Medium 338's vs. Big 338's
I recieved several messages when I posted on another thread some of my thoughts concerning best use for the medium size 338's like the 338 RUM, 338-300 RUM and standard 338 Lapua. These thoughts were based on average long range hunting situations where a guy needs to be on the money first shot. I stated that in my opinion these size cartridges are best with 225 and 250 grain bullets for the ranges they are best suited at long range hunting. Which inside those ranges the lighter bullets have far less drop and not much difference in wind. They do not push the 300 grain bullets fast enough to increase that range very much. To do that a guy needs a big 338. All the messages basically stated how popular some of these cartridges were for long range hunting. I have been doing this a long time and these are the reasons I shoot big 338's off the 378 wby, 416 rigby and Excalibur cases. I think they are self explanatory. I used 2800 fps for the three medium sized ones and 3100 fps for the big 338's. I know somebody is going to say I get 2850 or a little more in theirs but there are just as many that get 3150-3200 in the big 338's. But these are averages.
Extreme long range hunting is extremely difficult and you must put every odd in your favor to do it succesfully every time. Once you get beyond 1000 yards you need every possible fps you can get to help you out. Both these velocities have a zero of 2" high at 100 yards which is a common zero for me.
300 SMK at 2800 fps and 5000 feet elevation where I live and 10 mph wind.
1000 yards, drop 233.8", windage 41.6", 1882 fps, 16" drop in 25 yards.
1200 yards, 376.7", 62.6", 1722 fps, 20.5" drop in 25 yards.
1500 yards, 682.2", 104.8", 1501 fps, 30" drop in 25 yards.
300 SMK at 3100 fps same as above
1000 yards, 181.3" drop, 35.7" windage, 2123 fps, 12" drop in 25 yards.
1200 yards, 293.8", 53.6", 1951 fps, 16" drop in 25 yards.
1500 yards, 533.2", 89.3", 1709 fps, 23.5" drop in 25 yards.
My point was if you plan on shooting much over 1000 yards you need to look at a big 338. Out to that range the lighter bullets in the medium size 338's have much flatter trajectories and better on game performance than the 300 SMK. Windage is not enough of a factor to 1000 yards to make that much difference. That is why all my medium size 338's are all loaded with the lighter bullets and the big 338's that can get a 300 grainer near or over 3100 fps are loaded with the 300's.
Look closely at the most important factor of hitting big game at extreme range. Judjing the range correctly! With the medium size 338's at 1200 yards your dropping 20.5" every 25 yards. At 1500 yards your dropping 30" every 25 yards! How many rangefinders can hit accurately within 10 yards at that range. Now say you have 15 fps deviation from your input velocity and add another 5" to your problem here or 9" at 1500 yards. That means you have got to hit your range within about 12 yards just to hit an elk decent at 1200 and maybe 6-8 yards at 1500 yards. That means with everything else perfect. Now say your gun groups 10" at 1200 yards and your shot is at the bottom or top of that group. Now you see why every fps and every inch is important in extreme range hunting. I have done it and I know.
Now with a big 338 at 3100 fps. It drops 83" less at 1200 yards and 150" less at 1500 yards. windage is 9" and 15" less. It drops 16" every 25 yards at 1200 and 23.5" every 25 yards at 1500 yards. 15 fps change shot to shot is 3" at 1200 yards and 6" at 1500 yards. That gives you a few more precious critical yards to be off your mark and still hit your animal. Maybe about a 25% better chance. That is what I was talking about.
Predictions are difficult, especially when they involve the future
Last edited by Long Time Long Ranger; 04-22-2011 at 08:41 PM.