Mini-14 rebarrel


Uncle Ethan
January 9, 2003, 10:58 AM
I have a series 181 Mini in .223- I am going to put a match Shilen barrel on it- should I go longer than 20" , and heavier than the Colt H-Bar? When I turn the barrel section where the gas system operates, should I keep it round, or can I leave it heavy and mill a flat? Thks, Ethan

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Jim Watson
January 9, 2003, 11:44 AM
I have a 187- Ranch with ARS heavy barrel. I ordered it at 24" and found it completely unwieldy. I had it shortened to 20" which helped a lot with the balance and did not hurt accuracy. (I also had my AR A3 Flattop cut from 24" to 18.5" and turned to A2 diameter; heavy barrels are for long range target shooters and husky young snipers.)

It measures about .930" over the chamber for 2 inches from the receiver ring. It has about a half-inch taper down to .725" straight to the gas block. The action slide was cut to clear. It is now has about as big a clearance radius on the slide as does not risk breaking into the gas cylinder.

I can see that the barrel is turned down under the gas block but can't tell exactly how much or whether the gas block is stock or was reamed out to take as large a barrel as possible. Eyeballing the calipers held up in front of the barrel and gas block it might be about .700" but don't take that as gospel, measure. I see no sign of a flat under the gas block, but have not taken it off to look.

In front of the gas block the barrel diameter steps back up to about .760". Dunno why they did not just make it straight from the chamber to the muzzle, with or without the band for the gas block. Mine is still a little heavy; I think I would like it better if it were .725" or even .700" straight from chamber to muzzle.

I think it an interesting project. Mine is now almost a MOA rifle without replacing or rebedding the stock.

Uncle Ethan
January 9, 2003, 01:30 PM
You've been a lot of help- I think I should check the barrel diameter on my Rem 788 in .223- it's a tack driver and doen't lose accuracy when it heats up. What was your A2 barrel diameter? Was that where you got your .725Dia dimention? Thks again for the help, and anyone else out there with info please jump in. Ethan:cool:

Dave P
January 9, 2003, 05:13 PM
anyone else out there with info please jump in

Are you sure you want to spend that kind of money on a mini14? Couldn't you buy an AR for just a bit more $? I don't like ARs at all, but they are much more accurate than most any mini14.

Jim Watson
January 9, 2003, 06:13 PM
The .725" diameter was what ARS put on it, I did not do the work myself. I am rated NRA Mechanically Inept. Barrel diameter between the chamber and the gas block depends on how much of the operating slide you can cut away to clear the barrel without cutting into the gas cylinder. Your 788 may not signify there. Diameter of the A2 I went by on the AR was about .610" under the handguards but very uneven. My FLG turned mine to .630" straight.

You are probably right. I was wild for a walnut .223 at the time. I would not do it again, there are so many parts and procedures available for the AR.

4v50 Gary
January 9, 2003, 06:47 PM
You may want to machine a gas block for the stationary gas piston too. Remember to keep the piston at the same height so the angle of entry of the op-rod doesn't change. The diameter of the gas port may have to be smaller with that 20" barrel. The pressure will remain a mite bit higher (18.5" v. 20" bbl) for a slightly longer time. Drop a drill rod into the gas port of the bbl to determine what diameter it is (w/out my notes, I think it is something like .060").

Another thing to keep in mind that the factory gas pipe can rotate if the gas tube is removed.


Uncle Ethan
January 9, 2003, 07:12 PM
Jim- thks for the info- sorry I'm so dense , but please explain [FLG turned mine to .630"] -are you referring to the factory diameter of the H-Bar beyond the gas port/sight??

Dave P.- Thks for the info- unfortunately I live in PKR and refuse to register my AR15's, so I had to remove them from the State. I am trying to make an accurate rifle out of what's legal now.

4v50 Gary- I will work with the gas port diameter- I never thought of that- what is the [ factory gas pipe?] that can rotate. I see the gas block and the screw in gas nozzle that fits into the op rod, but I don't see a gas pipe??? I'm about to remove the barrel, but now I'm afeared.:uhoh:

Jim Watson
January 9, 2003, 08:51 PM
When I had my AR A3 barrel cut down, my gunsmith turned the barrel down to .630" under the handguard, leaving the chamber, the section under the gas block (front sight bracket) and muzzle end as was. Similar to a GI A2 barrel profile, just a bit shorter. Not the same as what you will be doing to a Mini.

Parts nomenclature (in Numrich catalog): You have the "Gas Block, Top and Bottom" held together by four "Gas Block Screws." The "Piston (Gas Pipe)" protrudes back from the bottom gas block into the cylinder in the operating slide; what you call the 'nozzle'. All these are visible when assembled. There is also a "Gas Port Bushing" inside the bottom gas block between the gas port in the barrel and the Piston/Gas Pipe. Looks like you could make different ID gas port bushings to control operation although it would be a chore to change them out; unlike the regulator on a FAL. But I am not taking mine apart to see.

Knowledge comes from taking things apart. Wisdom comes from putting them back together.

Uncle Ethan
January 9, 2003, 09:14 PM
Knowledge comes from taking things apart. Wisdom comes from putting them back together. And an increased vocabulary comes from re-assembling them wrong the third time.:fire: :D

January 10, 2003, 10:54 AM
How much was the barrel?

Uncle Ethan
January 10, 2003, 12:01 PM
About $260 give or take- about what you can get one for already threaded at Brownell's. I bought a blank so I can try out an idea for an integral muzzle brake [flash hider]. All in all, the cost of the used Mini plus barrel, etc will be about what I got for the AR-15.

January 10, 2003, 01:33 PM
I have a Ranch Mini 14 that has over 6000rds thew it. I'm betting that in another couple years I'm gonna want a new barrel. Spending $300 for a rebirth would be worthwhile to me.

I got two Mini 14s and actually like the "light and handy" rifle that its meant to be. But my one Mini 14 gets more use that any other semi-auto I own. It would just be fun to have.

Uncle Ethan
January 10, 2003, 07:06 PM
I plan on a 22" overall length for the barrel. I will grind a 3/8" boring bar at 11 degrees and after drilling 2" down the muzzle I will use the boring bar to re-crown the muzzle- then drill muzzle brake and anti-twist holes in the last 1". See how that works- I know it will be legal.

January 10, 2003, 10:10 PM
Uncle Ethan,
Takea look at for some good info on the mini-14.

January 11, 2003, 01:15 AM
Are you putting iron sights on the Mini 14? Or scoping? I've seen pictures of some of the Mini 14s that were rebarreled and they just looked a little funky. Even if I don't use the iron sights I would want to have a post on the front of the gun.

What are you doing?

Uncle Ethan
January 11, 2003, 03:20 PM
I plan on iron sights -and will machine out of aluminum a combination upper handguard -scope mount anchored at the gas block and the rear sight so both can be used. My biggest problem will be deburring magazines and trying enough after market mags to get 6-8 mags that work reliabily.

January 11, 2003, 04:13 PM
I changed the springs and followers on 4 USA mags that absolutely would not function. They all go to the range with me and have been flawless. I only buy PMI mags now.

Uncle Ethan
January 11, 2003, 05:37 PM
What exactly do you mean about changing out springs and followers- what springs and followers did you use?

January 11, 2003, 07:29 PM has replacement followers and springs that are superior to the ones that my USA mags had. A follower has to move up and down the mag body staying "level". If the followers are too big, they can hang up inside the mag (even if it only occurs for a split second) and the mag will close on an empty chamber. If the follower is too small, it can nose-diver or wobble too much causing the gun to jam. I rarely see malfunctions due to bad springs. Its almost always an out of spec follower. One major reason USGI AR Mags are better than other AR mags is the magazine follower design.

I also had to take a pair of needle nosed plyers to the mag lips because the mag had a tendency to throw "live rounds" out of the gun. I would pull the trigger and have an spent case and a live round fly out.

I believe the magazine follower were about $3 a piece. If you have any problems with mags feel free to email me.

Here they are:

I put about 3000rds threw several of my USA mags since operating on them.

I'd trust them with my life.

Uncle Ethan
January 11, 2003, 10:43 PM
Thks SodaPop- I'll try them all and any who don't work I'll go to brownells.

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