Magnum vs. standard primers

[Tatume]

As I have been unable to find any standard primers for sale, but have had opportunities to buy magnum primers, I did. Yesterday I did a test comparing the two. Using Remington 2-1/2 standard large pistol primers, CCI 350 magnum large pistol primers, and two different military surplus powders, M9 and #105, I prepared four samples of test ammo. M9 and #105 powders were obtained from Jeff Bartlett at GIBrass.com. Burning rate appears to be similar to Unique. The two powders appear to be the same, but do not meter the same. M9 charges throw a little bit lighter than #105. The difference could easily be attributed to them being different lots of the same powder.

The test cartridge was the 41 Remington Magnum with 240 gr LBT WFN GC bullet. Moderate loads of each powder were assembled using standard primers, and loads using 1/2 grain less powder were assembled with magnum primers. Five shots of each combination were fired over the chronograph. Mean velocities of the four treatments were compared using ANOVA. There were no significant differences in average velocities, which were all very close to 1150 fps.

Magnum and standard primer velocities were pooled and variances were compared using the F test. There was no significant difference. However, it appeared to the Mk I eyeball that there may be a difference in variance, and a repeat test with a larger sample size might indicate a significant difference, with magnum primer loads being more variable. However, given that the difference is not significant at this level, even if found to be different with a larger sample size it probably is not important.

In conclusion, substituting magnum primers with an appropriate adjustment in charges and avoiding maximum loads can be a successful expedient during times of primer shortages.

[Larry Gibson]

In conclusion, substituting magnum primers with an appropriate adjustment in charges and avoiding maximum loads can be a successful expedient during times of primer shortages.

That is indeed the key to substituting primers.

Larry Gibson

[runfiverun]

I choose to use magnum primers in some loads willingly.
unique seems to burn pretty darn clean in many cases with the addition.

[Nocturnal Stumblebutt]

If only I had your problem, my local supply has 20-30k Win LP, and that's about it, occasionally Win SP, or some CCI 350, but I haven't seen Magnum SP in 6 months.

[44man]

The key is working loads in the .41. But standard primers will give better accuracy.
You read a chrono but no groups.
A spark will fire, that is all.
OK, you got the same velocity so now we need to see the groups at 50 yards from both primers.
I will go along with not finding primers and anything to keep you shooting is good. Use what you can get.
Please put the chrono away, it does not show accuracy.

[BBQJOE]

I've heard it said that magnum primers were created to solve a problem that didn't exist.
I think an interesting test would be to prime two cartridges, one with regular and another with magnum, and seat bullets on them with no powder.
Fire each one, and see how far they get lodged in the barrel.
This might be a rather accurate test as to the extra pressure of the magnum primer.

[NoZombies]

Thanks for the testing. I plan to use up the magnum LP primers I was able to find over the summer, and keep my stash of standard LP primers for just in case.

Anyone have experience loading with LP mag's in the .45 ACP?

[44man]

Thanks for the testing. I plan to use up the magnum LP primers I was able to find over the summer, and keep my stash of standard LP primers for just in case.

Anyone have experience loading with LP mag's in the .45 ACP?
OH NO. The LP is too much and the ACP is better with a SP primer.
ONLY AS A LAST RESORT.

[Bwana]

Reminds me, I need to get a copy of Chicken Little for my grandson.

[jonp]

OH NO. The LP is too much and the ACP is better with a SP primer.
ONLY AS A LAST RESORT.
Are you joking here? I found some LPM and was going to sub them into a 44Mag with a reduction in powder on target loads and was thinking of trying them in my 45ACP starting on the bottom end.

[uscra112]

Found that using Mag SR primers in .223/5.56 full-power loads using milsurp powder (pulldown 844) made no difference at all on the Chrony. Am loading all those 5.56 loads for my SIL now with magnum primers to preserve my STD SR primers for better things. Don't load any pistols that use the large primer so can't speak to that.

[44man]

Nothing says you can't use them if loads are worked but I am sure you will see a difference in how they shoot.
I am only thinking of accuracy.
The reason I don't chrono to look for accuracy is many of the best loads will show larger numbers.
The ACP is also a very small case and a LP mag is getting close to not even needing any powder! [smilie=s:

[Muddydogs]

All I shot is CCI mag primers out of everything. Never had a problem in .45, .40, or 38 as well as my rifles. All I can find on the shelf is CCI standard primers around here which is no big deal as my loads are worked up for Mag primers I just push in a standard and keep shooting. I am saving my mag primers and using the standard ones now. Except for LRM, I will only load CCI LRM in my hunting rifles, it sucks when its below zero outside, the crosshairs are on an Elk and the 7mm Rem Mag hang fires.

[hydraulic]

How come Winchester LR primers are marked "for standard or magnum loads"?

[jonp]

Nothing says you can't use them if loads are worked but I am sure you will see a difference in how they shoot.
I am only thinking of accuracy.
The reason I don't chrono to look for accuracy is many of the best loads will show larger numbers.
The ACP is also a very small case and a LP mag is getting close to not even needing any powder! [smilie=s:
Well, that sure would cut down on the cost of reloading and solve the powder shortage problem!

[Dave C.]

I use Winchester large pistol standard/magnum as my go to primer for
my 45 acp target loads. None better!

Dave C.

[44man]

I use Winchester large pistol standard/magnum as my go to primer for
my 45 acp target loads. None better!

Dave C.
The WW is not as high a pressure. I tested many primers in the .45 Colt. 150's shoot good, WW shoots very well but a full mag opens groups. I really did see a difference with the 150 and WW trading places with groups a lot of times.
That makes it hard for me to pick the primer to use.
The WW is not as good as a 155 in the larger calibers like the .475. I see the 150 with larger groups, the WW better but the 155 best.
I have done thousands of primer tests and the ACP shot best with a SP primer.

[gareth96]

Or make two batches of glue bullets and see if the magnums shoot further..

[Elkins45]

How come Winchester LR primers are marked "for standard or magnum loads"?

I was told the reason is because of the WW ball powders. Because ball powders are supposedly harder to ignite, WW upped the hotness of their primers so they would give satisfactory ignition with their own powders. I don't know if that is true or where I read it (maybe here?) but this explanation certainly passes the logic test.

[44man]

Or make two batches of glue bullets and see if the magnums shoot further..
I have tried and a mag primer only moves a lead boolit a little more. It appears there is no meaning at all but there sure is a difference at the targets. Even with tiny readings from the chrono, one primer always shoots better then another.
I have seen all the tests for flash out of muzzles and on and on. It has never proved a thing.
I depend on groups only and consistent ignition. Since 1956 I have never, ever had a failure of any kind with the .44 or .45. In fact no other caliber from .38 to large bore rifles.
ONLY the .454 with the SR primer and reduced starting loads.
But accuracy has been the goal from day one and that is where primers will alter what you get.

[44man]

I was told the reason is because of the WW ball powders. Because ball powders are supposedly harder to ignite, WW upped the hotness of their primers so they would give satisfactory ignition with their own powders. I don't know if that is true or where I read it (maybe here?) but this explanation certainly passes the logic test.
A lot of sense there. 296 does need more heat but it does not need more primer pressure. The powder is wonderful with just a Fed 150. I feel the WW has fire without extreme pressure.
296 is not hard to ignite, it needs to be near the fire.

[chirodr1]

I have also substituted magnum primers for large pistol primers in 45 ACP and have not had any signs of excessive pressure. I began with a decreased load and worked up from there.

[NoZombies]

Nothing says you can't use them if loads are worked but I am sure you will see a difference in how they shoot.
I am only thinking of accuracy.
The reason I don't chrono to look for accuracy is many of the best loads will show larger numbers.
The ACP is also a very small case and a LP mag is getting close to not even needing any powder! [smilie=s:

Yeah, I've got plenty of standard LP primers for accuracy loads, I plan to use the LPM primers in the loads for my sub-gun. Accuracy is somewhat less important to me in those.

Before people criticize me for wasting ammo, Please understand, this is simply part of how I chose to turn my money into noise. I have more single shot guns than I do auto-loaders, but I try not to discriminate.

[zidave]

I use SPM for when I load up Blue Dot in 40s&w. A lot less unburnt powder

[bgoff_ak]

OH NO. The LP is too much and the ACP is better with a SP primer.
ONLY AS A LAST RESORT.

Ive used both in my 45 and 44 SPCL loads, 44 mag and rifle I only use mags.
there are actually a lot of rounds that use the mag primers, the 454 uses a small rifle, AR's should use the 7 1/2 ( it even says right on box for the 6' in very small print )

I've also been told ( and maybe its a wives tale ) but when its aught below mags only. i think some of the newer powders have additions to them to allow this to be true, varget etc. this allows for less case position sensitivity and better handling of temp extremes. supose it matters also on your case prep and flash hole size, powder, local temp etc etc...

if some one does fire off some glue sticks i would love to know what the outcome is...

[44man]

SP primers seem to be more interchangeable. I used either in the .357, never seen a difference. I had extreme accuracy with 2400 and a SP mag primer.
I don't have a .41 but the difference between a LP and LP mag in the .44 will show a large difference in group size with the mag primer averaging groups 3 times larger.
Yes, I even tested both primers in the .475 and .500 JRH with 296 This shows a reversal with the standard primer making groups 3 times larger then the mag. There were no failures in the large cases with a standard primer.
The Fed 150 will ignite the 45-70 in my BFR but the LP mag is more accurate and is what I use. This gun can hit 1" targets at 100 yards.
Primer testing is as important as a lube test for accuracy.
It is still that all primers shoot and all lubes work to some extent but what shoots the most accurate?
To find an accurate load with readings from a chronograph is a waste of time. You can get down to a 1 fps difference and spray the target. The differences in velocity between primers is also a waste of time. Too many look for speed. I will never understand why 20 to 50 fps is better?????
It is true that I have strong opinions about primers but it was from hundreds and hundreds of tests.
I have stated that if you have good loads for your .44 and put mag primers in half and standard in the other half, bring them here for me to shoot, I will tell you which has which primer.
I also mention to work loads but it was not about chamber pressure, it was to see if you can achieve accuracy. To reduce the load 1/2 gr for the mag primer will show you nothing in a revolver about chamber pressure, you just can't tell what pressures you are getting and a mag primer is safe with any book load. They were worked with mag primers and pressure tested. Chances are both primers will still use the same powder charge for the best group with the primer you choose.
Use what you like and what you can find to buy, there is no problem.
But it is 100% wrong to state the .44 MUST use a mag primer with H110 and 296. After all, I get the .500 JRH to fire with a standard. Any problems can be traced to dies or other loading practices. The mag primer is then used to overcome something wrong and mask a problem. If you get a squib load with a standard primer, don't blame the primer.

[ku4hx]

I've just recently started testing CCI Small Pistol Magnum primers in 9mm. So far I've worked up to a load of 5.4 grains Power Pistol using Lee's 124 grain RNL sized to .357". My standard (non magnum primer) load for that boolit with Power Pistol is 5.5 grains. Flawless functioning in our various 9mm guns for the loads with the SPM primers and they have performed as well as the non magnum primer loads.

I normally don't use magnum primers in applications where they are not called for, but I felt the need to discover for myself what all the talk was about. I do have a nice supply of small pistol magnum primers and I'd like to use them. I shoot far more 9mm, 40 and 38 Special that I do 357 Magnum.

[44man]

True, as I said, not much difference in SP primers, at least none I found.
My only idea is a LP mag in the .44 can break case tension early. Can a boolit move a little before full ignition?
I really don't know and can't prove a thing but something shows up at the target.
Is it case volume? Over the years I have come to believe it is.

[fredd.sss]

Does anyone know if there is a difference between the cup thickness, LP primers vrs LPM primers. I have some older Win LPM primers (white box). I have TC 23 inch 3030 barrel and a TC 30 herret 14 inch barrel. I use Win LR primers now but would like to try Win LPM primers in the 3030 barrel with cast boollits, using unique, red dot, 2400, and BLc2. Is the LPM primer cup thick enough not to get punctured beign fired in the contender?..Thanks..Fred

[facetious]

Have any of you heard of SPM and SR being the same thing? Saw this on the GBO site

http://www.go2gbo.com/forums/index.php/topic,276803.0.html

[ku4hx]

Have any of you heard of SPM and SR being the same thing? Saw this on the GBO site

http://www.go2gbo.com/forums/index.php/topic,276803.0.html

I have no intention of trying to find the website so my comment here should be treated strictly as hearsay. A number of years ago, I read a website article where the author, or lab maybe, had tested what they referred to as "Primer Brissance Rates". What they did was use high speed photography to analyze various aspects of a primer's "flash". Two things stuck in my mind: 1.) For a given maker's primers, the flash of the magnum primer was greater than the flash of the standard primers. 2.) Some maker's standard primer's flash was as "vigorous" (or nearly so) as some maker's magnum primers. What did this prove? I'm not all that sure it proved anything, but the pictures were impressive. I don't recall anything particular about Winchester primer.

Primers and their usage tend to fall into the "web lore" category for me. Somewhat along the lines of no lead in Glock barrels, cast boolits will ruin your bore and etc. I have no test facilities, so I can't duplicate and validate anybody's test conditions and conclusions; I have to rely on my own results. In over forty years of loading and shooting under all sorts of conditions, I've found primers to be a single element among many in the assembly of quality ammunition. Quite frankly, I've often found such things as neck tension, type and degree of crimp, bullet composition (cast, plated or jacketed) and the ammunition's physical temperature to have more effect on ignition of "hard to ignite" powders than primer power.

When I first started out loading, there were no mentors in my location and there was no internet. All I have was the manuals I bought (and read voraciously) and the gun rags that showed up in the mail box on a monthly basis. Because of that, I relied mostly on what Lyman had to say and with respect to primers just did what they recommended. I still do to a large extent.

As to the post on the website referring to CCI comments, I've found over the years shooting sports manufacturers to be among the very best for customer service and product information. But I've also found a few individuals who were not quite up to speed on their product and advice.