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  • Rapier

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    This is an article I wrote for Perfect Union a couple of years ago.


    Mini 14 Mystery
    Getting the Mini-14 to Shoot

    Probably one of the most exasperating guns I have ever run across is the little Ruger military rifle. Yes, the Mini-14 is a military rifle….. Bill introduced the gun as a vehicle for Ruger to get into the armament business with third world countries. It is not and never has been a “sporting gun” that can be used by the military, it is exactly, 180 degrees the opposite, a military gun that can be used for sporting purposes.

    Most folks are not aware that Ruger, as a company, is a large presence in world arms trade. When a country secures an arms purchase loan from the US and the “loan” requires a US manufacturer as supplier, Ruger can put a soldier in the field for less than $700 while Colt is hard pressed to field a soldier for $1,000. This is where the Mini 14 shines and why the Mini was developed, according to Steve Vogel, former Ex VP of Ruger and their head of foreign sales.

    If you own a Mini or are thinking of buying a Mini you need to be aware that the Minis have three barrel twist rates, by date of manufacture of the barrels. The only way to tell exactly what twist your particular rifle has is to test the twist with a tight patch and a cleaning rod. These are the general prefix numbers for the twist rates:

    Up to 184 1-10 twist
    185 to 196 1-7 twist
    196 to present day 1-9 twist

    The above is why load data for a Mini without the twist rate included, means nothing to a reloader, unless your gun just happens to be the same twist as the gun used for load development. Why the different twist rates? The US Department of Defense changed the bullet weights for the 5.56 mm NATO or 223 round. The military ball ammo started at 55gr, went to 69gr then settled on 62gr. The Mini-14 followed the bullet weight change by changing to the standard twist used in the M-16 or now the M-4.

    If the twist rate is not bad enough, the Mini barrel is a thing of horrors; it is thin and has an even thinner spot in the middle. It tends to whip or flex at the muzzle as the gun is fired, slinging bullets everywhere. This can be somewhat modified by cutting the barrel length to less than 17 inches (but more than the ATF minimum rifle barrel length of 16) and adding a heavy, long, flash hider or muzzle break. Usually a Mini can be changed from a 4-inch shooter to a 2-inch shooter in such a manner.

    Most Mini actions fit pretty sloppy in their stock. The action can be glass bedded in the stock, which will also reduce the group sizes. There are several sites on the net that illustrate the areas to be glassed to achieve the best results. It beds very similar to an M-14.

    I bought a Mini 14 Stainless about 4 years ago. It is not the only Mini I have owned but it is the gun I decided to make shoot if it ruined the Pope’s day or week. It is eerie to me how similar the Mini is to its daddy the M-14. As a former military armorer and rifle team member, I am quite familiar with the M-14.

    With the subject gun the first thing that I did was to strip the bore of all copper using a Shooters Choice soak with the chamber plugged and the bore filled for 8 days. This required the barrel being stripped down to the action and the gas port being plugged with a wood peg. The rest of the parts were cleaned back to steel. The gas block was put back on without Locktite, which was a mistake.

    The next thing I did was to buy a John Masen muzzle break, which is a long and heavy muzzle break that fits over the skinny barrel for about 2 inches and extends out about 4 inches. The muzzle break adds a lot of weight and stability to the whippy thin barrel. This cut the groups to 2 inches without doing anything else.

    At the range I discovered that the gas block that was not staked or set with Locktite had cracked. So I had to buy a new gas block, which Ruger does not sell and is a factory-installed item. I ended up buying the Accuracy Systems Inc. gas block from Brownell’s as a replacement. A word about this, the Ruger gas block is not milled square, nor is the hole round, so trying to make a perfect fit by adjusting the split or opening is a non-starter. About the best you can do with a Ruger block is to eyeball it to be close and make sure you red Locktite the screws. The ASI block is milled square and round, so it can be adjusted to fit perfect and with red Locktite the screws can be set and torqued to hold without cracking the corners.

    After replacing the gas block I decided to do a trigger job and returned to the range with a new gas block and a 2-¾ pound trigger. The first group I shot with the 2x Bushnell scope that was on the gun when I bought it was 2 inches. That would not do so I replaced the scope at the range with a 3x12x50 tactical scope using Warne rings. The groups with two loads went into 1 inch. One of the loads was from reloads sold by Black Hills, their 55 gr SP loads using military brass. So we were on the right track.

    I returned to the workbench when the target crown cutter from Midway arrived. I had ordered the crowning tool to facilitate the re-crowning of the factory barrel in a home shop. I have learned over the years that most factory barrels can be made to perform better if the crown is re-cut and left alone, without sanding or polish. I just let the first bullet clean off the burrs leaving the muzzle cut sharp and square. I replaced the muzzle break.

    Back to the range we went with several loads to test. I found that the rumors are true; the Mini is picky about its ammo and will shoot 2 inches with just about anything but to get sub MOA you need to find its preferred load. During this outing two such loads were found, a group with 53gr Sierra HP bullets and IMR 4198 that shot .77-inch groups (3 groups of 3 rounds each) and a hot load of AA 2230 that put a set of 55gr Hornady SP bullets into a group of .354 inches.

    Was I satisfied? Nope, I was going to cut 2 inches off the barrel, set the muzzle break back against the first step in the barrel and Acraglass the barrel to the muzzle break, making the last two inches of thin barrel thicker but solid. The result, with a re-crown, should have made a solid heavy barrel rifle that would consistently shoot half MOA, if my idea worked. This was not done as the barrel is all different diameters.

    Here is a recap of modifications by the item:

    Stock: Glass bed the action per the videos on the net. Note, the Mini beds like an M-14 watch a video and note the trigger guard locked just barely open.

    Add a butt extender from Brownell’s to lengthen the pull. The factory stock is way to short for me and my 15 1/8 inch pull.

    Action: clean the action thoroughly and keep it clean and lubed with synthetic grease and lubricants.

    Trigger: Do a trigger job, reducing the trigger pull on the primary or second stage to a crisp 3 pounds. This can be done per the video on this site http://greatwestgunsmithing.com/mini trigger low quality.html

    Bore: Clean the bore regularly with a good copper solvent.

    Barrel: First try removing the front sight and replacing it with the long muzzle break by John Masen. If that does not get you where you want to be, re-crown the barrel with a target crown as found on Midway.com If you are still not pleased, cut the barrel off 1.90 inches, crown the barrel, cut a keeper pin notch and set the muzzle break back to set firmly against the first step on the barrel.

    Gas Block: The Ruger gas block is not milled square nor is the hole round, it is oblong, it can’t be tightened to give 100% equal pressure on the barrel. It might be possible to mill the facing surfaces square but I suggest you buy an after market gas block, such as the ASI adjustable block. Replace the block to achieve 100% equal pressure side to side and red Locktite the screws in place once the equal spacing has been attained. Measure the space between the block's top and bottom with calipers once you have it torqued.

    Scope; note this gun has a Wichita scope base and Warne rings with a decent tactical scope.

    Accuracy Strut: This is simply a steel rod hung below the barrel to change the harmonics of the barrel. I have not tried the feature as I decided I could stiffen the barrel by use of the muzzle break. But you can test this method by buying two clamps from Cheaper Than Dirt and suspending a steel rod of about 5 inches in length down below the barrel, between the rear of the muzzle break and the front of the gas block.

    One thing that you should know about the early guns and the thin barrel, all is not what it appears to be. From the chamber taper, going towards the muzzle, the barrel is .561 in diameter until it gets to just forward of the gas block. Then the barrel tapers up from .561 at the gas block to .578 just before it steps down behind the front sight. Then at the step behind the front sight the barrel steps back down to .561 out to past the front sight band where the barrel steps down once again to .555 So if it occurred to you, as it did to me, that you could cut two inches off the barrel and move the muzzle break back nearer to the gas block and thus get in effect a thicker, stiffer barrel, you would be wasting your time because you do not have a straight barrel of .578 in diameter to deal with. The .578 diameter is only about 1 inch long. It is fairly obvious how and why the Mini would do better with a straight barrel of a larger diameter than .578.

    A photo of the weird barrel dimensions is below as is a picture of the finished gun.

    Ed
     

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