Magnum primers for .308 .270 ?

[PaulT]

Hi guys,

I am sure it's not the first time it's discussed but couldn't find it so here it is.

When I look at the reloading data, I can see that sometimes they use a magnum primer, sometimes not depending of powder or burning rate or amount of powder, so if I am working up a load using a magnum primer to load the .308 or the .270... is that something you experts would advice not to do?

I don't mean switching primers for a already developped load, I would not do it that way, but if someone begins with the published starting load using a mag primer and work is way up, .

Lets see your opinions...

 

[Hitzy]

Mag primers can increase pressure up to 5000psi over standard primers, but that mostly occurs with the fastest burning rifle powders.
I use mag primers for anything I load with ball powder, cleaner burning. I don't use them with extrudeds as they burn clean enough for me with standard primer, and I don't use anything slow or big enough to require them.
If you think you have pressure problems, run the same load over a chrony, one with a standard primer, one with mag, and see what the difference is.

 

[Scott_N]

X 2 about the ball powder, I almost always use magnum primers with ball powder. I also use them for some hunting loads when I expect the weather to be very cold.

Like you have already assumed, you'll be OK as long as your work your loads up like you would any load during development.

 

[prosper]

Military 308 loads use standard primers and ball powder. Good enough for me I always start with standard primers, and maybe, might someday consider moving to magnum primers if I ever have problems with accuracy. Generally, the coolest primer that will get the job done will also be the most accurate one.

 

[todbartell]

dont need them in a 308, doesnt use anything slower burning than 4350 usually. exception may be when using W760

in a 270, Id try them if I was loading H1000 or similar

 

[Glockster]

My general rule of thumb is to follow the reloading manuals and if not listed there; standard "06 (.473) case head size and or smaller gets standard primers, anything bigger, magnum primers.

 

[Ishootguns]

You might consider using magnum primers if you are going to be using the shells for hunting in the winter time when its colder.
Dave

 

[downwindtracker2]

It's a good question,but I'm not sure there is an answer. When working with a compressed load of couple slow powders,one extruded,one ball,I hoped to get it well and truly lit,so I tried the magnum primers I had against standard ones.CCI200,WLR,CCI250.Guess what,the standards went quicker! The more compressed loads went slower!

 

[martinbns]

I've nver tried a magnum primer in a 308, buyt both of the 270's I've loaded for preferred magnum primers. The first one magnum primers amde a huge difference to accuracy.

 

[PaulT]

Magnum primers

Well.. it's all good advice and it's not because I want to argue but let's say I go by the books, for .308 loads. In this case, my Nosler, Speer and Hornady reloading books.

SPEER manual with Start38gr/2295fps-Max42gr/2550fps of BL-C2, 168gr bullet use a mag primer and NOSLER manual for the same powder/bullet weight doesn't, Start42.5gr/2468fps-Max46.5gr/2698fps .

SPEER with start42gr/2448fps-max46gr/2720fps of win748 and 150gr bullet use a mag primer and HORNADY manual doesn't for the same powder/bullet weight start41.8gr/2400fps-Max48.4gr/2800fps . Same thing with 180gr bullet and win760 powder....

That's why the question .... if 2-3 bullets makers are doing tests with the same powder and bullet weight and the results equals: One used a mag primer the other one didn't ya know what I mean?

So there must be a personal preference at some point if for 2 major cie using same powder/bullet weight end up using different primers (that are burning differently) to achieve the same results?

Now, to return to the initial question, does it make that much of a difference using mag primers (knowing that some bullet makers do, some don't) to develop a load for the .308 if one proceed normally, examining brass for pressure signs? Or is it a bad reloading habit?
Not that I don't want to buy some either, just that I have a couple of 1000's of mag primer and if I can use them, why not use them also for my .308 and .270 .

Thanks

 

[mikeelliot]

I use mag primers in 270 when using IMR4831/7828 and RL 22.
I have found more consitent loads using them with slower powders in my rifle.

 

[downwindtracker2]

In my limited test,none. But primer lots do vary. My last brick of Winchester produced fliers,this brick has real tight velocity numbers.They say Federal magnum 215 are hot,as are the Winchester magnum. If there is a big difference you are going to have to back off and work up.

 

[ben hunchak]

i think you could simplify things in those two calibers by starting with mag. primers and ball powder and std. primers for ext. powders! Go from there and hopefully that will be the same in reloading manual.

 

[Gatehouse]

Liek any other time you work up a load, you start low and go up.

SO if you started with a mag primer, you just work up, hopefully using achrony. Don't work up wiht one primer and then switch to another (brand or magum/regular)

Why do differnet manuals list different things? Easy- they are using different gear, different powders etc. SOme of them may find they get better ignition with a magnum primer with one load. Possiby some companies dont' even try the magnum primers.

 

[Boomer]

The rule of thumb I generally follow is that when powder charges exceed 50.0 grs I use a magnum primer, and for use in exteme cold I use a magnum primer.