If all else fails call RRA and give them your serial number. If you bought a complete new rifle they can tell you what barrel you have.

Quoted: Quoted: Quoted: Quoted: They're ALL wylde chambers they safely shoot both 5.56 and .223 No, they're not. They offer both Wylde and 5.56 Nato (Wylde only in the 20" barrels, no 5.56 option). WIZZO my understanding is that wylde is standard on they're rifles.  Mine is the m4 entry tactical.  16" "r4" profile barrel. . . . comes standard with the wylde chamber.  Not just the 20 inchers.   OHHHHHH  I see what you're saying . . . well.  If I'm wrong then I'm wrong.  My apologies WIZZO. Maybe you should check out this web site and see what rifles come standard with wylde chambers. Entry tactical rifles come standard with 5.56 chambers.

excuse me . . . i've been "checking out" that web site for years  . . i checked it out for a years before I was finally able to get my m4 entry tactical . . .  I was checking it out before most people knew what RRA was.  if you checked it out you'd see it says the chamber is .223/5.56 NATO chamber . . . meaning it shoots both the .223 and 5.56  it's a wylde chamber.  I may have made a mistake earlier, but i DO know what chamber my own rifle has thanks.  I guess you just like to kick people when they're down.

You may want to check again...

http://www.ar15.com/forums/topic.html?b=3&f=118&t=265616

Quoted: Quoted: Quoted: Quoted: Quoted: They're ALL wylde chambers they safely shoot both 5.56 and .223 No, they're not. They offer both Wylde and 5.56 Nato (Wylde only in the 20" barrels, no 5.56 option). WIZZO my understanding is that wylde is standard on they're rifles.  Mine is the m4 entry tactical.  16" "r4" profile barrel. . . . comes standard with the wylde chamber.  Not just the 20 inchers.   OHHHHHH  I see what you're saying . . . well.  If I'm wrong then I'm wrong.  My apologies WIZZO. Maybe you should check out this web site and see what rifles come standard with wylde chambers. Entry tactical rifles come standard with 5.56 chambers. excuse me . . . i've been "checking out" that web site for years  . . i checked it out for a years before I was finally able to get my m4 entry tactical . . .  I was checking it out before most people knew what RRA was.  if you checked it out you'd see it says the chamber is .223/5.56 NATO chamber . . . meaning it shoots both the .223 and 5.56  it's a wylde chamber.  I may have made a mistake earlier, but i DO know what chamber my own rifle has thanks.  I guess you just like to kick people when they're down.

Your actually right and wrong... You can shoot ,223 OR 5.56 NATO ammo, thats the correct part... The incorrect part is, its not a Wylde chamber...

With a NATO chamber it is safe to use .223 ammo... With a .223 chamber it is not safe to use 5.56 NATO ammo...

i would go RRA over bushmaster any day.....i love mine and the upper fits great on just about every lower i have put it on

Here, this should also help put an end to this nonsense...

ar15.com/forums/topic.html?b=2&f=38&t=149540&page=1

Quoted: Quoted: Quoted: Quoted: Quoted: They're ALL wylde chambers they safely shoot both 5.56 and .223 No, they're not. They offer both Wylde and 5.56 Nato (Wylde only in the 20" barrels, no 5.56 option). WIZZO my understanding is that wylde is standard on they're rifles.  Mine is the m4 entry tactical.  16" "r4" profile barrel. . . . comes standard with the wylde chamber.  Not just the 20 inchers.   OHHHHHH  I see what you're saying . . . well.  If I'm wrong then I'm wrong.  My apologies WIZZO. Maybe you should check out this web site and see what rifles come standard with wylde chambers. Entry tactical rifles come standard with 5.56 chambers. excuse me . . . i've been "checking out" that web site for years  . . i checked it out for a years before I was finally able to get my m4 entry tactical . . .  I was checking it out before most people knew what RRA was.  if you checked it out you'd see it says the chamber is .223/5.56 NATO chamber . . . meaning it shoots both the .223 and 5.56  it's a wylde chamber.  I may have made a mistake earlier, but i DO know what chamber my own rifle has thanks.  I guess you just like to kick people when they're down.

Yeah, thats real obvious