FMJ into HP?


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yenchisks
June 28, 2009, 01:58 AM
Can one make a fmj into hp and use it for hunting?;):rolleyes:

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seanie!
June 28, 2009, 02:19 AM
There's some dies(?) to drill out the tip of bullets to turn them into hollow points. I'm not sure how well they work. The Box o' Truth also did a test where the bullets were pulled, turned around, and then seated back in the casing. They worked quite well if I recall correctly.

Sunray
June 28, 2009, 04:16 AM
A milsurp ball round? It doesn't work. The jacket is still too thick to expand reliably. Milsurp ball isn't accurate enough either.
There are commercial FMJ's that are made for hide hunting though. Thinner jackets.
Box o' Truth is a bunch of guys, with a web site, playing with firearms for their own amusement. Science, it ain't. They make that very clear too.
"...pulled, turned around..." Not enough accuracy. Guys playing. Think Mythbusters with guys who know about firearms.

jim in Anchorage
June 28, 2009, 04:42 AM
They can leave the jacket in the bore.

Tinpig
June 28, 2009, 10:18 AM
A recent issue of the Garand Collectors Association Journal had photographs of a display in a Luxembourg WWII military museum.
One picture showed old loaded Garand clips recovered from the battlefield in which each FMJ bullet had been neatly drilled out at the point.
The caption stated that this had been done by "farmers for hunting."

Tinpig

ants
June 28, 2009, 11:42 AM
Can you do it? Sure, get a hollow pointer kit and knock yourself out.

Will you make a good hunting round out of it? No. One of the greatest advantages of a hollow point (or soft point) is that the jacket fully encloses the base. This makes it more accurate, and keeps the bottom end of the jacket together for controlled expansion with reasonable penetration. FMJ is the opposite: closed at the nose, but open at the base; and since the exposed lead at the base is generally poorly formed, the gases flowing around the bullet tend to knock it around a little, impeding accuracy.

If you hollow point an fmj, you have the worst of all worlds, not the best of all worlds. But yes, you can do it if you want. No law against it.

Tommygunn
June 28, 2009, 11:42 AM
My father, a Korean War vet, once told me that soldiers would sometimes use bayonets or knives to cut "X"s into the nose of .30 Carbine rounds, and thus turn them into sort of amateur "dum-dum" bullets. It was officially frowned upon ... and I don't really know how well it worked.


They can leave the jacket in the bore.

I wouldn't bother doing it with modern ammo. Whether or not it would leave a jacket in the barrel ...?????? -- but why find out the hard way?
Play safe. Buy the right ammo from the start.
FMJ can always be used for target practice.

JShirley
June 28, 2009, 12:38 PM
soldiers would sometimes use bayonets or knives to cut "X"s into the nose of .30 Carbine round

This is the very definition of a "dum-dum" round. It would be a severely prosecutable offense in the U.S. military.

J

Zoogster
June 28, 2009, 02:34 PM
They work, but they don't work as well as factory formed heat treated rounds.
The art of expansion has come a long way in the last few decades and the better commercial rounds heat treat different sections of the jacket to cause the jacket to fail at predictable locations. That achieves the uniform expansion which results in something that looks like an opened flower when shot into water (water resists differently than random tissue and bone, so the water results are a little more perfect than reality.)


FMJ is the opposite: closed at the nose, but open at the base;
Not all FMJ are open at the base, and there is TMJ which are always closed at the base.

They can leave the jacket in the bore. If the round is open at both ends it is possible. The X cut done by some in the past reduces that because the prongs still going over the top hold in the lead. While simply drilling it out or cutting the top off a bullet open at the base makes it a real possibility.

The result is usualy not the same as a modern hollowpoint.
It will reduce tissue flow around the projectile, which does increase tissue damage, increases resistance, and will reduce penetration. In that regard it is more like a softpoint in performance.
With jacketed bullets it causes the jacket to peal away and fragment to the depth of the cut which would increase wounding to the depth those petals remain attached.
Tissue cannot flow well around a random changing jagged shape. It can flow around a smooth rounded projectile readily. The result is the jagged shape results in resistance and damage to tissue that would have simply flowed around a FMJ round. This reduces penetration and increases wounding, though not to the extent of a modern hollowpoint.




soldiers would sometimes use bayonets or knives to cut "X"s into the nose of .30 Carbine round

This is the very definition of a "dum-dum" round. It would be a severely prosecutable offense in the U.S. military.

Certainly not something the military would be friendly about.
They are not "dum dum" rounds however.
It turns out that the actual "Dum Dum" rounds had the entire top simply cut off rather than an X cut into them. Creating a jacketed soft point that was also open at the base. This was very unsafe as the jacket became a tube open at both ends. That could result in the lead and jacket seperating leaving the jacket in the barrel with simply the lead shot out as a projectile.
The next round would result in disaster. That was a primary reason the practice at the time was frowned upon in official channels (before Hague.) Simply cutting an X leaves a tube where the lead has four prongs holding it in at the front. This is far less likely to result in the lead being shot through the jacket, though if the center of the X is very large it is a possibility. As a result the X is much safer for the user. The X also gives an indentation for tissue to enter, creating resistance that both smashes more tissue, reduces tissue flow, and helps to push the four prongs of the X apart which would be absent on just a soft point. A soft point would allow greater unharmed tissue flow, but the soft lead would also expand consistantly increasing the diameter of the wound channel more consistantly in a predictable manner.
Finaly the random hand cutting on the round is going to be aerodynamicly imperfect resulting in a much less accurate projectile.

So a round with an X will do more tissue damage than a FMJ, likely less than a modern hollowpoint, and will have levels of penetration in between both while being less accurate than either.

rcmodel
June 28, 2009, 03:06 PM
Don't do it, it's potentially dangerous.

A jacketed bullet is a closed copper cup, with a soft lead core.

A SP or HP bullet has the open end of the jacket at the nose, and closed at the base.

A FMJ bullet is closed on the nose and open on the base.

If you drill it out to make a HP, it is now open on both ends.
In effect, you have created a hollow tube, with a lead core in it.

Bore pressure can cause the soft lead core to squirt out, leaving the copper tube stuck in the barrel.

And as already noted, it won't work anyway.
The nose section of the jacket is much thicker from where the cup was swaged down into a point. Too thick to act like a HP anyway.

rc

Deanimator
June 28, 2009, 03:21 PM
FMJ jackets are not designed to deform the way an HP jacket does. They're typically too thick to function correctly, even when modified.

Additionally, typical FMJ jackets are drawn from the nose, leaving an open base. Opening the nose, leaves both ends open, leaving the possibility of pushiing the core out of the jacket and leaving the latter lodged in the barrel.

Tommygunn
June 28, 2009, 06:27 PM
soldiers would sometimes use bayonets or knives to cut "X"s into the nose of .30 Carbine round

This is the very definition of a "dum-dum" round. It would be a severely prosecutable offense in the U.S. military

I rather doubt they made a point of telling their COs about it. ;)

A number of "unauthorized" things happened in Korea (as well as, I'm sure, most other wars) but they are really beyond the scope of a websight about guns.

dullh
June 28, 2009, 07:24 PM
Some of the questions on here defy logic. Some have too much free time? Trying to introduce a comic element to the forum?

If you want hollowpoint bullets buy hollowpoint bullets.

riverrat373
June 28, 2009, 08:46 PM
Not to mention that modifying fmj bullets would change the weight and therefore affect velocity, pressures, accuracy, etc!

unspellable
June 28, 2009, 08:58 PM
I once tried this with a 30 Army (30-40 Krag) hard ball round. The lead core went out the muzzle and left the jacket part way up the bore. Would obviously be a disaster to put a second round after it. The lead core would have been very undersized relative to the rifling so who knows where it went or how fast.

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