Hey folks,

May seem like a stupid question to some of you folks, but here goes:

I've got an older Rock River Arms rifle that is marked '5.56'. I tried running .223 Remington 55 grain Wolf through it, and had some issues.

I'm wondering if the older RRAs did not have the 'Wylde' chamber, and will only feed 5.56 reliably, or if there is a brand of commercial .223 available that should work

I'd like to go shoot on Friday, but the local stores don't sell actual 5.56, and i'd rather not overnight ship 5.56 just to get it here by then, so I'm wondering if Eagle, Olympic, or some other commercial .223 might work without a hitchd.

Any help/advice would be appreciated.

Thanks.

It's probably not the chamber dimensions that are the problem but the fact that Wolf is somewhat underpowered.  I have an upper that won't feed wolf but will feed Winchester value-pack .223 all day long.  

Try Walmart's Winchester White Box. 40 rnds. $7.73

The type of chamber has nothing to do with whether the round will feed or not. Keep in mind that the dimensions of .223 and 5.56 are identical (a LOT of commercial .223 reloads use LC 5.56 brass). The only difference is in the free space between the end of the chamber and the rifling (the "lead"). If Wolf doesn't feed, either try other magazines, or other ammo.  Maybe your rifle is finicky as to the bullet shape, some brands have a more "pointy" bullet, or longer, or whatever.

People say that Wolf is underpowered, in reality it's as powerful as any other commercial .223. I have chrono'ed 55 gr Wolf several times, from different lots, and obtain the same velocity as 55gr from UMC or Winchester (right over 3000 fps from a 20" barrel). It's only underpowered when compared to the 5.56 loads.