I've been pretty cautious in load development, mostly staying with the lightest load that regulates. I was wondering how you all decide on what is maximum and in fact what parameters you would use to decide the best load.
Thanks
Bfly

BF I think you answered your own question "load that regulates". This in combination with the published "performance envelope" of the caliber will give you everything you need. An extra 50 or 100fps will not make any difference IMHO. Thus, for my 500/416 I have a load that regulates and comes in at around 2300 fps with a 400 grain bullet. Similar specs are available for all the rimmed calibers including the 9.3x74R, 7x57R etc.
Peter.

quote:

mostly staying with the lightest load that regulates.

...which isn't necessarily a safe load. I've worked with rifles that would not regulate at a safe pressure, and had to be re-regulated.

It can be a little tricky, as you can't use conventional pressure signs as a guide. First, find reliable external performance data, and note barrel length. Standard performance of double rifle cartridges is often standardized in significantly longer barrels than are typical on sporting rifles. Adjust your velocity expectation with the standard weight bullet for the difference. If possible, shoot some standard ammo (Cordite for the English calibers) over a chronograph to establish a baseline. Use only propellants that you have pressure tested data for. Work up, shooting over a chronograph, to standard velocity as adjusted for barrel length. When you get there, assume you're at or close to max. Pressure tested data strongly suggests that you will be. If the barrels aren't together yet, try another powder.
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"Serious rifles have two barrels, everything else just burns gunpowder."

Thanks. I had a case come apart way back in the early sixties in a bolt rifle when I was groundhog hunting. I had pepper freckles around my right eye (protected by my glasses) and on my left hand where powder came down around the magazine. They lasted several years. That's when I stopped hotrodding cartridges. I already only used data that includes pressure test data and I'm doing the basics as advised by 400NE. So I'll keep doing that.
Thanks
Bfly

Once you have found a load that shoots to regulation and you have gotten it through published, tested data and then velocity proves within expectation, it doesn't cost much to have it tested here in the states or to have it tested by the Birmngham Proof House. I think Kynamco will also pressure test loads.

JPK

Another thought - beware of the long standing conventional wisdom that higher velocities can be achieved in the Cordite flanged nitros with modern, slow burning propellants at lower pressures than Cordite produced at standard velocities. It's a myth.

For example, late run Kynoch factory Cordite .450 NE ammunition was pressure and velocity tested in a manufacturer's modern pressure gun. Ammunition was then loaded to the same velocity with H4831 and tested in the same gun. Same pressure.

For the flanged nitros, standard test barrel lengths and velocities can be found here:

http://www.new-kynoch.apt-site...artridge%20range.htm
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"Serious rifles have two barrels, everything else just burns gunpowder."

Oxymoron: hotrod double rifle loads!! One way to take people out of the genepool.

Rich
Buff Killer

Graeme Wright's pressure testing revealed that more velocity was available at the same pressure with modern powders vs cordite for most, if nor all, NE catridges.

This is contrary to what 400 Nitro Express writes, but read it yourself in Wrights books.

But utilizing that extra velocity - and who knows how much it might be, Wright didn't explore that - would require reregulating the rifle. Why bother?

BTW, I do think that 50fps or 100fps is significant as hell in a rifle shooting 2050 or 2100fps, the gain in preformance is non-linear, but if you've got a vintage rifle, live with its limitations, or get rid of it and hunt with a different option, imo.

JPK

quote:

Graeme Wright's pressure testing revealed that more velocity was available at the same pressure with modern powders vs cordite for most, if nor all, NE catridges.

I'll believe Hornady, thank you. They tested both in the same pressure barrel. Actually discussed this with Graeme in Reno. He didn't seem surprised.
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"Serious rifles have two barrels, everything else just burns gunpowder."

A rule of thumb to determine max pressure as stated by a couple of old timers I met at a range was wait till someone blew up their gun and back off alot!