Remington 700 Rifle Forums banner

5.56 or .223

4K views 2 replies 3 participants last post by  Grendel 
#1 ·
This is one that has probably been asked before, but can my 1970 vintage Model 700 varmint special labled .223 safely handle 5.56 ammo? When I bought it new it was to shoot 5.56 ammo, although I did not do much, mostly handloading for it. I see some new bolt action rifles such as the CZ 527, are listed to handle both loadings safely per the factory catalog.
 
#2 ·
With a lot of M-885 62 gr 5.56 Nato ammo on the market (surplus) it's a good Idea that you avoid it in your rifle. The Leade is longer in the NATO Chamber to prevent high pressures with this longer bullet. A lot of manufacturers lengthen the chambers to accommodate the NATO ammo due to it's availability on the market.

If you buy the M-193, 55 gr ammo there will be no problem. It is not 5.56 mm NATO ammo as the 55 gr bullet was never adopted as a NATO standard. For all practical purposes it's the same as .223 ammo which the M-16 was developed around.

If you keep your rifle in it's current condition just make sure to stick with 55 gr FMJ-BT ammo if you buy any Military Surplus. The longer bullets (base to ogive measurement) can create an over pressure limits condition. May survive one, two, maybe a half dozen incidents. It's when it finally stresses metal in the weapon enough times to break something that the problem occurs. Think "bending a paper clip" or even 'squeezing a balloon'.
 
#3 ·
BLUF: Don't shoot 5.56 ammo in a .223 chamber.
The 5.56 is a much higher pressure round to ensure reliable action in a semi/full auto weapon. Nothing to due with longer bullets. The gas relief section in the chamber (where the brass case ends and the bullet starts) of the .223 is shorter and will burn out with 5.56 ammo. The Wylde chamber is a good choice for both since the gas chamber is a bit longer than the .223.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top