FN-FMJ vs. FN-HCL Penetration

[alleninvegas]

I'm wanting to come up with a reliable woods carry round. I'm looking for a pistol round (i.e. 10mm) that has exceptional penetration.

Just about everything online suggests using a flat nose, or wide flat nose, hard cast lead projectile.

My question is, could a flat nose fmj projectile with the same size meplat as a flat nose hcl projectile get the same amount of penetration.

Why or why not?

Cheers

 

[rockquarry]

Lots of changeable factors here, but...I doubt there would be a great deal of difference in penetration even though copper has roughly three times the hardness of the hardest cast bullet (about thirty BHN). I suppose it would depend on how thick the jacket covering is on the FMJ bullet. The thicker it is, the less distortion there would be if it hit a hard object.

With regard to a thirty BHN cast bullet (that's hard, but I don't know if there is a defining BHN for "hard cast"), these could be made by those who cast their own bullets, but I don't know if commercial casters make bullets that hard. It seems there would be little demand.

With a very hard bullet, I'd be concerned with the bullet shattering, but that's speculation. I've seen bullets cast from a mixture slightly below the hardness of linotype (around 22 BHN) partially shatter when fired through thicknesses of paper after penetrating no more than 8'' to 10". However, that's from memory but should be fairly close.

Heat treating a bullet with more than the usual amount of tin in the mix should make the bullet less susceptible to shattering. I haven't heat-treated bullets in a long time and never found an advantage to the process for my purposes.

Regardless, you might find a softer bullet with adequate tin in the mix and a BHN in the 15 -16 range might penetrate better and hold together better than a truly hard one.

There seems to be an Internet fascination with "hard cast bullets" these days. I don't know where this started and don't deny that they may serve some usefulness (again speculation) in some situations, but I can't imagine what the situations might be.

I've never found an advantage to using a jacketed bullet over a well-fitted cast bullet of the proper alloy for the load in any handgun cartridge, but exceptions may exist.

 

[Ivan the Butcher]

On car doors and body panels. Hard Cast Lead (HCL) projectiles will penetrate much further! AS you hit the walls of metal, The HCL will have some of the outer surface scraped off and keep going. The FMJ will hit areas of enough resistance to deform soft lead and deform the lead out the back of the jacket and stop the bullet.

My experience was with 45 ACP, using my cast (and water quenched) Wheel Weight 185 gr automatic SWC's (1000 fps) verses 230 grain military RNFMJ's (850 fps). Not one of the FMJ's attained 4 metal wall penetration, Usually 2 and about 10% went through 3 walls. About 50%+ of the hard cast bullets went through 4 walls! However, the exit holes were about 9mm in diameter. (In 1984 I didn't think to check the metal wall thickness.)

RN's have been known to deflect when hitting large bones in big and dangerous game hunting, while semi spitzer bullets tend to penetrate. On the reduced scale of handguns, you can still expect more deflection from RN bullets.

I have ZERO experience with coated and plated bullets, but the consensus is, they are softer alloy and will deform against things like bone or structural members.

I hope this helps,

Ivan

 

[dla]

I'm wanting to come up with a reliable woods carry round. I'm looking for a pistol round (i.e. 10mm) that has exceptional penetration.

Just about everything online suggests using a flat nose, or wide flat nose, hard cast lead projectile.

My question is, could a flat nose fmj projectile with the same size meplat as a flat nose hcl projectile get the same amount of penetration.

Why or why not?

Cheers

Usually jacketed flat nose bullets use a soft alloy, so they tend to deform pretty quickly. But they will penetrate much better than a hollow point. The cheap stuff we shoot at the range is pretty good woods carry fodder because it will penetrate.

Hardcast at 18bhn will still deform a bit with the meplat edges rounding. Hardcast at 20+ bhn will look like it could be reloaded again. I'm on the fence about how much harness is needed to maximize the effect of a wide meplat. Custom ammo maker Randy Garrett believes in super hard - I can't argue with him, but I've never seen something not killed because the bhn was only 18.

So if a guy is on a budget, and doesn't reload, then the JFP like that used in Blazer Brass is the best penetrator.

If a guy reloads, use the widest meplat 18bhn minimum bullet you can find.

IMO of course.

 

[mikld]

For big critters, I doubt if you would notice the difference in penetration in dangerous animals. But my woods carry is either a 4" 357 Mag loaded with SWC of 12-15 BHN or a 2"' 357 with the same "hot" SWC load, but the only dangerous animals in my area are small mountian lions (rarely seen) and tweekers. I've never had to shoot car doors, cinder blocks or large dangerous animals so my "little" 357 Magnums are plenty...

 

[WR Moore]

Just a quibble. Depending upon where you live, the use of FMJ in the woods might conflict with the game laws. OTOH, I've never seen anything about plain lead bullets. I doubt there'd be a significant difference in penetration. Penetration requires velocity and projectile integrity.

If you're talking grizzly or similar defense, forget the 10 mm.

 

[Maurice H]

I'm looking for a pistol round (i.e. 10mm) that has exceptional penetration.

Here's an excellent choice from Montana Bullet Works, a 200 gr WFN (link).
Heavy, wide and flat with a sharp meplat edge. Push these at 1200 fps for a full power load (not nuclear). This bullet is far less prone to deviation because of the wide meplat, sharp edge and hard composition. Less apt to deform/deflect. A deep, straight and tuff mutha. (Juiced by Accurate #9 or Longshot.)

FMJ has a round or smaller flat nose (apt to deflect) and soft(er) lead (deformation) that will send it off-track and/or in pieces. No comparison to the 200 WFN above.

 

[Nevada Ed]

Berry's makes a bullet for the 10mm that might work for you.

It is a 180 grain flat point , that is thick plated vs the standard coated target bullets.

Some of their bullets have a hollow base that allows for more powder
if you want maximum loads.

Good shooting.