Mini-14 ammo

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Apr 14, 2022
81 and just picked up my first Mini-14 in .223. I'm a Springfield/Garand man but age and weakness/arthuritis are creeping up on me. For decades I have head peripherally about not being able to shoot USGI .556mm in the Ruger. Didn't make sense to me there it is. This gun is a 1995 Ranch Mini and the owners manual clearly says "...use either standardized US military, or factory loaded sporting .223....". I am not a huge fan of .223 for military use BUT... I'm going to give it the benefit of the doubt. BUT WHAT is the deal on which ammo is safe to use!!?? Fur shur I'll never have a tupperware version of this or any other.

Anyone got any 10 or 20 rd mags they want to sell ? I received a 5 and a 30 with the gun.
Mar 24, 2002
Oregon City, Oregon
There remains so much misinformation between the .223 and 5.56.

The pressures are close enough to the same to be a non-issue.

The differences are, a 5.56 chamber has a longer freebore, to allow heavier bullets with an ogive farther forward. A .223 chamber has a shorter freebore. A heavier bullet may cause the longer ogive to contact the rifling before the cartridge is completely chambered. This could cause stiff chambering to not chambering at all. It could push the bullet into the case a tad bit, and could cause an over pressure. It may be an issue with some guns and not others. My experience... a 52 gr 5.56 load will chamber in many .223 chambers, where a 62 grain or heavier, or even differences between bullet designs and bullet seating depth, may not.

Is There a Difference Between .223 and 5.56? | The Arms Guide
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Apr 10, 2005
Note that the caliber marking on most all of the Mini-14 receivers which have been manufactured over the past (almost) 50 years read "cal .223". It does not read "Cal .223 Remington.".....In other words, the Ruger Mini-14 is in fact a .223 caliber weapon. In addition to that, you may also note that the chamber is configured in a manner that allows it to safely utilize either .223 caliber sporting ammo or 5.56 x 45 military ammo, just like the Ruger Manual states....So, if ya don't want to take what the manual say's at face value, and if your mind just can't get past the "Cal .223" marking on the receiver, give Ruger Customer Service a call. They'll be glad to help you understand......Now, having said that, there's also this; Ruger did for a while (and maybe still does) offer a specially modified "Target Model" Mini-14 which was designed to be used with caliber .223-Remington ammo only. That particular model should not be fed any type of .556x45 ammo, dot-period. Ruger is very specific about that.....Hope this helps clear the matter up.

Mar 29, 2017
Going with what the poster printed that the manual said. "Standardized US military or factory loaded sporting .223."
Ok what the heck does that mean? US military is 5.56mm stamped not .223. No wonder people get confused.
I understand the differences between the 2. Wayno got it right, except the 52 gr should say 55 gr bullet.
When I owned several mini 14s, I only fired handed loaded 5.56 brass with 55 gr. bullets. But when the 62gr. USGI came out, I always wondered would they be ok or not.
I moved on and only have 5.56 chambered guns. But have been asked a few times about firing 5.56 in rifles listed as .223. My answer is follow the manual or as mentioned don't ask me call the guys who build the gun.