Primers for . 375 Holland & Holland Magnum

[orpington]

The Lyman 49th Edition recommends magnum primers. Makes sense, it’s a magnum round. Except searching on the internet, not all loads for this round suggest a magnum primer. One poster to a thread suggested that loading this round with a standard, non magnum primer could blow up ones rifle. I find that had to believe and if anyone suggests how this is even possible based on the primer utilized, please let me know.

Given the current primer shortage and that I have many CCI large rifle primers and no magnum ones, I would prefer to use large rifle primers.

First, an elementary question. What is the difference between standard large rifle primers and magnum ones?

I would “guess” any problems that might arise would be from hot loads. Given that it is a .375 Holland & Holland Magnum being discussed, and I really don’t wish to leave my shoulder in the next county, I will stick to light loads only.

 

[WeekendReloader]

I believe some powders need a magnum primer to ensure positive and consistent ignition. I know in magnum handgun loads, some of the popular powders are picky like this too.

 

[orpington]

I would be using powders that I have on hand that have been used regularly in rounds like .30-06 and .270 with a CCI large rifle primer.

 

[Blue68f100]

Do you have any CCI #34's ? If so these are considered a mag class primer. They will seat a little deeper than a std primer, but you should not have any problems setting them off with your rifle.

 

[Lennyjoe]

OP, there's a good thread here on primers: Primers: Using Small Pistol, Small Pistol Magnum and Small Rifle in Pistol Ammuntion. | The High Road. Though the thread talks about small primers, there is good info in the responses to help you out.

Also, what powder do you plan on using so we can give you suggestions on if a magnum primer is necessary or not.

 

[BigBore44]

Try a different reloading manual. What is your bullet weight? Are you shooting cast bullets since you’re referencing the Lyman manual? What powder? I don’t know how much experience you have with reloading. So I’m cautious to make suggestions. There are powders that cross from 30-06 to 375 H&H like H4350. But many will not.

 

[lightman]

Thats a large case and usually uses slow burning powders so a magnum primer is usually used in this situation. But you can't go wrong following the load data in the book. Blowing up a gun!!! LOL, I doubt it!!!

 

[orpington]

I have reloaded for over a decade. Just not .375 Holland & Holland. In fact, there is no real hurry on this as I actually don’t own a .375 Holland &Holland chambered rifle, only just Forster dies, a shell holder, once fired brass, and a partial box of Sierra 300 grain .375 spritzer jacketed bullets. I just tossed the .30-06 and .270 out there as they are somewhat larger cases as compared to the multitude of other calibers I have loaded for, many in black powder. Of course, this is not a black powder load, but, for example, a recent smokeless powder reloading session was one in which I loaded 22 rounds .270, 51.5 grains IMR 4350 behind a 130 grain SP #2730 Hornady bullet. Powders I have right now include IMR 4895, IMR 3031, IMR 4064, H4198, IMR 4350, and H 4895. I have other powders, such as Unique, Bullseye, and IMR 4227, as well as the required Fg, FFg, and FFFg. These latter powders are just mentioned but they would not be of the type for this rifle and appropriate loads.

I was thinking, as published in Lyman #49 of starting with 73.0 grains of IMR 4350 behind the 300 grain Sierra bullet with, of course, a standard large rifle primer. I would load 5 or so to start, pending getting the rifle.

I put the cart before the horse because I got a fabulous package deal on it all. It’s only a matter of time before I get a pre 64 Model 70 in .375 Holland & Holland Magnum, but a surprisingly high number of those out there have been monkeyed with.

Now who out there wants to sell me one of these that hasn’t been monkeyed with for a reasonable price?

 

[edwardware]

One poster to a thread suggested that loading this round with a standard, non magnum primer could blow up ones rifle.

Detonation overpressure is the Yeti of the handloading world; everyone's got a second-hand story, no one's got a headmount.

In my personal experience with .375H&H, an LRP will work ok under some powders, especially at high case-fill. As you reduce case-fill, you'll begin to get a random barely perceptible delay between 'click' and 'BOOM'. As you further reduce case-fill, the delay varies more. It's quite disconcerting.

An LRPM solved the problem entirely.

Note: an LRP worked fine under low-pressure Red Dot loads, because it's MUCH easier to start.

 

[orpington]

Okay, it appears that high case fill, and thus, hotter loads, are more conducive to using a large rifle primer than a less filled case with a lighter load.

Which means that as I never hand load hot loads, especially to begin with, it appears I an ill-advised to use anything other than a magnum primer with my lighter starting loads???

 

[Swampman]

It depends on the powder, in the past I've used standard primers in reduced loads with Red Dot, 4759, 2400 and even H4895.

These were all cast bullet loads, if I was loading 300 grain jacketed bullets I wouldn't use anything slower than 4759 or 5744 with standard primers. I wouldn't even do that unless I had reputable, published data.

Google "secondary explosion effect".

 

[Archie]

I'd really like to hear the explanation of how using a standard LR primer could cause a pressure excursion violent enough to blow up a rifle. Or even strain the chamber or locking lugs.

 

[Laphroaig]

If standard LR's was all that I had, I would definitely work up a load with them. I'd bet with moderate burn rate stick powders there won't be much of a difference.

I've always felt that magnum primers make the biggest difference with hard to ignite ball powders.

 

[Swampman]

I'd really like to hear the explanation of how using a standard LR primer could cause a pressure excursion violent enough to blow up a rifle. Or even strain the chamber or locking lugs.

S.E.E. isn't something that can be adequately explained in a forum post, especially by someone like myself that has only a very basic understanding of it.

Think of a hang fire situation where the powder smoulders and creates gas under pressure, then the gas detonates as a high explosive rather than burning like powder is supposed to.

...I've always felt that magnum primers make the biggest difference with hard to ignite ball powders.

This.
Think of a hard to ignite powder containing nitroglycerin coupled with inadequate ignition that allows the nitroglycerin to form an explosive gas instead of burning progressively as designed.

If you want a better understanding of a poorly understood subject, you'll have to do some research. My understanding and interest is mainly limited to avoiding the factors that can cause it in my own ammunition.

 

[ms6852]

According to Sierra Manual , one does not always need to use a magnum primer on a magnum firearm. If you use a fast propellant you could use a standard primer. I would just start your loads at 5% less of what you normally load. Now the information I stated the question was based on a gun and not a rifle. But I do know that magnum primers burn longer and that is why magnums primers work better on slow or medium burning propellants.

 

[orpington]

It seems a little far fetched that using standard large rifle primers vs magnum primers would blow up a rifle. And you’re sure it had nothing to do with the (too hot) loads that might have been tested in a round that was primed using standard primers?

it’s sort of like in veterinary medicine acepromazine was contraindicated in dogs with a history of seizures because we were taught that it caused seizures in dogs with a history of them. I always found that to be difficult to find credible. And, here it is: https://pubmed.ncbi.nlm.nih.gov/16822767/

That is, acepromazine does not demonstrate a propensity to cause seizures in dogs with a history of seizures. It was probably when acepromazine came out, a dog with a history of seizures was given the drug, and the dog would have seizured anyways, but the common lore was you shouldn’t give acepromazine to a dog with a history of seizures as it causes the dog to seizure.

My guess is it’s the same backwards logic here...

 

[Reloadron]

Looking at an old Speer #12 manual and the 375 H&H. Some powders they call out a magnum primer and some they don't. Primers are selected based on the powder. Most will suggest a magnum powder for ball powders but also for large powder loads like found in the 375 H&H magnum. With a 270 grain Spitzer SP bullet using Re 15 as an example they load 67 to 74 grains of powder and use a standard CCI large rifle primer. However with a 285 grain Grand Slam bullet using the same Re15 powder 68 to 72 grains they use a CCI large rifle magnum primer. Go figure? Hornady calls out a Win Large Rifle Magnum primer for all their H&H 375 loads. I didn't look at Lyman or Sierra data.

Either way I also find it hard to believe using a standard primer verse magnum would cause a pressure spike great enough to blow up a rifle. Even with the slower ignition I just can't see it happening.

Ron

 

[Archie]

S.E.E. isn't something that can be adequately explained in a forum post, especially by someone like myself that has only a very basic understanding of it.
Think of a hang fire situation where the powder smoulders and creates gas under pressure, then the gas detonates as a high explosive rather than burning like powder is supposed to.
This.
Think of a hard to ignite powder containing nitroglycerin coupled with inadequate ignition that allows the nitroglycerin to form an explosive gas instead of burning progressively as designed.
If you want a better understanding of a poorly understood subject, you'll have to do some research. My understanding and interest is mainly limited to avoiding the factors that can cause it in my own ammunition.

I am passing familiar with 'secondary explosion effect' (S. E. E.) and the main cause seems to be an under load - leaving large airspace in the case - with a slow burning powder. You are correct, no one knows exactly what causes the problem in the sense it cannot be duplicated on command, so to speak. However, I have no information nor see any probability that using a standard rifle primer is potentially responsible.

Swampman, your explanation is possibly the best suggestion I've read here, but it seems a bit short considering what I do know. Or at least seems possible. ("Knowing" has a high bar in my world.)

 

[Jerry M]

If you're plinking with that rifle try standard rifle primers. If you'll be using it to hunt moose or bears in the arctic, lions or cape buffalo in Africa, or water buffalo in Australia hold out for magnum primers for your load development.
A click ............ bang on paper is way different than when something can hurt/kill you and the people around you.

Good luck

 

[orpington]

I am passing familiar with 'secondary explosion effect' (S. E. E.) and the main cause seems to be an under load - leaving large airspace in the case - with a slow burning powder.

It seems to me that most of not all loads have a fair amount of powder leaving the possibility of a large amount of airspace an impossibility.

 

[Mark_Mark]

I have brass, bullets, dies, powder... the press, now I just need the rifle

 

[TheHermit]

I've been handloading for .375 H&H since 1994 and I've used almost exclusively large rifle primers for this caliber with good success. Bullets that I've used range from 220gr Hornady FP to 350 gr Barnes SP & FMJ. Powders that I've used most are VV N140, VV N150, H4895 (for short barrel loads) and VV TinStar (for 235 gr @1550 fps practice loads).

I find it extremely unlikely that switching from magnum primer to regular primer in an otherwise safe .375 H&H load would cause excess pressure.