what does boat tail mean? .223

Isinner · 04-23-2009, 03:34 AM

223 Rem 55 Gr FMJ Boat-Tail.

Never heard that term..

What does M193 Ball...

Thank you

EriccCartmann · 04-23-2009, 03:43 AM

Boat tail just means the end/tail is tapered. Makes for a more stable flight, thereby lowering the ballistic coeffeceint, a lower bc = good. Lower BC means faster bullet at distance (not at the muzzle), thereby having less bullet drop at distance giving you more accuracy.

Ball is just another term for FMJ and not a hallowpoint round.

NYECOGunsmith · 04-23-2009, 03:50 AM

The FMJ means Full Metal Jacket.
A boat tail projectile is one where the base of the bullet is beveled or chamfered slightly.
This serves two purposes. It makes loading it into the cartridge mouth easier, but more importantly it also provides a smooth flow surface around the projectile as it exits the muzzle. Anything that upsets that gas flow at the muzzle as the projectile exits the muzzle, such as a nick in the base or "heel" of the projectile, will cause the projectile to yaw slightly or greatly, depending on amount of disturbance. The bevel, because it is self guiding into the case upon loading, reduces the chances of a nick being produced on the base when the projectile is seated.
A nick in the muzzle's crown will also cause a projectile to yaw. You can actually mash the nose of the projectile out of shape, and it will still fly true.
But scar up the base edges, whether flat or boat tailed, and its going to go somewhere other than exactly where you wanted it to go.

As for M193 Ball, that is mil spec ammo for the 5.56x45 NATO cartridge.
It means that the projectile will be full metal jacketed, weight 55 grains +/- 2 grains, and from a 20 inch test barrel will attain a velocity of 3,250 FPS, +/- 40 FPS. It is supposed to attain an accuracy of 3 MOA at 200 yards for an average of 10, ten shot groups.
And if it is true NATO spec ammo, there should be a "+" sign inside of a circle as part of the head stamp information.

Everything EricCartmanm says is also true, he just types faster than I do!

Isinner · 04-23-2009, 03:55 AM

Thank you both very much

04-23-2009, 03:34 AM	#1
Isinner BBQ GURU Join Date: Jan 2009 Location: Northern Nevada Posts: 190 Mentioned: 0 Post(s) Tagged: 0 Thread(s)	what does boat tail mean? .223 223 Rem 55 Gr FMJ Boat-Tail. Never heard that term.. What does M193 Ball... Thank you __________________

04-23-2009, 03:50 AM	#3
NYECOGunsmith Obsessed Member Join Date: Nov 2008 Location: Over the Hump in Pahrump, NV Posts: 3,994 Mentioned: 0 Post(s) Tagged: 0 Thread(s)	The FMJ means Full Metal Jacket. A boat tail projectile is one where the base of the bullet is beveled or chamfered slightly. This serves two purposes. It makes loading it into the cartridge mouth easier, but more importantly it also provides a smooth flow surface around the projectile as it exits the muzzle. Anything that upsets that gas flow at the muzzle as the projectile exits the muzzle, such as a nick in the base or "heel" of the projectile, will cause the projectile to yaw slightly or greatly, depending on amount of disturbance. The bevel, because it is self guiding into the case upon loading, reduces the chances of a nick being produced on the base when the projectile is seated. A nick in the muzzle's crown will also cause a projectile to yaw. You can actually mash the nose of the projectile out of shape, and it will still fly true. But scar up the base edges, whether flat or boat tailed, and its going to go somewhere other than exactly where you wanted it to go. As for M193 Ball, that is mil spec ammo for the 5.56x45 NATO cartridge. It means that the projectile will be full metal jacketed, weight 55 grains +/- 2 grains, and from a 20 inch test barrel will attain a velocity of 3,250 FPS, +/- 40 FPS. It is supposed to attain an accuracy of 3 MOA at 200 yards for an average of 10, ten shot groups. And if it is true NATO spec ammo, there should be a "+" sign inside of a circle as part of the head stamp information. Everything EricCartmanm says is also true, he just types faster than I do! __________________ Steve Just because you are paranoid doesn't mean someone ISN'T OUT TO GET YOU! Just because a complaint was never filed doesn't mean a defective parachute was never made. I've been to three world's fairs, two rodeos and a goat roping contest, but I've never seen the likes of the stuff that goes on around here before!

04-23-2009, 03:55 AM	#4
Isinner BBQ GURU Join Date: Jan 2009 Location: Northern Nevada Posts: 190 Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Thank you both very much __________________

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04-23-2009, 03:43 AM	#2
EriccCartmann Hobbyist among Operators Join Date: Oct 2008 Location: Mom's Basement Posts: 1,127 Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Boat tail just means the end/tail is tapered. Makes for a more stable flight, thereby lowering the ballistic coeffeceint, a lower bc = good. Lower BC means faster bullet at distance (not at the muzzle), thereby having less bullet drop at distance giving you more accuracy. Ball is just another term for FMJ and not a hallowpoint round.