On many of the forums dealing with big game and riflery, the 375 H&H is spoken of in very postitive terms. One of the best all arounders made. Not the best at some things but certainly adequate. When talking of double rifles the 375 Flanged Magnum seems to come up short. I thought that the Flanged version was only 100 f/s slower than its belted brother and if so, at reasonable distances, shouldn't the performance be equal? Many PH's in Africa(Doctari) even suggest that the 375 H&H be loaded down a bit as the extra velocity is unnecessary for the task. What's up with that? Does this stem from the fact that there is a difference in accuracy in bolt guns vs double rifles or is there more to it than that??

I think it is "PR"/spin. The 9.3x74R has a great rep, and has a bit less whallop than the 375 Flanged. The biggest draw back for the 375 Flanged, is reloading components, namely brass avaliblity and cost.

Plus, most people think of DRs as having larger bore sizes.

Keith

lb404

The ONLY "fly in the ointment" about the 375 Flanged is finding brass.
Once you have some it is no big deal.
There is a slightly better chance of finding 9,3x74R factory ammo.... but it is not of concern to you.

If you were buying a whole second rifle the 9,3 usually is about hald as expensive as the sane rifle in 375 H&H or Flanged, so the 9,3 is a better choice thwere. However for you the 375 Flanged is not a bad choice.

As to performance in the field, have no fear, after using my 9,3 for several years the 375 FL will work just fine.

There is nothing wrong with your choice of the 375 Flanged and the 450/400 3 ".

A 450 3 1/4" would be a great choice as well.

If you go with the 450/400 you might ask Searcy if he will make a 375 H&H, as you can get ammo for that most anywhere.

I am well aware of the "problems" that may ocur with the 375 H&H double. However moat people that have them report no problems.

I would like to have a 375 H&H double as I have a fair amount of H&H ammo and brass. I have shot news guys 375 Chapuis 375 H&H and it shot very well.

And as many of you know I hunt with a Blaser R 93 so I am not afraid to "go out on a limb" and test new technology.

THE "NORMAL " 375 H&H BELTED IS YOUR ANSWER.
you can buy ammo anywhere in the world for it
there is no reason to hesitate ordering your double rifle in that caliber - all the good makers will chamber for it without question.

but pair it with a 450 - 3 1/4 or better a 470 and forget that nonsense about the old obsolete cartridge they are telling you is so great.

if it was so great and so desirable it would never have been put aside as it was.

next they will be trying to revive the 50 maynard rimfire for it's smashing power.

fyi - the 450/400 WAS REPLACED by the 375 h&h

for all the decades you could not buy 450/400 ammo you could get a steady supply of 375 h&h

think about that one - and ask yourself WHY ?

well because the 375 REPLACED the older round.
simple, isn't it . now you know.

Thanks for your responses. The reason I chose the 375 Flanged and the 450-400 is bullet weight and speed. The big bullet going slow of the 400 paired with a lighter bullet in the Flanged going about 300 f/s faster. With lighter bullets in the 375 one can get a flatter trajectory and a little more range. I have 200 rounds of horniber brass now and 200 more comming soon. That should be enough for a while. I am still waiting for the 450-400,3" horniber brass to show up.

quote:

Originally posted by tomo577:
THE "NORMAL " 375 H&H BELTED IS YOUR ANSWER.
you can buy ammo anywhere in the world for it
there is no reason to hesitate ordering your double rifle in that caliber - all the good makers will chamber for it without question.

but pair it with a 450 - 3 1/4 or better a 470 and forget that nonsense about the old obsolete cartridge they are telling you is so great.

if it was so great and so desirable it would never have been put aside as it was.

next they will be trying to revive the 50 maynard rimfire for it's smashing power.

fyi - the 450/400 WAS REPLACED by the 375 h&h

for all the decades you could not buy 450/400 ammo you could get a steady supply of 375 h&h

think about that one - and ask yourself WHY ?

well because the 375 REPLACED the older round.
simple, isn't it . now you know.

Not a truthful statement in the bunch. The .375 Flanged Magnum is the one for double rifles, the .375 Belted Rimless is for magazine rifles. As originally loaded, the difference is 75 fps, 2425 vs 2500 - miniscule. However the difference in pressure is not. CIP max average for the Flanged Magnum is 47,137 PSI, the Belted Rimless is 62,366 PSI. Aside from the significant issues of rimless shells in doubles, the lower pressure is definitely what you want in a double. Most DR makers will chamber for Belted Rimless - because of the demand created by buyers who don't know any better, not because it's a good idea. Butch will chamber both, at least he used to, but I'll bet he didn't recommend the Belted Rimless over the Flanged Magnum, did he?

quote:

- the 450/400 WAS REPLACED by the 375 h&h

for all the decades you could not buy 450/400 ammo you could get a steady supply of 375 h7h

think about that one - and ask yourself WHY ?

well because the the 375 REPLACED the older round.

Pathetic. The .375 didn't replace the .400. In doubles, there were more .400s built AFTER the .375 was introduced than there were .375s. Kynoch loaded .400 Jeffery from it's introduction until they closed down in 1973. It remained popular the entire time. Kynoch loaded the .400 long after they DROPPED the .375 Flanged Magnum (the one intended for double rifles}. By the early '80s BELL and ASquare were loading .400 again. The .470 was unavailable for the same period of time that the .400 was. The .400 remains more available today than the .375 Flanged Magnum.

Interesting that Tomo makes a false statement, then asks you to think about it.

The Horneber brass is decent. However, by the time your gun is ready, I imagine that Hornady .400 brass will be available. I have 20 rounds of it, and it's good looking brass.
------------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

Back in the day...
One reason the 450/400's were so popular was that nearly every double rifle maker made them.

Not so with the 375 Flanged. It was mostly a H&H item.

Enter the 375 H&H and "Bolt Rifle Trash".
As more and more of the "Common Man" started hunting, bolt rifles became more widespread in use. Doubles were just too expensive.

Also as BIG big game bags became smaller the 375 took over as the "allround" rifle, for the "new" hunters.

As a side note, IF the double would have remained in widespread use scopes would have been mounted on them just like they were on bolt rifles.

lb404, make no mistake about it the 375 FL is a most excellent calibre, and if it had been "released to the trade", and double rifles were still in "widespread" use it would be very popular.

I feel the 400's are a pretty big step up over the 9,3/375's.

I see nothing wrong with a 9,3x74R or a 375 Flanged double paired with, or as a two bbled set, with a 450/400.
If it was me I would definately scope the 450/400 as well.

Also there would be nothing wrong with a 450 3 1/4" bbl with the 375 FL.
I probably would not scope the 450 bbl.
But I do not have a valid reason why.
Is that Strange?

Claw mounts in no way interfere with the iron sights... so even if you only used the scope on pigs with the 350 Hornadays, it would not be a bad plan.

Lb404, the bottom line is do what you think best for you.

I DO KNOW this, a scoped 375FL double and a scoped 400 double would be one of the best set of hunting rifles on the Planet.

I have hunted North America, and been to Africa with a 9,3 double, a 450/400 double and a 450 No2 double. I like all three.

One thing to remember is that the action has to be sized o the largest caliber in the pair. Consequently, if you include a 470 you will need a larger action which will necessitate the breach end of the 375 or 450/400 barrels having to be thicker than necessary. This means more weight for the lighter caliber. Don't be surprised if your rifle is heavier when fitted with the smaller caliber versus the larger caliber. Even with the 450/400, 375 combo because the 375 has a smaller chamber and bore there will be more metal in the barrels which will likely mean a heavier 375 and a very possibly a change in ballance.

465H&H

465H&H

what 465H&H said.

Rich

400 nitro

Welcome to the 21 century. Yes in todays world you can have your double rifle and your rimless case too. There has been alot of developmend in extracters since 1912 when the 375 belted rimless was introduced. I personally would rather have a rimmed case as well but not in a .375.

There is a wifes tail that many or most of us double rifle shooters fall for. We belive that high pressure is a problem for a double rifle. That is not true at all. I had a talk with Butch Searcy about wear on the hinge pin of a double rifle. As he explained it to me the problem is the pressure from a heavy low velocity bullet causes backtrust and pushes the case against the action which in turn pushes the barrels away from the recevier. of course this causes alot of stress on the hinge pin. If you referance P.O. Ackley's handbook for shooters and reloaders. In the chapter on pressure. His experimentation showed that with a high pressure case that the case walls expanded and gripped the chamber walls. This decreased backthrust and in some cases elimenated it. So it could be said that a high pressure round is actully better for a double rifle. I had a long talk with German gunmaker Alois Myar about this around a campfire on a hunting trip and he completely agreed with me on this and had come to the same conclution himself.

quote:

Originally posted by Akshooter:
400 nitro

Welcome to the 21 century. Yes in todays world you can have your double rifle and your rimless case too. There has been alot of developmend in extracters since 1912 when the 375 belted rimless was introduced. I personally would rather have a rimmed case as well but not in a .375.

There is a wifes tail that many or most of us double rifle shooters fall for. We belive that high pressure is a problem for a double rifle. That is not true at all. I had a talk with Butch Searcy about wear on the hinge pin of a double rifle. As he explained it to me the problem is the pressure from a heavy low velocity bullet causes backtrust and pushes the case against the action which in turn pushes the barrels away from the recevier. of course this causes alot of stress on the hinge pin. If you referance P.O. Ackley's handbook for shooters and reloaders. In the chapter on pressure. His experimentation showed that with a high pressure case that the case walls expanded and gripped the chamber walls. This decreased backthrust and in some cases elimenated it. So it could be said that a high pressure round is actully better for a double rifle. I had a long talk with German gunmaker Alois Myar about this around a campfire on a hunting trip and he completely agreed with me on this and had come to the same conclution himself.

Pure fantasy. DRs chambered for the high pressure rimless rounds come off face faster than those chambered for lower pressure flanged cartridges designed for double rifles. It isn't surprising that so many of the .375 H&H doubles I've handled have been off face. The British knew that partly because they never measured chamber pressure. They measured bolt thrust only , with base copper crusher guns, which measured bolt thrust via compression of a copper pellet between the case head and breech face. They also knew from experience that the high pressure rounds knocked the guns off face faster - and the British built more double rifles than anybody. That's why they went to the trouble of designing "paired" cartridges like the .375 Flanged Magnum and the .375 Belted Rimless Magnum.
------------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

400 nitro
I need a little referance here. Please quote me your source that the British have built more doubles than anyone else. I think that may be the pure fantasy your speaking about. What were talking about here is the capacity of a break open rifle to handle pressure. Regardless of it having two rifle barrels or one or three you know that the German and Austrian gunmakers have not been afraid of high pressure rounds dating back as far as centerfire rounds have been around. I have seen many older double shotguns that had gotten loose over the years. Are you going to tell me it was the pressure that did it.I don't think so. I have a Ferlach made (Borovnick not sure that's the proper spelling) bockbuchsflinte (combo gun) that is chambered for .222 are you going to tell me that this high pressure rifle is going to shoot loose anytime soon. I don't think so this little rifle is tight as a drum and shoots 1/2 inch. I'm sure your going to tell me that my .338 win mag double rifle made by Franz Sodia in Ferlach won't last more than a few rounds but amazingly it's as tight as a drum and has never faild to extract.
Anyway you said it yourself the brits measured backthrust not pressure so why are you saying that pressure is the problem. I think you need to think this through so that you will understand the differance.

If I was going to to get a 375 H&H double I would only consider 2.

The with its large wide locking lug and twin parallel hooks.

Or the strongest double rifle action, the Blaser S-2.I find the S-2 to be a very large 375 H&H.

The Chapuis has 3 frame sizes, one up to 9,3 one for the 375, and then the 470 size frame.

The 450/400 Evolution had at DSC was on the 375 frame.

quote:

Originally posted by Akshooter:
400 nitro
I need a little referance here. Please quote me your source that the British have built more doubles than anyone else. I think that may be the pure fantasy your speaking about.

If you think someone else built more, you're dreaming.

quote:

What were talking about here is the capacity of a break open rifle to handle pressure. Regardless of it having two rifle barrels or one or three you know that the German and Austrian gunmakers have not been afraid of high pressure rounds dating back as far as centerfire rounds have been around. I have seen many older double shotguns that had gotten loose over the years. Are you going to tell me it was the pressure that did it.I don't think so. I have a Ferlach made (Borovnick not sure that's the proper spelling) bockbuchsflinte (combo gun) that is chambered for .222 are you going to tell me that this high pressure rifle is going to shoot loose anytime soon. I don't think so this little rifle is tight as a drum and shoots 1/2 inch. I'm sure your going to tell me that my .338 win mag double rifle made by Franz Sodia in Ferlach won't last more than a few rounds but amazingly it's as tight as a drum and has never faild to extract.

Amazing. Just because someone makes it means it's a good idea? Sure, the Ferlach makers in particular have chambered quite a few DRs for rimless magnums. The last one I remember handling was a Ludwig Borovnik in .378 Weatherby. It didn't look like it had been carried to the mailbox and back, but it was loose as a goose . Likewise a .300 Win Mag from Sodia. The most grossly off face DR I've ever seen was a fairly new Chapuis in .375 H&H Belted Rimless Magnum. The bores would have almost passed for unfired. The number of off face rimless magnum chambered doubles I've handled over the years is definitely disproportionate. For the most part, these aren't "older guns" that have "gotten loose over the years". They're often more recent guns that don't show that much use and are obviously off face prematurely.

By the same token, I periodically see pre-WWI fixed-pin British boxlock DRs chambered for their flanged nitros, that are used up and the barrels shot smooth out, but are still dead on face, yet don't show the tell-tale dovetailing of a re-jointed fixed pin gun.

A number of factors can contribute to a drop-down barrel action coming off face, but to say that excessive pressure isn't one of them reflects a fundamental ignorance of the type. To follow your logic, we should switch to a steady diet of proof loads for our .400s, .450s, and .470s (and even proof loads for these produce less pressure than a STANDARD .375 H&H Magnum), because the high pressure would cause the case to stick to the chamber walls better, thus reducing bolt thrust which would be gentler on the guns and extend their useful life.

You say you have a rifle from Borovnik, but you don't know how to spell the name? Right...

With respect to the extraction issues of double rifles, your failure to appreciate the gulf between your comment that your .338 Win Mag "has never failed to extract" and the easily obtained certainty of "can't fail to extract because it has a rim" is also indicative of your failure to grasp one of the basic concepts of DRs.

quote:

Anyway you said it yourself the brits measured backthrust not pressure so why are you saying that pressure is the problem. I think you need to think this through so that you will understand the differance.

The Brits measured bolt thrust because they believed it to be the critical measurement. With the "paired" cartridges, they wanted the flanged version to produce less thrust because they were to be used in double rifles. Given the limitations imposed by paired cartridges, they did this primarily by reducing pressure and testing. They found that reducing pressure reduced thrust, so the flanged versions were loaded to lower pressure.

By the way, regarding your comment that "the German and Austrian gunmakers have not been afraid of high pressure rounds dating back as far as centerfire rounds have been around"...the Germans did it the same way as the British. The rimmed versions of their "paired" cartridges (7X57R, 7X65R, 8X57R) have been loaded to substantially lower pressure than their rimless counterparts "dating back as far as centerfire rounds have been around".
------------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

400 nitro

You have obiously got your mind made up and are unwilling to listen to a little input from others. I've only tried to point out that you can make pressure work for you in certain cases but unfortunantly you have made it a hostile debate. I admit I've been sucked in by you and threw it back but this go's against my nature and will start backing off.
You obivously think the Brits are the last word in doubles and I will be the first to admit that the long tappered cases of the british will be the last to benifit from pressure. This was pointed out by Akley in his experiments hince the straight walls of the Akley improved cases.
Your observations and experiances have definantly been differant from mine I must say it seems like every ferlach you talk about is loose. All my ferlach guns are tight but I'll admit that so is the one british double I own.

Yes I will admit my nemisis. I can't spell Borovnik just like half the other words on this post but I do own one.

to interject here, does the high pressure and sloping shoulder, tapered body enter into this equation anywhere? If you went with a 375H&H improved design, would that have any effect on the case thrust. Ackley thought so, but his best example was the 30-30 Imp with the M94 test bed. Hardly germane here, except for the theory...

Keep talking...

Rich
still...

My understanding is that Akley concluded that the stright case and sharp shoulder reduced backthrust in all cases but I don't know if his experiments went any farther than the 30-30 imp he wrote about I would assume they did.

Gentlemen
Remember one thing. A sloping case releases itself from the chamber walls with the slighest bit of extraction distance and force, so less chance of stuck cases or sticky extraction. The lower pressure of "Proper" nitro express cartridges addressess these issues as well.

"Back in the day" double rifle makers/users were not concerned about case effeciency, ie getting the max fps out of a certain case size.

They made the size of the case so they could get the velocity they wanted, at the pressure they wanted.

Which is why a 450 No2 case is larger than a 460 WBY case but is a little over half the pressure.


As much as I would like to have a 375 H&H double rifle I feel now is the time to tell a little story. I was having a comversation with the owner of a German double rifle company.
I was wanting a 375 H&H. He told me, We make them because the market demands it. I would not recommend YOU buy one, get the Flanged, or consider the 9,3x74R.

If I did get a 375 H&H double I would use factory ammo spairingly and load to Flanged pressures.

With the exception of someone having a 2 bbled set made with bbls of 450/400 or 450 3 1/4", and thus on the larger frame getting an extra set of 375 Flanged bbls, I think a double in 9,3x74R would be in EVERY WAY superior.

It can be smaller, lighter, trimmer, factory ammo can be found, I bought 3 boxes of Norma 9,3x74R just today.

N.E.450 no2

I have to say that you hit the nail on the head concerning the extraction advantages of the tappered case. Akley adressed this in his experiments as well and conclueded that only a couple of degrees of tapper was needed for reliable extraction. Having said that I'm sure the last thing on his mind was a double rifle.

The British technology back 75 to 100 years ago really did not concern it's self with a case designed to lower backthrust and maintain high pressure. They just resinged themselves living with the backthrust and building the guns around that. In this example chamber pressure and backthrust are one in the same. It was the right way to go about it back then. I never said that increasing pressure in these rounds would be an advantage if nothing else the cases couldent take it at least not the old vintage ones.
Where dose the .375 fit into this, I'm not sure I'd say somewhere in the middle. I'd say that the higher pressure of this case probably dose reduce backtrust but the slightly slopping body of the case probably limits it's ability to take full advantage of it.
The question is can we bring double rifles into todays world and reap the benifits of modern cartriges. Some may not want too but for others there are many gunmakers working on any issues that arise with the modern cartriges.
One really good analogy that comes to mind is the .454 casull. It has a stright case and runs at pressure never dreamed of 30 years ago yet it is shot out of a revolver and extraction isn't a problem. On another post you mentioned having a Blaser k95. it is a really good example of a moderan break down rifle that dosen't have the problems we have been talking about here. In the 30 years since this rifle and it's predecesser the K77 have been around I've not heard any complaints about them getting loose and they chamber it for the 300 weatherby.

Pressure is very much a concern with traditional double rifles.
They give all the hunting performance necessary in their power range.

If you need more "power" go to a larger case, say form a 400/360 and a 375 Flanged 2 3/4" to a 360 No2 or a 375 Flanged Magnum, or a larger bore.

I have shot my 450 No2 around 3300 times, my 450/400 about 1400 or so. Borh are still tight on the face.

The way foward for doubles in higher pressure modern cartridges is with new designs. Stronger steel may help a little.

The Chapuis with its wider locking bar and parallel hooks might be stringer, still there is only one lockin bar and no dolls head fastiner.

The only Chapuis I have ever herd of being off face was the 375 that 400 Nitro mentioned, and aparently it was BADLY off face.
So even that design can be over stressed.

Chapuis does make the double in 300 Win Mag.

The Blaser just might be the strongest double rifle locking system out there.
We will just have to wait and see how they hold up.

As to rimless cartridges in doubles.

I think a 375 H&H double would be a great gun, iof it did not shoot off face and would never have extraction/ejection malfunction problems.

However when the owner of a big double rifle company will not recommend it, and a well known double rifle craftsman, amoung many others feel the same, there is some cause for worry.

I have 2 rimless drillings and the K 95 in a rimless calibre. I have never had any pronlems with them, but they will not be within 6 yards of an elephant either.

I chose to take the advise of several experts and go with the rimmed 9,3x74R.

It was good advice.

Still I like the thought of a 375 H&H double...
Or double in 458. It would be nice to walk into a store and buy your ammo off the shelf if necessary.

Also durring load development of my and friends doubles I have experienced sticky opening and where the double refused to open until you banged on the bottom of the rifle with the heel of your hand.

Not a good thing to happen when facing DG. That extra 50 or even 100fps is not worth it.

With the 400 and up 2000 to 2150 fps is all you need IMHO.

At least it has been for me.

Perusing around the internet I came across a new Chapius Brusse AGEX 375H&H with a left handed stock I could have for $7,500.00. Considering that I'm looking at a 9.3 in the group buy I got excited until I read this thread. Seems I should stick with the 9.3.

Sticky cases are a sign of exsesive chamber pressure and I don't think any of us here would'nt want to back away from that. Even if that amount of pressure reduced backthrust it would then be to much of a good thing and self defeating.
I'm curious what powders are you using in the old British calibers. I assume your using somthing really slow burning and using a filler or buffer to prevent pressure spikes from reduced loads.

I agree the blaser systom must be one of the strongest systems going I think you can be the source of info on that between your new doppelbuchsdrilling and your K95. A couple of other new designs out there worth a look at is the Schering system from Ferlach and George Hoenig's system. They are very unconventanel but pritty cool. Check it out at www.finefirearms.com/hoenig.html.
Also Martin Hagn has built his falling block in a double rifle that should be dead solid forever no mater what you feed it.
You mentioned a .458 in a double. I think that would probably work. At least as well as my .338. I have a photo at home of a Holland & Holand royal in .458.

I have seen the info on Georges doubles in tnhe past. Fine craftsmsanship from what I have read.

I have done the most shooting/experimenting with my 450 No2.
I have worked up loads that shoot very well, regulate, and to the sights with IMR 3031, RL 15 and IMR 4831.

I must use filler with all powders in the 450 no2 because the case is so big. I like RL 15 the best.

I still use IMR 3031 with 350gr bullets as i have a lot of it on hand.

I also have Nitro for Black loads with IMR 4198.
Akshooter
I think you can use almost any modern powder and have safe loads in the vintage doubles you just have to use the right amount and be satisified with the velocity you get at proper presure.

KPK has had excellent results and service from his 458 Marcey Thys.

DennisHP

I will say you cannot go wrong with a Chapuis in 9,3x74R.
However I am "testing" the Blaser R 93, the K 95 and the D99 Duo.

Maybe You should test the 375 H&H Chapuis.
New Guy has one. I shot it a few times at the last DRSS event. It was very accurate with the factory Federal 300gr Nosler Partitions I had for my R 93.

quote:

Chapuis does make the double in 300 Win Mag.

But Chapuis does make a 300 Mag.

http://www.heirloomarmes.com/chapuis_pop.htm

I agree. buy the .375 and if your concerned about excesive pressure / backthrust then load it to flanged pressures. Play with the bullet weight up and down untill you find a sweet spot in regulation. Or pick a load you like and reregulate.

Mike
That is what I said they DO make a 300 Win Mag.

Sorry, I mis-read your post.

About twenty or thirty years back I owned for a time what some would consider the apogee of an all-round double rifle, a Westley Richards in .375 H&H with detachable boxlocks (plus an extra set of locks in the case) and a peepsight in the rib. Best Quality. It was in new condition throughout, quite beautiful, and gave continual extraction and ejection trouble with everything I tried to shoot in it including handloads. It put me off high pressure cartridges for double rifles forever.

Heare is something intersting a 375 Magnum Rimless
http://cabelas.com/cabelas/en/content/community/gun_inv...sp?hierarchyId=10473
What were they thinking.
Bill

Vandalism IMO

Looks like a rechamber.

The reason the 375 flanged was loaded to a lower pressure was so the 2 fired cases would extract from a hot, dirty chamber. This is true of the rimmed euro cases also.7x57-7x57R. Less pressure with the rimmed cases. Tom

19 Tons is 42,750 psi

quote:

Originally posted by trmungle:
The reason the 375 flanged was loaded to a lower pressure was so the 2 fired cases would extract from a hot, dirty chamber. This is true of the rimmed euro cases also.7x57-7x57R. Less pressure with the rimmed cases. Tom

No, not really.

quote:

19 Tons is 42,750 psi.

If you mean 19 tons is 42,750 PSI chamber pressure, no, it isn't. Apples and oranges.

The 19 tons marked there for the .375 Belted Rimless Magnum is 19 tons (it's actually 19.5) bolt thrust as measured in the British base copper crusher guns (BaseCUP). It is NOT chamber pressure. The Brits now use BAR, which IS chamber pressure. Thus, the standards for the .375 Belted Rimless Magnum, old and new, are 19.5 tons bolt thrust and 4300 BAR, or 62,366 PSI chamber pressure. Those for the .375 Flanged Magnum are 18 tons, and 3250 BAR, or 47,137 PSI.
------------------------------------------------
"Serious rifles have two barrels, everything else just burns gunpowder."

quote:

The 19 tons marked there for the .375 Belted Rimless Magnum is 19 tons (it's actually 19.5) bolt thrust as measured in the British base copper crusher guns (BaseCUP). It is NOT chamber pressure. The Brits now use BAR, which IS chamber pressure. Thus, the standards for the .375 Belted Rimless Magnum, old and new, are 19.5 tons bolt thrust and 4300 BAR, or 62,366 PSI chamber pressure. Those for the .375 Flanged Magnum are 18 tons, and 3250 BAR, or 47,137 PSI.

A 32.31% increase in chamber pressure resulted in a 8.33% increase in backthrust Hmmmmm.

My very limited knowledge on the subject has produced a question: if the 375 H&H belted generates pressures too high for a double, why do double makers produce one? Risking problems with extracting/ejecting, and the rifles coming off face would give the rifle's maker a problem product at best and a non-selling product at worst.

I find it hard to believe that there would be 19 tons of thrust against the locking bolts of a double gun. At 60,000psi the thrust would be about 10-12,000 lbs against the breech face depending on the ID of the cartridge. Tom