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/...Ruger used as their design basis the M-1 Carbine of WW II fame. It was designed for the 30 Carbine cartridge which was essentially a pistol grade cartridge. Stepping up to more powerful cartridges without strengthening the original design did not give good results.
I learned years later that after the using public complained bitterly Ruger hired one or two independent gunsmith/engineers to make the Mini 14 more accurate. Their final efforts were deemed too heavy for commercial sales. ....
A superbly accurate rifle requires an action that has its 'mass' in the proper places along with a long stiff tendon. The Remington '700 is better in these features than the Winchester '70 and thus became the standard design of a long distance accurate rifle. The Mauser is good in 'mass' placement but lacking in a good solid tendon. You naysayers may now jump in with your testimonials. .....
I agree with you in theory on the benefits of stiff actions and barrel tennons in bolt action rifles. However, at practical ranges a well made Mauser or Model 70 (a Mauser derivative) will still shoot far better than the nut behind the trigger. And for that matter a poorly made Rem 700 won't out shoot either of the other two. Differences in barrel quality far exceed the differences due to action and barrel tennon stiffness in the real world.
It's also an apples to oranges comparison. I get 1/2 MOA accuracy on my AR-15 bull barrel varmint rifle and neither the action nor the barrel tennon is anywhere near as stiff as a Mauser or Model 70 bolt action.
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I disagree with you entirely that the .30 M1 Carbine was the design basis for the Ruger Mini 14. While the M1 Garand, M1 Carbine, M14 and Mini 14 all share rotating bolt configuration, the gas systems are all distinctly different.
The M1 Carbine uses a short stroke gas tappet to drive a fairly heavy slide/operating rod. The piston's movement is not much more than about 1/4", but it's enough to get the heavy slide moving to complete the cycling of the bolt.
The M1 Garand used a long stoke gas piston system, where the piston was on the end of the operating rod and ran inside the gas cylinder, with the other end of the operating rod camming the rotating bolt open and closed. This gas system was very sensitive to gas port pressure and slow burning powders could create excessive pressure that would bend the operating rod.
The M-14 was an improvement on the Garand's gas system in terms of using a short stroke gas tappet. The stroke however was about 4 times longer than the tappet on the .30 M1 Carbine. However, like the M1 Carbine, it was much more tolerant of wider pressure ranges.
In contrast to all of the above where there is a piston that moves, the Mini 14 uses a gas pipe fixed to the gas block that then drives a comparatively heavy slide assembly. It's considered to be a short stroke system, but the "piston" action is again 3 times longer than the gas tappet movement on the .30 M1 Carbine. Since the "piston" is fixed, the cylinder (which is a hole in the front of the slide moves aft to create the piston stroke before the gas is vented.
The gas system design on the Mini-14 actually has a lot more in common with the gas system design on the FN FAL, which uses a similar fixed gas pipe, as does the AR-18 / AR-180 rifle.
In terms of the trigger group the Mini 14 has a lot more in common with the M1 Garand and M14 than it does with the M1 Carbine.
In short, aside from the rotating bolt and general shape and of the slide, the Mini 14 has very little in common with the M1 Carbine.
The Mini 14 is a very reliable design. Don't confuse "reliability" in cycling with the potential for breakage. And the major problem with wear and parts breakage (particularly in the selective fire versions) stems from the severe over gassing of the action. The standard gas bushing is around 0.080" in internal diameter, when it's rare to encounter a Mini-14 that needs more than 0.045" or 0.050" to cycle reliably. All that extra gas just needlessly increases slide and bolt velocity, which in turn and increases wear, and increases vibration in the rifle, aversely affecting accuracy.
The accuracy treatment I give my Mini 14s (described above) will turn a 1-10 twist pencil barrel Mini-14 into a 1.5 MOA five shot group rifle at 100 yards with quality 55 gr FMJ ammo. I'll argue that it's what the Mini 14 should have been in the first place when it was introduced in 1973.
That 1.5 MOA accuracy is identical to the 1.5 MOA accuracy I get with the same 55 gr Hornady FMJ load in my department surplussed 20" SP1 and my M16A1 clone (department surplussed M16A1 upper half on a Nodak Spud NDS-16A1 lower).
Another issue that complicates accuracy in a Mini 14 is the change over the years from a 1-10" barrel to a 1-7" barrel to a 1-9" barrel. Low quality 55 grain ammo generally won't shoot as well in the overly fast 107 twist barrel as it will in a 1-10" barrel, while the 1-10" barrel is just a bit on the slow side for 62 grain M855 ammo. 1-9" is ideal for M855 and works pretty well across the board for anything under about 69 grains.
But if you own one of the older skinny barrel Mini 14s and have no idea what the barrel twist happens to be, selecting the wrong bullet for it is a possibility.
