Magnum Primers...is my thinking correct ?

[JonB_in_Glencoe]

after reading the thread on Winchester primers, I thought I'd start a new thread requesting input on Magnum primer usage.

My understanding of use of Magnum primers are for one of the three following conditions.

1. shooting in extreme cold conditions

2. loading Tall and Large size cases (ie belted magnums and larger)

3. loading very light loads. (where the powder occupies less than 50% of the space available, examples would be some 38spl loads, 45LC loads or some rifle "gallery" loads)

Disclaimer: always take all the precautions of working up a load using the prescribed instructions in a respected reloading manual.

[Rocky Raab]

Jon, I've never subscribed to the idea of using mag primers in very light loads. The logic escapes me.

But I'll add one other condition as a substitute: When using certain very hard to ignite spherical powders, such as W296/H110 or H380.

[felix]

Number three is very incorrect. Use filler, or use a powder easier to ignite, perhaps both. ... felix

[JonB_in_Glencoe]

Rocky,
the logic of using a mag primer in a light loads is about the position of the powder in the case. If the gun is tipped downward right before firing, the powder could flow away from the primer, making it more difficult to ignite. Now a primer that provides a longer and hotter flame should overcome that difficulty more so than a standard primer.

whether it's correct or not, I can only assume.

[grouch]

I've tried it several times over the last 50 yrs with cartridges up to 30 - 06, mostly with light loads. Magnum primers have not EVER helped - they've always been worse.
Grouch

[Rocky Raab]

Jon, while it has been shown that powder position can indeed have an effect on pressure and velocity, it is doubtful that it has any effect in real life. To show the effect, one has to deliberately tip the gun and then carefully raise it so as not to re-distribute the powder.

In real life, the gun is held more or less horizontal (I have yet to aim at my own boot with one), and the action operated between shots. Both these things tend to jostle the powder evenly along the case. Then there's what I call the "leafblower effect" of the primer going off. That stirs everything into a perfect maelstrom inside the case.

Try this: prime a case. Put a small pile of powder on your sidewalk. Now place the gun muzzle an inch from the pile and fire the primer. Even inches away from the primer (the whole length of the barrel) that pile of powder simply disappears. If it stirs powder that much from so far away, it must do so even more thoroughly inside the cartridge.

[fredj338]

I only use mag primers w/ large amounts of ball powder. Even in magnum rifle cases. Unless the powder volumn is over 70gr, it gets a std primer. The only handgun loads that get them are H110/W296 in any of the magnums.

[geargnasher]

I only use Magnum primers if a standard primer fails to supply consistent ignition. IME it IS necessary to use magnum with 296 in the .44, otherwise it simply won't light.

One of the things I've noticed about SOME reloading books, especially those put out by or affiliated with companies that also make primers, like Speer, is that magnum primers are often listed where they are unnecessary: Gotta sell mag primers, too, right?

Gear

[felix]

It's the length of the cartridge, not the amount of powder per se. I would still start with mild primers with the wide-bodied 70 grain cases. ... felix

[mpmarty]

Heck I even use LP primers in 45/70 loads and they work just fine. I don't use Magnum primers at all as I don't use 296 or H110. My H380 loads in 22/250 light off just fine with standard primers but there we are talking about a relatively small case. My 7mm Remington Magnum burns H870 just fine with standard LR primers too.

[jonblack]

My usage of small pistol magnum primers is a bit unorthodox. I use them because I have them. Several years ago I bought about 15k at a great price. Since then I have worked up 9mm loads and 380 Auto loads. I am also about to work up a .40 S&W load. Over at the Brian Enos forum, many shooters use them in this manner.

As a side note, I should explain that all of my loads are "plinking" loads. I do not load max loads. As long as the load cycles the gun and hits the steel I am shooting at, it is fine for my needs. In the SD role I use factory ammunition.

jonblack

[jmsj]

Before the "Big primer shortage" I used Winchester LP primers in all my large pistol primer cartridges, cast and jacketed. For cost and convenience it was easier to stock one primer. It seemed like they were the first to disapear when primers became scarce. Last week I was able to buy 2000 of them locally for the first time in long time.
My most accurate load in my Ruger Bisley Vaquero .45 Colt uses Winchester large pistol primers, a 255gr RNFP and 2400 powder. They seem to work well in my .45acp and .44 magnums as well.
I have not done the extensive testing that others here have, I wish I had the time to. But for now I'm glad to be able to get them again.
jmsj

[lwknight]

It is commonly excepted that Standard LP primers in 44 mag with 2400 is just fine.
If you only have magnum primers then reduce the load some.
I cannot say what percentage to reduce the load because every powder is unique.

[sagacious]

If one uses the WLP primer, one need not worry about when to use a magnum primer.
Simple and effective.

[44man]

Let's see, when did H110 and 296 first come out? Can't remember but my .44's and .45's have never seen a mag primer with either powder except for testing.
They triple groups, plain and simple, even WLP will open groups.
It is entirely not true that a .44 needs a mag primer for ANY powder.
Even the .475, .454 with .460 brass, the .460 and up will all ignite with a standard LP primer but the larger cases are more accurate with mag primers.

[Bass Ackward]

I use magnum primers for light loads and pistol primers for full case, low pressure situations. Same logic as Jon uses. Cause I hate filler other than powder.

Every load gets the safety test. And if it shows powder position sensitivity at any season of the year, (cold is usually the worst) it is reworked with a magnum primer.

Why? Because it's not the strength of the average primer in the box. It's the strength of the weakest one in cold weather that causes problems.

But in truth, I don't load many "light" loads for rifles any more. Handguns either. If I need a lighter load, I use a case design safer for this purpose.

[abcollector]

44man,

Just trying to understand what you spoke of- are you saying that you don't use LPM primers for powders like H110/296? And don't like using Win LP primers for these powders also because in both cases, they open up the size of groups? Cast or jacketed are treated the same? Do you use a heavy crimp? In your experience, would this apply to the .357 mag as well?

I'm just trying to understand this thing about always use Magnum primers with powders like H110/296.

Thanks Sir.

[Whitespider]

...Then there's what I call the "leafblower effect" of the primer going off. That stirs everything into a perfect maelstrom inside the case...

I'm not so sure I buy that one Rocky. If there's enough powder in the case that some of it is in front of the flash hole, then yes we would have some stirring. But if the powder charge is small enough to put the level below the flash hole, I don't think so, or at least not enough to be described as a "perfect maelstrom"; It would be more like a flutter of just a few of the grains resting the surface of the charge.

It's sort of a physics thing; pressurizing something doesn't usually stir up the contents, but the rapid release of pressure will. I have a little one-gallon yard sprayer, made of translucent polystyrene; ya' know with the hand pump on the top. Well, I installed a tire valve in the top so I can quickly pressurize it with an air compressor. If I fill it to a level below the tire valve and hit it with compressed air the surface of the contents barely gets a ripple on it. But, if I leave the top lid off, and than hit it with compressed air, I get soaked by the contents as the pressure flows out the top.

You also have to consider the "time" factor. As the pressure flows into the case the "flow" has to flow long enough to overcome the inertia of the "at rest" powder grains. But as the pressure builds inside a sealed container the speed of the "flow" is rapidly reduced; the smaller the container, the less "time" the "flow" has to act on the contents.

Try this experiment. Take a 2-litter soda bottle (representing the cartridge case) and install a tire valve in the bottom (representing the flash hole). Now put some sugar (representing gunpowder) in the bottle so that when you lay the bottle on its side the sugar is well below the tire valve. Screw the lid on tight and hit the tire valve with compressed air (representing primer ignition) for a split second so you don't split the bottle. You will notice that very little, if any, of the sugar grains are disturbed. OK, now repeat the experiment but this time replace the screw-on lid with a tight fitting cork (representing the bullet), try and get as tight a fit as possible. Now hit the tire valve with compressed air and watch the sugar as you do; only when the cork blows out does the "perfect maelstrom" happen, probably carrying a large amount of the sugar out the mouth of the bottle.

Now if you apply this to a cartridge... Normally the powder has ignited long before (relatively) the bullet leaves the case. The "perfect maelstrom" doesn't happen until after the bullet is well on its way down the barrel because it would need to accelerate to a point where pressure is rapidly flowing out of the cartridge case.

[felix]

Rocky is right on, Whitespider! Primers are shocking devices. ... felix

[Rocky Raab]

The gas jet from the flashhole is indeed a powerful blast of high-speed, incandescent gas and particles, not a "spark" as some folks envision.

Nonetheless, since my last post yesterday, I have been re-thinking the issue of magnum primers with small charges in large cases, and I am forced to make a small retraction or concession. I know that in small cases, a too-hot primer can and does unseat the bullet before the powder can ignite (most obvious in the Hornet). That causes a great deal of pressure/velocity variation and lost accuracy. That being the case (pun intentional) it should also be true that in a larger volume, a mild primer may not develop enough heat or pressure to properly ignite even a small powder charge. A certain amount of pre-pressure is required - possibly as much as 10,000 psi - before powder can ignite properly.

So, I'll concede that in some instances, a magnum primer may provide improved ballistic consistency even with small charges. The logic no longer escapes me - not completely, at least.

[Whitespider]

Well maybe felix, but I'm not so sure.
I've seen the "leafblower effect" or "perfect maelstrom" theory presented in print many times, but have never seen results from any experiment or test that support it. When it comes to primers most of what's believed to be true has never been put to comprehensive test; usually it's just something some so-called "gun guru" observed in a particular set of circumstances, reported, and then it becomes repeated over time as fact.

Foe example; the ridiculous notion that a "magnum" primer is "hotter" than every other "standard" primer; or that "magnum" primers should only be used in "magnum" loads or with slow powders. A "standard" Federal large rifle primer could easily be "hotter" than a "magnum" Remington large rifle primer. I use the primer that produces the most uniform ballistics in my gun, with my load, regardless of the "standard" or "magnum" designation on the box, in fact I totally ignore such "designation(s)".

I won't go so far as to say the "perfect maelstrom" theory is impossible; but what I am saying is, "Show me the proof."

[Hardcast416taylor]

One thing nobody has touched on yet with using either type of primer is the uniformity of the flash hole. I have tested this theory of reaming the inside of the case at the flash hole with one of those uniforming tools made by RCBS or Lyman and others. It does make a difference, maybe you won`t notice it with hunting or just blastin` loads, but it helps calm down a group from the bench.Robert

[Lee]

I see both sides of this thread, and there is some very good debate here. Perhaps "perfect maelstrom" is not the best choise of words, as even in nature, nothing is "perfect". But the primer, as stated, is not a spark, but rather a super hot jet of gas.
Try this, primer a cartridge, auto or revolver. Chamber, then in a subdued lighting, fire. What you see is one heck of a hot jet of gas leaving the barrel, just from a primer.
It tells me all I need to know about primers!
Now, standard vs. magnum?? My jury is still out on this one. I still see quite a bit of conflicting advice regarding usage of magnum primers. So, thread on, boys!!!

Now someone mentioned 45-70. I do not recommend this, but it is a charge I use;
36.6g of BLC-2 driving a 300g FN boolit, standard rifle primer. I've chronyed about 1250fps. It will punch a hole in one side of a 5(?)gal propane tank, and not exit the other side. (so much for recovery!!) Used in a Pedersoli Sharps. The BLC-2 I have is mostly spherical with a few flat discs. Original opened by me, so it's not a mix. That is not much in the case, I charge by hand to ensure no double charges.
Make of this what you will, just remember this is NOT RECOMMENDED BY ME......
;-)

[44man]

44man,

Just trying to understand what you spoke of- are you saying that you don't use LPM primers for powders like H110/296? And don't like using Win LP primers for these powders also because in both cases, they open up the size of groups? Cast or jacketed are treated the same? Do you use a heavy crimp? In your experience, would this apply to the .357 mag as well?

I'm just trying to understand this thing about always use Magnum primers with powders like H110/296.

Thanks Sir.
That is true, I do not go to the Fed 155 until the case is large enough and that starts with the .475, even the 45-70 only uses a LPM but the .44 and .45 brass is too small for the pressure of a mag primer. Yes, a standard primer can be "hotter" but have less pressure. I like the Fed 150 for these.
If you hunt or shoot at 20 below zero, you might want a mag primer but I have hunted in very cold weather without a need so far.
I do not use a heavy crimp, just enough so boolits don't move under recoil. I use good neck tension but found even a looser fit is still good as long as tension is even. Sorting loads according to seating pressure has shown no loss of accuracy with each batch, just a change in POI for the whole group shot.
Never have I found ignition problems with a standard primer using those powders.
The .357 is different with the SP primers, you need to test each primer.
Even SR primers can change things around. We worked with starting loads of 296 in the .454 using SRM primers and had many fail to ignite and stick boolits in the bore. Only when the load reached max did they all go off but accuracy still suffered. We tried all primers.
Then we cut down .460 brass and used LP and LPM primers. Even the standard LP primer ignited any load of 296 but the LPM was the most accurate with accuracy twice as good as a SRM. So you see the LP primer is better then the SRM when it comes to ignition but the SRM had enough pressure to drive the powder and boolit well down the bore.
Using a LPM primer with small charges of fast powder in the .44 can push the boolit down the bore as the powder is lighting.
It also happens with a slow powder and either way, accuracy suffers because you are changing the case capacity different for each shot depending on boolit movement.
Using soft boolits with minimum tension and crimp with a mag primer and NO powder can drive the boolit a surprising distance down the bore. Hard boolits and tight neck tension with a decent crimp can also have a boolit move from a primer alone.
If you did this in a rifle without a cylinder gap, drive the boolit out and have it stop in the bore before the powder fully lights, you can set yourself up for an S.E.E. event. Since the boolit is close to or against the rifling, there is more resistance to movement, unlike the throat in a revolver. Now take a rifle with a long throat like the Swede and the boolit has little resistance and can go out and stop at the rifling, it is possible to blow up the gun.
I contend the only thing saving the silly things revolver shooters do is the gap. What those things do for accuracy is anyone's guess.
But "shoots good and goes off" is the standard saying.

[lwknight]

I'm just trying to understand this thing about always use Magnum primers with powders like H110/296.

Thanks Sir.
It was Winchster that first said to use only magnum primers with these powders.
They are the same powder under 2 different names.
In the days of old , Winchester primers were stronger than other primers so Winchester did not have "Magnum" primers till later. The 296 was developed by winchester for winchester ammo using winchester primers.

Today the powder is the same and magnum primers are needed to equal he original loads and Winchester now makes primers in standard and magnum so that their primers are basically the same as everyone elses.
Its a marketing thing. If the lyman manual says use Remington #2 1/2 primers then winchester primers would not have been substituted till they made standard primers.

[44man]

I made a test today. I loaded a .44 boolit, cast hard, with full case tension when loaded and a decent crimp. Federal 155.
NO powder. I did not hear the primer go off at all, just the click with the hammer falling.
The cylinder was locked up and it took a brass rod to force the boolit back so I could spin the cylinder.
Now imagine a soft boolit with low case tension, the boolit can enter the barrel.
Adding powder to lessen the air space can push a boolit farther.
Why would anyone fool with such stuff?

[lwknight]

If you lower the airspace a lot by using a lot of gun powder , the primer will push the bullet all the way through the barrel and through several feet of air.

[Rocky Raab]

Not to confuse the issue, but H110/W296 may well be a special case, or exception. It is a heavily deterred powder that requires a very hot and long-lasting primer flame to properly ignite, and then it also requires a lot of resistance to KEEP burning. There have been well-documented instances of 110/296 either failing to light, firing with a a noted delay (hangfire) or seemingly detonating. All at what seemed to be random occurrences.

The problem is almost certainly related to a reduced charge, a lightweight bullet, low neck tension - or some combination of those factors. This photo (not mine) shows a reduced charge of H110 that seemed to be a 'dud". You can see that all the deterrent coating is blown/burned off of what appears to be about a half charge of powder. The remaining raw nitrocellulose is fused together. This was probably only a guardian angel from being a burst gun or worse. In this condition, any re-ignition of the powder would have resulted in an "explosion" or SEE.

http://i27.photobucket.com/albums/c170/RockyRaab/hangfire.jpg


With H110/W296, you MUST use a full charge, a heavy bullet, high neck tension AND a magnum primer.


But, with ANY OTHER POWDER BUT 110/296, it is not unreasonable to develop loads with a mild or standard primer, and move to a magnum primer if you see large velocity variations or suspect poor ignition.

[JonB_in_Glencoe]

The gas jet from the flashhole is indeed a powerful blast of high-speed, incandescent gas and particles, not a "spark" as some folks envision.

Nonetheless, since my last post yesterday, I have been re-thinking the issue of magnum primers with small charges in large cases, and I am forced to make a small retraction or concession. I know that in small cases, a too-hot primer can and does unseat the bullet before the powder can ignite (most obvious in the Hornet). That causes a great deal of pressure/velocity variation and lost accuracy...

you have me a little worried here.
How likely is this for 38spl ?

I loaded 500 rds of 38 spl about 2 months ago,
mostly for friends, I did keep a box of 50 for myself.
the recipe is:

Fed #200 Mag Pistol Primer

3.5 gr. titegroup, which is 0.3 gr more than the starting charge in
LEE's reloading manual, and spec'd to go about 900 FPS with a standard primer.

I used a 125 LRNFP (not a TL) cast with WW alloy unsized & Lee alox lube
these were cast by another friend as I haven't started casting yet.
He said they fall at .359ish.
they were seated to a crimp groove and I used the LEE Fact. Crimp Die and
applied a Heavy Crimp as specified in LEE's instructions.

I have used Mag primers for 38 spl before with no problems with
heavier bullets...and I can't find that load data...probably a different powder, probably Unique.

Do you think I may have an issue with these ?
should I be calling my friends to get this ammo back ?
Jon

[Nose Dive]

OK...Limme jump into this one too....

Mag primers vs Standard offer some things above the standard. I don't have the TIME vs TEMPERATURE graph here to add, but, when published, (years ago by Western,,I think) is really showed the differences.

Simply, the MAG prime offers more heat (not that much really, if you study the submitted graph) ove a longer period of time. So's your getting more ignition temp inside the cartridge for a longer time frame. = more ignition? I guess yes. The reall difference if you see the graph is TIME. Things are buring inside longer. The intent here, another one of my quesses, is to ignite more of the powder with PRIME energy vs. powder burn energy.

What and which, if either, offers more complete ignition. I use some 2400 in the .44. Nasty sutff and seems to me, some of it never ignites as I see trash in the barrel. Dirty stuff. Could be burnt ash...probably is. But the BOOK says use MAG PRIMER to get done what they want done. So, I follow the instructions and never had any problems.

Like the rest of the fellas... I would not venture into 'load book' composition efforts with small poweder charges and MAG PRIMERS. Could 'DETONATE"...KA BLEWY..and your gun and hand may be gone.

Like I say, Mag Primers have a MAGNUM job to do. They usually appear in rounds with LOTS of very hot powder and they just burn a bit hotter for a longer time.

Get a good reloading manual and follow the instructions. "DON'T--VENTURE INTO THE UNKOWN".. That is why they spend so much money on acquiring the data for the RELOADING MANUALS.

Nose Dive

oh yea...might try a 'test'... Load one emply round,,no powder and NO BOOLIT with Standard primer and do the same with a MAGNUM primer. Again..NO POWDER..NO BOOLIT. Next time you are in the field... Shoot both of them. You will see and feel the difference. My son says the MAGS sound loader too but am 1/2 deaf from firing 104's. But try it and you will see..MAG primers are indeed hotter. Be sure the pistol is pointed away from everthing and everbody... They DO SPRAY OUT FIRE...

ALL GUNS ARE ALWAYS LOADED.

Nose Dive

[rhead]

A mag. primer is something that I try if I am getting vertical stringing. Sometimes the greater priming force will help the problem, sometimes the tougher primer cup will cause more erratic ignition. If it helps the situation I keep them If it makes things worse on gives no advantage I go back to standard primers or try pistol primers if the pressure levels make the attempt practical.
USUALLY the standard primer for that case will give the best results. Sometimes a different primer will give positive results.

[44man]

you have me a little worried here.
How likely is this for 38spl ?

I loaded 500 rds of 38 spl about 2 months ago,
mostly for friends, I did keep a box of 50 for myself.
the recipe is:

Fed #200 Mag Pistol Primer

3.5 gr. titegroup, which is 0.3 gr more than the starting charge in
LEE's reloading manual, and spec'd to go about 900 FPS with a standard primer.

I used a 125 LRNFP (not a TL) cast with WW alloy unsized & Lee alox lube
these were cast by another friend as I haven't started casting yet.
He said they fall at .359ish.
they were seated to a crimp groove and I used the LEE Fact. Crimp Die and
applied a Heavy Crimp as specified in LEE's instructions.

I have used Mag primers for 38 spl before with no problems with
heavier bullets...and I can't find that load data...probably a different powder, probably Unique.

Do you think I may have an issue with these ?
should I be calling my friends to get this ammo back ?
Jon
They will cause you no problems. You can do stuff with a revolver without much chance of danger, remember the gap.
I would say accuracy will not be the best if you are target shooting.
The SP primer is much different then a LP, the amount of compound is a lot less.

[44man]

Not to confuse the issue, but H110/W296 may well be a special case, or exception. It is a heavily deterred powder that requires a very hot and long-lasting primer flame to properly ignite, and then it also requires a lot of resistance to KEEP burning. There have been well-documented instances of 110/296 either failing to light, firing with a a noted delay (hangfire) or seemingly detonating. All at what seemed to be random occurrences.

The problem is almost certainly related to a reduced charge, a lightweight bullet, low neck tension - or some combination of those factors. This photo (not mine) shows a reduced charge of H110 that seemed to be a 'dud". You can see that all the deterrent coating is blown/burned off of what appears to be about a half charge of powder. The remaining raw nitrocellulose is fused together. This was probably only a guardian angel from being a burst gun or worse. In this condition, any re-ignition of the powder would have resulted in an "explosion" or SEE.

http://i27.photobucket.com/albums/c170/RockyRaab/hangfire.jpg


With H110/W296, you MUST use a full charge, a heavy bullet, high neck tension AND a magnum primer.


But, with ANY OTHER POWDER BUT 110/296, it is not unreasonable to develop loads with a mild or standard primer, and move to a magnum primer if you see large velocity variations or suspect poor ignition.
This is exactly what I got in the .454 until I got close to max loads and I was using all of the SRM primers made. I suspect that is what you got that failure in.
The SR pocket in the .454 is an abortion and starting loads of H110 and 296 in the manuals should never be listed, only max loads. The SR primer runs out of heat fast and airspace in the case damps it out.
All of those primer tests showing sparks shooting out of a barrel do not show what is going on in a loaded round. Move a boolit out of the case with primer pressure and you increase the air space and that is like reducing the charge.
Take a close look at factory .454 loads, Extreme neck tension and a crimp that ruins brass, it is because of the SR primer.
Is it not strange that when posts are made about the .454, a lot of responders say they use Rem 7-1/2 primers---HEAT.
I would never make a blanket statement that a mag primer must be used in the .44 and .45 because a standard primer can have more heat, less pressure and keep the boolit in place and the powder tight to the flash hole for good ignition.
54 years with the .44 mag will prove you wrong 100%. It sounds too much like you repeat what you read without experience.
My .44 loads have a SD of 11.5, MAD of 9.9 and an ES of 29 fps, all with the Fed 150 primer.
Keep the .454 out of this, all you discovered was it uses the wrong primer. Or you had other issues by loading the wrong way. Don't blame the powder.

[Rocky Raab]

Couple points to different posters:

JonB, I think your loads will be fine, but I can't guarantee it because they are "outside the book" data. At least you are near the Start load, which ought to build in a cushion.

44man, allow me to re-emphasize that the photo I posted is NOT from my loads, nor is it my photo. It was part of another discussion on this same issue, related to H110. I have never loaded for the .44 Mag and wouldn't own one simply because I don't need one. My discussions here are intended to be about internal ballistic theory, not to relate my own experiences.

To those using 2400 powder, Alliant now strongly recommends the use of standard primers ONLY with this powder (with all their powers, in fact). Unburnt kernels of powder after firing are almost always due to a load that is underpressure for that powder. Powders are designed to burn within a given pressure range. If you load to below that range, it simply will not burn as well. Sometimes that means that some of it will not ignite, or some will only partly ignite and go out. Yes, powder can and does go out - often due to contact with cold gun metal, which transmits heat away from the powder fast enough that the powder can't generate it quickly enough to keep itself burning.

[Whitespider]

My .44 loads have a SD of 11.5, MAD of 9.9 and an ES of 29 fps, all with the Fed 150 primer.

;) Ahhhhh yes... The Federal #150 is the great undiscovered Large pistol Primer; much closer to the description of a "good all-around" primer than the ever popular Winchester offering.

[45r]

Fed primers are excellent and they are my most used but 296 always gets CCI-350 in 41,44 mag and 45colt loads for me and rem 7 1/2 in 454 casull with 296.I use fed primers for mid-loads in 454 casull.I go by what the manuals say and what I read in Handloader and it works.I'm sure you can get good groups with standard primers with 296 with good neck tension and a case full of powder but I have heard of problems in cold weather so I stick to CCI-350's.Handloader did a primer test with H-110 and a contender and CCI-350 shot as well or better than the other primers.If you have a great deal of experience like 44man using standard primers with 296 in average weather I'm sure it works well but I've never seen any manual not warn about reducing 296 charges and to use mag primers.If I want to use standard primers I use 2400 or Vitt N-110 and despite what some say it has always been very accurate in any of my revolvers with the right amount of powder.I've got 1 1/2 to 2 1/2 inch groups at 50 yards with 296,2400, and Vitt N-110 and that is good enough for me.The weather gets pretty cold here so I've been using Vitt N-110 for hunting most of the time.I have used the Win LP with my Vitt N-110 hunting loads but have changed to FED LP for Vitt N-110 cast boolit loads.

[2wheelsoff]

This came up in a google search ("magnum primer" temperature"):

http://www.shootingsoftware.com/ftp/Pressure%20Factors.pdf

Finding is that magnum primers do not affect pressure in the loads they experimented with.

I am very new at this so no knowledge on the subject other than what I am reading online.

I have been reading on magnum primers as I bought them online, and can't return them....trying to find out if I should buy non magnum pistol primers (small) or just try loading these.

[Bass Ackward]

It all depends.

He liked focusing on barrel temperature. What does temperature do to your barrel? I have slugged some that get tighter when the temperature falls, assuming bore diameter contracts.

I have seen some that get tighter as the temperature climbs. Evidently, the steel expands 360 degrees thus expanding in closing bore diameter. You can't predict it either as no correlation has been seen in barrel or bore diameter.

With heat, the bore can walk changing POI. It does what it does forcing you to adjust.

I have run case neck tension tests. With older brass using 18 grains of 2400 in a 44 Mag, .002 case neck tension a magnum primer provided no more velocity and accuracy was the same. From .004 to .006 the Fed 150 won. At .008 the tide turned BACK in favor of the magnum primer. So I repeated this with annealed brass and the Fed 150 won at all dimensions down to .008 as case neck tension seemed to matter less. With the 2400 load anyway. With another powder, this could be all different.

So nobody can tell you what you will need or do not need and referencing multiple sources for comparison will provide you some statistical chance. So will staying with the slowest powders for that application. In the end, you simply have to test.

[44man]

44man,

Just trying to understand what you spoke of- are you saying that you don't use LPM primers for powders like H110/296? And don't like using Win LP primers for these powders also because in both cases, they open up the size of groups? Cast or jacketed are treated the same? Do you use a heavy crimp? In your experience, would this apply to the .357 mag as well?

I'm just trying to understand this thing about always use Magnum primers with powders like H110/296.

Thanks Sir.
Mag primers are NOT needed in the .44 or .45 with H110 or 296 unless just maybe you shoot in way below zero temps. I hunt in very cold weather without any change.
The pressure pushes out any bullet before good ignition, the cases are too small. I use nothing but a Fed 150 primer.
I do not use a heavy crimp, only case tension with a moderate crimp. Roll only into the crimp groove.
The .357 uses a SP primer and you need to test, I don't own a .357.
WLP are just a shade better then a full mag but still opens groups.

[XWrench3]

the ONLY place i use a magnum primer is in a magnum caliber, that uses a hard to ignite powder AND jacketed bullets. the reason i state jacketed bullets is because that is the only bullet i am going to shoot at that kind of velocity which equates to a LARGE amount of powder. i am not so much on the temperature thing. i guess if i was going to shoot in the artic circle somewhere, i would want magnum primers. since i never plan to go there, i will just use my magnum primers in my 44 magnum and 300 magnum loads. when i download these, i simply use standard primers.:Fire::Fire::Fire:

[a.squibload]

Good thread, thanks all. I have always worried about using a "too hot" (i.e. magnum) primer in a medium load,
always used non-magnum in slow loads.

For confirmation: a primer without powder WILL push a boolit halfway down a 7½" SBH barrel.
No, it wasn't mine!

Also remember those plastic bullets for indoor use, look like a little green pill bottle?
Primer only, no powder.
A freind long ago pinned a paper target on the curtains, the plastic bullet cut right through and cracked the glass.
Same guy, not me!

[white eagle]

I use a mag primer when a standard is not as accurate

[Mal Paso]

A couple months ago I experimented with light loads ( 14gr ) of 2400 in the 44 Mag cartridge. Combustion was Very inconsistent. Sometimes it felt like a 44, sometimes it felt like a 22. Adding a Magnum Primer "helped" but wasn't quite "there". BLT had given me some 44 Special Cases and I did a side by side experiment.
Boolits were Lyman 429421 from the same batch, Gun was 4" Redhawk All loads got a solid roll crimp. BLT's Chrony ( before it was Shot :grin:).

14gr 2400 Mag Case Federal Match Magnum Primer
760 fps
847 fps
824 fps
873 fps
846 fps
846 fps

14gr 2400 Special Case Wolf Standard Primer
930 fps
973 fps
891 fps
907 fps
965 fps
950 fps

IMHO Mag Primers help light slow burning powders but do not raise the cartridge pressure Enough to Solve combustion problems. I'll leave it to better shots than myself to talk about flyers.