I picked up a Ruger mini 14, all wood stock, serial # 181-xxxxx (don't remember the rest of the serial # and it is not here). Dates to 1978-80 era and is marked 223. I know the 5.56 is loaded to higher pressure. I have 450 rounds of 5.56 I would like to shoot in the mini 14. Rugers are typically way over built, will the mini 14 handle the 5.56 ok ??? Always wanted one of these, and got caught in a weak moments at gunshow.

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Charlie

I have a later model Mini 14. The owners manual states that 5.56 and .223 are both ok. That may not have always been the case.

I don’t believe the early minis have the long lead needed for the 5.56 to keep pressures down.

NO!!!

You cannot fire 5.56 in a chamber marked .223. The 5.56 nato bullet sits deeper into the chamber than .223, practically touching the lands of the rifling. If you fire 5.56 nato in a .223 chamber, a overpressure spike & possible BOOM! can happen.

You can however safely fire .223 in a chamber marked 5.56.

Some, but not all, .223 guns are capable of handling the NATO round. I would think that most would be marked 223/5.56 but only Ruger can tell you if it isn't obvious in the gun or manual.

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"He was kinda funny lookin'"

According to the Ruger forum all Mini 14s are chambered to fire the 5.56 even if marked 223 with the exception of the target model 223. A call to Ruger would verify. Many said that it was right in their owners manual.

All I know about it is I have fired a lot of 5.56 ammo through my older mini 14 with no high pressure signs.
My brother had one of the very early ones with the external bolt release. Same thing.

Some also note that the Mini 14 is marked 223 NOT 223 Remington.

Worse case you could easily have throat reamed a bit

Back in '75 when I got my first Mini-14 (A 180 series), I called Ruger twice with the question of adaptability and an engineer and a nice CS lady were both adamant that they would safely handle both.
When I asked the engineer why he said that Bill wanted to keep the Mini-14 off the fed's radar. That's why Ruger only made factory 5 round magazines available to citizens for decades.

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I don't have Alzheimer's- My wife had me tested.

Send the factory an email with the serial number, and get a written response. That is what I would do

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Pete
I ain't no fortunate son

I bought a Mini 14 back when they first came out, and the manual made clear they could shoot .223 or 5.56 -- and the same is true of the vast majority of rifles marked .223. Manufacturers are well aware that folks will use the two rounds interchangeably, and for the most part they make their chambers accordingly. The exceptions are those rifles that have match-spec .223 chambers, and in those cases the "danger" of firing 5.56 is real, but very, very small. Although some 5.56 rounds in some chambers may create slightly higher chamber pressures, those pressures are generally still well within the design limits of the action. Just as a clarification, the design pressure of the 5.56 is NOT higher than that of the .223. It is the very slightly different case dimensions that can cause higher pressures in tight chambers.

The "no .308 in 7.62-chambered guns" rule is a different matter. The .308 IS loaded to significantly higher pressures than the 7.62 (that's right -- the civilian cartridge is hotter than the military), and there are thousands upon thousands of 7.62-chambered rifles out there with 1895 Mauser actions not designed for the higher pressure.

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Pisgah

I bought one back in the early 90's and have fired both .223 & 5.56 with no problems. Have also mixed them in the same mag. with no problem.

Those who state the manual says you can use either round in a Mini-14 are correct.

About pressures though, the .223 and 5.56x45 mm chambers are slightly different. The major differences being in freebore and leade. The 5.56 has a longer freebore and slightly more gentle angle of the transition to the rifling than the .223. The intention being to mitigate pressure spikes by getting the bullet moving with less effort. I've never done a chamber cast of a Mini-14 chamber, but I expect it's actually either a 5.56 mm chamber.

I don't have anything around that gives me the MAP of the .223, but the Maximum Average Pressure (per Black Hills Ammunition-they load a LOT of it) of the 5.56 round is 60,000 psi. I believe that of the .223 is 55,000 psi. Loading data that includes pressures seems to hold their load data below that point.

Given variation of production examples it's doubtful that there's any real, significant danger when firing 5.56 in a .223. The tight chambered target gun Pisgah notes is a probable exception. Even then, the most likely result isn't pieces of gun flying about.

I cannot lay hands on it right now, but a while back I read an excellent online article about .223/5.56. The author tried dozens of civilian and military loads in.223 and 5.56 in several rifles -- one chambered for .223, one in 5.56, one in .223 Wylde. In almost every case, the .223 loads produced higher pressures than the 5.56 loads -- even when the 5.56 was fired in tight chambers and the .223 in military chambers. Essentially, he concluded that the average pressures for the two cartridges were somewhere between 50K and 60K -- in other worse, basically a wash.

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Pisgah

The Mini WILL safely fire 5.56 rounds.


You probably won't be happy with the accuracy of this rifle, but maybe you'll get lucky.

Agreed, I never owned one that was accurate enough to commit suicide with, but they run like a Singer sewing machine. The older models tended to shoot ammo with heavier grain bullets better. Winchester 64 grain SP ammo shot well enough in mine to use for deer hunting.

BTW, Ruger factory 20 round mags used to have astronomical prices, I have no idea of current prices. Clyde Armory in Athens, GA had dozens of used ones for about $25.00 each a few weeks ago.

Some attribute part of the accuracy problem to the thin whippy barrel.

I made a muzzle break for mine threaded the end of the barrel for the brake, then made a sleeve that slipped over the end of the barrel and butted up to the clamped on piece at the end of the forearm that holds the gas port. I made it to a length where the brake tightened against it and put the end or the barrel under tension. Improved my groups. Still not a target gun, but I can hit a coyote with it at 200 yards and have done so. I have several bull barreled guns if I want groups.

It's a 5.56 chamber. Ruger marked the Mini 14 .223 to make it seem less military, more sporting

Here we get into the issue between established MAP specifications and what's actually produced when companies load to a velocity spec with a selection of powders and bullets. They aren't loading to max pressure, they're loading to velocity at any acceptable pressure below MAP. The idea that every load is treading on the max pressure limit is a myth.

I expect you're correct, with most loads you'd be having really bad day to show dangerous pressures in most production chambers. OTOH, unexpected environmental/mechanical conditions is one reason 7.62 X 51 mm has a lower MAP than .308. [Think about boxes of ammo baking in desert sun/tropical heat.]

The load manuals that show separate loads for 5.56 mm in rifles with 5.56 mm chambers tend to show heavier powder charges. Since the barrel lengths are generally different than for .223 it's hard to make apples/apples comparisons, particularly when a load may be optimized for a 16 inch barrel.

Oh please, not the .308 vs 7.62 legend AGAIN! We've been over this elsewhere.

Rant: Another gun rag gets .308 vs 7.62 NATO wrong


The statement about the 1895 Mausers is true as they are marginal for either headstamp.

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Release the Kraken

They're sure not target rifles, but mine has dropped many hogs at 100 yds, maybe not exactly where I aimed, but good enough. It would still be a fun gun even with worse accuracy.

...I have my Mini 14 owners manual dated 1991 in my hand...

...cover says...

...MINI-14 RIFLE... .223 (5.56mm) Caliber...

...on page 3 it states...

...Mini-14 rifles are chambered for the .223 Remington (5.56mm military) cartridge and are designed to use either standardized U.S. military, or factory loaded sporting .223 (5.56mm) cartridges manufactured in accordance with U.S. industry practice...

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A Country Boy Can Survive

Not meant to be a target gun. Meant to hit a coyote at 200 yards

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Forum consigliere

Ruger, like many gunmakers, still have copies of the owners manuals online. This copy is from the 181 series, 1978-2004. See page 10.

The RUGER® MINI-14® RIFLES are chambered for the .223 Remington (5.56mm) cartridge. The Mini-14 Rifle is designed to use either standardized U.S. military, or factory loaded sporting .223 (5.56mm) cartridges manufactured in accordance with U.S. industry practice.

https://ruger-docs.s3.amazonaws.com/...14-181-186.pdf

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Get off my lawn!

I used to work for the Cal DOC and worked often as an armorer and rangemaster. The Mini-14 was, and still is, a primary duty weapon. We put a couple of gazillion rounds of .223 and 5.56 thru them interchangeably with zero problems, including the early models. As noted above, download a manual if it will make you feel better. You probably should have one in any case.

One word of caution. The 77gr 5.56 round probably wasn't a thing when they wrote the Ruger 1978-2004 manual.

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Release the Kraken

I have a 180 and a 181 that I bought new and have fired thousands of LC and WCC ball as well as a Norinco and IMI ball through them over the decades. Still got them and still shoot them.

Thanks to everyone for the info.

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Charlie