M193 vs. M855? Comments???
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ULVER,
for CQC use m193, it's the better choice for CQC & 150 - 200yard work, after 200 yards the 193 starts to lose the upper hand as velocity drops.
the 855 was intended for europe use where we would be fighting a "moderen" army wearing vests, it didn't work if "africa" becouse the skinnys weren't wearing armour vests, so it "poked" right through without so much as a YAW!
for CQC use m193, it's the better choice for CQC & 150 - 200yard work, after 200 yards the 193 starts to lose the upper hand as velocity drops.
the 855 was intended for europe use where we would be fighting a "moderen" army wearing vests, it didn't work if "africa" becouse the skinnys weren't wearing armour vests, so it "poked" right through without so much as a YAW!
For those who like the Lake City/Federal XM193-there is a hot deal at http://www.wholesalehunter.com/privatespec...cials/deals.htm
at $150 a case of 1,000 rds.
at $150 a case of 1,000 rds.
mikr: With 7 grains weight difference? I think the steel penetrator is also a factor for M855.
7 grains is 13% difference in mass - a whole lot!
M193: Defined by: Mil-C-9963F 55 grain bullet at a velocity of 3,165 from a 20" barrel @ 78 feet from the muzzle.
It's ballistic coefficient is typically .243
M855: Defined in MIL-C-63989 a 61.7 grain at a velocity of 3,000 fps from a 20" barrel @ 78 feet from the muzzle.
It's ballistic coefficient is typically .304.
Kinetic Energy of a bullet is M * V * V which is mass multiplied by square of velocity.
At 78 feet from 20" barrel:
M193: (55 * 3,165 * 3,165) / 1,000,000 = 550.95 units
M855: (62 * 3,000 * 3,000) / 1,000,000 = 558.00 units
M855 has 1.3% higher energy is beacuse square of velocities differ by 'only' 11% which is less than 13% difference in mass.
So, despite being slower, M855 has slightly (1.3%) higher energy because 11% deficit in (square of) veocity is compensated by 13% extra mass. More of 855's energy is due to mass rather than velocity compared to faster m193.
On top of that M855 retains energy better due to:
1. better ballistic coefficient (being longer)
2. slower speed - since air resistance is roughly proportional to the square of the velocity - the faster it goes, the faster it loses energy over the same distance! After certain distance (4-500 yards?) M855 will not only have way more energy but even more velocity than m193!
Why would anyone shoot lighter ammo then? Because recoil is proportional to M * V, not V square and trajectory of faster bullet flatter - less bullet drop.
If you expect to shoot at closer range (0-200 yards), having more controllable weapon and less sensitivity to aiming errors as well as lighter burden (or more ammo you can carry) of is more important than extra energy.
I think the steel penetrator is also a factor...
Ballistics-wise steel penetrator being lighter than led shifts the bullet's center of ballance backward and makes it less stable in the air. That necessitates at least 1/9" spin to balance the bullet. Older M16s with 1/12" can shoot M193 no problem but cannot shoot M855 accurately even at 100 yards - especially in colder air. The bullet starts to tumble after it leaves the barrel.
Supposedely heavier steel-tipped M855 is better against flack-jacketed troops at longer distances than M193.
Here goes my first post!
voruzon
7 grains is 13% difference in mass - a whole lot!
M193: Defined by: Mil-C-9963F 55 grain bullet at a velocity of 3,165 from a 20" barrel @ 78 feet from the muzzle.
It's ballistic coefficient is typically .243
M855: Defined in MIL-C-63989 a 61.7 grain at a velocity of 3,000 fps from a 20" barrel @ 78 feet from the muzzle.
It's ballistic coefficient is typically .304.
Kinetic Energy of a bullet is M * V * V which is mass multiplied by square of velocity.
At 78 feet from 20" barrel:
M193: (55 * 3,165 * 3,165) / 1,000,000 = 550.95 units
M855: (62 * 3,000 * 3,000) / 1,000,000 = 558.00 units
M855 has 1.3% higher energy is beacuse square of velocities differ by 'only' 11% which is less than 13% difference in mass.
So, despite being slower, M855 has slightly (1.3%) higher energy because 11% deficit in (square of) veocity is compensated by 13% extra mass. More of 855's energy is due to mass rather than velocity compared to faster m193.
On top of that M855 retains energy better due to:
1. better ballistic coefficient (being longer)
2. slower speed - since air resistance is roughly proportional to the square of the velocity - the faster it goes, the faster it loses energy over the same distance! After certain distance (4-500 yards?) M855 will not only have way more energy but even more velocity than m193!
Why would anyone shoot lighter ammo then? Because recoil is proportional to M * V, not V square and trajectory of faster bullet flatter - less bullet drop.
If you expect to shoot at closer range (0-200 yards), having more controllable weapon and less sensitivity to aiming errors as well as lighter burden (or more ammo you can carry) of is more important than extra energy.
I think the steel penetrator is also a factor...
Ballistics-wise steel penetrator being lighter than led shifts the bullet's center of ballance backward and makes it less stable in the air. That necessitates at least 1/9" spin to balance the bullet. Older M16s with 1/12" can shoot M193 no problem but cannot shoot M855 accurately even at 100 yards - especially in colder air. The bullet starts to tumble after it leaves the barrel.
Supposedely heavier steel-tipped M855 is better against flack-jacketed troops at longer distances than M193.
Here goes my first post!
voruzon
Welcome to the forum voruzon. I enjoyed, your very detailed comparison of the M193 versus the M855, and In general theory in a bolt gun I would agree, however there are more variables in the mini you might want to consider. Most older mini's are a 10" turn, not 12", and will handle the 62 gr M855, but the big thing with mini's is the barrel is very thin and flimsy so the harmonics are very pronounced. I would recomend to anyone, shoot a box or two, of both types to determine which shoots best in YOUR gun. As we know, no two guns shoot the same especially the mini's.
Thank you, cajungeo.
I ment older military M16s not Minis, of course.
Older 10" Minis should handle M855 no problem - unless you shoot in a very cold weather when air density increases.
The issue is not an "inaccuracy" but the bullet developing major wobble, tumbling and flying sidewise just a few yards from the barrel. The best barrel in the world will not correct that.
The bullet may actually end up to 30 degrees off the intended aiming point - so better watch out for friendly troops or obstacles (ricochet risk) seemingly safe from the line of fire!
Many people who want Mini as a survival rifle include "nuclear winter" in their EOTWAWKI scenario. Those better get modern 9" Mini or stick to the M193 ammo in cold weather.
Speaking of steel cores inside bullets - they tend to bounce something wicked off solid objects!
I was once present when a guy shot 4 rounds from inside the hangar having forgeten that the MG in a T-72 MBT was about 4 feet to the right and coupla feet below the sight line... The bullets were bouncing off surfaces and tanks inside the handgar for good 4 seconds but it seemed like minutes. Nobody was hit.
So if one's SHTF plan involves shooting inside concrete bunker/basement - he'd better go easy on steel cored bullets.
voruson
I ment older military M16s not Minis, of course.
Older 10" Minis should handle M855 no problem - unless you shoot in a very cold weather when air density increases.
The issue is not an "inaccuracy" but the bullet developing major wobble, tumbling and flying sidewise just a few yards from the barrel. The best barrel in the world will not correct that.
The bullet may actually end up to 30 degrees off the intended aiming point - so better watch out for friendly troops or obstacles (ricochet risk) seemingly safe from the line of fire!
Many people who want Mini as a survival rifle include "nuclear winter" in their EOTWAWKI scenario. Those better get modern 9" Mini or stick to the M193 ammo in cold weather.
Speaking of steel cores inside bullets - they tend to bounce something wicked off solid objects!
I was once present when a guy shot 4 rounds from inside the hangar having forgeten that the MG in a T-72 MBT was about 4 feet to the right and coupla feet below the sight line... The bullets were bouncing off surfaces and tanks inside the handgar for good 4 seconds but it seemed like minutes. Nobody was hit.
So if one's SHTF plan involves shooting inside concrete bunker/basement - he'd better go easy on steel cored bullets.
voruson
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