[popforall]

My local gun store just received some CCI 450 small rifle magnum primers. I have heard that that are OK to load in .223/5.56. Has anyone had experience with that? Thanks.

 

[howlnmad]

I've used them instead of SR with no problems. But I don't load near max loads.

 

[popforall]

That is what I have heard. Stay in the lower half of charge load and should be OK.

 

[jim brady]

Like anything else when you swap components - work up your loads. It's crazy that all that seem to be universally available are 'magnum' primers. The manufacturers can make magnum primers out the wazoo but can't produce standard primers? Somethings fishy here.

 

[mathews691]

Like anything else when you swap components - work up your loads. It's crazy that all that seem to be universally available are 'magnum' primers. The manufacturers can make magnum primers out the wazoo but can't produce standard primers? Somethings fishy here.

Perhaps because they CAN be used in place of "normal" primers, but normal primers can't be used at magnum pressures?

For the record I have used magnum large pistol in my trapdoor 45-70 for quite some time. The pressure in those loads are around 14k, well under a 357 middle of the road pressure. I have never had the slightest hint of an issue.

 

[howlnmad]

Perhaps because they CAN be used in place of "normal" primers, but normal primers can't be used at magnum pressures?

I load 7mm RM with IMR4350 and 140 Noslers all the time. Book calls for LRM primers but I have been using standard LR for years with no problems.

 

[jim brady]

Just thinking about the difference between the mag primers and the standard primers. The main difference being the hardness of the primer cup. Wondering about the ability to withstand very much more higher pressure with a magnum primer vs. a standard primer..... Primer cups are not as thick as the brass webb in a cartridge case, so I wouldn't imajine that the strength of the primer cup really would add to the strength of the cartridge case. Maybe a little if any at all.

That being said, there is a difference and swapping one for the other isn't something to just take for granted. There is also supposed to be a difference in the power of ignition, but everything I read so far seems to point to very little to no difference in the pressures created on firing. That IS everything that I've read - and that certainly doesn't make me any sort of expert on primers.

 

[vassago]

Perhaps because they CAN be used in place of "normal" primers, but normal primers can't be used at magnum pressures?

And what are magnum pressures? .357 magnum, 44 magnum and the like are the same pressure as 9mm luger/.40 S&W (.44 1K higher I'll give you that).
Also you will not find many cartridges with a higher pressure than .223 or 5.56 which are using a "normal' SR primer.
As far as I know a magnum primer is used for hard to ignite powders and/or large powder columns, not necessarily magnum rounds.

Coincidently I bought 2 bricks of Murom SRM primers because they were cheap-ish and I was fairly sure my pistol would ignite them with little issue.
I measured the velocities with both S&B SPM and above SRM and the difference was too small to measure with my small sample size of 5 rounds each.
(Ie. no evidence of higher pressure of hotter primer)

 

[mathews691]

And what are magnum pressures? .357 magnum, 44 magnum and the like are the same pressure as 9mm luger/.40 S&W (.44 1K higher I'll give you that).
Also you will not find many cartridges with a higher pressure than .223 or 5.56 which are using a "normal' SR primer.
As far as I know a magnum primer is used for hard to ignite powders and/or large powder columns, not necessarily magnum rounds.

Coincidently I bought 2 bricks of Murom SRM primers because they were cheap-ish and I was fairly sure my pistol would ignite them with little issue.
I measured the velocities with both S&B SPM and above SRM and the difference was too small to measure with my small sample size of 5 rounds each.
(Ie. no evidence of higher pressure of hotter primer)

I was going off the numbers in one of my manuals.....I will try to remember this after I get home tonight and post it up here. I believe I also ran the numbers in quickload to see what it thought about the pressures.

 

[popforall]

And what are magnum pressures? .357 magnum, 44 magnum and the like are the same pressure as 9mm luger/.40 S&W (.44 1K higher I'll give you that).
Also you will not find many cartridges with a higher pressure than .223 or 5.56 which are using a "normal' SR primer.
As far as I know a magnum primer is used for hard to ignite powders and/or large powder columns, not necessarily magnum rounds.

Coincidently I bought 2 bricks of Murom SRM primers because they were cheap-ish and I was fairly sure my pistol would ignite them with little issue.
I measured the velocities with both S&B SPM and above SRM and the difference was too small to measure with my small sample size of 5 rounds each.
(Ie. no evidence of higher pressure of hotter primer)

Thanks for all the thoughts

 

[Hawg]

Perhaps because they CAN be used in place of "normal" primers, but normal primers can't be used at magnum pressures

I wish I'd known that when I was loading .44 magnums with W296 and standard large pistol primers (CCI 300).

 

[Gudaki]

I've loaded thousands with magnum small rifle without any issues.