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Double Rifles, Single Shots & Combinations >> Building Double Rifles & Gunsmithing
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snky35
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Loc: Ireland
Possible to convert a 9.3x72r to a 9.3x74r ??
      #206849 - 10/04/12 07:50 PM

I have a Holland &Holland Climax model Double rifle that was originally built as a 360 caliber but at a later point has been converted to a 9.3x72r.....I was wondering is it posible to convert this to a 9.3x74r......It has been nitro proffed with the first re-boring and is stamped at 19 Tonnes...
Anyone have any ideas...

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AkMike
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: snky35]
      #206867 - 11/04/12 02:03 AM

I wouldn't! Enjoy it as it is.

The steels used back in the day aren't up to the quality of todays. With that in mind a `smith would need to find out how much steel is in the chamber area to be able to safley hold that round.

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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tinker
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: AkMike]
      #206871 - 11/04/12 04:43 AM

I'm with Mike on this one.
Can we see photos of your rifle?
What does it weigh?
How long are the barrels?



Also -- Welcome to the site!





Cheers
Tinker

--------------------
--Self-Appointed Colonel, DRSS--



"It IS a dangerous game, and so named for a reason, and you can't play from the keyboard. " --Some Old Texan...

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snky35
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: tinker]
      #206872 - 11/04/12 06:00 AM

Will post pictures as soon as I can figure out how to. It was built in 1885 and in great condition....works really well as is but wouldnt mind some more umphh. Thus the 9.3x74r would give this and expand its uses.

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AkMike
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: snky35]
      #206874 - 11/04/12 06:10 AM

There's a couple of problems I can see with this idea.
#1 The quality of the steel used back then.
#2 The amount of 'meat on the bone' after a rechamber to the X74 in the chamber's pressure chamber.
#3 The bore size isn't going to be the same as needed for the X74. I have 2 X72r' and the diameter is .363 and .365 on the different rifles.
#4 There isn't enough steel in the barrel bore to take out to bring it up to the .366 needed for the X74 because the twist is not going to be the same. IIRC they need .020 minimum for a re-bore and re rifle.
I would also suspect that the action would'nt be strong enough for the higher intensity of the X74.

If you want 'more get up and go', find another rifle and upgrade. It'd probably be cheaper and better.

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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Tatume
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: snky35]
      #206875 - 11/04/12 06:13 AM

Your 1885 vintage rifle was built for black powder and should be used with black powder or suitable substitutes. The pressures of the 9.3x74R were not envisioned at the time your rifle was designed or built. If it is as nice as you say, someone (perhaps even me) might trade a nice 9.3x74R rifle for it. (Oops! Didn't notice the Ireland address. Sorry, can't trade.)

--------------------
Take care, Tom
NRA Life Member

Edited by Tatume (11/04/12 06:15 AM)

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snky35
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: Tatume]
      #206877 - 11/04/12 07:01 AM

Allthough it was originally black powder proofed it has since been nitro proofed. 19 tonnes is stamped on it from nitro proofing. There appears to be a lot of meat on the barrells but as you say the action could be a problem. I will post pictures and measurements just in case it could be possible.

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AkMike
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: snky35]
      #206878 - 11/04/12 07:19 AM

Check and see what the rate or twist is to the rifling along with slugging the bore.
Wright shows the X74 @ 19.4 tons.

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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AkMike
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: AkMike]
      #206879 - 11/04/12 07:29 AM

Another thing to look at would be IF you have all the work done and it fails re-proofing then you would have a very expensive tomato stake for the garden plot. (0 value)

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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tinker
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: AkMike]
      #206880 - 11/04/12 07:31 AM

These guys know what they're talking about here -- and as noted above there's likely a solid 9.3x74r rifle out there near you that could work as trade bait if you really wanted to go that direction.

I can't wait to see your photos!

To figure out the photo issue, click this link:
How to post photos on NitroExpress




Cheers
Tinker

--------------------
--Self-Appointed Colonel, DRSS--



"It IS a dangerous game, and so named for a reason, and you can't play from the keyboard. " --Some Old Texan...

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AkMike
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: tinker]
      #206881 - 11/04/12 07:34 AM

Quote:

there's likely a solid 9.3x74r rifle out there near you that could work as trade bait if you really wanted to go that direction.

Cheers
Tinker



True! I know I've seen a Belgian X74 at Micks Guns over there.

http://micksguns.com/

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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AkMike
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: AkMike]
      #206882 - 11/04/12 07:43 AM

LOL, another after thought..

The firing pin diameter is probably too big for a higher intensity cartridge like the X74. I doubt that they are bushed all ready. A dovetail slot would need to be cut and filled across the breech.

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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4seventy
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: AkMike]
      #206884 - 11/04/12 09:09 AM

Quote:

Check and see what the rate or twist is to the rifling along with slugging the bore.
Wright shows the X74 @ 19.4 tons.



Mike, I think that would surely have to be a misprint.
There is no way that the service pressure of the 9.3X74R could be that high.
Kynoch currently lists the .375 Belted Rimless Magnum at 19.5 Tons, and it is a 62,000 psi cartridge.
The 9.3X74R is rated at only. 49,000 psi, which I would expect would be somewhere around 16 tons.

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4seventy
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: snky35]
      #206885 - 11/04/12 09:18 AM

Quote:

Allthough it was originally black powder proofed it has since been nitro proofed. 19 tonnes is stamped on it from nitro proofing. There appears to be a lot of meat on the barrells but as you say the action could be a problem. I will post pictures and measurements just in case it could be possible.



snky35,
Welcome to the forums!

I would love to see a couple of photos of the proof and re-proof marrks on your rifle.
The 19 tons sounds very high for a re-proofing to 9.3X72R.
I wonder if the 19 tons mark is a genuine proof mark.
It would be great if you get a chance to post some photos.
Thanks

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AkMike
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: 4seventy]
      #206886 - 11/04/12 09:40 AM

Quote:

Quote:

.
Wright shows the X74 @ 19.4 tons.



Mike, I think that would surely have to be a missprint.




I just double checked that again.. His 3rd edition shows it as 19.4 tons. Page 112 top of page.

It could very well be a typo. But it's all I have to go by.

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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DarylS
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? *DELETED* [Re: AkMike]
      #206889 - 11/04/12 10:34 AM

Post deleted by Daryl_S Thankyou, 4seventy, for the explaination. It was well put and quite understandable.

Sorry - my mistake in misunderstanding the 'system' of pressure measurement ie: Ton's - I deleted this post due to it's incorrect suggestions.



--------------------
Daryl


"a gun without hammers is like a Spaniel without ears" King George V

Edited by Daryl_S (12/04/12 12:54 AM)

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4seventy
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: DarylS]
      #206894 - 11/04/12 11:23 AM

Quote:

19 Long Tons is 42,560PSI 19.4 Long Tons is 43,680PSI





Daryl
"19 Long Tons" is an expression of weight, not pressure. The British (cartridge pressure) system uses (long) Tons per square inch. Tons per square inch was shortened to "Tons" on some of the proof stampings.

You cannot directly convert the British Tons per square inch cartridge pressure system, to psi {which has been measured using a different method}, in the way you have done it here.
Your method of simply multiplying the "Tons" by 2240 will give very inaccurate and dangerous results.

As I mentioned above, The British system rates the .375 H&H Belted Rimless Magnum at 19.5 Tons per square inch, and that is a 62,000 psi cartridge.


Quote:

By the looks of this, if there is enough steel for the re-chamber, one can hold pressure down by not shooting factory ammo and only shooting mid range handloads - more powerful than the 9.3x72, yet not as high pressure as 9.3x74 ammo 'could' be loaded to.





Regardless of what soft loads are intended to be used by the owner, the gun would still be required to withstand re-proofing.
This will be tested at FAR higher pressure than what a factory 9.3X74R is rated at.

Note....
I've edided my original wording in this post more than once in an attempt to clarify some points.




Edited by 4seventy (11/04/12 07:25 PM)

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500Nitro
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: 4seventy]
      #206895 - 11/04/12 11:56 AM

I would just buy a 2nd hand, light weight double rifle in 74R
and leave this as it is. Too many if's and but's IMHO.

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AkMike
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: 500Nitro]
      #206897 - 11/04/12 12:29 PM

As it is now, do you shoot hand loads or factory loads in it? Do they regulate well?
If you hand load what's your recipe?

--------------------
"When you see that in order to produce, you need to obtain permission from men who produce nothing; when you see that money is flowing to those who deal not in goods, but in favors; you may know that your society is doomed." Ayn Rand

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snky35
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: AkMike]
      #206905 - 11/04/12 07:57 PM

Firstly thanks Guys for all the help. I have had this gun a long time and am rather attached to it and thus wanted it to fit all purposes....Right now I only shoot deer with it and the odd boar. My options are to buy another 74 or to get it modified...Regulations in Ireland mean getting another 74 will be dificult...thus my quandry....








Edited by CptCurl (11/04/12 08:51 PM)

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snky35
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: snky35]
      #206906 - 11/04/12 08:23 PM

I shoot factory S&B loads in it and they regulate really well to be honest ...no complaints at all....On average about 2 inches at 70 yards....Or at least last time I tried it on paper thats how it shot. I must admit I use it on game and have only tried it on paper once or twice...but on game I have shot many doubles of Deer so it is not so bad...

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tinker
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: snky35]
      #206907 - 11/04/12 08:34 PM

Very nice rifle!

I would not chance the modification.
Others here might think otherwise.

Thanks for getting the images up!
Do you know who did the change to 9.3?




Cheers
Tinker

--------------------
--Self-Appointed Colonel, DRSS--



"It IS a dangerous game, and so named for a reason, and you can't play from the keyboard. " --Some Old Texan...

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snky35
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: tinker]
      #206908 - 11/04/12 08:58 PM

I cant remember off hand who converted it .....it was one of the london gun makers...Will check when I go home and get back to you.......Think it could be Rigby....

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CptCurlAdministrator
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: tinker]
      #206909 - 11/04/12 09:04 PM

That's a nice rifle. Let me present my thoughts on the question at hand.

It appears the rifle was re-proofed at the London proof house in 1982 (if I'm reading the stamp correctly). I'm assuming the re-work to 9.3x72 was done just prior, and the re-proof was occasioned by the re-work to the new chambering.

In 1982 the "preferred" choice would have been 9.3x74R just as it is now. That being the case, it is hard to imagine that the gunmaker who converted this rifle overlooked the larger round and foolishly chose the obsolete round. I believe the choice was made for a reason, and I believe the reason was the professional judgment that the x74 round would be too much for this rifle. There would be no other logic in chosing the obsolete round.

The same logic applies today. I would leave well enough alone. I certainly would not convert to x74 with the idea of using non-standard light loads. The next owner might not know the protocol.

I see the rifle lacks a third fastener. That may have been a factor in the choice for the lower intensity round.

In the end, if the discussions on this forum do not satisfy you, the best course of action is to consult Holland & Holland. The maker can give you expert advice to be relied upon. Nobody here has that expertise.

As stated, I would keep it and enjoy it "as is". There's plenty there to enjoy.

Curl

P.S. My warm welcome to you as a new poster on the forums! Please join in often.

--------------------
RoscoeStephenson.com

YOUR DOUBLE RIFLE IS YOUR BEST FRIEND.



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500Nitro
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Re: Possible to convert a 9.3x72r to a 9.3x74r ?? [Re: CptCurl]
      #206912 - 11/04/12 10:31 PM


Very nice rifle, thanks for posting the picture.

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