ORIGINAL: dmurphy317
The loads on that website are quite a bit conservative compared to the manuals I have, some of which are only a few years old. Be that as it may, my load works well and shows no signs of over pressure.
I dug out my old manual. Dang this thing is old, older than me, c. 1959. It is a speer manual. The max load for 150 bullet and 3031 is 34 grains and yields MV of 2407. I notice that 30 grains yields 2162 MV which is right in line with Hodgdon's website with 30.5 grains yielding 2192 MV.
My Speer Manual has no information on pressures but the Hodgdon website has them listed for starting loads and maximum loads.28.7 grains yields 28700 cup, 30.5 grains 36000 cup. There is an increase in pressure of 25.4% for an increase in muzzle energy of 10.50%.
This, the way it is with smokeless. Much higher increases in pressure than increases in muzzle energy. So how high will the pressure be with the 34 grain load in the Speer Manual?
First there is an increase of 20.5% in muzzle energy.
Assuming perfect efficiencies of the breech pressure there would be a corresponding increase in the pressures lifting pressures from 36000 cupto 43,200 cup.
BUT THIS CAN'T BE CORRECT, there isn't perfect efficiency. Given we know a unit increase in muzzle energy results in a 2.5 times increase in pressure (between 28.7 and 30.5 grains 3031), using this relationship will bring us closer to an accurate estimate of pressure.
Increase in pressure= 2.5 x Increase in muzzle energy = 51.5%
Pressure 34 grains = 1.515*36000 cup= 54,500 cup
OK, now this isn't a measurement, and perhaps its too high.If it is we still know its between 43200 and 54,500. Obviously it approachesmagnum pressure and it should be clear that the design of the cartridge falls short of limiting pressures at the higher velocities.Even so,the context as to whether its safe depends entirely onthe rifle the load is used in. The same manual recommends pressures below 40,000 for lever action rifles.
Regarding factory ammo, I have never found 30-30 ammo with MV near 2400 fps. Not saying it isn't made. Just saying that it involves some context in that this kind of loading isn't appropriate for many 30-30 rifles. I would think most manufactures load their 30-30 ammo just I have found it, in the neighborhood of 2100 MV so that they are not overloaded for any rifle.