Can I use magnum primers in my .44mag?

[MCAinSTL]

When I first started reloading, about a year ago I purchased a box of large magnum pistol primers for my .44mag before I read the reloading data to find I needed regular large pistol primers.

For some reason I thought a mag pistol would use mag primers. Go figure.

I would appreciate any assistance in this matter.

[Magnum Wheel Man]

there are loads & powders out there that call for magnum primers... you just need to look around a bit more...

[Brian Pfleuger]

You can safely use magnum primers with most powders, you just need to back your load down 10% and work back up looking for pressure signs.

The exception would be powders that list loads that say not to ever go below a certain number. In that case, IIRC, you would back off about the same amount but you must be very careful to make sure that you don't get any squibs before you fire the next round.

[Unclenick]

Use of magnum primers is required mainly for slow powders that are harder to light, like H110 and 296 (actually the same St. Mark's powder branded for Hodgdon and Winchester, respectively). The main function of the magnum primer is to pressurize the case more at the beginning of the powder burn, which helps slow powders get up to burn speed. This matters to the magnum pistol cartridges especially in revolvers, where the barrel/cylinder gap drops the pressure as the bullet base exposes the gas to it. The higher starting pressure improves the completeness and consistency of their burn.

Because of that extra pressure, magnum primers can also improve consistency with faster powders that are being used in quantities small enough to leave a lot of empty space in the case. You just have to try with your own loads to see if it helps. I have seen switching to magnum primers from standard primers raise pressure equal to as much as 4% or so of powder charge, so I usually recommend you reduce charge 5% when you switch to a magnum primer, then check the average velocity over a chronograph to see how it compares with what the standard primer produced, and creep it back up to match the performance using the standard primers.

Winchester large pistol primers (WLP) are a compromise that are both for magnum or standard loads. In other words, they are on the stiff end of standard and the low end of magnum primers. They are the only LP primer made that way, AFAIK. So, if you see them specified in a load, that is not telling you whether you need magnum or standard primers. They are just a convenience that keep people from having to keep two separate types in stock. They seem to work.

A useful article on primers is here.

[totaldla]

I've found that most of the "slow" powders for 44 mag (AA#9, Enforcer, LilGun, W296/H110) benefit from a mag primer. Note: Wolf Large Pistol Magnum are on my "suspect" list because of short cups and weak charge.

You can see Chrono results of regular versus mag primers in the 329pd info load data section.

[Ozzieman]

Thank you Unclenick for that great article.
Some time ago I tried an experiment on reloading rounds that should have used standard primers. I tried same load and bullet standard vs. mag primers and although I had no measurement equipment to prove anything. I did find that loading normal pressure 9mm with mag primers gave poor results.
From my experience and suggestions from others I thought that the explanation in the article you attached was the problem. I am glad that there is some documented proof that what happed was what others suggested.
That the bullet had been propelled out of the case by the magnum primer before the powder had fully ignited.
Again thanks.


http://thefiringline.com/forums/show...&highlight=9mm

[DiscoRacing]

I use them for mine with titegroup

[dmazur]

I was going to mention that cold weather concerns can also be a reason for the use of magnum primers with slow powders, like H110, but I see that was covered in the linked article.

I'd save them for use with the loads that require them, and buy additional standard primers for target or SD loads.

You could use the magnum primers with some H110 and load up a couple of boxes for hunting or protection from 4-legged critters. Then they wouldn't be sitting around taking up space...

[totaldla]

Problem with using standard primers in 44 mag is that the very best powders (at least the ones I know of) are ball powders. My Chrony results show that ball powders work best with CCI350 primers (I can't speak for Federal 155 - can't find them).

Mid-range powders worked well with standard primers when the load was towards the max - which agrees with the linked article.

I've not tried this with other ball powders, but I did test a max load of Enforcer ignited with standard and two different mag primers - again the mag primers did the best.

I purchased Wolf Large Pistol Magnum primers and the result suggest that there is nothing "magnum" about them. The only "slow" powder that worked with Wolf LP mag primers was 2400, and it is a flake, not a ball powder. I'm not sure how much more effort I want to put into working with the Wolf LPM, I'm likely to sell them back to Wolf (I managed to score a couple bricks of CCI350). One more problem with Wolf LPM is that they are 0.116" tall versus the CCI350 at 0.119". The SAAMI primer pocket spec for large pistol is .118" -.122". Probably wouldn't matter much with a 1911 where the firing pin can extend a ways, but it is an issue in a S&W revolver with a frame mounted firing pin.

[ghh3rd]

There are those who swear (and have provided proof) that using Mag primers for their .44's loaded with H110/W296 actually opens up their groups.

Others have said they only use them when in below zero weather to add extra spark to ignite the cold powder.

Randy

[grubbylabs]

In my speer #13 book it has several loads listed with using magnum primers. My new 7th edition Hornady has the Winchester LP primer used for all loads it looks like.

[zxcvbob]

A magnum primer when it's not really needed will raise the pressure somewhat (often without much increase in velocity.) If your loads are right at the max already, back off the powder a little and work them up again. If your loads are low-to-middle range, don't worry about it at all.

Or, you can just put the LPM primers back on the shelf and save them until you need them someday (ball powders like 296, especially in cold weather.)

[totaldla]

Originally Posted by ghh3rd

There are those who swear (and have provided proof) that using Mag primers for their .44's loaded with H110/W296 actually opens up their groups.

Others have said they only use them when in below zero weather to add extra spark to ignite the cold powder.

Randy

Well that's the difference between accuracy and consistency. I don't doubt their results as I have seen some of my most accurate loads have a rather wide Standard Deviation. But my chronograph tells me that W296/H110 is most consistent with CCI350 magnum primers - from my revolver. Given the number of variables in the reloading & shooting process, YMMV.

I have seen a lot of loads posted that are way over max, which may make a standard primer work better. And perhaps a longer barrel evens things out as well. Like I said - variables.

[sc928porsche]

Usually, for me, if the case says mag on it, I use a magnum primer.