Krag Discrepancy

[mr.tickle]

I was going through my reloading manuals on reloading a 220gr RN for the 30/40 Krag. My goal was to load them close as possible to 2000 fps and not to exceed that. My plan was to use IMR 4350 (since I've had good experience with this powder).

I noticed quite a discrepancy between two of my manuals.

In the 49th edition of the Lyman manual, it states max loading is 45 gn with a velocity of 2177.

Now in the Hornady 9th edition it states not to exceed 40.5 gn and lists the velocity as 2000 fps.

Who is right? 5 gn seems like quite a discrepancy.

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[Parashooter]

And Sierra lists 44.4 grains 4350 (maximum) at 2100 fps from a 22" barrel.

Loading data lacking pressure figures is simply a reflection of the authors' subjective judgment about what constitutes a safe load. Some sources are more conservative than others - but most caution maximum loads must be approached carefully from below while looking for signs of excessive pressure. Unfortunately, the usual "signs" (flattened primers, sticky extraction, etc) don't normally appear until US Krag pressure limits have been grossly exceeded.

One eminently sensible approach is to employ a chronograph during load development, testing incremental increases only to the point where an acceptable combination of accuracy and velocity is achieved. In a 30" Krag barrel, that's likely to be somewhere around 40 grains IMR4350 with those 220-grain bullets.

Unless you're hunting brown bears or angry moose at close range, there's little practical reason to employ such heavy bullets. Lighter bullets can be gentler on rifle, shoulder, and wallet - often while delivering equal or better accuracy from bores in good condition.

[vintage hunter]

In the 49th edition of the Lyman manual, it states max loading is 45 gn with a velocity of 2177.

Now in the Hornady 9th edition it states not to exceed 40.5 gn and lists the velocity as 2000 fps.

Who is right? 5 gn seems like quite a discrepancy

There's more to load data than just a powder charge weight. It also includes what type/brand of primer, case and bullet were used. As long as you use the same compenents the manual calls for both sources are right. Start deviating and you could be in for trouble.
There's lots of variables to consider so all manuals will be different, no two will list the exact same max charge for a given bullet weight. This is why it's so important to start with the lowest charge listed and work up while watching for pressure sighs.

[browningautorifle]

Like stated here already they're both right. Some give you a greater safety margin is all. Start at the bottom and work up.