magnum primer question

[rayg]

I picked up a couple of loose boxes of mixed primers which included one box of large rifle magmun primers. What application are magmum primers used for and would there be a problem in using them in place of regular primers with light cast bullet loads?
One thought is, when using light loads of I-4227 powder and unless the powder is positioned close to the primer there could be some non-uniform discharge. Would the use of magnum large rifle primers help offset the positioning problem?
Ray

[Trey45]

Just my 2 cents, use of magnum primers where non magnum primers are called for will increase pressures. Others here know way more about this than I do, I'm just offering what little I know on the subject.

[Sven]

In rifle cartridges, I have always figured magnum primers are mainly for use with ball powder, or maybe all heavy charges in large cases. I generally use mag primers in my 7mm mag, but don't in my .257 Roberts or 7mm-08. I would use mag primers if I used something like H414 or H380 in the .257 or 7mm-08. That's generally what my Speer manual says.

I've never really done much with real light rifle loads.

[Huntducks]

I don't shoot cast for any rifles except 30 carbine that said.

When working up a load for accuracy I will always add mag primers into the mix makes no diff what caliber 17 to 400 my powder is not a factor ball or stick, in some cases the accuracy improves others it's the same:drinks:

[2ndAmendmentNut]

Magnum primers are for use in magnum calibers and rarely do you find sane data suggesting other wise. Keep in mind that the guys that get hurt in reloading are not only the ones that go above listed data but also the ones that go below. There is a reason there is a minimum and a maximum. Stay safe.

[Shiloh]

I had a slow batch of surplus pull-down 4895. Mag primers helped some, by lowering the standard deviation. I shoot cast almost exclusively, so I don't use the remnants of that powder.

A coyote hunter I know uses them for positive ignition when hunting in sub-zero Upper Midwest winter nights.

Shiloh

[Larry Gibson]

rayg

Magnum primers can help with ignition in the case you mentioned. However, given a standard load that you have worked up and use, magnum primers will increase preasures because the hotter flame does alter the time pressure curve of the load making it burn faster. With light cast bullet loads this increase in pressure alone is generally not a problem. Where it becomes a problem is if the increased time/pressure curve (increased accelleration curve) exceed the limits of the alloy, the lube or th causes the velocity to increase beyond the RPM threshold.

Bottom line is; if you are going to use magnum primers with a known load then drop the powder charge 10% and work back up.

Larry Gibson

[Lead Fred]

CCI #34 military primers are of magnum grade according to CCIs website.

These are used in 30 cal (M1, M1a, AK) and 22 cal (ARs).

These are not magnum rounds at all.

.

[Larry Gibson]

CCI #34 military primers are of magnum grade according to CCIs website.

These are used in 30 cal (M1, M1a, AK) and 22 cal (ARs).

These are not magnum rounds at all.

.

They are indeed "magnum" primers. They are made for the 30-06, 7.62 NATO and the 7.62x39 (says so on every carton and 100 primer box). The intended purpose is for use with milsurp rifles, primarily semi and full automatics. Most of these cartridges in a milsurp context are loaded with ball powders. Thus the "magnum" type #34s work very well.

However, in some of my recent pressure/accuracy testing with various primers I have found that, given the same load, pressures and velocities with the #34s increase considerably. I also have found that even with worked up loads using this primer that with reduced cast bullet type loads using fast and medium burning powders that accuracy is not as good as when compared with other primers including WLRs. Basically I've found that the CCI #34s ar hot primers.

Larry Gibson

[Lead Fred]

Yes the primers are hotter than standard, yet none of the firearms are of magnum size, in fact the M1s have a limtied pressure requirement due to the op-rods.

Until I bought two cans of Ball-C Lot 2 last week to try in my 30-30, All Ive ever used is IMR extruded (s?) powders.

Except the bolt gun. I use #34s in everything else.

For the bolt gun, I use federal match, which are really hot.

I was under the impression for cast boolits you want to keep your FPS below the leading threshold, and use only standard primers.

But then shooting cast is new to me for centerfire, and Im here to learn.

[felix]

That is true, Fred! Keep the ignition fire and lube viscosity at their respective minimums necessary to make your maximum expected accuracy. ... felix

[lylejb]

in the context of primers, "magnum" is somewhat misleading. "magnum" primers are simply loaded with a larger, higher temperature, priming mix. That is to say, they are "hotter". typically they are used for harder to light powders, such as ball powders, regardless of the caliber, magnum or not.

you asked about reduced loads with magnum primers. Have you tried the regular load yet? Are you having inconsistant sound / recoil / velocity / or vertical stringing? You may not actually have a problem!!

you didn't say what caliber you are loading, or how reduced it is. Magnum primers are hotter, and MAY improve ignition, if needed. I would try a few of the regular loads, you may not NEED any more.

LB

[fredj338]

It depends. I have run vel. test using the same components & switching diff. brands of primers as well as std. vs magnum. In some caliber/bullet/powder combos, there is no appraciable vel. variation. That tells me not much els is going on pressure wise. In other cases, there is a considerable increase in vel. It is wise to drop your powder charge 5% (10% maybe if you are already running max.) & work back up. A chronograph helps, as there are no free lunches, you will often get an increase in pressure w/ an increase in vel. all other things being equal. If you are using low pressure or midrange loads, switching prrimers out has shown little variation for me.

[Huntducks]

I have read above posts and many of you assume that there will be prssure increases because a mag primer is hotter NOT SO.

I have a Oehler 43 and really used it a lot till about 4 years ago new putter old system as it ran on windows 95/98 and my old back up putter died i'm to cheap to up grade to the oehler XP software and even to lazy to set up the strain gages dam things cost to much.

I did darn near every caliber I owned except lever guns and a few short cases most pressure jumps all measured in PSI only increased 150 to 300 PSI and some as low as 20 PSI all depended on powder and sometime on case Mfg but I don't load full throttle so they where way under max some time there was no improvement in accuracy some even got worst W/mag primer I think the biggest pressure jump I saw was with Varget powder in 243 it was 2grs under max and the pressure was several 1000 psi over but even without mag primers it was up I only fired like 4 rounds I thought I made a mistake and pulled all bullets when I got home, now the almost full can of Varget has been sitting since.

FPS is no indication of pressure.

[felix]

FPS is not a function of MAXIMUM pressure, but IT IS a function of AVERAGE pressure. ... felix

[rayg]

I just was trying to find a use for the mag primers instead of having them just sitting on the shelve going nothing and wondered what I could use them in.

Where I thought I could use them is with my light loads of 16-21 grs of I-4227 powder charges in my .303 British and 8mm loads. With those light loads You need to make sure to tilt the case to position the powder against the primer using that powder in order to get uniform ignition. I thought a hotter primer would eliminate that need. I heard some folks use large pistol primers which are hotter then the rifle primers, to help eliminate the position problem with that powder also.
Ray

[smlekid]

I tried a load in my No4 with std and magnum primers I wanted to chrony the loads and compare velocity as well as accuracy
unfortunatly after shooting a string with the std primers someone asked to put some pistol loads over the clubs chrony and first shot killed it!!! shot a toucj low!!!! so I didn't get to check the velocity with the mag primers I did get to shoot a group with each
as you can see the mag primers shot lower and opened up the group
this was with Winchester 748 and 150gr Hornady (yea I know) bullets
left group is standard primers right magnum

[rayg]

If I'm not mistaken, the lower group indicates higher velocity. Ray

[Larry Gibson]

I have read above posts and many of you assume that there will be prssure increases because a mag primer is hotter NOT SO.

I have a Oehler 43 and really used it a lot till about 4 years ago new putter old system as it ran on windows 95/98 and my old back up putter died i'm to cheap to up grade to the oehler XP software and even to lazy to set up the strain gages dam things cost to much.

I did darn near every caliber I owned except lever guns and a few short cases most pressure jumps all measured in PSI only increased 150 to 300 PSI and some as low as 20 PSI all depended on powder and sometime on case Mfg but I don't load full throttle so they where way under max some time there was no improvement in accuracy some even got worst W/mag primer I think the biggest pressure jump I saw was with Varget powder in 243 it was 2grs under max and the pressure was several 1000 psi over but even without mag primers it was up I only fired like 4 rounds I thought I made a mistake and pulled all bullets when I got home, now the almost full can of Varget has been sitting since.

FPS is no indication of pressure.

I definatel concur that fps is not an indication of psi.

FYI; in my primer tests of 6 different LR primers recently in the .308W with H4895 under 311291 bullets in the 2300-2500 fps range pressures (psiM43) varied 7,700 psi from the lowest to the highest. That is about a 15-17% increase in psi. Fps increased 99 fps or a 4-5% increase. Perhaps not a great increase either way as foar as cast bullet loads are concerned but it could be a cause for concern if one is pushing a max load with jacketed and makes a switch from standard to "magnum" primers. With cast it also can decrease the accuracy be changing the time pressure curve and or putting your load ablve or below the RPM threshold. Just providing such for your information. Hope you can get your M43 back on line as it will be interesting to compare notes.

Larry Gibson

[jaycocreek]

I to have wondered about mag primers in loads not specified for them.You can read articles from different people whom get different results from a high pressure change in certain calibers, to none at all.

Speaking of the CCI#34 Mag primer here is what Randy Garrett had to say about it.

Ron,

When I switched from CCI200 primers to the CCI34 primer, the pressure measurements remained unchanged. I know that the conventional wisdom is that they will increase pressure, since they are a magnum primer, but when actually measured, the numbers remained the same. When I first started building commercial ammo I used magnum primers, and received all kinds of guff from handloaders, saying that they were "unnecessary." I'm not sure what unnecessary means when we are talking about consistent ignition, especially when a guy occasionally finds himself hunting in cold weather (and I love to hunt in the snow), but since many hunters do find themselves hunting in the cold I see no reason to use a lesser primer to ignite my powder. Also, the built-in protection against "slam fires" (as the military calls them with the automatic guns) or recoil induced magazine ignitions has got to be a plus for anyone shooting heavy loads in a tubular magazine.

Jayco