Do magnum primers increase pressure?

G

g-manz35

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Want to load some BLC2 in my 30/30. I want to use magnum primers as they are recomended by some manuals. Does this increase the pressure or change how much powder you can use?

Going to use min 33gr and max 37gr behind a 150 gr Sierra BTSP

Thanks G
 
It can increase pressure. Just start at your min charges and work up just like any other load. Probably don't need it for a 30-30 but I can't see it hurting anything. If they recommend it try it.
 
My speers manual recomends magnum primers for 223 using BLC2. It also show Mag primers for several other calibres using BLC2 including the lighter bullets in 30/30. In the heavier bullets it does not list BLC2 as an option. I got the load info for the 150gr bullets from my Lee dies and the Hodgdon online load data, but those loads aren't specifying Mag primers??

Thanks
 
From my research on the topic the short answer is : normally, yes. By how much is dependant on variables like the powder type, powder volume, temp etc. The 'rule of thumb' used by many is to reduce loads established with regular primers by at least 1 grain when substituting a mag primer, perhaps a bit more if you are using warmer loads, and work up again.

Different brands also have different brisance. I would have to research the links again (I have lost the info, should have printed and filed it!) but if you google it there quite a bit of research out there in various cartridges in respect to veloctiy and pressure changes when using mag primers.

IIRC Win primers often create a little more pressure than others BUT in different cartridges and different powders sometimes any mag primer can have almost no difference and other times quite a bit. It seems the 'normal' change in average pressure seems to be about a 1000-2000psi increase, but can be more....


To be safe start low and work up...as always.
 
it`s somewhere on here in the reloading section, but some powders (ball i think) burn better with hotter primers.
 
Spawn-Inc said:
it`s somewhere on here in the reloading section, but some powders (ball i think) burn better with hotter primers.
Click to expand...

I have read it many times that Ball powders such as BLC2 should be used along with magnum primers. I will be loading this load for the first time so I will be starting at the min and working up. I will google and see what I find. I could throw a couple reg primers in some cartriges to compare.

G
 
In the real world, magnum primers didn't come on the market until the mid 1960s.
How do you think all the reloaders got along prior to magnum primers? I can tell you that. They got along just fine, thank you.
Also, in the real world we live in, I have used magnum primers off and on in both rifles and revolvers. I have never detected the slightest bit of pressure differnce, depending on what primer was used.
Of the loads I have tested, the chronograph was also unable to detect any differnce in velocity.
You do what your book says, but but to me a primer is a primer and I make no allowance whatsoeve, whether or not I have a standard primer or the so called magnum primer in the case.
 
The NRA did a test years ago, swapping primers in a 30-06 with no other changes in the loads. The results varied from nearly no change in pressure to 10,000 PSI difference. There was sometimes no difference in velocity, even with the high pressure loads, but fooling the pressure-gun was somewhat harder.

I normally use magnum primers with ball powders, or Winchester.
 
"...start low and work up..." to what? Do you think that "pressure signs" can tell you the difference from non-magnum primers? Specifically what brand, as they vary quite a bit? There are so many variables that "published loads" are recognized as +/- 10 percent of what you might experience away from the loading bench. There is so much uncertainty in pressure, and so much margin of safety built into firearms, that if you don't exceed published loads, you can substitute primers (and brass, and bullets, and powder lots, and....) and be "safe".

I've never found magnum primers made any difference with ball powders or magnum cartridges, or in cold weather.
 
There is good reason why most manuals specify magnum primers for ball powders. Balls powders are harder to ignite.

There is another variable at play - loading density.

if the case is fully packed with powder, the pressure pulse of a primer is much higher, because the case is already full. A deep seated heavy bullet can add to the pressure pulse.

But if the case is not full, ignition problems can occur. In my handloading I have identified two ignition problems I can induce when using ball powder and standard primers.

You want to be sure you don't create either of these when making your hunting ammo. On the other hand, if you like experimenting, try making these problems on purpose.

1) A light bullet and a light charge of ball powder with no mouth crimp. The result is either click-bang (slight hangfire because of poor ignition) or just click.

2) A light bullet, no crimp and a full case of powder. The primer pulse pushed the bullet out of the case and the powder does not ignite.

I recently found that I had 1000 rounds of 223 ammo loaded with BLC2 and standard primers. 55 gr bullets. About 1 in 20 would not go bang. rather than tear them all part and switch to magnum primers, i ran them through a Lee factory crimp die. The added pressure has made this ammo almost 100% reliable. I use it for practice. Would not trust it for a match.

A magnum primer is not issue for pressure, so long as you use it in the work up. The reason it can add to pressure is because of better ignition of the powder, which is what it is intended to do.

Most of us have made a lot of ammo with standard primers and not had a problem. We just never knew how close we were getting to a problem, until one day one more variable went against us. This could be light neck tension, a light bullet or cold weather.

If you need 100% reliability, I suggest a magnum primer with ball powder. Lots of neck tension or a crimp is good insurance, too.
 
Ganderite said:
I recently found that I had 1000 rounds of 223 ammo loaded with BLC2 and standard primers. 55 gr bullets. About 1 in 20 would not go bang.
Click to expand...
Wow, one in twenty ... think it was a bad batch of primers maybe?

The reason I ask is I just took a quick look at my last year and a half of reloads (~150) using BL-C2, light neck tension and 55gr bullets .... zero failures.

Steve
 
savage223 said:
Wow, one in twenty ... think it was a bad batch of primers maybe?

The reason I ask is I just took a quick look at my last year and a half of reloads (~150) using BL-C2, light neck tension and 55gr bullets .... zero failures.

Steve
Click to expand...

No. But it is an old lot of non-canister powder. And the neck tension was so light that some bullets would fall out when i tumbled the ammo.

I have since replaced my sizing die, which was worn out.
 
It might help this discussion to explain why ball powders are harder to ignite.

It is the dream of every power developer to have a powder that generartes high velocity for a given pressure level. This is done by trying to extend the pressure curve, so pressures do not drop so quickly.

Pressure is developed by burning powder. A piece of powder burns like a log in your fireplace. From the surface. So when powder is ignited, the surface is on fire. The available surface is at the maximum at time of ignition and as the powder burns, the surface area gets smaller, just like the log. As the surface gets smaller, less gas is generated and pressures drop.

At the same time the surface is getting smaller, the bullet starts down the bullet, increasing the volume the gasses have to fill, and this also drops the pressure quickly.

So the ideal power would start burning slowly and then get faster and faster. A "progressive" powder.

Some extruded powders have a hole through the kernel, so that the powder burns both on the surface and on the inside. As the outside surface burns and gets smaller, the inside surface burns and gets bigger. This makes the rate of gas generation more uniform and less peaky.

A ball powder has the most problem, because the surface area is maximum at the beginning and then gets smaller. To counteract this, the powder is soaked in a deterrent, that initially retards burning. As this deterrent layer burns off, the powder burns faster and faster. In practice this works quite well, except the deterrent coating makes the powder harder to ignite. This is why the manuals call for magnum primers for ball powder.

The standard Winchester primer is quite hot. It is designed to ignite ball powder.
 
I have used the BLC2/30-30 combination from the very first hand-load I ever made, in fact it WAS the first hand load I ever made. Magnum primers are not only safe but as Ganderite says, a good idea. Never mind velocity, simply concern yourself with accuracy. If a load is accurate, it is fast enough. Last batch I made up says I was using 36.5 with some Hornady 150's and a CCI 250
 
Magnum primers do increase pressure and usually gives a slight increase in velocity due to the higher pressure. If you have worked up to a safe load, all is fine, but changing from regular primers to magnum primers in a maximum load where the manual does not prescribe magnum primers, will cause unsafe pressure, whether you can see it or not. Magnetism exists, but you cannot see it. High pressure results, even if you cannot see it.

Go read the article "Priming and Pressure" in Handloader 279 magazine (August 2012) on page 18-19. That test was done in +P handgun loads where the difference between the lowest and highest pressure, by just changing primers, resulted in a 59% increase in pressure. Yes, fifty nine %!!!

Always reduce powder charge and work up to a new safe load when changing any component.
 
H4831 said:
In the real world, magnum primers didn't come on the market until the mid 1960s.
How do you think all the reloaders got along prior to magnum primers? I can tell you that. They got along just fine, thank you.
Also, in the real world we live in, I have used magnum primers off and on in both rifles and revolvers. I have never detected the slightest bit of pressure differnce, depending on what primer was used.
Of the loads I have tested, the chronograph was also unable to detect any differnce in velocity.
You do what your book says, but but to me a primer is a primer and I make no allowance whatsoeve, whether or not I have a standard primer or the so called magnum primer in the case.
Click to expand...

When using big cases like the Rigby, Jeffery, and .378 Weatherby, one way was to load small charges of Bullseye under the main powder charge to ensure complete ignition. Of course today dulplex loading, be it for priming or adjusting the burning rate, is frowned upon in North America (less so overseas) because with primer's like Federal's 215 it isn't necessary for priming, and there are few holes in burning rates that still need filling. I primarily use magnum primers, I never know if my loaded ammo will be used in warm or cold weather, and around here, the logistics of keeping a single type of primer makes my life easier. There is an argument to be made that better accuracy is realized with the least amout of primer violence that will reliably ignite the powder charge, but you need a very accurate rifle to tell the difference. I use match primers for my target rifle . . . sometimes.
 
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