a bunch. The magnum primers are harder to ignite.

[44 AMP]

If you talk to the people who make the primers, the usual answer you get is that the magnum primers contain a bit more priming compound than the standard primers.

This produces a slightly more "powerful" flash, possibly of slightly longer duration. With some combinations of cartridge case and powder this can raise pressures but how much is not a standard thing and I have seen data ranging from "no appreciable difference" to 5000psi difference.

IF your not working with absolute max permissible pressure, you can PROBABLY swap standard for magnum primers without any issues.

HOWEVER, the RIGHT thing to do, to ensure not just safety but also acceptable performance is to drop the load back to starting levels and work up using magnum primers.

Just remember every cartridge component combination could give uncommon or unexpected results. Probably won't, but could.

I have heard stories about switching to magnum primers in small cases (such as 9mm pistol) and having the "extra" force from the magnum primer unseat the bullet prematurely. I have no idea if this happens or is just one of those stories, but it seems possible, under certain conditions.

Work up your loads using the usual methods, I doubt you'll have any problems.