8mm Mauser - changing bullets in Turkish Surplus Ammo

So...why not just but a box of commercial hunting ammo?

You simply cannot safely replace 154 grain bullets with 170 grain bullets and keep the same powder charge without dangerously increasing pressure.

A cursory glance at any reloading manual would tell you that.

If you just have to replace the 154 grain bullets, replace them with 150's.

Besides, your old surplus ammo is probably corrosive primed.

Shoot it up, clean the rifle with hot soapy water, and buy some decent hunting ammo.
Then later you will have some nice new boxer primed cases for reloading.

rc

I would not go heavier......like it has been suggested, go to a 150grn.........or get a chrono, reduce the powder load by 30%, slowly working it up 0.1 grain at time whatching for pressure signs from each shot. and chronoing the velocities as you go.........and make sure your insurance is up to date.

I have some of that Turkish 7.92mm ammunition, and if I remember correctly, it's already loaded pretty hot. If you load a 170 grain bullet in place of the 154 grain bullets, you'll probably put your eye out. Never go to a heavier bullet with the same powder charge or the pressures will go through the roof. That load would probably be close to the load used to proof test the rifle in the first place, but they weren't made to shoot a steady diet of those loads.

There's also more involved with pulling a bullet and replacing it. You'd have to neck size the brass again so it would hold the new bullet. If you don't have 8mm Mauser dies, then you wouldn't be able to do this.

Hope this helps.

Fred

The turk ammo is not "hot".
It's just loaded to full pressure.
But who knows what pressure standards they used in Turkey?

American SAAMI standards for the 8mm Mauser are held to a really low 35,000 PSI in deference to some really old rifles chambered for it in two different bore sizes.

CIP European pressure limit is around 50,000 CUP.

A lot of American load data supports the lower SAAMI standard.
If you were to pull 150 grain bullets out of U.S. loaded commercial ammo and seat 170's you would probably get away with it.

Full pressure Turkish military?
Probably not!

rc

OGuthrie,

Vihtavouri in their 1-97 reloading guide stated the following two relationships:

1.) For a 10% increase in bullet weight there is a 10% increase in pressure.

2.) For a 10% decrease in powder charge there is a 20% decrease in pressure.

This is valid for SMALL CHANGES, in identical cases, using the same identical powder. This relationship can be expressed as two simultaneous equations. With some high school algebra you can rewrite this as a single equation that solves for the new powder charge (call it C2). You know the weight for the first bullet (B1): 154 grains. You know the weight of the second bullet (B2): 170 grains. You know (or can find out) the weight of the first powder charge (C1).

Pressure (P) you don’t know, per se, but you know if it’s held constant it will be safe (otherwise the 154 grain factory load would of blown up, or at least exhibited some pressure signs). Big Hint: the “trick” to solving the equation is just letting P1 = P2 (in which case, the change in pressure equals zero).

You can do the math. Or, if you post the initial powder charge (the one from the cases holding the 154 grain bullets) I will do it for you, and give you the new charge weight (C2) for the 170 grain bullets. Would be best to measure at least five (just dump all five into one pan), and average. As always, reduce the C2 charge 10% and work up. That goes without saying. But, it never hurts to say it anyway.

I’ve used this relationship for years to load thousands of rounds of el cheapo “Mexican Match” ammo -- inexpensive unfired surplus cases, powder, and primers (many Berdan). Pull the military bullet. Weigh and save the military powder. Reload the cases with the new CALCULATED weight of military powder, and seat a nice commercial match bullet. I’ve done it with .223, .30-06, .308, 8x57, and .303 Brit. The military bullets I pull, I save, and use for light plinking loads in what ever rifle they happen to fit.