sectionnal density and penetration

[Slamfire]

I use sd as an indicator of penetration and choose bullets accordingly based on field experience. For example I favor my 416 Rem. Mag. for most hunting that I do, and choose 350gr bullets because these have a higher sectional density for increased penetration compared to 300gr bullets, 0.24 vs. 0.29 sd, or 20% higher.

Not as high an sd as 400gr bullets (0.33) but the 350gr TTSX has a rather impressive b.c. of 0.44. Always a compromise.

 

[chuck nelson]

And the SD of the bullet as it passes through an animal, is a function of how much the bullet expands. If the bullet expands to twice it's original diameter, the SD is reduced accordingly.

Absolutely.

 

[medvedqc]

so lets say between a swift a frame and a barnes ttx or ttsx which one need less of SD? ... 11 days before bear season and it s melting fast ...

 

[SHELL SHUCKER]

This should be good.

Agreed. Let the pigeons loose.

 

[Slamfire]

so lets say between a swift a frame and a barnes ttx or ttsx which one need less of SD? ... 11 days before bear season and it s melting fast ...

I get consistently good results with TSX or TTSX in 40+ calibers. That's what I'll be taking.

(Disclaimer: individual results may vary ).

 

[Dogleg]

so lets say between a swift a frame and a barnes ttx or ttsx which one need less of SD? ... 11 days before bear season and it s melting fast ...

Black bears? Pick a bullet that you would cheerfully use on a whitetail and clobber it.

 

[medvedqc]

Black bears? Pick a bullet that you would cheerfully use on a whitetail and clobber it.

grizzly on the table too ... if i work my butt a little lol ...

 

[c-fbmi]

Phil..........for energy transfer AND penetration I'd go with the Swift A-frame. What cartridge you thinking about using for bear hunting........9.3X62?..........or are you thinking your 375?

 

[Dogleg]

grizzly on the table too ... if i work my butt a little lol ...

Not much difference, just substitute "elk" for "whitetail". Bears, even grizzlies just aren't very big.

What caliber are you using?

 

[medvedqc]

i opened for the discussion not for me but i will use a 9.3x62 or 375 ruger ...

i do not know yet .... on the 375 i m thinking on 270 grains tsx and for 9.3x62 i do not know yet: a lot of good bullets in this caliber ....

or the 340 ... but the barrel is long ...

 

[Dogleg]

i opened for the discussion not for me but i will use a 9.3x62 or 375 ruger ...

i do not know yet .... on the 375 i m thinking on 270 grains tsx and for 9.3x62 i do not know yet: a lot of good bullets in this caliber ....

or the 340 ... but the barrel is long ...

Well, since you mention the .375 and the A-Frame............you wont go wrong there.

I've got a fair amount of experience with the .375s and the TSXs. It's a solid killer of just about anything from Steinbuck at maybe 20 pounds to giraffe at 15 or 20 times that size, and can do it from any angle. I've already done it; so has Douglas. Having said that, the A-frame is twice the bullet.

 

[Slamfire]

The 9.3mm 286gr Nosler Partition bullet has an impressive SD of 0.307, and an even more impressive BC of 0.482. I load this bullet at about 2400 fps MV in my 9.3x74R Ruger No.1-S.

It's also a favorite, and have been meaning to try it.

9.3x74R Ruger No.1-S with Bushnell Legend Ultra HD 1.75-5x32mm scope

9.3x74R and 308 Winchester

 

[chuck nelson]

Can we please acknowledge that sectional density is almost meaningless and quit worrying about it.

 

[Why not?]

I will be packing my 9.3X62 with 270 gr Matrix for most of the Spring hunting. Also along for the ride will be my 340 Wby loaded with 225 Remington Cor-Lokt Ultras at over 3000 fps, which I sighted in yesterday at 300 meters, just in case we have something that far away. It puts a mag full into less than five inches at that range.

As for the A-Frames, the 150 gr loaded to 3200 fps in my 270 Wby is absolutely devastating on all big game. Holds together as well a Matrix Bonded Cores, and penetrates as well as anything I have used.

Ted

 

[CoonT]

What are the odds of this conversation moving from big game, to penetration on 'terminator-style' robot drones?

No?

Just moose, eh.

Damn.

 

[medvedqc]

The 9.3mm 286gr Nosler Partition bullet has an impressive SD of 0.307, and an even more impressive BC of 0.482. I load this bullet at about 2400 fps MV in my 9.3x74R Ruger No.1-S.

It's also a favorite, and have been meaning to try it.

9.3x74R Ruger No.1-S with Bushnell Legend Ultra HD 1.75-5x32mm scope

9.3x74R and 308 Winchester

the partition bullet was my favorite bullet up to the test in milk jugs ... that bullet didnt make it that good ....

 

[medvedqc]

Can we please acknowledge that sectional density is almost meaningless and quit worrying about it.

Chuck,

we need that .... spring is coming and bear fever hunting is in ....

 

[Why not?]

As always, bullet placement wins..........

Ted

 

[bearkilr]

As always, bullet placement wins..........

Ted

Thanks for that Ted. I'm going to print a couple of those off.

 

[Slamfire]

Sectional density is an important factor. Empirically it correlates with penetration, and you can see that ballistic coefficients are directly proportional to it -