30cal penetration explained

Calibres, cartridges, ballistics tables and ammunition information.

30cal penetration explained

Post by Bang-sticks » 13 May 2017, 1:22 pm

Question that's been bothering/confusing me for a while now.
Why does everyone insist that 180gr penetrate better than 150gr.

I understand out past 200m that the 180gr bullets are carrying more energy and so should penetrate deeper.
But my standard hunting range is under 150m. From the ballistics data I have the 150gr bullets are carrying more energy at this range so would it be correct to assume the 150gr would be a better choice.
The more I learn about reloading and ballistics the less u seem to know.

Your help is much appreciated

Bang-stick
Bang-sticks
Recruit
Recruit
 
Posts: 12
Western Australia

Re: 30cal penetration explained

Post by bigfellascott » 13 May 2017, 2:17 pm

I don't worry about ballistics or other statistics, I only worry about how it performs at the business end so to speak, it doesn't take much to work out if its upto the job or not and most of that depends on where you place the shot!
User avatar
bigfellascott
Lieutenant General
Lieutenant General
 
Posts: 5289
-

Re: 30cal penetration explained

Post by Apollo » 13 May 2017, 3:36 pm

Bullet weight, velocity, penetration etc no matter what calibre all depends on what you are shooting at..ie what type of creature if hunting. Big, small, thick or thin skin etc etc etc.

You should be able to find a better idea of searching for what most use for a certain creature. Then distance comes into the factors, plus calibre cartridge.

As far as comments go give everyone a hint of what you are wanting to use and what creature.
Apollo
Warrant Officer C1
Warrant Officer C1
 
Posts: 1327
New South Wales

Re: 30cal penetration explained

Post by bigfellascott » 14 May 2017, 9:11 am

Yeah I think the bullet design (type of construction used for the projectile) is probably more important that anything else - some are designed to really penetrate, some expand rapidly and some a bit of both, as Lindsay said it would be helpful to know what type of game you are wanting to hunt with it, then we may be able to direct you in the correct direction so to speak.
User avatar
bigfellascott
Lieutenant General
Lieutenant General
 
Posts: 5289
-

Re: 30cal penetration explained

Post by Bang-sticks » 14 May 2017, 10:35 am

I mainly shoot pigs out of a 30-06 using 150gr hornady interlocks. But heading to the nt and may get a shot at a buff. I have been told 180gr projectiles are better & penetrate deeper. Was curious as to why as the 150gr are carrying more energy out to. 200m.
Bang-sticks
Recruit
Recruit
 
Posts: 12
Western Australia

Re: 30cal penetration explained

Post by bigfellascott » 14 May 2017, 12:06 pm

Bang-sticks wrote:I mainly shoot pigs out of a 30-06 using 150gr hornady interlocks. But heading to the nt and may get a shot at a buff. I have been told 180gr projectiles are better & penetrate deeper. Was curious as to why as the 150gr are carrying more energy out to. 200m.


Ah roger that, yeah who know why some penetrate better than others but I would think it would be that one is traveling faster at the 200m range so might make penetration deeper but would imagine the heavier projie would be slightly better at greater ranges but still reckon the construction would probably make a bigger diff than outright weight.

If it was me I'd be having a look at the ACP monolith projies, they should go well on Buff I would think. :thumbsup:
User avatar
bigfellascott
Lieutenant General
Lieutenant General
 
Posts: 5289
-

Re: 30cal penetration explained

Post by duncan61 » 14 May 2017, 1:59 pm

180 gn Corelokt will do the job
.22 winchester .22hornet .222 .243 7mm rem mag cbc 12g
User avatar
duncan61
Officer Cadet
Officer Cadet
 
Posts: 1905
Western Australia

Re: 30cal penetration explained

Post by Bang-sticks » 14 May 2017, 4:00 pm

duncan61 wrote:180 gn Corelokt will do the job

Duncan not trying to be rude but do u know why 180gr core-lokts are any better than 150gr interlocks? Both carry similar energy out to 200m with the 150gr slightly ahead. They also have similar construction so that's not part of the equation. So why would the 180's be better than 150's?

Just trying to understand ballistics better. I get that the projectile construction has a major role but why is 180 better than 150 @<200m all other things being equal?
Bang-sticks
Recruit
Recruit
 
Posts: 12
Western Australia

Re: 30cal penetration explained

Post by Supaduke » 14 May 2017, 8:14 pm

Momentum.
Heavier bullets require more resistance to stop.
Heavier bullets soak up more energy from the powder to begin movement. Hence heavier bullets travel slower with similar powder loads.
Heavier bullets have greater trajectory and require more holdover.
Heavier bullets are less affected by atmospheric conditions.
If bullets are like for like the heavier bullet will penetrate further.

Lighter bullets fly flatter
Lighter bullets are often more frangible and can come apart more on impact.
Lighter bullets fly faster so what they lack in mass can be countered with speed and kinetic energy.

The easiest way I can describe it.

You can throw a pebble quite fast and quite far, hit something and it will hurt but probably not fatal.
Lob a brick, probably only able to throw it a few meters but if you hit someone with it.....
Supaduke
Warrant Officer C2
Warrant Officer C2
 
Posts: 1230
Victoria

Re: 30cal penetration explained

Post by bladeracer » 14 May 2017, 8:18 pm

Supaduke wrote:Momentum.
Heavier bullets require more resistance to stop.
Heavier bullets soak up more energy from the powder to begin movement. Hence heavier bullets travel slower with similar powder loads.
Heavier bullets have greater trajectory and require more holdover.
Heavier bullets are less affected by atmospheric conditions.
If bullets are like for like the heavier bullet will penetrate further.

Lighter bullets fly flatter
Lighter bullets are often more frangible and can come apart more on impact.
Lighter bullets fly faster so what they lack in mass can be countered with speed and kinetic energy.

The easiest way I can describe it.

You can throw a pebble quite fast and quite far, hit something and it will hurt but probably not fatal.
Lob a brick, probably only able to throw it a few meters but if you hit someone with it.....



You forgot ballistic coefficient which can allow heavier bullets to shoot flatter and lighter bullets to retain more energy, especially as range increases.
Practice Strict Gun Control - Precision Counts!
User avatar
bladeracer
Field Marshal
Field Marshal
 
Posts: 12655
Victoria

Re: 30cal penetration explained

Post by Bang-sticks » 14 May 2017, 8:47 pm

Supaduke wrote:Momentum.
Heavier bullets require more resistance to stop.
Heavier bullets soak up more energy from the powder to begin movement. Hence heavier bullets travel slower with similar powder loads.
Heavier bullets have greater trajectory and require more holdover.
Heavier bullets are less affected by atmospheric conditions.
If bullets are like for like the heavier bullet will penetrate further.

Lighter bullets fly flatter
Lighter bullets are often more frangible and can come apart more on impact.
Lighter bullets fly faster so what they lack in mass can be countered with speed and kinetic energy.

The easiest way I can describe it.

You can throw a pebble quite fast and quite far, hit something and it will hurt but probably not fatal.
Lob a brick, probably only able to throw it a few meters but if you hit someone with it.....


Supaduke that all makes sense. I think my issue is that I'm assuming the energy of the is equal to momentum but maybe its not.
Bang-sticks
Recruit
Recruit
 
Posts: 12
Western Australia

Re: 30cal penetration explained

Post by Supaduke » 14 May 2017, 8:48 pm

Yes, if motivated with more energy a heavier projectile can fly flatter. BC also comes into play. It's a complex thing for sure. It's like the torque vs horsepower arguement. Similar results achieved by different methods.

Classic example would be a tiny .204 round scooting along at near enough to 4000fps vs a 45/70 chugging along at 1800fps. Both are going to really ruin a fox's day. It's really an unwinnable arguement.

I guess it depends on what you like
Fast and light
Slow and heavy
Or somewhere in the middle.
Speed is good
Weight is good
You can't have both without really upping your powder charge which leads to uncomfortable shooting. It depends where on the spectrum you like to be.
Supaduke
Warrant Officer C2
Warrant Officer C2
 
Posts: 1230
Victoria

Re: 30cal penetration explained

Post by bladeracer » 14 May 2017, 9:07 pm

Supaduke wrote:Yes, if motivated with more energy a heavier projectile can fly flatter. BC also comes into play. It's a complex thing for sure. It's like the torque vs horsepower arguement. Similar results achieved by different methods.


Higher BC allows a heavier bullet to shoot flatter and retain more energy at the same velocity - you don't need to push it any harder, you can in fact run it slower and have the same terminal ballistics.

For example, the 180gn Interlok BTSP versus the 180gn Interlok Round Nose versus the 150gn Interlok BTSP- both 180gn bullets at 2600fps and the 150gn at 2900fps. Then below that I've shown the 150gn BTSP but at 2600fps. Even at the same 2600fps velocities, the little 150gn bullet retains more energy than the 180gn RN out past 200 yards.

180gn BTSP - BC .452 at 2600fps:
50yds - 2504 ftlb
100yds - 2318 ftlb
200yds - 1978 ftlb
300yds - 1678 ftlb
400yds - 1415 ftlb

180gn RN - BC .241 at 2600fps:
50yds - 2340 ftlb
100yds - 2017 ftlb
200yds - 1477 ftlb
300yds - 1062 ftlb
400yds - 759 ftlb

150gn BTSP - .349 at 2900fps:
50yds - 2548 ftlb
100yds - 2315 ftlb
200yds - 1899 ftlb
300yds - 1543 ftlb
400yds - 1242 ftlb

150gn BTSP - .349 at 2600fps:
50yds - 2039 ftlb
100yds - 1844 ftlb
200yds - 1496 ftlb
300yds - 1203 ftlb
400yds - 959 ftlb
Practice Strict Gun Control - Precision Counts!
User avatar
bladeracer
Field Marshal
Field Marshal
 
Posts: 12655
Victoria

Re: 30cal penetration explained

Post by Bang-sticks » 14 May 2017, 10:05 pm

So I got all inspired and did some highschool physics. This is going to be a bit long winded but hopefully it all makes sense

These numbers are for my 30-06 but formulas are the same.
Momentum=mass x velocity
Energy = 1/2mass x velocity²

So mass for 150gr is 0.00972kg and 180gr is 0.01166 kg

Velocity for 150gr = 2900fps or 883.92m/s and the 180gr =2600fps or 792.48 m/s

So energy for these two loads are as follows
150gr - (0.00972/2) x 883.92² = 3797.18
180gr - (0.01166/2) x 792.48² = 3661.38
From this we can see that the 150gr carry more energy at least at the muzzle. Which is what I was confused about as the 180s are supposed to penetrate deeper.

Introduce supadukes polite clip around the ears to consider momentum.

So the momentum of each is as follows

150gr- 0.00972 x 883.92 = 8.59
180gr 0.01166 x 792.48= 9.24

So the 180s are carrying a fair bit more momentum.

So what does this all mean. Well momentum is the ability for an object to continue moving. The higher the momentum the harder to slow it down (Think loaded road train vs smart car). So when a 150 gr bullet meets resistance such as the target it slows down faster than the 180gr and do penetrates shallower.

I hope that's not all to confusing and what I have written makes sense.

Obviously bullet construction etc comes into it but if all else is equal the 180gr penetrate deeper because of momentum and the energy figures provided on ballistics software only tells part of the story.
Bang-sticks
Recruit
Recruit
 
Posts: 12
Western Australia

Re: 30cal penetration explained

Post by Supaduke » 14 May 2017, 10:49 pm

bladeracer wrote:
Supaduke wrote:Yes, if motivated with more energy a heavier projectile can fly flatter. BC also comes into play. It's a complex thing for sure. It's like the torque vs horsepower arguement. Similar results achieved by different methods.


Higher BC allows a heavier bullet to shoot flatter and retain more energy at the same velocity - you don't need to push it any harder, you can in fact run it slower and have the same terminal ballistics.

For example, the 180gn Interlok BTSP versus the 180gn Interlok Round Nose versus the 150gn Interlok BTSP- both 180gn bullets at 2600fps and the 150gn at 2900fps. Then below that I've shown the 150gn BTSP but at 2600fps. Even at the same 2600fps velocities, the little 150gn bullet retains more energy than the 180gn RN out past 200 yards.

180gn BTSP - BC .452 at 2600fps:
50yds - 2504 ftlb
100yds - 2318 ftlb
200yds - 1978 ftlb
300yds - 1678 ftlb
400yds - 1415 ftlb

180gn RN - BC .241 at 2600fps:
50yds - 2340 ftlb
100yds - 2017 ftlb
200yds - 1477 ftlb
300yds - 1062 ftlb
400yds - 759 ftlb

150gn BTSP - .349 at 2900fps:
50yds - 2548 ftlb
100yds - 2315 ftlb
200yds - 1899 ftlb
300yds - 1543 ftlb
400yds - 1242 ftlb

150gn BTSP - .349 at 2600fps:
50yds - 2039 ftlb
100yds - 1844 ftlb
200yds - 1496 ftlb
300yds - 1203 ftlb
400yds - 959 ftlb


True but we are talking like for like. Not a bullet with an aerodynamic advantage.

The 150gr going at 2600fps vs the same shape 180gr has nearly 25% less energy.
Like I said it's an unwinnable arguement.

It could then be argued that the round nose would create a more traumatic wound channel. We can go around and around but the physics are there.
Speed vs weight vs felt recoil vs drag vs bullet behaviour on impact.
It's a sliding curve x,y graph. There will always be compromise somewhere it's all about perception as to what you believe to be most important.

On top of all that there are practical considerations like barrel life and component costs.
Supaduke
Warrant Officer C2
Warrant Officer C2
 
Posts: 1230
Victoria

Re: 30cal penetration explained

Post by Jamesb570 » 31 May 2017, 10:05 pm

Smarter fellas than me hve explained the physics of it all and done the maths but it comes down to torque versus horsepower. Not sure if you are a gearhead but my understanding is this;
Momentum vs velocity = Do you want to be hit by a ferrari going 180km/hr or a double decker bus going 60 km/hr - both are going to kill you.
Bullet construction is like controlled crumple rates - an FB holden will transfer more impact energy to the object it hits because of the stiffer construction of the body and a new commodore has contolled crumple zones to expend energy in the crumple process , not transfer it to objects around it. That is one contributer to the deeper penetration equation.
Then you come to torque versus horsepower - do you want the ability to do work and deliver pulling power or develop rpm and produce speed.
Think of a deisel vs a petrol motor - both can do similar things but one is better suited to speed and one is better suited to power. A 150 gn pill is a petrol engine that goes hard but bogs down unless it can rev freely, 180gn pill is a deisel that won't go as fast top end but will work harder in the tough stuff and pull through.
There is a range where one is better, then a point that the two are equal and then they cross over the other is better.
Tougher the game then you want more torque - lighter the game then horsepower is king.
Not sure if that helps at all but it helps me get my head around the difference.
A man can not have too much red wine, too many books or too much ammunition ~ Rudyard Kipling (allegedly)
User avatar
Jamesb570
Recruit
Recruit
 
Posts: 17
New South Wales

Re: 30cal penetration explained

Post by duncan61 » 31 May 2017, 10:14 pm

Good explaination
.22 winchester .22hornet .222 .243 7mm rem mag cbc 12g
User avatar
duncan61
Officer Cadet
Officer Cadet
 
Posts: 1905
Western Australia

Re: 30cal penetration explained

Post by brett1868 » 31 May 2017, 11:22 pm

In discussions like this ill leave it up to Roy....

"The history of Weatherby® began in the mid-1940s when a young cartridge "wildcatter" named Roy Weatherby set out to change the world of firearm performance. Contrary to then-popular thinking (heavy bullets pushed at slow speeds), Roy believed that lightweight bullets traveling at super high speeds provided the best combination for one-shot kills. Based upon that philosophy, he spent the next decade developing the high-powered Weatherby Magnum cartridges for which the company is known today (.224, .240, .257, .270, 7mm, .300, .30-378, .340, .338-378, .375, .378, .416 and .460)."
How's my posting?
Complaints, Concerns - 13 11 14
User avatar
brett1868
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 3017
New South Wales

Re: 30cal penetration explained

Post by Oldbloke » 01 Jun 2017, 12:00 am

"Classic example would be a tiny .204 round scooting along at near enough to 4000fps vs a 45/70 chugging along at 1800fps. Both are going to really ruin a fox's day. It's really an unwinnable arguement. "

But only one will kill a buff.
The greatest invention in the history of man is beer.
https://youtu.be/2v3QrUvYj-Y
Member. SFFP, Shooters Union.
SSAA, the powerful gun lobby. :lol: :lol: :lol: :lol:
Hunt safe.
User avatar
Oldbloke
Field Marshal
Field Marshal
 
Posts: 11192
Victoria

Re: 30cal penetration explained

Post by happyhunter » 01 Jun 2017, 6:03 pm

If it's the same bullet type, say Sierra Pro Hunter 150 grain and the same in 180 grain, the 180 has a thicker copper jacket and needs a higher velocity to achieve the same expansion as the 150. The 180 deforms less, has more mass, retains more mass and carries more momentum so penetrates further.

Also, less than 150 meters the 180g bullet is travelling slower, so see my above point.
happyhunter
Warrant Officer C1
Warrant Officer C1
 
Posts: 1303
Other

Re: 30cal penetration explained

Post by Oldbloke » 01 Jun 2017, 8:00 pm

Sooo.... To sum up. Bigger is better if you want more penetration.

:lol:
The greatest invention in the history of man is beer.
https://youtu.be/2v3QrUvYj-Y
Member. SFFP, Shooters Union.
SSAA, the powerful gun lobby. :lol: :lol: :lol: :lol:
Hunt safe.
User avatar
Oldbloke
Field Marshal
Field Marshal
 
Posts: 11192
Victoria

Re: 30cal penetration explained

Post by Supaduke » 01 Jun 2017, 11:07 pm

That's what the wife said.....
Supaduke
Warrant Officer C2
Warrant Officer C2
 
Posts: 1230
Victoria

Re: 30cal penetration explained

Post by brett1868 » 01 Jun 2017, 11:39 pm

Supaduke wrote:That's what the wife said.....


Nahhh...Short and thick does the trick but long and thin gets more in :)
How's my posting?
Complaints, Concerns - 13 11 14
User avatar
brett1868
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 3017
New South Wales

Re: 30cal penetration explained

Post by bigfellascott » 02 Jun 2017, 7:40 am

I found this an interesting result

The hole was made by a 22-250 using 55gn projectile, the other marks on the plate are from 222, 223, 308 and 338 Lap I would have thought the Lap and 308 would have done more damage if not penetrated but being Hardox 500 I wouldn't have thought any of them would have penetrated to be honest so was very surprised the 22-250 achieved it whilst the bigger stuff didn't.

Image


This lot are made by 308, 223 and 22-250 - what I noticed was the 308 and 22-250 had pretty much the same penetration depth but the 308 of course had a slightly larger diameter hole for obvious reasons but penetration was pretty much the same on the plate (I think we were 200m or 300m away) can't remember now but I was surprised to see how similar the penetration depth was but I would imagine that may well change the greater the distance became (well I assume that would be the case)

Image
User avatar
bigfellascott
Lieutenant General
Lieutenant General
 
Posts: 5289
-

Re: 30cal penetration explained

Post by duncan61 » 05 Jun 2017, 12:10 am

We shot at a 10mm mild steel plate at 110 metres the .22LR knocked the paint off the .222 nearly made it through the .243 blew a 10mm hole and the 7mm blew an 18mm hole.Nothing went through the 10mm biz alloy even a 7mm 175 gr Winchester fail safe at 30 metres made a small bulge on the other side.I want my APC made out of bizalloy not aluminium
.22 winchester .22hornet .222 .243 7mm rem mag cbc 12g
User avatar
duncan61
Officer Cadet
Officer Cadet
 
Posts: 1905
Western Australia

Re: 30cal penetration explained

Post by bigfellascott » 05 Jun 2017, 4:16 am

I put that hole down to velocity + diameter - we were both very surprised when I could see the grass through a hole LOL sure as hell wasn't expecting that and neither was my mate. I would have thought the 338 Lap would have made some sort of mark on the plate but all it left were splash marks, same with the other cals - hardly a scratch on the plate then I sent one from the 22.250 and NEK Minute :shock: I figured I'd better stop shooting it or run the risk of turning it into Swiss Cheese :lol:
User avatar
bigfellascott
Lieutenant General
Lieutenant General
 
Posts: 5289
-


Back to top
 
Return to Calibres, cartridges and ballistics