Bushmaster 223 or 5.56

[myglockisa23]

This may sound stupid but will the 5.56 function properly in my Bushmaster? On the side of the rifle it has 223-5.56..... I've only shot 223 ammo in the Bushmaster XM but will try the 5.56 since it is cheaper at Gander Mountain....

[kestrou]

In a word: yes.

I don't have a link to the spec handy, but the rule of thumb I've always heard is to buy the upper chambered for 5.56x45 and it feeds .223 fine. Supposedly uppers chambered for .223 don't feed 5.56 as reliably.

kestrou

[RMTactical]

http://www.ammo-oracle.com/body.htm

[chakup]

yep a 5.56 chamber will feed 5.56/.223. some match/target .223 chambers I have heard won't feed 5.56.

[Mnukedude]

5.56 works fine in a Bushy upper. They are specifically designed to handle it. Not all AR's are, but this maker builds 'em for it.

[scowan007]

From Bushmaster's catalog:


.223 Remington or 5.56mm: We’ve had numerous inquiries about .223 Rem. versus 5.56mm NATO
ammunition. The short answer is that all Bushmaster barrels are chambered for the 5.56mm cartridge. Most of
our barrels are stamped 5.56 NATO - usually just ahead of the front sight. Despite the fact that our Lower Receivers are
stamped CAL.223-5.56MM, our chambers, barrels, and bolts are designed to withstand the higher pressures of the 5.56mm
cartridge. We do this for the safety of our customers, and because our rifles have always been built following the military
pattern. In any of our barrels, the .223 Remington cartridge can be fired safely.
So, what’s the difference between the two cartridges? They have basically the same exterior dimensions
and length, but the 5.56 is usually loaded to produce higher velocity and chamber pressures. It has thicker case walls
for the extra strength needed to handle those higher pressures. The difference comes in the chambering of the rifle, and
that difference is in "Leade" (more commonly known as the throat) which is the portion of the barrel directly in front of
the chamber where the rifling has been removed to allow room for the seated bullet. In a 5.56mm chamber the throat
is typically .162" – in a .223 chamber it’s usually .085"(about half that dimension). The result of firing a .223 cartridge
in the Bushmaster 5.56mm chamber is a slight loss of velocity when measured against the 5.56mm cartridge.
However, if you own other (non Bushmaster) rifles specifically chambered for the .223 Remington, you
should not use 5.56mm ammunition in them as it is considered by SAAMI (Small Arms and
Ammunition Manufacturers Institute) to be an unsafe ammunition combination. (This 5.56mm/.223 Rem.
information from Bushmaster Gunsmithing and the Winchester Law Enforcement Ammunition Website.)

[JWP]

+1 but i routinely load 223 for match shooting and winchester 223 brass is only 1-2 gr lighter than lc brass

i don't see any loading differences in using either for 223

308/30-06 brass is way heavier than commercial equivalents and the 2gr drop in charge for them is REQUIRED