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Random Gun Post: Mini-14 Woes

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Random Gun Post: Mini-14 Woes

Postby Zancarius » Thu Apr 07, 2016 3:37 pm

As an almost bi-annual installment of my random gun posts, I wanted to share some recent experiences I've had with my Ruger Mini-14. Since most of us grew up or live in states where exposure to firearms is relatively commonplace, I hope not to offend (with apologies to our Australian members should they ever return).

Before I explain what is alluded to in the topic insofar as woes I've encountered with this particular rifle, I think some background is in store. The Ruger Mini-14 was originally introduced as a .223 caliber/5.56mm (NATO) chambered rifle built as a scaled down replica of the venerable M14, which itself traces its lineage to the M1 Garand of WWII notoriety (the M1 is also one of the few rifles that uses a true "clip," not a magazine). Coincidentally, the Mini-14 and its variants have been used by a number of militaries and law enforcement offices worldwide and, as with its predecessors from which it borrows its design, is generally considered a robust, reliable firearm. It isn't typically known for its accuracy, but the design itself has markedly improved over time to such an extent that it has periodically surfaced in sporting venues. Mine, from my own experience, has been one heck of a tack-driver.

Unfortunately, Mini-14s occasionally suffer from a few noteworthy drawbacks that affect rifles of specific manufacture: magazine-related failures, metallurgical flaws, and others. In particular, mine has been experiencing a failure to eject/extract (henceforth known as FTEs) for reasons that eluded me until earlier this week when I had an opportunity to fire it. A cursory Google search suggests this is a fairly common problem.

Here's the patient:

mini-14-full.jpg


This particular rifle is a series 195 (based on serial number, which is blotted out in the above image), suggesting its date of manufacture may very well be sometime in or after 1998. I don't recall precisely when I got the rifle, but it was certainly after 1999 and possibly as late as 2002. I've had the rifle for years and never fired it until recently. To say it's in mostly pristine condition would be an understatement if it weren't for the exception of some minor scratches on the stock behind the receiver and wear marks on the barrel from disassembly. The scratches were on the stock when I got the rifle and were likely handling scuffs from the time it was on display at the local gun store.

When I first took it out to shoot earlier this year shortly after getting a new AR15, it jammed after two rounds with an FTE. My father was the only one who previously fired it, doing so only to test his .223 load data on an assortment of guns (including this one). For him, the stock 5 round magazine worked fine--this jam was on an OEM 20 round magazine, pictured above outside the firearm. After some inspection, we concluded from severe outgassing around the piston following the few rounds that were fired that the problem might have been related to manufacturing burrs or rough edges, and I elected to order some grease in effort to mitigate any such possibility. (It's worth mentioning older manufacture Mini-14s such as my own have a history of somewhat reduced manufacturing quality and the castings are quite rough in places--I'll take some pictures of worn down spots on mine as an illustration when I clean it again.)

Suffice it to say that earlier this week, my dad and I took it out to shoot again with the intent of testing the grease. I applied it along the op rod inserts, the top of the bolt recess, the locking lugs, the bolt cam recess, and the top of the bearing surfaces on the bolt, oiling only those parts that needed it--namely the portion of the op rod that slides along the barrel, the recoil spring guide pin and its assembly, and the bolt hold back lever/ejector. For all intents and purposes, if the problem was related to lubrication, it's highly unlikely to occur with appropriate application and a high quality grease.

I should take a moment to pause and link to a fantastic maintenance series on this exact subject created by Brownells. If you're in the market for a Mini-14 and are curious about maintenance, this series is one you absolutely must watch. Unless, of course, you're already familiar with maintaining M14s and their progeny (or ancestors if you're lucky enough to have a good quality Garand--in which case I'm jealous).

Curiously, the first magazine I fired worked almost flawlessly, experiencing an FTE only on the last round. My father shot the next magazine and experienced failures on the second, fourth, sixth, and tenth rounds (or thereabouts). My luck didn't hold beyond that first magazine and degraded rapidly for the remaining 6 trials with sporadic failures ranging from 2-5 times per 10 rounds. All but the last magazine appeared to cause some degree of failure (including the stock 5 round magazine that shipped with the rifle and worked well in prior tests). All magazines were Ruger OEM parts. Older Mini-14s are reputedly somewhat particular about the magazines used, but I've read few failure reports traceable to OEM ones purchased either directly from Ruger or elsewhere.

Puzzling.

But as I fired the last magazine, the characteristics of the gun's ejection cycle began to change. Initially, it was flinging spent casings (when they'd extract, that is) about 20 feet to my right at a low angle almost parallel with the horizon. On the last magazine, it was starting to fling the brass in an arc almost approaching 35-40° with a final landing zone some 30-40 feet away. No further failures occurred, and we finished off the last of the vintage 1985 ammunition my father brought.

I should note that it's not a problem with the ammo; my AR15 fired every single round from this batch without trouble, and it was all carefully hand-loaded and hand-weighed. My father's hand-loads are meticulously manufactured with velocities that often have a standard deviation of less than 10-15 feet per second--better than factory. Trust me--it's most assuredly not an ammo-related issue.

Suffice it to say we returned home at a loss. That is, until I disassembled the firearm to clean it, when we discovered by accident the extractor assembly was impossible to move by hand. Then it clicked: The only way the gun was likely to be rechambering spent brass after having cycled the action back far enough to cock the hammer would be if it couldn't eject the brass at all. If the extractor was too tight and refused to cooperate with the ejector during the bolt's backward cycle, it became a likely suspect. Combined with the observation that the gun's characteristics changed noticeably over time, ejecting the brass at a higher arc as we approached 150 rounds through it during a single trip, the suggestion that it was a wearing-in problem rather than a manufacturing defect was the most plausible explanation.

That evening, I set to to work on the bolt and decided I would disassemble it to further determine whether or not the extractor was the problem. My efforts were brought to a screeching halt as I discovered the extractor plunger simply would not budge. Bearing in mind that the Mini-14's bolt design was changed in the mid-1990s from a replica of the M14's bolt with an ejector pin on the bolt face to a fixed ejector on the side of the receiver (actually part of the bolt hold-back lever), it seemed that a frozen extractor plunger would make it impossible to take the bolt apart. I sprayed it down with Ballistol and let it soak for a half hour or so and waited.

At this point, you need a picture of the bolt to understand what's going on. Here's what mine looks like with the extractor plunger circled in red:

mini-14-bolt-circled.jpg


And here's a post that illustrates the bolt in its disassembled state.

The trick is to depress the plunger far enough such that the miniature lug on the topmost part of it is retracted far enough out of the extractor's locking recess to push on the extractor pin from below. Then it's a matter of hammering (delicately) the extractor out of the bolt with a brass punch or similar.

Unfortunately, if the plunger won't move, there's nothing much you can do.

I must've worked on it for a good half hour or so, depressing the side of the plunger with a screw driver until it finally started to wiggle. After dozens of attempts, I started noticing brackish solution coming out from around the plunger, and I began to wonder if it was either corroded or gummed up with something. I knew it had to be removed at this point for a proper cleaning, but I wasn't sure how long it was going to take.

But hey, you know what? Sometimes shear dumb brute force is the only way to get things to cooperate. And that's what I did: I placed a screwdriver on the top of the plunger and pushed it as hard as possible until it finally gave away enough such that I could push on the extractor (I did this about 3 times before it finally gave way). With the extractor removed, the plunger and its spring finally came out (with some coaxing) and to my surprise, it was coated in a thick, partially dried, black grease. I'm still not quite sure what the grease was (graphite impregnated, leftovers from manufacturing, something else entirely?), but it had hardened and only liberal application of Ballistol to the area was enough to loosen it up after some manual labor.

While I had the bolt apart (detail strip, am I right?), I decided to clean everything I could reach. Hence, if you look at the picture (above) of my bolt, you'll notice that sucker is really, really, really damn clean. (Well, minus the little bit of aluminum grease leaving white streaks on everything.) My father also loaned me a set of locking pliers to pre-wear the extractor plunger's spring by compressing it for a day or so. Only after this fiasco did I discover others who had similar problems: The spring might be a little too potent. After I first extricated the spring, it was absolutely impossible to compress by hand. I believe the compression treatment worked, because it now gives slightly under substantial force.

I'll be taking the rifle out again when the weather's nice to see if this resolves the problem. I suspect it might, but the only way to verify my suspicions is with range data. The extractor is a bit looser now and finally yields to firm pressure not unlike my AR15's. Gone are the days where it was absolutely stuck, and I'm hopeful this is the resolution it needed.

So, there you have it. I'll post some updates when I get back to the range. I know I pestered some of you (hi Matt and Hunter!) for suggestions since I was at a loss for ideas. Fortunately, it looks like it was something relatively minor, but my initial inclinations were to suspect something a bit more difficult to fix.

Happy shooting!
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Re: Random Gun Post: Mini-14 Woes

Postby MaxRile » Fri Apr 08, 2016 12:49 am

Have you compared your bolt to another to get an idea of what your looking at/for?
Have you soaked it over night in a bowl in gun oil?
What does it look like when its nasty/dirty?
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Re: Random Gun Post: Mini-14 Woes

Postby Zancarius » Fri Apr 08, 2016 9:50 am

1. Yes, but I think the problem is resolved (see above).
2. No need. It's clean. Hence the point of disassembling it.
3. Haven't shot it enough to get it dirty due to prior extraction issues.
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Re: Random Gun Post: Mini-14 Woes

Postby Zancarius » Fri Apr 08, 2016 8:54 pm

I should note that Hunter suggested I purchase a Lubrikit for testing, which I did and which you can see in the picture of the bolt. It's the same grease as Lubriplate's SFL-0 just in a smaller, easier to manage kit. Hunter has the 14oz tin, purchased because of its reputedly low odor (which I agree: it has almost no odor to speak of). It's also a food safe grease used in manufacturing facilities, so it's considered non-toxic.

If you're in need of grease, I'd highly recommend SFL-0. Brownells sells the 130-A milspec grease that was originally intended for use with the M1A/M14 and derivatives, but it's also a petroleum product that's a little bit more toxic. I cook quite a lot, so I don't want to cross contaminate things I make (also why I use Ballistol although some people greatly dislike the smell).
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