Magnum Primers and 2400

[Sky Master]

I have several hundred small magnum primers on hand that I used with 296. I'm currently using 14gr of 2400 with 158gr JHP and standard primers in my 357 but would like to use up the magnum primers. Would I need to reduce this charge or can I stay with the same charge?

 

[steveno]

back off a couple of grains and work back up. obviously 2400 doesn't need magnum primers but as long as you work up to a load it ain't going to hurt anything

 

[jimbob86]

I had better velocity with standard primers and a 158 XTP over 14 grains of 2400 than with magnum primers.......

Dunno why. Just is.

 

[rclark]

Would I need to reduce this charge or can I stay with the same charge?

Back off a grain. 2400 is primer sensitive.

Here was my test results back to back with .45 Colt :

18g 2400, 255 SWC, CCI-300 1022fps average
18g 2400, 255 SWC, CCI-350 1181fps average

That is a 159fps difference which is 'significant'.

If you were using Unique (not primer sensitive), you would be able to use either no problem.

 

[azklmsr]

i've seen significant sensitivity with Unique and mag primers, 125 JHP. 9.4gr, std primer, no pressure signs. 8.8 gr and mag primer, very sticky extractions. This was on a GP100.

2400 and 45 LC, Blackhawk. 20 gr, std primer, 255 grain LSWC, no sign of pressure. 18 gr, same bullet and gun, Mag primer, sticky extraction.

So my experience has me back off considerably from non mag primers first.

Good luck and please post your results

azklmsr

 

[Sevens]

I chose Alliant 2400 in the first place because it works phenomenally well in many loads without the use of a magnum primer. For me, I'm willing to give up the extra bit of velocity that H110/W296 will almost certainly provide for the ease of stocking only the primers I've used for so long... and not having to add magnum primers to my shopping list.

It has been the result of some testers and experimenters (NOT me) that using a magnum primer in a load with 2400 is not a great trade off and can disrupt accuracy and repeatability. The theory is, as I've read, that the strong primer blast and shock starts a forward movement of the bullet before a proper burn and development of gas can do that work. I'm sure this is quite dependent on bullet pull and/or crimp.

I have NOT come up with this theory on my own, I have NOT done my own testing and I will NOT guarantee that this is anything more than a theory, but it's not something I simply came up with in my own head to justify my avoidance of magnum primers.

To the OP: It's a horrible idea to insert a magnum primer in to ANY load developed with standard primers without reducing the charge and working back toward it. Always has been, it always will be. This is a very basic rule in most any load manual.

 

[chiefr]

Concur with Sevens.
I have been using 2400 for over 40 years now and have never used magnum primers.

 

[dahermit]

Concur with Sevens.
I have been using 2400 for over 40 years now and have never used magnum primers.

2400 may or may not be the same now as then. When Elmer Keith was still alive, 22 grains of 2400 behind a 255 KT cast bullet would leave a significant amount of unburned powder on the ground in front of the shooter. As a result, many shooters back then used magnum primers in an attempt to get all the powder to burn. Elmer wrote about that, but his opinion was that standard primers were good enough anyway. But, inasmuch as I have not seen references to 2400 powder leaving so much unburned in recent history, they may have changed the formulation.
I remember putting an eight foot length of news print paper on the ground in front of my .44 magnum and shooting...There was so much unburned 2400, one would think, "There has to be something wrong." But, that is just how it was.

 

[rclark]

i've seen significant sensitivity with Unique and mag primers

Interesting... In .45 Colt I got the following results which tells me it isn't. Only 8fps difference which isn't much pressure difference. I've tested other powders too BTW (HS-6, Green Dot, Trail Boss, etc) as this has been an 'interest' to me. Plus I like to see the difference in SD, and ES as sometimes it is a 'surprise'. I'll have to do some .357 mag tests too it looks like .. though my loads are mainly target loads (light to medium) for this peanut caliber.

8.5g Unique, 255g SWC, CCI-300, 977fps, 17 SD, 56 ES
8.5g Unique, 255g SWC, CCI-350, 985fps, 21 SD, 82 ES

It's a horrible idea to insert a magnum primer in to ANY load developed with standard primers without reducing the charge and working back toward it

Only time this is an 'issue' is loading at the MAXIMUM end of loading range. If only using loads in the 'middle' or 'light' it is no big deal ... even with 2400.

 

[rclark]

I've read, that the strong primer blast and shock starts a forward movement of the bullet before a proper burn and development of gas can do that work.

I do believe I have experienced this with Trial Boss working at the higher end. I was getting 'lower' velocities with the Magnum primer than the Standard primer. My tests were 'back' to 'back' tests where only the primer was different. Trail Boss Tests

 

[Sevens]

Only time this is an 'issue' is loading at the MAXIMUM end of loading range. If only using loads in the 'middle' or 'light' it is no big deal ... even with 2400.

This is true, I suppose... however... as general safety guidelines go, I don't tend to "qualify" my statements to cover every little detail that any handloader might encounter... ya know?

It's good habit and a fine guideline to NEVER switch out a primer and substitute a magnum primer in it's place without re-working the load.

As you say... yeah, the world isn't going to end if you do it in a medium or mousefart load. Still not a great habit to get into.

 

[GeauxTide]

I'm also with Sevens. I've used 2400 in the 70s and bought a can last year. It's faster and cleaner burning. I've used it in +P 44SPL and 45LC loads and like it.

 

[Sevens]

Oh, also... 2400 still leaves a bit unburnt in any round I've used it in. New production Alliant 2400. Just how it runs, I suppose. Still works great and I don't worry about it.

 

[Miata Mike]

Oh, also... 2400 still leaves a bit unburnt in any round I've used it in. New production Alliant 2400. Just how it runs, I suppose. Still works great and I don't worry about it.

Do you think using a magnum primer instead of a regular primer would help "burn more" of the powder or not? I had some cool fire balls with some .357 loads last time out with a 6" Ruger Security six. Must have been enough unburned powder to cause it. I might add that it was pretty obvious in the daylight.

 

[Sevens]

I don't know -- and honestly... the loads I use work so well that it's just not a concern I care about fixing. The unburnt particles don't bother me, they don't slow any of my guns down, they don't really matter to me because the load performs so well.

It definitely does seem to be a calling card of 2400... unburnt granules.