Sectional Density

[joelkdouglas]

Why do we ignore sectional density of 338 caliber bullets? I keep thinking about building that 338-06 or 338-06 AI.

I only ask because the 210-grain PT .338 bullet has a sectional density of 0.263, and I've read (i.e. from Chuck Hawks and others) that a SD of .280 is beneficial for elk/moose/bear. However, the 210-grain PT is a RMEF bullet, and everyone speaks very highly of it. Superb construction, shoots well.

As an aside, a 180-grain AB or PT .308 out of my .30-06 is also below the supposedly magic .280 SD mark, and I shoot them at elk every chance I get.

I realize the answer is probably "bullet construction" of the PT and AB. However, I wouldn't shoot a 200-grain .308 cup and core bullet at an elk if I got to choose, even with a SD of 0.301. Just wondered about your opinions.

 

[JD338]

You bring up a good question.
The fact is the 338 210 gr PT penetrates way more than it should.
I used this bullet in my 338 RUM at 3200 fps MV and shot a bull elk through both shoulders at 350 yds. Exit hole was the size of a golf ball.
Accuracy is excellent in my rifle, shooting under .5 MOA out to 500 yds.

JD338

 

[FOTIS]

Sectional density was a really important factor of yesteryear. Given the same diameter & construction the higher SD bullet will penetrate more. The lack of premium and super premium bullets made it a necessary evil... in a way.
With cup and core bullets SD and jacket thickness was pretty much the only thing to guide you.
Bob Hagel and some others deemed an SD of .250 as a minimum for large game.
So if you were handloading C&C bullets ie Core locts, Sierra and others an SD of .250 or over would give you (hypothetically) good results.

These days SD is not that applicable. For example a 338 win mag with a 210 TTSX will easily out penetrate a Speer 275 gr when pushed to their relative speeds.

The same can be said of a 130 Partition of .277 caliber versus a .277 150 Sierra BT per se.

 

[SJB358]

Fotis and Jim nailed it. I still keep it mind, cause all else being equal, the premium bullets with high SD cause alot of destruction and penetrate far. Never shot the 210 in my 338, but man, if I could find them on sale I would love to try them.

 

[Anonymous]

I guess the way to think of it is that in days of yore (how's that) when you wanted a bullet to penetrate you simply had to add more bullet- since the bore dia is already full, it just adds length...then the sectional density goes up. The additional weight and bearing surface slowed it down and slower impact velocity slowed expansion and as a result- penetration increased. Short of FMJ (which limited expansion to zero)- that was the only way to increase penetration.

As others have said- none of this applies today with monometal construction, bonded cores, etc.

I think the heavy for caliber for bullets are an anachronism today- the .30 cals in 220gr and up, the 250s in the .338s. A lot of guys like those heavy bullets but these days they aren't really required.

I've seen 150s shot clean through big bull caribou, an 87gr .257 shot through a black bear at long range and a 210 Partition shot through 4'+ of moose and its still whistling across the tundra for all I know- by the old numbers, none of those bullets should have been all that good on the repective animals and many old timers would have said they're inadequate.

 

[Oldtrader3]

Maybe I can add a little to what has already been said, all of which is good logical stuff. I have been using this bullet in .338 WM's and .340 Wea Mags since 1968 for elk hunting. I believe that the compound core construction and H-mantle Partition of this bullet enables it to mechanically outperform its indicated sectional density because it does not behave like a cup and core bullet, even a bonded one.

The Partition design gives this bullet a higher Moment of Inertia coefficient which is a fancy way of say it deflects and deforms less as it penetrated than cup and core bullets. It will always deliver approximately 60% bullet weight to the end of the wound channel and will normally penetrate even an elk fully. These properties probably heighten the bullets performance to that of at least other makers 225 grain bulets and the cup and core 250 grain bullets.

This bullet was the standard where I lived in the rocky mountains for 20 years as the elk bullet number uno! Of course the 250 Partition has been around as well and is even moreso. However, a lot of elk hunters like the performance of the 210 Partition without the recoil of the 250 Partitions. Their are other reasons as well but this I think, are are the main ones.

Besides I forgot to mention, my .340 Bee will push a 210 Partition to over 3100 fps. No elk on earth can walk unscathed away from a good lung hit with that!

 

[SJB358]

Man, I might just have to buy some 210's. Your talking me into it Hodgeman! I've resisted a long time. Maybe I need to give them a shot.

 

[257 Ackley]

I've told you already Scott...that 210 is a tough bullet. It would be a screamer out of your 338. Look what it did with my whimpy 338-06. :roll:

 

[Anonymous]

SJB- that 210gr .338 is an absolute killin' machine in the .338WM. I don't have a .338 but hunt with a friend that's hammered a bunch of stuff with them- impressive is an understatement.

Another overlooked bullet in .338 is the 180 AB... that's pretty light for a .338 and a magnum moves them downrange pretty fast. But- they hold together well, penetrate like crazy and shoot very flat. A friend hit a moose with one this year- pulled it out of the offside hide with a perfect mushroom...chest cavity looked like an RPG hit it.

I could easily live with a .338-06, .338WM or .340Wby and only one variety of those bullets and be happy as a clam.

 

[FOTIS]

I will be shooting the 210 PT at 3k from my 338 Winnie #1 Ruger......when the winds die down. :roll:

 

[BK]

I was a G. Sitton fan (fanatic?) when he was still alive, and he was a big proponent of SD, but he always claimed that an SD of .250 was where bullets for big game really started, so that 210 grain .338 was right where you wanted to start.

 

[gerry]

I'm with everyone as well on this one too. In the past one of the "problems" with a round like the 35 Whelen was supposed to be lack of sectional density but bullet testing has shown a premium 225 gr (sd .251) outperforms a 250 gr conventional. I have just ordered some 200 gr Barnes TTSX and Accubonds (sd .223) and am pretty certain they will perform very well.

 

[SJB358]

SJB- that 210gr .338 is an absolute killin' machine in the .338WM. I don't have a .338 but hunt with a friend that's hammered a bunch of stuff with them- impressive is an understatement.

Another overlooked bullet in .338 is the 180 AB... that's pretty light for a .338 and a magnum moves them downrange pretty fast. But- they hold together well, penetrate like crazy and shoot very flat. A friend hit a moose with one this year- pulled it out of the offside hide with a perfect mushroom...chest cavity looked like an RPG hit it.

I could easily live with a .338-06, .338WM or .340Wby and only one variety of those bullets and be happy as a clam.

I have some 180 and 200gr AB's. Might have to shoot them and see what they do.

 

[Oldtrader3]

I shoot the 180 AB's and BT's, when I can find them, in my .338 Federal. They are accurate and I can get pretty close to 2700 fps which is good for a small case like the .338 Federal, considering that this velocity beats the .30-06 with a smaller case. Typically, I can shoot 5-shot groups at about 3/4 of an MOA with the 180 BT's att 100 and 200 yards.

However, I can get decent goups, not as good as the 180 gr or 200, with the 210 Partition in the .338 Federal and achieve about 2580 fps which gives me a decent mid-range elk cartridge on a smaller rifle frame than the Mark V. Not too shabby for a bullet that will penetrate and perform as the 210 Partition is known for.

 

[FOTIS]

This is a perfect example!

If you're getting 2700 fps with the 180 BT's in the 338 Fed then you're copying every aspect of the 180 30-06's virtues except SD. Now if you were using a 180 gr TTSX or Partition or Swift then the higher SD of the 30-06 (with standard bullets) would go out the window!

 

[SJB358]

Man, plus you have the smack of the 338 bullet! Sounds like a win win to me.

Heck, I even have some 180 AB's/BT's on the shelf. Just haven't had a chance to shoot them yet. Nosler says close to 3300 with the 180's in the 338! That would be a SCREAMER!

 

[FOTIS]

I get 3100 with the 200's and imr 4350 Scott!

 

[35 Whelen]

I will say that JD338 has this one down when he says it works better than it should. As almost everyone that I knew in Alaska that wasnt a handloader was shooting those Fed Premiums in 210 95% of the time in their 338WMs; and all of us raved about how well they actually worked. It was nice to have the option of a handful of 250s, on a wounded bear. But the fact remains; that combo of a 338 /210 Nosler; is most certainly a tried and true performer! I have no doubt that a 338/06 would just be ditto as well. So regardless of what the figures say about it in a book, in the real world it works!

 

[SJB358]

I get 3100 with the 200's and imr 4350 Scott!

WHAT!!! Send me some data Fotis. I might have to load some of those up tonight! Those are SCREAMERS!! Son of a gun, if they shoot well, I am going to be pretty mad at myself as those bullets have been sitting on my shelf for awhile!

Thank you Fotis.

 

[Oldtrader3]

That is correct Fotis, I do not have the case capacity in the .338 Federal to track with the .30-06, just a bigger diameter bullet.