Originally Posted By: DAB[/quote]
You got me confused as [beeep], I always heard that FMJ's do not expand or break up and that is whey they are a no,no for hunting.
You are the first person that I have ever heard say that FMJ's fragment. I never tested them.
Help me out here would you please?
Hope you are not getting Hollow points mixed up with FMJ's.
DAB
Perhaps a quote from the ammo oracle will clear it up for you.
Quote:Testing by combat surgeon Col. Martin L. Fackler, MD (USA Medical Corps, retired), determined that M193 and M855 bullets (both FMJ bullets*) need to strike flesh at 2,700 feet per second in order to reliably fragment. Between 2,500 fps and 2,700 fps, the bullet may or may not fragment and below 2,500 fps, no significant fragmentation is likely to occur. If there isn't enough velocity to cause fragmentation, the result is a deep, 22 caliber hole, except an area where the yawing occurred, where the diameter of the hole grows briefly to the length of the bullet.
* added by me
What you have heard is correct. Well partly. They do not "expand", but they do fragment by design. The fragmentation is brought about by the bullet "yawing" or tilting to one side as it strikes tissue (or whatever you hit). The forces then exerted on the sideways bullet tear it apart. That is how FMJ ammo is designed to work. It is not designed to hit bone and stay together and keep penetrating like "expanding" bullets will. To the contrary it is designed to do maximum damage with minimal penetration, and at proper velocity and on a human target with a chest thickness of 8-12+ inches it works reasonably well.
FMJ is not suitable for deer hunting for several reasons but one of them is that if the bullet falls below 2700fps it will not fragment properly or possible at all leaving a .22 caliber hole that will not kill quickly or cleanly but will often result in a fatal wound over time. Namely about 6 hours after you give up looking for your buck.
The pictures above are all of FMJ bullets and as you can see thay do indeed fragment if everything goes right.
Well then you might ask, why not just make sure to take shots where your velocity will stay above the magical 2700fps? Won't FMJ ammo be ok then?
Not necessarily, as the bullet fragments it breaks into tiny pieces which have very little individual mass, and penetration is far less than ideal. A FMJ that hits a shoulder or even a rib(which is what happened to one of the deer I saw wounded)may simply "splash" off leaving a superficial wound.
Again let me quote the Oracle.
Quote:
Assuming true M193 or M855 ammo, velocity is the key. Velocity is dependent on barrel length and environmental conditions.
As barrel length increases, the bullet is propelled faster by the expanding gasses in the barrel, imparting more velocity on the bullet, resulting in a longer range before a fired bullet drops below 2700 fps. A shorter barrel imparts less velocity, and therefore the bullet has less range.
Temperature, altitude and humidity are other factors. As temperature or altitude increases, air becomes less dense and bullets travel faster. Contrary to common conceptions, as humidity increases air also becomes less dense and helps bullets retain velocity.
It is important, then, to keep in mind that any statistics given can only be approximate and can be affected by a wide range of factors. But as a baseline, these numbers are what you could expect for 75° F, 25% humidity, at sea level, from various barrel lengths:
Distance to 2700 fps
20" Barrel M193 190-200m
16" Barrel 140-150m
14.5" Barre 95-100m
11.5" Barrel 40-45m
M855
140-150m
90-95m
45-50m
12-15m
As you can see, barrel length and ammo selection make a major impact on fragmentation range.
I fully understand that there are probably hundreds of deer killed every year with .224 FMJ ammo, but I also know from my own eye witness experience and many others who care to be honest that there are an inexcusable number of wounded or lost deer every year due to poor bullet or caliber choice. You owe it to the deer(elk, etc) and you owe it to your hunt to make the quickest and cleanest kill possible and FMJ ammo is just not a reasonable option when for a few pennies more a bullets designed for that job is available.
...descending from soap box because it occurred to me that noone actually hinted they wanted to hunt with FMJ ammo
One more thing, google AR15.com ammo oracle and you will find more info on FMJ ammo than you could imagine existed. I've read it several times and still reference it occasionally.
Hope that clears it up.
Ricky
