Hi Cheeshead:
I'll try to get through this subject as best I can. When the 325 WSM first came out my first thought was there is a great case for a whole family of wildcats. From 338 to 358, to 366 (9.3mm) to 375, and even up to 411 and 416. My first two choices would be the 358, and the 411. There are pretty good bullets available in both calibers. The 411 benefits from the 450/400 3" and from the 405 Winchester both of which shoot 411/412 bullets. My first reason for liking these calibers is I like to shoot a lot at least a 100 rounds a month, mostly out of rifles. But I have a 357 Revolver and used to have a 41 Magnum. If I had a 411 rifle to go with it I'd buy a Taurus Tracker in 41 Magnum in a heartbeat. Needless to say I like shooting heavy cast revolver bullets and don't mind shooting them out of the rifles as well as the pistols.
On the following site which is one of the best. I didn't even mind paying to join.
http://ammoguide.com/cgi-bin/ai.cgi?sn=LLcpOeAhms&catid=427 I found a great load for the 325 WSM. 61.5 grains of H-380 under a 220 grain Swift bullet. I use so much H-380 that I buy it in 8 pound kegs. It's great in short barrels and medium cases. The reported velocity of this load is 2669. Internal Ballistics being the funny thing it is you can only do linear extrapolation so far. But I think we can go up to 358 with a linear estimate and then may have to shave off a few percent on the 411.
The June-July issue of Handloader magazine has a great article in it about how calculate the muzzle velocity of a different bore diameter and bullet weight using known data from the same case. Rules 2 and 3 apply to this case. Rule 2 is that in cases of equal capacity but different bore size velocity increases or decreases at 1/4 the difference in the area of the bullet diameter. Rule 3 says that in the same case muzzle velocity increases or decreases at 1/2 the difference in bullet weight. So Rule 2 is {([(.358/.323)^2 - 1] / 4) + 1} * 2669 means that the necked up case could drive the 220 bullet at 2,821 fps. Applying Rule 3 we add 250 to 220 and divide by 2. So to adjust up to the 250 grain bullet weight [([(220 - 250) / 250] / 2) + 1] * 2821 = 2652
I think I'm going to have to write a computer program to do that again. While the examples in the article make sense figuring out the math was painful even for me and I minored in Math in College. In the end the extra bore diameter and the extra bullet weight almost cancel out. But here is the promised ballistics chart for your 358 WSM with a good high BC 250 grain bullet. I used the Nosler 250 grain for these calculations.
Calculated Table
Range Drop Velocity Energy Time
(yds) (in) (ft/s) (ft•lbs) (s)
0 -1.5 2652.0 3903.5 0.000
50 1.0 2564.1 3648.9 0.058
100 2.1 2477.9 3407.7 0.117
150 1.8 2393.3 3179.2 0.179
200 -0.0 2310.4 2962.8 0.242
250 -3.4 2229.2 2758.0 0.309
300 -8.6 2149.5 2564.3 0.377
I'd assume a couple of grains more powder than the 325 WSM. So if I took a guess and went with 64 grains of H-380 to get this performance the Muzzle Efficiency would be 61 ft-lbs / grain of powder. That would put the 358 WSM into the 2nd grouping but still pretty good.
Have a Great Day!!
