Headspacing .375 H&H Off the Shoulder?

Discussion in 'Handloading and Reloading' started by Swampman, Oct 9, 2019.

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  1. Swampman

    Swampman Old Fart

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    I've been loading .338 Win Mag and .303 British to headspace off the shoulder for decades with no problems and greatly increased case life even though they were "designed" to headspace off of the belt/rim respectively.

    I acquired an old SAKO Finbear in .375 H&H a while back and I'm starting to load for it. I have a couple molds including a beautiful 270 grain Mihec HP and 99% of my shooting will be with cast bullets, mostly velocities at or below @ 2000 fps.

    The rifle will be mainly used as a range toy, with some use against deer or hogs while stand hunting (unless anyone here wants to volunteer for an unpaid gun bearer position; special consideration given to those that can say "Bwana" or "Sahib" in a convincing accent while carrying what feels like a very well balanced 20 pound rock bar :)).

    While studying up on the cartridge I've read several times that it's one of the very few belted magnums that really "needs" the belt for setting headspace.

    Other than the shallow, easily moved shoulder, is there any real reason to entirely leave headspace regulation to the belt?

    I've been partial length resizing (without touching the shoulder) and it seems to be doing fine, but I haven't shot it enough to get a handle on case life expectancy or how it'll work when the shoulders require "bumping". With the price I had to pay for Norma cases, I'd really like to make sure they last as long as possible.

    Anyone out there with .375 experience that can tell me of any problems, or if they've had success in increasing case life by using the shoulder to headspace?

    Also, any experience with powders for mid level cast bullet loads outside of the usual 4759, 5744 and 4895 suspects?

    Thanks,
    Swampman
     
  2. MEHavey

    MEHavey Member

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    Yes. I've been shoulder-headspacing a 375H&H for the last 20 years.
    No problemmo at all.
     
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  3. Varminterror

    Varminterror Member

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    This, but 18, not 20 years for me.
     
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  4. cheygriz

    cheygriz member

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    I headspace all belted rounds on the shoulder.
     
  5. Herman B

    Herman B Member

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    After the first firing all headspacing is from the shoulder in the interest of accuracy and brass-life. Annealing will help extend the life as well.
     
  6. GooseGestapo

    GooseGestapo Member

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    My .375 headspaces off the shoulder. Lacks a belt!
    (.375 Ruger)
     
  7. Varminterror

    Varminterror Member

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    It also has 67 thousandths wider shoulder to headspace on.
     
  8. Swampman

    Swampman Old Fart

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    Even more important is shoulder angle, the Ruger is about twice as steep as the H&H.

    Overall though, I dont see the Ruger as that much of an improvement, especially when you consider that it came out almost a century later.

    Still, the responses that I've received in this thread, along with my own limited experience, suggest (to me at least), that the "belted magnum" may have been more about marketing hype than headspace control pretty much from the beginning.

    The .375 H&H started out as a proprietary cartridge, meaning Holland & Holland had total control over the production of both the guns and ammunition. I know they didn't have CNC machinery or ISO certification, but they did have master craftsmen, extremely rigid quality control/inspections and a sterling reputation to uphold.

    I'm pretty sure that Holland's could've made their .375 safely without a belt, I suspect that they put it on and called it a "Magnum" to gain market share. Whatever the reason, it pretty much set the standard for the next 80 years or so.
     
  9. Varminterror

    Varminterror Member

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    There really was a point in history where manufacturers thought the belt was necessary to reinforce the casehead/body junction of magnums.
     
  10. fguffey

    fguffey member

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    From the beginning the rim was designed to hold the case to the rear of the chamber. H&H designed the belt to hold the case to the rear of the chamber; if the case was held back and prevented from moving forward; little consideration was given to the fit of the case in the chamber. The purpose of the case was to fill the chamber when fired. If the case was held back the shoulder did not move forward, again the case formed to the chamber.

    Problem: If the case was not held back by the belt when fired the case locked onto the chamber. When the case locked to the chamber the case head stretched between the case head and case body.

    The cases in the old days had what we call excessive tapper; that started with the 303 British and early belted cases required the 'almost straight case' because the British had little interest in moving to smokeless powder that was developed by DuPont. The British stayed with a string form of propellant called cordite. (Makes no sense) it was impossible to stuff strings of powder into a case with little or no tapper. They had one failure, it was the 284 that was similar to the Ross. The 284 was designed to replace the 303 British, again the British had no interest in to moving away from Cordite. The new rifle design suffered from 'cook off' so they stayed with the 303 when the P13 was introduced.

    When sizing the belted case with little tapper reloaders assume the case head spaces on the shoulder of the case. If the reloader avoids shortening the case from the shoulder to the case head he is also avoiding sizing the body of the case. I avoid sizing the shoulder and the case body when sizing bottle neck cases.

    F. Guffey
     
  11. Slamfire

    Slamfire Member

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    Shoulder spacing is the only way to go if you want your cases to last!. If you do not control the "cartridge headspace" with the "chamber headspace", and the distance from from the base to the shoulder is such that there is a lot of clearance with the chamber shoulder, you will experience case head separations in a couple of reloads. The base to shoulder dimensions of belted magnums were not standardized, one reason was, these things were made with the consideration that the owners would only shoot new factory ammunition. The industry really wants to sell you nice, expensive, loaded ammunition. They are not happy campers when you try to reduce their profits.

    Now for me, the first thing I do with these $2.00 to $3.00 cases, is fireform them in the rifle by lubricating them. Such as this:

    gVfDIiq.jpg

    T66hqbn.jpg

    Vhr0qQj.jpg

    hair gel is vasoline with perfume. Vasoline will work fine. I don't recommend industrial greases, which will also work as a lubricant, because the grease will get all over your fingers. I often bring something to munch on at the range and industrial tribological additives are not meant to be ingested.

    What lubricanting the case does, it prevents the shoulders from gripping the chamber. Once the case shoulders grab the chamber, it fixes the case in place. And since you are shooting something with a unknown amount of clearance between case shoulders and chamber shoulders, if it is a lot, the sidewalls will have to expand to allow the base to reach the bolt face. Which will cause case head separations.

    Like this:

    ivZMmgt.jpg

    But, by breaking the friction between case and chamber, instead of the case adhering to the chamber, the case will slide to the bolt face. Once there, the case shoulders will fold into the chamber shoulders and there will be no sidewall stretch at all. That is the important point: no sidewall stretch at all, the case will be stress free and perfectly fireformed to your chamber.

    By the way, lubricated cases shoot just fine:

    in this rifle

    mt2wCE5.jpg
    CdTPuSj.jpg

    did this at 100 yards

    ac6c1Nh.jpg

    and at 300 yards, with the cases in the pictures
    UnkHFhV.jpg

    It does get a bit messy after a 100 rounds. This was with a 30-06


    KBwf8NK.jpg


    Now that you have fired your lubricated cases, go buy an L.E. Wilson Adjustable Case Length Headspace Gauge. Read the instructions, but this will allow you to set up your dies so that you don't push the shoulders too far back. I recommend setting the shoulders around 0.003" from chamber length. This will allow sufficient clearance to feed and extract your cases, and not so much clearance you will have case head separations.

    If you plan to shoot your belted magnum cases a lot, you might need a Belted Magnum Collet Resizing Die. The maker, Larry Willis, knows everything there is about belted magnums. He has a great Q&A page, and what I read, and what I know, just reinforces what a horrible design these belted magnums are! I continue to read in print writers praising the belted magnums to high heaven, and yet, what a bother these things are to reload. Because base to shoulder lengths are not standardized, every rifle has a different base to shoulder measurement, and once you set up your L.E Wilson case gauge for that rifle, you have to re adjust it for the next rifle, in the same caliber. And ditto for your sizing die.

    I also have had belt rim lock in my 375 H&H. I was using 235 grain bullets which left a lot of space in the magazine. The cartridges shifted on recoil, and the top round in the magazine slide behind the bottom round, and the belt on the top round locked on the rim of the bottom round. I was able to clear the jam by pushing on the stack, but I will tell you, that does not make me feel that a belted magnum round is something good to have in a dangerous situation. Not if you don't have a lot of time to 1) figure out why your bolt won't close and 2) get your thumb in there and push the stack down, hopefully clearing the jam. Be a bugger if it did not clear the jam, depending on the situation. No in-print writer will ever admit this happens with this case design, but if it happens to you, you will be a believer. This design is just great for single shot rifles or double rifles, but things with rims, fins, and belts will jam more often than rimless cartridges.

    If you plan to go after something big and bad with your 375 H&H, pay attention to this. Shoot the rifle with full power loads and with the magazine filled. And, shoot it rapid fire to see of the rounds slide around in the magazine. And maybe weld a bayonet mount to your barrel to convert your rifle into a spear, if you don't have time to clear the jam!
     

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    Last edited: Oct 13, 2019
  12. Swampman

    Swampman Old Fart

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  13. Slamfire

    Slamfire Member

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    The British absolutely knew how to head space cartridges on the shoulder and the 416 Rigby is an example. I have a number of Martini BSA International 22lr rifles, and when you look at their sights, and their advertising, the British businesses were no different than American vendors in selling expensive proprietary gadgets. Of course the claims for the gadget were phenomenal, but the actual performance was less than the advertising.

    For a double rifle I would prefer rims to grab, and rims are wider so they would be more positive on the ejector. The belt was probably one of those things that avoided someone's patent and you could always claim that it made the case stronger, but it does not.


    Dagmars (named after a busty female celebrity) and fins did not change the aerodynamics of the vehicle, but they sure sold a lot of cars!

    Vxn09MF.jpg

    EEH805d.jpg
     
  14. fguffey

    fguffey member

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    The best thing that ever happened to the long tapered case was P.O. Ackley. Back to Cordite; it is and was possible to stuff cordite into a case, it was almost impossible to stuff it into a case that was not tapered. Back In those days there was little consideration given to head spacing on the shoulder, back then the case shoulder did not make it to the shoulder of the of the chamber when fired. The shoulder on the fired case was not the same shoulder the shooter started with meaning the new shoulder formed when fired and the case expanded to fill the chamber.

    F. Guffey
     
  15. Muddydogs

    Muddydogs Member

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    My buddy who I help reload with just acquired a 375 H&H along with dies, close to 200 pieces of new R.P brass, 50 ish pieces of ? times fired brass and some misc bullets that he doesn't really care about. I load a lot for a lot of different calibers but haven't fire formed anything yet, I load for my 7mm Rem Mag but am using already fired brass so I just bump the shoulder back on it.
    Sounds like to get the most out of this new brass we should fire form it but is it worth the powder and bullets to actually load and shoot the brass just to fire form or should we load up the new brass and once its fired just bump the shoulder back a little. 200 rounds loaded might be enough ammo for the rest of his hunting days.
     
  16. Archie

    Archie Member

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    I have always consider 'belts' as a rather deep rim with an extractor groove in it. I cannot see it doing much of anything. Perhaps on factory ammunition, but not reloads.

    Once fired, the case should 'fire-form' itself to the chamber. By NOT full length resizing and using only one rifle, it should remain fitted to the chamber, i.e. headspacing on the shoulder (and belt).
     
  17. lightman

    lightman Member

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    I've never loaded for the 375 but I have loaded a lot of other belted magnum cartridges. I have always sized the cases to headspace on the shoulder.
     
  18. 243winxb

    243winxb Member

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    Anyone get a bulge in this area, that keeps a round from chambering? 20191015_124139.jpg
     
  19. Herman B

    Herman B Member

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    That is the exact bulge that is corrected by the Belted Magnum Collet Resizing Die mentioned in post # 11. The collet is first placed on the brass, snugged all the way to the belt, then it's put in the shellholder and pressed into the die. No more bulge and the brass will then chamber. I use the collet die for 7mm Rem Mag and 375 HH.
     
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  20. 243winxb

    243winxb Member

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    That area may be unsupported in a sloppy chamber when the case head is held against tne bolt face. More a neck sizing only isssue and its not common.
     
  21. fguffey

    fguffey member

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    And then there is a very good chance it has nothing to do with a sloppy chamber. If the case head is not against the bolt face when fired the case has no choice but to stretch between the case head and case body if the case body locks onto the chamber.

    I have never experienced case head expansion in front of the belt, I have never found a case that had case head expansion in front of the belt that did not have case head expansion in the extractor grove. One day I found 2 boxes of 20 cases each with expansion in front of the belt. The expansion on all cases was .017", the extractor grooves had the same problem. The owner of the cases complained to me about not having the correct case holder. He wanted to borrow 'the other' RCBS #4 shell holder. I suggested he use a small hammer.

    the hammer I use is called a gasket cutting hammer. He was not hurting for belted cases, after sorting through the cases that would not fit the #4 RCBS case holder he was left with 420.

    F. Guffey
     
  22. Archie

    Archie Member

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    The problem you describe likely comes from the loaded round - and resulting empty case - being fired in a different rifle. Not a 'sloppy' chamber, but 'looser' (still without tolerances) than the second rifle.

    I have that phenomenon in several of my non-belted cartridges. I would check to see the case isn't separating, but other than than, it's no big deal.
     
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