Primer for 375 H&H

The load data in Lee Modern Reloading lists a large rifle primer for its loads. I was also looking on the Hodgdon website and the loads are listed with a "large rifle magnum match". For example, the Lee load for the 270gr Barnes X h4350 is2465 fps with 75gr and 50068 psi. Meanwhile the Hogdgon lists the same load with the same velocity but pressure of 42,800 CUP. I did not note any velocity difference in the simple comparison but did note that the apparent difference in pressure. Am I comparing apples and oranges with pressure measurements? My question is whether to use the magnum or regular primer? and I thought the magnum primer should create more pressure??

There is a difference between CUP and PSI. If you want to make your head spin, go here for something of an explanation: https://www.shootingsoftware.com/ftp/psicuparticle2.pdf

As far as primers go, I use the Fed 215's in my .375H&H. I have read here and there of guys getting better accuracy using non-magnum primers in magnum calibers. Worth a try if you're not getting good accuracy from the magnum primers I guess.

Phil is right, PSI and CUP are not the same, but for one exception I am aware and don't try to understand why. Well you can if you want. The .45-70 Govt apparently will show the same number for either. I didn't make that up, I read it from a reliable source, don't remember who. I don't usually start with mag primers, rather I see how std work first. Mag primers have a tendency to boost pressures at times. I never found a need for them in the .375 even with large doses of slow burning powders. Your mileage may vary.

sestoppelman said:

Phil is right, PSI and CUP are not the same, but for one exception I am aware and don't try to understand why. Well you can if you want. The .45-70 Govt apparently will show the same number for either. I didn't make that up, I read it from a reliable source, don't remember who.

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And hence the head spinning. You'd think there'd be a simple conversion formula since both are measuring pressure, but there isn't. So I simply don't even follow pressure tables very much. While the typical pressure signs (flattened primers, sticky bolts, extractor marks) are somewhat crude and from what I've read exhibit only well after "high" pressure has been exceeded, I use them along with my chronograph to tell me when I'm reaching a point where I need to back off.

The pressure tables are a nice reference point, but in my opinion they're only that and should not be taken as gospel truth one way or another as either safe or dangerous. Each and every load combination (brass, primer, powder - type and weight, bullet) is different for each rifle, or should be at least assumed so. What is too high a pressure in one rifle may be perfectly fine in another.

Interesting article. I thought I read somewhere that the bad stuff starts at 60,000 psi. Then this CUP business just confused things. The only bullets I have been able to find locally is a 270 Speer boat tail and 285 grand slam but no speer manual lol! Thanks for the advice.

I use CCI 250 (large rifle magnum) primers for all loads except low velocity with cast bullets in my .300 Weatherly and .375 RUM. I use plain large rifle CCI 200 primers for the cast bullet loads.

I've had good results with sub moa groups and long case life with both of these rifles.

In use Fed 215's in my 375 HH and I have had no issues with pressure nor accuracy, the gun is a tack driver, sometimes the shooter isn't though...

My 49th Lyman loading manual says Large Magnum Primer for any 375 load

I use Fed Mags in my 375, 75 grains IMR 4350 Max for 270, Min for 300 but I like life simple.
I use Fed Mags in all my rifles,
In my son's 270, there's a one grain differnce when switching to standard primers.

One more vote for the Federal #215 Primer, when making your .375 H&H hand loads.

However, the above only applies if you're not suffering from Velocity Madness and therefore willing to keep your powder charges at a sensible and tame level.

I do not care for "hot loads" in any caliber but, if I did like them/load them, I would be very nervous about the #215 primer possibly causing pressure spikes, especially in hot weather or, when firing multiple shots in a row, thereby heating the barrel/chamber up, such as at the rifle range.

That primer was I think developed for the .378 Weatherby and so, in theory appears like it might be a bit hot for the H&H version but, it does not seem to matter for my admittedly low velocity loads (300 gr round nose, soft or solid, at 2400 fps).

With this primer, IMR 4350 powder and 300 gr bullets, firmly roll crimped in the old H&H, I have experienced my best accuracy in the several bolt actions, plus one single shot (Ruger) and one double (Merkel).

If you get a chance, read Dr. Robertson 's must read book "Africa's Most Dangerous", especially Page 103, first paragraph, wherein he concludes that the .375 H&H, firing a 300 grain premium soft point seems to perform better on buffalo at about 150 fps BELOW factory ammunition standard velocity.

I'd like to say that great minds think alike but, I have only shot one buffalo, whereas no doubt he has taken hundreds at least.

Furthermore, I did not even use the .375 caliber for my meager one buffalo so, I am not worthy to compare my experiences with his in any way.

I can however say that this load has proved quite accurate and also, super effective on antelopes and piggy wiggy, not to mention easier on the shoulder than factory standard 300 gr loads are (I'm a recoil sissy so I would know).

Blah, blah, blah.

Velo, how many grains were you using with the IMR4350 and 300s?

Grady said:

Velo, how many grains were you using with the IMR4350 and 300s?

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Hi Grady,

My wife is a lawyer and gets annoyed if I post powder charges on the internet but this is such a mild load that if any hackers blow themselves up, they obviously deviated from it by a large margin.
In other words, they did't use this data or, they fired it with an obstructed bore, etc., whatever.

Anywhooo, it is 73 grains of IMR 4350, 300 grain Hornady round nose bullet and Federal 215 primer.
I prefer Winchester brass but again, it is so far down the power scale that, it likely will work fine in any brand of brass, originally manufactured as .375 H&H.
Winchester brass supposedly has just a slightly higher volume capacity but it cannot possibly be much, for crying out loud.
I just like Winchester because it seems to last longer / more firings and resizings than some of their competitor's brass seems to last.

Cheers,
Velo Dog.

If you get a chance, read Dr. Robertson 's must read book "Africa's Most Dangerous", especially Page 103, first paragraph, wherein he concludes that the .375 H&H, firing a 300 grain premium soft point seems to perform better on buffalo at about 150 fps BELOW factory ammunition standard velocity.

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Mr. Robertson is a wise man but im gonna go ahead and disagree with that idea. reducing the velocity would only improve performance if the bullet being used is not suited for the higher velocity (IE:Woodleigh softs).

as for choice primers for the 375 H&H, the Federal 215 is easily my first choice! ive heard good things about CCI primers as well.

STAY AWAY from Winchester and Remington primers! my brand new Winchester M70 Safari was just damaged last weekend by a faulty Remington 9 1/2M primer. ive had issues with Winchester primers in the past, mostly with them failing to ignite (they are too hard).

-matt

Hi Matt85,

Differences of opinion are what make conversations interesting and thankfully, we all are entitled to believe whatever we want to.

Also, I am curious how a faulty Remington primer damaged your Model 70.

Also, I am curious in what types of firearm/s have you experienced failures to pop Winchester primers ?

I have heard of this in Remington Model 700's but never first hand from anyone and it was not regarding Winchester primers, it was regarding CCI primers.

A Gunsmith told me he has had Model 700s brought in with this problem but, it's usually from either residue build-up in the firing pin tunnel or, from an after-market light weight striker (meant to speed up lock time) having been installed by some uber accuracy zealot.

Cheers,
Velo Dog.

Velo, Thanks for the info. I promise I will not do anything crazy with the data. I like you do not like to play around on the Max side of the reloading data. I prefer accuracy over velocity any day!

Grady said:

Velo, Thanks for the info. I promise I will not do anything crazy with the data. I like you do not like to play around on the Max side of the reloading data. I prefer accuracy over velocity any day!

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Amen to that brother, amen to that,

I was not worried in the slightest about your judgement, but have to consider some anonymous hacker type geek, who then tries to sue me for blowing his rifle in half by doing something way off center, claiming he used my data.

When I discovered reloading (age 16), and for the first few years, I came down with a standard case of Velocity Madness, just like so many beginners do.
Then I got better.

Velocity is usually fine but accuracy is usually final.

Best Regards,
Velo Dog.

Velo Dog said:

Velocity is usually fine but accuracy is usually final.

Best Regards,
Velo Dog.

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I try for both!

Usually attainable with some fiddling.

If you have to settle for one though, no doubt....you need to be able to hit what you are shooting at.

As Colonel Townsend Whelen said, "Only accurate rifles are interesting". I guess we would also say "only accurate loads are interesting".

Sure wish I could find my copy of "Mister Rifleman".

I'm using Federal 215 on the .375 H&H Mag.

You should buy more than one loading manual. There can be quite a difference in the loads shown. Get the manuals published by the companies that make the bullets or powders you're planning to shoot. I load for eleven different rifle cartridges and five different pistol cartridges. So I own manuals from Lyman, Speer, Sierra, Swift, Barnes, Nosler, and Hornady, and also consult the online loading data published by powder companies. When I start working up a new load, I can roughly average the various loads to come up with my own starting load. So much for mathematical precision.

To be honest, I usually don't start at the published starting loads. I usually start around the midpoint between starting and max loads, based on judgment and experience with similar loads. Each shot I fire for the first half dozen rounds, the case gets a close examination for pressure signs.

In my experience, the Speer manuals are usually the hottest among the other manuals I own. That is, they show starting and max loads up to several grains more than other manuals, where they're all loading the same bullet, case, and powder. I've seen pressure signs when going with Speer's max loads.

Have you guys ever tried Reloader 15, Iv'e got some pretty tight groups using 63.5gs with a 270Gr bullet ,altho I haven't chrono'd them yet

I use CCI 250's and WLRMP with no issues for all bullets weights. Best 300gr load in my rifle (BRNO ZKK 602) is 76gr H4350 using WLRMP in WW cases. 100yd 3 shot group 0.90". Avg velocity is 2513fps.
Fun load: Hornady 220gr FP, 66.5gr IMR 3031, CCI 250, WW cases. 3 shot 0.50" group 100yds, 3 shot 4" group at 300yds.
Looking forward to trying some Hornady 250gr GMX's to see how they do at 300yds.