Penetration and impact velocity...

[dakotaelkslayer]

After the "use enough gun thread," I see that most believe that "bigger is better" when it comes to elk. Bigger, seems to mean magnum velocity not just big bullets. How does bullet impact velocity correlate to penetration when using jacketed bullets? I know that when using hard cast bullets, up to a certain point, around 2200fps, velocity is no longer the friend of penetration. But I haven't a clue about jacketed.

Jim

 

[JD338]

Magnum impact velocities can sometimes be less than lower velocities of standard calibers. The bullets expands quickly and starts to slow down faster. Keep in mind that there is also more shock from the higher velocity. If you are going to use a magnum caliber, best to use a heavier weight bullet.

JD338

 

[FOTIS]

......... How does bullet impact velocity correlate to penetration when using jacketed bullets?
Jim

That depends on the construction of the bullet.

Let's take 3 different bullets.

Partition--- the higher the velocity the more penetration---up to a certain velocity. We're talking velocities we will never see in our lifetimes. Then you're pushing them past the design envelope.
ie Ross Seifried pushed the 85 gr partitions past 4000 fps and they broke up in his bullet box from his Custom 6mm Mach IV. 7mm mag case to 6mm.

BT--the higher velocity (over 3000 fps) the less the penetration.

E-tip--Will not brake up. The faster the bullet the more penetration.....how fast can you push it?

 

[FOTIS]

BTW if you are intrigued by the 6mm MK4 see below

http://www.singleactions.com/240Incinerator.pdf

 

[honkeetonkin]

240 incinerator........ I almost want one :twisted:

 

[FOTIS]

It's good for at least 500 rounds! :twisted: :twisted: :twisted: :twisted:

 

[cloverleaf]

Ok- here's an example that may or may not mean anything I shot an antelope at a measured 264 yds with a 100 gr BT. Bullet broke the near side shoulder/leg joint punched a hole through both lungs befre exiting. This was done with a lowly 250-3000 Savage. At best that means 2800 fps Muzzle velocity. By the time that bullet got to 264 yds I doubt it had 1000 ft /lbs of energy. He's dead and that bullet punched a nice hole in the far side. It dont take a Magnum...CL

 

[dakotaelkslayer]

Ok- here's an example that may or may not mean anything I shot an antelope at a measured 264 yds with a 100 gr BT. Bullet broke the near side shoulder/leg joint punched a hole through both lungs befre exiting. This was done with a lowly 250-3000 Savage. At best that means 2800 fps Muzzle velocity. By the time that bullet got to 264 yds I doubt it had 1000 ft /lbs of energy. He's dead and that bullet punched a nice hole in the far side. It dont take a Magnum...CL

....ya, makes sense. The "old timers" always liked heavy for caliber, round nose bullets for woods hunting or brush hunting. Obviously, this would slow impact velocity. Maybe they were smarter than I thought?! I always assumed that they did that because they thought they be able to shoot through the brush...

Jim

 

[dakotaelkslayer]

http://www.rathcoombe.net/sci-tech/ball ... nding.html

Interesting read...

Jim

 

[alpinecrick]

After the "use enough gun thread," I see that most believe that "bigger is better" when it comes to elk. Bigger, seems to mean magnum velocity not just big bullets. How does bullet impact velocity correlate to penetration when using jacketed bullets? I know that when using hard cast bullets, up to a certain point, around 2200fps, velocity is no longer the friend of penetration. But I haven't a clue about jacketed.

Jim

I started follwong my dad elk hunting 45 years ago. Between myself, family, friends, and guiding, I have seen over a 100 elk killed.

The majority of elk I've killed with a rifle have been with 270's and 150 grainers with a MV of ~2900fps.

The last 6 elk I've killed with a rifle have been with a 243 and 100gr Partitions running around 3000fps MV.

For my big game hunting here in the Rockies, I look for high sectional density in a bullet and a MV between 2800-3000fps. From my 30-06AI to my 243.

Everything else is just playing with guns and cartridges--which can be fun.

I'll say this: There is a segment of hunters who have been trending towards light for caliber bullets at ultra high velocity (kinda' the Roy Weatherby school of thought revived), and those loads often produce spectacular kills. But Ihave also observed a higher proportion of unpredictable, and less than desirable, results from those loads.........


Casey

 

[dakotaelkslayer]

Casey,
Tell me more about the 6 elk with the .243... Penetration, bullet path, distance, etc.

Thanks,
Jim