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Discussion Starter · #1 ·
A lot of shooters want to shoot imported Berdan primed steel case ammo in their Mini's. The Mini-30 wasn't designed to shoot that, and Ruger will tell you so. But part of the appeal of shooting the 7.62 x39 cartridge is being able to buy ammo for $5-$6 a box. Good brass case, Boxer primed ammo, like Ruger would like you to use, is more like $20 to $24 a box, although some, like PPU is good stuff and can be had for closer to $11 for 20 rounds.
I tried some Tula and Hornady steel case Berdan primed ammo in both of my Mini-30's. About 20 rounds out of 100 of the Tula failed to go off ( at least the first time, they all fired the second attempt). The Hornady was better, only 4 failed to go off out of the 100 I bought.
I bought my Mini-30's knowing that I would get reloading dies and do my own loads using quality brass cases and good ole Winchester primers, which I have done. But I wanted the option of having reliable ignition if one day (zombie apocalypse/ Red Dawn) I only had a case of Commie ammo available.
Some have installed a heavier hammer spring in the hopes of getting better ignition. DON'T DO THIS !!! Think about it. When you pull the trigger, the hammer strikes the firing pin and drives it forward. It can only go so far before it hits the "shelves" inside the bolt which limits its forward travel. Putting in a heavier hammer spring without modifying the firing pin to go forward farther, just puts an awful lot of stress on the firing pin, without making it strike a primer any deeper. That's why many end up breaking their firing pin.
Ruger will not sell you a spare pin without you sending the Mini in to them for fitting and test firing. Mini's are not "one size fits all" when it comes to bolts and firing pins. My 2 Mini-30's are from the same production run (189 series) and do not have the same size bolts or FP's.
I would not try to modify your factory pin as they are impossible to get unless you send your gun in to Ruger and ask for a spare to be fitted.
The replacement pins sold by Glend Arms do not hold up well, many break after less than a hundred rounds, or the tip will bend. They are made of softer steel than the Ruger factory pins.
What you can do, is order a spare from a Florida company called Iron Sight Precision. These are quality, heat treated stainless pins and appear to be identical to the factory pins, except are oversize in length.
You have to first, ensure that the pin doesn't protrude out the back of the bolt, when the pin is pushed forward. My factory pins are slightly below flush when the pin is all the way forward. The Iron Sight replacement pin. when test fitted into my bolts, fit below flush in one, and in the other, way sticking out. That is why Ruger won't sell you a pin to put in yourself, all Mini bolts are slightly different. To get the new pin to fit farther inside your bolt, you will have to relieve the tapered shelf part way down the pin, with a milling machine if you have one, or just with emery cloth, until it goes further inside the bolt, matching the fit at back of your factory pin.
One thing to check before going further, is to make sure the face of your bolt does not have a raised rim around the firing pin hole. Mine did not have this machining mark, but if your's does, it will need to be removed to ensure the face of the bolt around the firing pin hole is smooth and even.
Next you will notice that your new replacement pin is sticking out of the bolt face a lot more than the old pin (this is "protrusion").
I cannot tell you exactly how much protrusion you should go for, as all Mini's differ slightly, but as an example, most Mini's seem to have around .030" to .032" tip protrusion. An AK or SKS might be as much as .050" or more. What you want to go for is more protrusion than the factory pin, but not so much as to pierce primers if you happen to switch ammo and fire some Boxer primed ammo like W-W or PMC. I took off the tip of my new pin, using emery cloth, until I had what I measured as .038" protrusion.
Brownell's sells a firing pin protrusion gauge for $40, that would be worth it if you are going to fit a lot of spare pins. If you are only going to do one, you can get by with using some auto feeler gauges.
I tested 60 rounds of Tula with the new pin, and had all ignite reliably. (Tula seem to be the worst for the Mini, due to the primer being seated deeper in the case, the Mini usually has a hard time reaching them). I then shot 50 rounds of my hand loads, loaded with Winchester large rifle primers, and a box of 20 PMC FMJ factory loads. All were fine, firing pin hit was deeper than the factory pin, but no pierced primers. If you over do it and try too much protrusion, you will pierce a primer. Make sure you are wearing good safety glasses when you test fire! That is a good practice when doing any shooting.

Here is the link for the Iron Sight Precision firing pins:
Ruger Mini 14 Firing Pin
I bought mine off E-Bay but had trouble locating it doing a few different searches. I have recommended these on other forums, so it appears people have been ordering them, it looks like Iron sigh Precision is out of stock at the moment, they probably didn't anticipate the demand that was there for a good quality spare pin for the Mini.
 

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Nice write up T. The rear of the firing pin is just as important as the pin protrusion at the face of the bolt. Good info bro.
 

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Nice article, thanks. I also own a Mini-30. Have been running it on a steady diet of Silver Bear ammo. Mine eats this ammo like potato chips. Others' experience may vary.
Happy Thanksgiving.
 

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Very nice write up. I ordered a new Mini-30 in the early 90's. I only used good brass cased ammo and after shooting up a few boxes, I started to work up some loads for it. The problem was that I went through a half dozen different powders and many different brands and weights of projectiles and could hardly hit paper at 100yds.

I knew I wasn't going to have a M.O.A. Target gun, but minute-of-deer would have been acceptable. It went bang every time I pulled the trigger but was just horribly all over the map. I slugged the barrel thinking I may need to use bullets larger than .308, but it checked out fine.

It turned out that inaccurate guns are neither interesting or fun so It accompanied me to the next gun show and didn't come home. If I had that happen to me now, I'd ship it back and let the factory solve the problem. I'd like to come across another one because I liked the rifle. Besides, I still have dies and all my brass that I came across the other day.
 

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Very nice write up. I ordered a new Mini-30 in the early 90's. I only used good brass cased ammo and after shooting up a few boxes, I started to work up some loads for it. The problem was that I went through a half dozen different powders and many different brands and weights of projectiles and could hardly hit paper at 100yds.

I knew I wasn't going to have a M.O.A. Target gun, but minute-of-deer would have been acceptable. It went bang every time I pulled the trigger but was just horribly all over the map. I slugged the barrel thinking I may need to use bullets larger than .308, but it checked out fine.

It turned out that inaccurate guns are neither interesting or fun so It accompanied me to the next gun show and didn't come home. If I had that happen to me now, I'd ship it back and let the factory solve the problem. I'd like to come across another one because I liked the rifle. Besides, I still have dies and all my brass that I came across the other day.

1466,
When you slugged your barrel what did it measure? There's an ongoing debate over the true bore size of the 30's. I recall an article in American Rifleman (late 80's maybe 1989) in regard to the Mini 30. It stated the bore size was .308. I don't think they would have published that data if they hadn't received that info from Ruger or actually slugged the barrel themselves. I had that rag for years but can 't find it now. It had a red cover with a picture of the Mini on it. Wish I could find it.
Any info would be appreciated.
 

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Discussion Starter · #7 ·
The guy that wrote this article claims that senior personnel at Ruger state that no Mini-30's were ever made with a .308 bore, and that they'd like to actually see one, and not just hear about one that someone once owned. Not sure where he got his info, it would be nice to verify by talking to someone at Ruger, like a historian or engineer, not just the lady who answers the phone when you call Southport.
Real Guns - Ruger's Mini Thirty Tactical Rifle Part II
 

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The guy that wrote this article claims that senior personnel at Ruger state that no Mini-30's were ever made with a .308 bore, and that they'd like to actually see one, and not just hear about one that someone once owned. Not sure where he got his info, it would be nice to verify by talking to someone at Ruger, like a historian or engineer, not just the lady who answers the phone when you call Southport.
Real Guns - Ruger's Mini Thirty Tactical Rifle Part II
I read the complete series over on the PU. It was entertaining but his claim without substantiation holds the same credence as the article published in the American Rifleman. I doubt a national magazine would publish information without some sort of verified information or knowledge. In regard to the Real Guns authors statement, I'd want names, employment history and a first hand statement from these employees before I'll give it any weight. Without that just hearsay. As we have discussed before, calls to Ruger CS often times gets a number of different answers.

In the post by 1466 he stated he slugged his barrel and his .308 bullets checked out. That is why I asked him what the measurement was. Hopefully he'll chime is with some info. Until some verifiable proof is produced I'll put more faith in the American Rifleman than the Real Guns article.
 

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I have a M77mkII in 7.62x39. I called Ruger and was told my barrel was .310. I have hand-loaded for it using .311 projectiles. It seems to like the Hornady's the best. Although I also have a GSR in .308, I will stick with .311s for the M77.
 

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One mini 30 owner said Ruger changed to the larger bore in summer of 1990, and another owner said 1993, so ???. Of course, history and memory don't often match up. I would assume that any rifle getting warranty work needing a barrel replacement would have ended up with new .310 bore barrels after that time.

EDIT: I googled this and came up with this info...

In a 1990 article in the American Rifleman, CE Harris discussed the Mini-30 quite a bit and stated ..."the SAAMI chamber is based on the one by Ruger in the Mini-30, which follows the form used by Lapua. It has a gradual forcing cone to ease the bullet transition from the .311 ball seat, into the Ruger's .308 groove dia. , vs .310-.311, common in Euro rifles of this caliber. In pressure testing, the effect of tighter .308 vs .311 groove dia was LESS than the influence of common throat variations."
 

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Just shot my first year of production Mini 30 today. Re-mounted a scope after losing some parts (now secured with Locktite). Feeding it Tula steel cased ammo. I get a FTF one of every two hundred rounds or so. The thing isn't incredibly accurate, but will punch out a bullseye at 25 yards, and will do so at 50 using a shooting stick. I think even on a bench rest at 100 yards it would not do so well, but still cheap shootin' fun.
 

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This information came from Brownell's gunsmith supply tech information about the groove dia. for the Ruger mini-30.



Ruger Mini-30 bore specs


This rifle is chambered for the 7.62 x 39mm cartridge. This cartridge, traditionally, uses a projectile with a nominal diameter of .311 to .312 inch.

At the time the Mini-30 was introduced very few bullet makers where producing .311/.312 inch bullets for reloading in the light 125-130 grain weight required. Ruger initiated the use of barrels with a groove dimension of .308 inch and a long tapered throat. The throat allowed the use of ammunition with .311/.312 projectiles by gradually squeezing them to the .308 diameter. In addition, ammunition loaded with more commonly available .308 diameter bullets could also be used.

Commencing in 1992 Ruger initiated a change to using .311/.312 nominal groove diameter, 1-10 inch right hand twist barrels in all Mini-30's. It was likely well into 1993 before all rifles coming off the production line incorporated the .311/.312 barrels.
 

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One mini 30 owner said Ruger changed to the larger bore in summer of 1990, and another owner said 1993, so ???. Of course, history and memory don't often match up. I would assume that any rifle getting warranty work needing a barrel replacement would have ended up with new .310 bore barrels after that time.

EDIT: I googled this and came up with this info...

In a 1990 article in the American Rifleman, CE Harris discussed the Mini-30 quite a bit and stated ..."the SAAMI chamber is based on the one by Ruger in the Mini-30, which follows the form used by Lapua. It has a gradual forcing cone to ease the bullet transition from the .311 ball seat, into the Ruger's .308 groove dia. , vs .310-.311, common in Euro rifles of this caliber. In pressure testing, the effect of tighter .308 vs .311 groove dia was LESS than the influence of common throat variations."
Hatchet,
BINGO!!! I'll have to say this article was the one I'm referring to. I was thinking 1989. Not too far off for 25 years ago.:D I remember the issue of excessive pressure being addressed in the article and it stating that pressure was a non issue and no ramifications from shooting .311 ammo. Has to be the same article. Can you post the link. I'm heading for Google to see what I can find. Thanks for the post.
 

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1466,
When you slugged your barrel what did it measure? There's an ongoing debate over the true bore size of the 30's. I recall an article in American Rifleman (late 80's maybe 1989) in regard to the Mini 30. It stated the bore size was .308. I don't think they would have published that data if they hadn't received that info from Ruger or actually slugged the barrel themselves. I had that rag for years but can 't find it now. It had a red cover with a picture of the Mini on it. Wish I could find it.
Any info would be appreciated.
Well I'll be dipped if I can find the actual article. I did find a picture of the magazine. Top right corner. Red cover with our beloved Mini pictured. I'm heading for the attic. Without the actual article confirmation all is still speculation.



Edit to correct myself: Evidently, if the 1990 article posted above is accurate then I'm confusing it with the issue of American Rifleman I was referring to. I've subscribed to American Rifleman for 35 years so a good chance I read that one also but can't pinpoint the issue. A good possibility I'm cross referencing them. I did find the issue I was thinking of and it is dated April 1987. Dang time is flying by. Closing in on 30 years. I can't find my issue so for kicks I'm going to order one up. Be interesting to see what it says. If anyone knows the actual 1990 issue that has the Mini 30 article please post it up. Got to get that one also. Thanks.
 

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Discussion Starter · #16 ·
It's possible that Ruger was still putting .308 barrels on Mini's in 1989 or even later, as they tried to use up those barrels. But the older of my two 189 series Mini-30's was made in late 1987 or early 1988, and it has a .310 bore. A guy named Beck over on PU has one made about the same time that has a .308 bore. So as those Mini's were being assembled, production workers were grabbing barrels from both piles.
 

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When I slugged the barrel It measured .308. I tried everything to make it shoot, but it just wasn't in it. This was done in 92. I don't have the rifle, but I still have all my shooting notes, dies, brass, and the actual slug. I can give the serial number and I think I can find the business card of the guy I sold it to.
 

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When I slugged the barrel It measured .308. I tried everything to make it shoot, but it just wasn't in it. This was done in 92. I don't have the rifle, but I still have all my shooting notes, dies, brass, and the actual slug. I can give the serial number and I think I can find the business card of the guy I sold it to.
Thanks for the valuable info. I'd love to have the 1990 American Rifleman article in hand. The 1987 edition with the red cover I posted was more oriented to reloading, though it did have a portion of the article devoted to the Mini 30 with the .308 bore. I wish I had my original Mini 30 back. Bought a 7.62x39mm AR instead. I would have loved a Mini but with the questionable QC of today I didn't want to roll the dice.
 

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Bepe, I wish I'd have kept that rifle now too. I was kinda mad at it at the time because I couldn't make it do what I wanted. I'd love to try to make it sing now with the knowledge and experienced gained in 25+/- years. 7.62x39 was the third round I began loading. Another interesting thing is that my dies came with two expander balls, one for .308 and the other for .311. They haven't been out of their box in 25 years either.
 

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I just wanted to concur with the original post. I have done what Sandog did, actually before he he put the Florida made firing pin in his rifle.

http://rugerforum.net/ruger-semi-au...3-series-mini-30-selling-my-183-series-2.html

Just as a refresher. He had suggested to me to buy the one listed in the original post. Now I never used Tula but it shot Wolf fine and Yugo Berdan primed brass rounds just fine. I didn't use one of Midway's depth gauges, just digital calipers. 0.038 is about the protrusion I went with. I've put about two hundred rounds through it since the new firing pin was installed. Only twenty rounds were of boxer primer, the rest were all Russian Berdan primers. I don't know if the rifle has the Ruger stock hammer spring or a Wolf extra power as I bought it used. I think it is the stock spring. Either way I had no failures to fire at all. Did have some failures to feed just on the first round with ex Soviet made ammo however. But that's a problem with the magazine feed lips being a tad low. Other than it was fine, worked no issues.

*Edit

Before I forget also stone the face of the bolt. Sometimes when Ruger finishes milling the firing pin channel it creates a divot on the firing pin face. I'd stone it flat by hand and I did that with my rifle.
 
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