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Thread: Murph - 7x75R

  1. #1
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    Default Murph - 7x75R

    Murphy,
    I've been researching the 7x75R Vom Hofe for a singleshot rifle project I'm scheming up. Was wondering if you have any information on this round. I have some very light, trivial history about it and the cartridge design specs along with some conflicting ballistic information.

    I can't seem to find any info on field experience, though ballistic data indicates it falls between the 7mm Rem Mag and the 7mm Weatherby Mag (at least for their factory loads). Huntington imports the brass, or can be made by necking down the 9.3x74R brass.

    Any thoughts or information?

    Thanks

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    Default 7mm Rimmed Metric

    I like the 7x65R Brenneke.

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    Wink 7x75r

    DP,

    I'm afraid you got me! I don't think I've even heard of it. I've seen and used the 7X65R in a drilling. It is basically the 7X64 with a rim and down loaded a little. Most of the European Rimmed cartridges were made to duplicate the performance of some other rimless caliber just for their use in break action guns. I don't know this one. I am familiar with the 9.3X74, I load for it and brass isn't hard to find. Norma makes it as does RWS, so making brass wouldn't be a problem but dies would be a custom set I would say and cost a couple hundred $$$.

    I know how it is, sometimes I just get a bug, too and have to have a certain caliber. I really like the 40 bore guns from our 19th or 20th century or English or European calibers. I want one of each.

    How about a 40-70 Sharps straight in a Shiloh saddle ring rifle.
    Maybe a 450/400 3" Jeffery in a Watson Bros Double!!
    Or just a 405 WCF in a takedown 1895 Winchester!!!
    No, a 40-65 in an 1886 carbine!!!

    Ahw! I can dream can't I?

    Good shootin.

    Murphy

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    Default

    I was talking to Martin Hagn last week and he's just finished a 450-400 for himself to take to Namibia. Built, of course, on one of his fine singleshots.

    7x75R is basically a necked down 9.3x74R, designed in 1939. I first became aware of it while looking at Philip Oliendorff's fine singleshots at the SCI show a few years ago (not like I could ever afford one of those!). It's had my interest ever since. The rifle, one of the Hagn's, has had my interest for the last decade or so, but the funds have been slow going into savings for it. Over the past year I've been fretting about the chambering. I'd like something in the 7 Mag class, but something older, and more traditional for the single.

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    Default 7mm Rimmed

    Quote Originally Posted by DPhillips
    I'd like something in the 7 Mag class, but something older, and more traditional for the single.
    I'm getting performance comparable to the 280, from my custom 7x65R barrel, on an Encore frame. These are mild loads, and I’m just starting to experiment. I think it will be close enough to the 7 mag to suit me. There is just only so much velocity that is actually useful. 3000 fps + exceeds my needs.

    In my opinion, if you want a rimmed performance cartridge in 7mm, "older, traditional, for single, 7 Mag class", it’s difficult to find a more practical choice than the 7x65R. Mr Brenneke really knew what he was doing when he designed this cartridge specifically for break open actions many years ago. There is absolutely no need for a simi-wildcat, something which you have to form brass for, or expensive dies & reamers, etc. unless you just really want something different. This wheel was invented a long time ago.

    Regards,
    KB

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    Default

    Quote Originally Posted by Murphy
    DP,
    Or just a 405 WCF in a takedown 1895 Winchester!!!
    Ahw! I can dream can't I?

    Good shootin.

    Murphy
    Here's my 1895 Winny. I had this one built before Winchester re-introduced the 405 and had no idea they had planned it. It's a 411 Hawk built by Fred Zeglin at Z-Hat Custom in Wyoming.

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    Quote Originally Posted by Kabluewy
    There is absolutely no need for a simi-wildcat, something which you have to form brass for, or expensive dies & reamers, etc. unless you just really want something different. This wheel was invented a long time ago.

    Regards,
    KB
    The 7x75R is available in factory ammunition in Europe, especially in Germany and Sweden. Non-existant here, especially with the current fad of short and fat cartridges here. The x75R case is about 2.95" for the case, well over 3" for the loaded ammunition. I guess if I go with a more available cartridge, it will likely be the 7mm Dakota. The Hagn does not actually need a rimmed cartridge, but the 7x75R VH just seems right for this rifle. I agree the 7x65R is a good one, though. My original plan was the 275 H&H Mag, developed in 1911-12, until I found out it used .287" bullets instead of the .284" 7mm. Same as the 280 Ross, 280 Halger and 280 Jeffery.

    The 6.5x68 seems to be a wonderful mountain rifle cartridge as well, but for some unexplainable reason, I'm stuck on the 7mm caliber.

  8. #8
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    Default

    Quote Originally Posted by DPhillips
    The 7x75R is available in factory ammunition in Europe, especially in Germany and Sweden. Non-existant here, especially with the current fad of short and fat cartridges here. The x75R case is about 2.95" for the case, well over 3" for the loaded ammunition. I guess if I go with a more available cartridge, it will likely be the 7mm Dakota. The Hagn does not actually need a rimmed cartridge, but the 7x75R VH just seems right for this rifle. I agree the 7x65R is a good one, though. My original plan was the 275 H&H Mag, developed in 1911-12, until I found out it used .287" bullets instead of the .284" 7mm. Same as the 280 Ross, 280 Halger and 280 Jeffery.

    The 6.5x68 seems to be a wonderful mountain rifle cartridge as well, but for some unexplainable reason, I'm stuck on the 7mm caliber.
    Intresting:
    I have had these kind of conversations before, and they are a little frustrating because they seem to shift as they go, not direct or predictable. For specific example: the 7mm Dakota is definately not old, traditional, or rimmed, or anything close to the criteria you specifically described in your postings, except near 7 mag performance. It's difficult to chase your logic. All the cartridges you mentioned are possibilities, if there is enough want. I just tried to give you the logical solution to your criteria, as I know it.

    Given enough money, it is possible to get into these obscure items, but for me the 7x65R is odd enough, and achieves something - namely near 7 mag performance, in a readily available proven cartridge, with CIP specs. I think you said it best with the words "non-existant" which generally applies to anything you mentioned. but the 7x65R.

    As you say, since the Hagn does not need a rimmed cartridge, I ask why do you not simply go with the 7 mm Mag? Then you don't have to worry about being "near" 7 mag performance, because you will then be "exactly" 7 mag performance.

    The 9.3x74R is an unusual cartridge, for a specific purpose, which is to enable a double rifle, with a small frame, yet allow adequate power for big African animals. It may have been originally cordite, but adapted well to modern powder, simalar in respect to the 45-70. If it was fatter, probably a larger frame would be necessary. If it was shorter, it couldn't hold enough smokeless powder to achieve 2300 fps. It's a good formula - in 9.3mm, for a break-open action. That doesn't likewise mean that it is a good formula in 7mm. The 7x65R is definately a good formula - shoulder, neck, overall length, etc. everything. There are very good reasons why some cartridges fade into obscurity, and others survive. The 7x65R is a survivor. None of the others you mentioned are, including the Dakota. The 7x65R has withstood the test of time, and will be with us as long as there is a need for smokeless powder, and big game to hunt. The others will not.

    I don't mean to be argumentative, just direct. No offence intended.

    Best regards,
    KB

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    Default

    Many times there is no logic in what I do.

    If I go with a more traditional rimmed cartridge, the 7x75R fit the bill. I wasn't really asking about the 7x65R in the original post and am not considering it. I do understand it is a fine cartridge, but not of interest. Why this makes a difference, I haven't a clue.

    If I go with a rimless cartridge (I was just typing out loud so to speak), it would be the Dakota.

    All I was looking for was more data on the 7x75R. Thanks for the info on the x65R though.

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    the von Hofe cartridges are very hard to get - even here in Europe! So ask twice where to get the amo for! What I heard is, that they are having high velocity and the the barrels donīt last much rounds ...

    Klaus

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    Thanks, Pigeon. The rifle's barrel is going to be a very interesting one and not one that I would want to have to replace after a thousand rounds...

    Powder capacity appears to be (roughly) around 80 grains of water, which approximates the 7mm Rem Mag, so unless loaded to extreme pressures, should not present greater barrel burning tendencies than the other relative 7mm's. While the case is nearly a half inch longer than the Rem Mag, it isn't quite as wide.

    I'm trying to keep the case size small enough (diameter) so that it will work in the Hagn small action, which I prefer over the medium.

    As Murph noted, sometimes there is no real rhyme or reason why we want what we want. If there were, we might all just use a 30-06 and be done with it! ;D

  12. #12

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    John Donnelly's "handloader's Manual of Cartridge Conversion lists the water capacity of the 7mm Rem Mag as 83.19 gr of water and the 7x75R Vom Hofe as 74.90 gr of water. In comparison the 270 Win is 67.39, the 284 Win is 64.59, the 280 Rem is 68.58, the 7x64 Brenneke is 66.22, the 7x61 Sharpe and Hart is 77.40, and the 35 Brown/Whelen is 76.93.

    He lists one load for the 7x75R: 175 gr RN bullet, 59.0 grains MRP and no velocity quote. There's an involved process for forming cases from the 9.3x74R.

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    Quote Originally Posted by BrownBear
    John Donnelly's "handloader's Manual of Cartridge Conversion lists the water capacity of the 7mm Rem Mag as 83.19 gr of water and the 7x75R Vom Hofe as 74.90 gr of water. In comparison the 270 Win is 67.39, the 284 Win is 64.59, the 280 Rem is 68.58, the 7x64 Brenneke is 66.22, the 7x61 Sharpe and Hart is 77.40, and the 35 Brown/Whelen is 76.93.

    He lists one load for the 7x75R: 175 gr RN bullet, 59.0 grains MRP and no velocity quote. There's an involved process for forming cases from the 9.3x74R.
    BB,
    Thanks for that info. This is what I'm finding, the data from one source to another isn't very consistent. I have loads from German sources showing max loads with 175 grain bullets higher than max loads with 140's. With the info you posted, I now have 4 different case capacities...

    Enough to drive a fella to drink!

    Again, thanks for the info there.

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    Default Rimless Sharps 5.56

    Just a note about rimless conversions to an 1874 Sharps replica.
    Converted with a 5.56 barrel change and mods to the drop block.
    Testing is in process 3/18/07. Concept can be made for any rimless.
    JW

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