.308 to .30-06 conversions?

[SFW]

This may be a foolish question, but I suppose it is always better to ask when it comes to reloading than to make a potentially fatal mistake...

If I have a load that works extremely well in a .308 can I apply that same load to .30-06 and expect similar results? Or are the two cartridges not really applicable to one another when reloading?

[Marco Califo]

A Logical Approach:
1st, know that they are not the same, and accept that.
2nd, for your bullet/powder combination find the load in each/both calibers.
3rd, Select the load that matches your rifle and brass.
They will be similar, but the manual makers already quantified the difference. Use the correct published load.

[hk33ka1]

I would not say that it is dangerous and with some powders, loads can be similar between the calibres, but you will not have the same accuracy or velocity using the same powder charge and bullet due to the different case capacities and the fact you would be using a different firearm. So if that perfect load in your 308 Ruger was put in a 30-06 case in a Sako it will not shoot the same. It would be like using the spark timing settings from my Harley on your Chevy.

Some people feel that certain powders with small charges can be dangerous although this usually applies to reduced loads with certain powders in large pistol cases.

A better and more plain explanation in the post above mine

[Slamfire]

Nah, they are different cartridges.

Though there is an almost combination that works well in both cartridges.

A 168 SMK with 41.5 grains IMR 4895 is a well established 308 M1a target load.

A 168 SMK with 42.0 grains IMR 4895 shoots very well in a 30-06 out to 200 yards. I have shot thousands of that load standing and sitting RF, never had the courage to try it at 300 yards.

[4runnerman]

hk33ka1--Hit it on the head. Back to load development for you

[Jimro]

SFW,

For the sake of simplicity, let us pretend that we have two rifles that are identical except one is 308, and the other 30-06.

Any load that shoots well in 308 will also shoot well in 30-06 if that load matches barrel time and velocity. Since the 06 has greater case capacity, you'll use more of any given powder to achieve the same barrel time and velocity.

However, in the real world you'll never get rifles that identical, so you will have to do a load workup.

Jimro

[Unclenick]

Peak pressure has a lot of dependency on the volume the powder starts burning in. Since, for a typical bullet, the .30-06 case has about a third again more capacity, these are obviously not going to be done by the same charge. With more powder in the .30-06 case, more total gas will be made, so the same peak pressure will produce more velocity in the .30-06 because the greater volume of gas doesn't let the pressure drop as quickly.

I ran some examples in QuickLOAD. Typically, to have the same barrel time (24" barrel) the .30-06 took about 18% more powder, had 10% lower case fill, had about the same peak pressure, and produced not quite 4% more velocity. For the same muzzle velocity, the .30-06 used about 13% more powder, had about 13% lower case fill, produced about 11% lower peak pressure, and had about 5.5% longer barrel time.

[SFW]

Thanks guys!