Primers. - LR vs Magnum

[Salavee]

Does anyone know, for sure, the difference between the two.
Does the Magnum primer burn hotter, is it a slighty larger charge or are they the same charge weight with the Magnum just formulated to burn a bit longer?
Try as I might , I never did find the answer.

[freeride]

From what I have found:

One of the biggest differences between magnum primers and standard primers is the amount of compound that is included in each. There is a very small quantity of primer in each cap, generally far less than a single grain, but there is a distinct difference in the amount in the standard primer vs magnum primers. This quantitative difference leads to a hotter burn when the primer is activated and the cartridge is fired.

Since magnum primers burn hotter and longer than standard primers, they can create max loads that are dangerous to the barrel and the shooter. They can ignite faster powders too quickly and can cause a dangerous pressure buildup. This also means, however, that magnum primers are much better at igniting ball powders than standard large rifle primers.

Another big difference is in the low-temperature performance. If the primer is going to be used to fire in very cold conditions or other situations where ball powder becomes harder to ignite, choosing to use a magnum instead of a standard can be advantageous, provided it doesn't create a compressed load greater than the maximum loads recommended in the reloading manual. This allows magnum primers to be used down to 20 degrees F.

[fps plus]

Do a google search , somewhere online there is a chart showing the information you are looking for. I’ve seen it before but don’t remember where .

[Pathfinder76]

In my experience Magnum Primers create 25-50 fps of velocity more than their standard counterparts. IF there is a change at all. You will not blow your face off switching between the two. I tend to back off a grain and then go from their if switching to a magnum primer.

[Albertajeff]

For my low velocity cowboy action loads if the primer fits in the hole it gets seated!

[David Henry]

The spark a primer throws is called "brisance" and the magnum primer throws a slightly longer spark of brisance than the standard primer. The reason for this is to ignite more evenly the longer powder column found in most magnum cartridges. Or that's what I have been led to believe. D.H.

[waldedw]

I'll share a little ooppss from about 40 years ago, I was loading some 280 ammunition with 140 gr bullets for my remington 700 mountain rifle, had a great load worked up with IMR 4831 right around 56.0 gr which was max.

Anyway after I got them all loaded and was cleaning up and putting everything away I realized I had used LRM primers and not LR, I was going to pull them all and change them out but thought I'll just try one and see what happens.

Long story short they shot great, no noticeable change in POI no tight cases, no signs of any pressure, now I have been very careful since and never did it again but I really don't think it makes a big difference.

[elkhunter11]

Originally Posted by waldedw

I'll share a little ooppss from about 40 years ago, I was loading some 280 ammunition with 140 gr bullets for my remington 700 mountain rifle, had a great load worked up with IMR 4831 right around 56.0 gr which was max.

Anyway after I got them all loaded and was cleaning up and putting everything away I realized I had used LRM primers and not LR, I was going to pull them all and change them out but thought I'll just try one and see what happens.

Long story short they shot great, no noticeable change in POI no tight cases, no signs of any pressure, now I have been very careful since and never did it again but I really don't think it makes a big difference.

The smaller the case capacity, the more using a hotter primer may effect the load. And I have found, that will smaller capacity cases, a milder primer can produce better accuracy.

[Salavee]

Originally Posted by David Henry

The spark a primer throws is called "brisance" and the magnum primer throws a slightly longer spark of brisance than the standard primer. The reason for this is to ignite more evenly the longer powder column found in most magnum cartridges. Or that's what I have been led to believe. D.H.

Thanks David. Thats my understanding as well. "Brisance" is the word I was looking for. I Googled it and found a Gigantic rabbit hole as it apllies to primers. Got a Skull cramp already. Lots of good and interesting info, but I'm thinking I'll stick with what little I know on the subject and carry on.

[stob]

Originally Posted by fps plus

Do a google search , somewhere online there is a chart showing the information you are looking for. I’ve seen it before but don’t remember where .

x2, plus there is a picture link somewhere of all primers being fired and you can see the differences... because of the pics i use the rem 9.5's for all loads ... a milder LRM but i like the flash characteristics ... sometimes when i have had time i have experimented with all primers to attempt to assess differences ... i found the federal LR match to give best accuracy on numerous occasions despite starting all loads with the 9.5's ..( 6.5x 55, 308, 3006, 7mm rem, 243, 9.3 x 62)

[Smokinyotes]

My 300wm, 7LRM and my nephews 338wm all shot terrible with Fed 215m primers. Switched to Rem 91/2 primers and the group size shrunk by about 2-3”. I never thought just switching a primer could make that much difference in group size. I’ve noticed magnum primers are about 25-40 FPS faster.

[catnthehat]

I run 450's in my .223 and my 6mmBR with excellent accuracy, under normal conditions ( wind switching , running 2MOA to about 4MOA) I can normally hold 96% or better for ten round strings at 500 and 800 meters, and a bit higher at 300, depending on how well I am reading the conditions that day. That works out to 2MOA or better for ten shots , with the odd inner ( 4) with the sling and irons

Cat

[whln]

if stored cool room how long before they would become unsafe or unusable?

[Salavee]

Stored Dry and Cool they will last for 30 yrs or more.

[waldedw]

Back when I started reloading in the late 70's and old guy told me boy I use Magnum primers if I'm loading ball powder or if the charge get's over 60gr, I smiled and said ok good to know, but never really followed his advise, I always went by the manuals and what they called for

[303carbine]

Gotta find'em before you can compare.

[Pioneer2]

Is all I use in everything.

[duceman]

Originally Posted by whln

if stored cool room how long before they would become unsafe or unusable?

i am using some old cil primers in the wooden packaging, from the sixties i think. they work just fine. i have no idea how they have been stored prior to my acquisition. i do know they spent at least 4 yrs in an insulated storage shed in a box in the yard with a bunch of other stuff by mistake.

i find it quite amusing when people won't purchase or use components more than a few years old.

[Bushrat]

Originally Posted by duceman

.

i find it quite amusing when people won't purchase or use components more than a few years old.

Heck I'd try em' even if they had been stored on the Titanic since 1912. A month or two ago a nice fellow gave me over 20 pounds of powder bought in the 60's, thought it was old, didn't want to mess with it. Works like it was made yesterday!

[elkhunter11]

I am using powder and primers over 20 years old, and I have used some over 50 years old. Only my shotgun primers are in the current packaging.

[duceman]

Originally Posted by Bushrat

Heck I'd try em' even if they had been stored on the Titanic since 1912. A month or two ago a nice fellow gave me over 20 pounds of powder bought in the 60's, thought it was old, didn't want to mess with it. Works like it was made yesterday!

haha! likewise on the powder.

[Salavee]

Originally Posted by waldedw

Back when I started reloading in the late 70's and old guy told me boy I use Magnum primers if I'm loading ball powder or if the charge get's over 60gr, I smiled and said ok good to know, but never really followed his advise, I always went by the manuals and what they called for

As Winchester Mfgs ball powders, they also produce some of the hottest LR primers. I've always figured there was a reason for that. I kinda think that old guy gave you some good advice. They work really well, especially if the outside temp drops a bunch.

[waldedw]

Originally Posted by Salavee

As Winchester Mfgs ball powders, they also produce some of the hottest LR primers. I've always figured there was a reason for that. I kinda think that old guy gave you some good advice. They work really well, especially if the outside temp drops a bunch.

Yes the old boy may have been onto something but I never did follow through with his suggestion, I do however know a guy that has been loading for 45 or 50 years and uses M primers for everything he loads that needs L primers.

[waldedw]

Originally Posted by Salavee

As Winchester Mfgs ball powders, they also produce some of the hottest LR primers. I've always figured there was a reason for that. I kinda think that old guy gave you some good advice. They work really well, especially if the outside temp drops a bunch.

Yes the old boy may have been onto something but I never did follow through with his suggestion, I do however know a guy that has been loading for 45 or 50 years and uses M primers for everything he loads that needs L primers.

[Grizzly Adams1]

Originally Posted by 303carbine

Gotta find'em before you can compare.

Nowadays you have to use what you can get. I use magnum primers because I'm told they give better cold temperature ignition.

Grizz

[Sashi]

tested my standard primers and magnum primer, found no noticeable change in the point of impact.

[waldedw]

I recently acquired a brick of CCI 450 small rifle magnum primers so I'm going to load some up in my 223 to compare with the rem 6 1/2 and 7 1/2 BR and cam-pro SR that I have, will see if there is any noticeable difference between the 4 it should be interesting.

[Salavee]

Originally Posted by waldedw

I recently acquired a brick of CCI 450 small rifle magnum primers so I'm going to load some up in my 223 to compare with the rem 6 1/2 and 7 1/2 BR and cam-pro SR that I have, will see if there is any noticeable difference between the 4 it should be interesting.

Thats a great idea, Plse post your findings. Are you going to try some LR and and LR Magnums while you're at it ? Maybe the old guy was wrong. I hope not, as literally thousands of old folks will be surprised.