so my qestion is can i take a 300 win mag case and load it to 308 standards? will this cause pressure problems/> do to the volume of the case and lack of powder?
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July 6, 2009, 09:25 AM
Check the loading manuals and do not go below the recommended minimum loads. In truth, most magnums are more efficient when loaded at or near the maximum. Even with their recommended minimum loads, you often still burn more powder than standard cartridges just to get the same velocity.
July 6, 2009, 10:32 AM
It's kind of a Catch-22. Bulky powder loaded up to somewhere in the shoulder of the case (e.g. 56-57 grains of IMR 4350 in .30-06) seems to give maximum accuracy. In my rifle, and I understand in most, there's a "sweet spot" that produces the best groups. A grain's difference is the difference between 1/2" and 2" 100-yard groups with a cold barrel in the hunting rifle. Pressure aside, you'd want to find a load that shot worth anything, and that might take a bit of experimenting.
You could probably find something that's REALLY bulky, but you may not find any published data for it. OTOH some people plink with cast bullets in a big rifle, and they have to be downloaded a lot. So there may be data out there you could start with. Check Lyman's manual for that kind of thing (not on-line, sadly).
Remington offers commercial ammo that's loaded to the specs you're talking about: http://www.remington.com/products/ammunition/ballistics/comparative_ballistics_results.aspx?data=RL300W1
I have no idea about the accuracy of these rounds, but you could try a box before investing in powders and bullets, just to see if your rifle likes this kind of load.
It does mean that there's SOME powder out there that will work safely, though, and is accurate enough for Remington to produce it as a factory load.
Hodgdon even lists a load using IMR Trail Boss, but it's REALLY slow.:)
There are plenty of .30-06-style loads you can find, but of course accuracy may not be great without a full case. (Contrary to popular belief, .308 is not equal to .30-06, unless you're talking about Garand .30-06.) The listed starting loads for H380 in .300 WM are about like max loads in .308, so that could be a powder to try.
This is a good site. Since Hodgdon now produces Winchester and IMR powders, you can see a wide variety of data.
July 6, 2009, 03:52 PM
i have done this w/ a 300 wsm, not a 300 win mag...
if i was to do this w/ a 300 win mag, i would consult my manual and see what the max charge was for the powders listed, get a good average of the max charges, then cut it in half, and that would be my start load w/ h-4895. work up in 1 grain increments until i was satisfied w/ the load. use mag primers.
good luck finding h-4895, and good luck w/ the load development!
July 6, 2009, 04:12 PM
(Contrary to popular belief, .308 is not equal to .30-06, unless you're talking about Garand .30-06.)
I always hear this, but my reloading manual has them within 100-150 fps at both the starting load and the max load. Do you have any data that I can look at or can you point me to a source to either verify or debunk this claim? I only have one data point right now and I don't consider that enough to make a call on my own.
July 6, 2009, 04:21 PM
Do Not reduce loads below the listed starting load with normal slow burning .300 Magnum powder.
If you want reduced loads, here is how to do it safely.
July 6, 2009, 04:29 PM
The Lyman #48 and Speer #13 both of which are in front of me have a few starting loads with 180 gr bullets @27-2800 fps and 150gr @ 28-2900 fps. These are in the high 308 to low 30-06 range of velocity. These are not "reduced loads" but simply starting loads, and I suspect other manuals will show similar.
July 6, 2009, 06:25 PM
32 to 52 grains of XMP-5744 will get you velocities between 2091 to 3030 with 150s. It's a fast burning bulky powder, less grains of powder, less ejecta, less recoil.
4759 is similar but I don't have any full pressure data with it.