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Old March 23, 2013, 07:56 PM   #1
David_S
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7mm-08 loads in 7x57 mauser - am I overlooking something?

Okay, I know ammo manufacturers (especially in US) tend to download the 7x57 supposedly because of all the old weak-action military mausers around, and it seems powder manufacturers do the same with their recommended loads.

For example I load my 7x57 with 139gr Hornady SST and ADI AR2209 (same as Hodgdon H4350). Both ADI and Hodgdon manuals give max rec load of 46.5gr for the 7x57 but 48.0C gr for the 7mm-08. (based on 140gr bullet as the closest to 139gr, though ADI also give a 7mm-08 139gr starting load of 47.0gr and max of 50.0C)

Now my 7x57 is a modern-action Winchester M70 Featherweight from 1985 or thereabouts and it just happens that my best load to date is 47.3gr which consistently gives 4-shot groups around 0.8MOA and 2,640 fps.

With this load my rifle is comfortable to shoot, and there are no overpressure signs such as sticky bolt, flattened primers or plateauing velocity. I can't see any reason not to continue with this load which is barely over the starting load of the 7mm-08, but wanted to check here in case I am overlooking something.

And no I don't want to trade the classic 7x57 for an upstart 7mm-08! There is something special about shooting a cartridge which has been around over a 100 years and which was the precursor of cartridges such as the 30-06, 308 and indeed the 7mm-08. And besides everything I point it at tends to fall over!
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Old March 23, 2013, 08:16 PM   #2
Jimro
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Yes your action can handle higher pressures. However a low pressure round aids in long brass life and ease of extraction. There is no reason not to continue using the load you like. I've found very good accuracy with a number of starting loads, and accuracy is the biggest factor in lethality.

Jimro
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Old March 23, 2013, 09:16 PM   #3
David_S
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Thanks for that quick clear reply, Jimro. And I agree with you that accuracy is more important than wallop! - David
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Old March 24, 2013, 10:26 AM   #4
hammie
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@DavidS: From some old tables of mine, the case capacity in grains of water for the 7 x 57 mm is 52.2 gr. The case capacity for the 7mm-08 is 49.9 gr. The capacities were determined by filling the case to the base of the neck. Given the shorter neck of the 7mm-08, the practical case capacity maybe even less for that cartridge.

If you can rely on the principal that the same load in a larger case generates lower pressures, then it would seem that the 7mm-08 data would be used as a guide for the 7x57 in modern rifles, with judgement and common sense.
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Old March 24, 2013, 10:53 AM   #5
jimbob86
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Quote:
my best load to date is 47.3gr which consistently gives 4-shot groups around 0.8MOA and 2,640 fps.
How does that treat you cases?

Quote:
@DavidS: From some old tables of mine, the case capacity in grains of water for the 7 x 57 mm is 52.2 gr. The case capacity for the 7mm-08 is 49.9 gr. The capacities were determined by filling the case to the base of the neck. Given the shorter neck of the 7mm-08, the practical case capacity maybe even less for that cartridge.
It does stand to reason, yes ......

I'd just keep in mind that all cases are not created equally- US manufactured cases may be less stout than the Euro-made cases, as theres no reason for them to be ..... dunno. I'd stick to the "start at the "Start load" and work up, anytime I changed anything.
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Old March 24, 2013, 11:34 AM   #6
hammie
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@ Mr. jimbob: Thanks for the added words of caution.

Years ago, I owned a "liberty" ruger 77, chambered for 7x57. Fired cases showed a funny ring near the base. Because I was worried about case stretching (it turns out they weren't stretching), I cross sectioned several cases. I couldn't see any difference in the web between winchester, remington, or norma cases. But that was decades ago and who knows how things have changed.

Anyway, I heartily agree with your advice.
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Old March 24, 2013, 12:50 PM   #7
David_S
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Thanks all.

Thanks Hammie and Jimbob for your input which confirms my original thinking. Just wanted some other opinions as a check.

I have been reloading the 7x57 since 2008 and have never had a split case or other case problem but I have never consistently reloaded over the rec. max. before. I use Federal for SP, Norma for BTSP and Winchester for the SSTs. This odd mix is what I had left over from shooting Factory ammo. I was driven to reloading by the varying availability of 7x57 ammo. No sooner had I got my rifle sighted in with one brand than it disappeared off the market. A good thing as it turned out as I never got anywhere near 1MOA groups with factory ammo.

The only problem I have had reloading the 7x57 is with Federal primers in Winchester cases. For some reason they are hard to seat properly and I had a few misfires or rather non-fires until I switched to Winchester primers.

David
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Old March 24, 2013, 01:00 PM   #8
hammie
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@davidS: You betcha. It seems like you're way ahead of me on all of this.
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Old March 24, 2013, 01:04 PM   #9
jimbob86
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You are welcome to my opinion (worth every penny you paid for it, too!)

When hand loading, when in doubt, I prefer to err on the side of caution ....
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