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1/25/2018 7:38:29 AM
Posted: 10/16/2003 5:45:45 PM EST
For the fragmentation guru's hanging around here I've got a question. Is the bullet in umc 55 fmj the same as M193. Or does each manufacture make a different bullet with different wall thicknesses. The end question is will UMC 55 fmj, or White box 55 grain fmj, and all the other, pmc, federal, so on and so forth, will they fragment at close ranges like 50 meters and under. It's probably been discussed before so I'll apologize in advance. I did see the wolf fjm on the ammo-oracle didn't really do much at real close range so that sort of answers my question but you would think that if federal and winchester make the 5.56 55 grain fmj they would use the same bullet for the saami stuff. That could be a totally foolish assumption though. I know the velocity is quite a bit lower but still if it's the same bullet you would think it would fragment at closer ranges. Does anybody know????????
Link Posted: 10/24/2003 8:08:41 PM EST
I'm really not a "fragmentation guru", but I did stay at a Holiday Inn Express last night... So I guess I'll chime in here since no one else has. The Short Answer: Commercially loaded 223rem 55gr FMJ ammunition may or may not have the same fragmenting properties as M193 Ball ammo. The Long Answer: The market for budget grade commercial ammo (UMC, USA, American Eagle, etc.) is very competitive, and if they find a way to reduce manufacturing costs it's a pretty good bet that they'll jump on it. Consideration of how it will affect the fragmentation of the round is the furthest thing from their mind when making cheap ammo. If it happens to perform the same way as military ammo, it will be entirely by chance. They figure that if you're actually planning on shooting something with a pulse, you'll use their premium ammo, where terminal performance is a major factor influencing cartridge design. You can do your own gelatin testing, but the bullets you test today may not be the same bullets that they are using when you buy the ammo again in a few months. For example: over the last 10 years I have seen Remington make at least 3 changes in the design of their 55gr FMJ 223 projectiles. And before you sarcastic folks ask: no, I don't run out with my calipers and compare every bullet in every box of ammo that I buy. Even though I may not have much of a life, I actually do have better things to do with my time. The changes I'm talking about were subtle, but if you were paying attention they could easily be seen with the naked eye. Additionally, as you mention in your post, the muzzle velocity of "generic" commercial ammo is often fairly low. Less gunpowder = lower production cost. All other factors being equal, this factor alone could easily affect the fragmentation. On a couple of occasions I have seen American Eagle 223 ammo that was so underpowered it wouldn't even cycle the action. Now granted, I may be splitting hairs here (I wouldn't like to be shot with ANY ammo, either underpowered or high powered), but I like to have as many advantages in my favor as possible, so if I'm the one pulling the trigger I prefer to use ammo with some "oomph" to it. I hope this rambling response answers some of your questions.
Link Posted: 10/25/2003 7:40:58 AM EST
This is by no means the end all test but I have used it for 30+ years and it will give you a good measure of expansion and fragmentation . 2 phone books soaked in water tied together set out at 50 meters shoot into them with your load .than get 2 more same process diff load ,compair the 2 and see for yourself .the thicker the phone books the better .now i know this is not very 21st century but you may be surppised by the results .good luck
Link Posted: 10/25/2003 9:03:52 AM EST
No one, not even the Army, tests 55gr or M193 Ball ammo for fragmentation as it's not part of the military specification. Recall that fragmentation wasn't even documented as a wounding mechanism until 1988. The bullet contruction of M193 Ball isn't special, it's just stand FMJ practice. The jacket has a cannelure in it to allow the case to be crimped tight so the projectiles don't fall out. Unless some bullet manufacture grossly diddles with the jacket it's likely that all cannelured copper jacket 5.56mm ammo will fragment just like M193 Ball. As long as it's moving fast enough. 5.45mm Soviet is different enough construction that it behaves very differently and is subsequently a very poor cartridge. Velocity is critical. The window opens ~2500fps and isn't fully open until ~2700. "Commercial" .223 is made to no velocity spec, so the velocity could be low, and normally is as the dollar savings in 10% less powder shows up nicely when you crank out several million rounds. My idea of "commercial" 5.56mm ammo is Q3131 or Q3131A, or XM193. -- Chuck
Link Posted: 10/25/2003 9:23:38 AM EST
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