Quote:
Originally Posted by Dean2
Coiloil 37
Sectional Density is the ratio of weight to diameter squared, or more accurately mass to cross section, so any time you increase calibre in the same weight of bullet the SD will obviously decrease. So a 180 grain 30 cal has an SD of .271, and the same in 338 has an SD of .225, but at 160 grains a 7 mm has an SD of .283, Does this mean we should all be using 7 mms of some sort and the 30 cal are handicapped.
The issue is, do you have enough SD to get the penetration you need. In my view as long as you have a heavy enough bullet in the calibre you are using for moose and elk to give you an SD of .250, which you hit at 200 grains in the 338, to .270 or better and a bullet that holds together you are fine. In the case of the 338 the 225 has an SD of .281, the 250 grain Bullet has an SD of .313. Any SD over .3 is consider a top choice for game needing deep penetration. Like any other cartridge, half the battle is picking the right bullet for the job. As far as B.C., to 350 yards I have never paid much attention to that factor, outside of not recommending RN bullets.
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I’m well aware of the definition of SD and how it’s applied. Doesn’t mean I agree with it being the end all be all of penetration. A 180 Berger vld has the same SD as a 180 Barnes but their penetration is vastly different. From my experience if I want more penetration I choose the correct type of bullet. I do believe mass is a contributing factor to penetration as well but not in the context of SD and that’s a different discussion then this.
Curious why I got the answer I did. Was it a deflection from your rounding skills or did you take what I wrote out of context and believed that was the necessary reply?
Should we all shoot .284 pills? I doubt it and that’s not where I was going. I too don’t care much about BC as I only shoot to 400 meters on game and any spitzer I load will get me there.
My original post was simply that your numbers were a little different from the load data online and artificially made the 338-06 look significantly better then the 30-06.
My point in the second post was that yes, the 338-06 gains frontal diameter, the ability to handle heavier bullets then it’s .308 brother and gets the benefit of a larger bore and higher pressure, both of which contribute to increased performance from that case. I don’t however believe it’s as versatile as the 30-06 and if your the type who cares about BC or SD it lags behind the 30-06 in identical bullet weights which is where I was heading.
When I want to shoot things with a .338 bullet I reach for my 338 win mag or if I want to roll a lever my .338 marlin express. I’m a big fan of the .338’s but also my 30-06 and personally haven’t found a compelling reason to have a 338-06. Doesn’t mean it isn’t great, simply not as versatile as the ‘06 and not as heavy a hammer as the .338 win
So far as versatility I’ve shot game with my ‘06 with everything from a 130 Barnes at over 3400 FPS to a 200 grain accubond at 2730 FPS. I have some 220 grain partitions loaded but only used them in a 760 carbine for tracking bears after I ran an arrow through their lungs so I can’t discuss their performance. I “feel” the ‘06 makes the most of that case and has very few shortcomings.