Varying the torque of the gas block screws works very well, in essence you are tuning the gun to a specific load, rather than tuning the ammo to the gun as in handloading, or buying a bunch of different factory ammo in the hopes that one or two shoot better.
I found that torques from 20 to 25 in. lbs. resulted in groups that were nearly half as big as those shot with 30 to 40 in. lbs. But those are my Minis, yours might like a bit higher than 20 or 25 in. lbs.
Once you find the torque that works for the ammo on hand, use some Locktite on the screws, especially important if you are running low torques.

So with the Picatinny rail you showed, are you just wanting to mount a light or Q.D. swivel out there ?
$60 seems like a lot for a tiny piece of rail, that money could be put towards an Ultimak or Samson railed handguard. Then you'd have the very best place on a Mini to mount a dot or LER scope.

As far as some rail to mount accessories, I use a pair of Magpul rails and mount them to the end of the fore end. You could mount another on the bottom of the fore end if you prefer that to side mounting.

The short chunk of rail is much more useful than just a swivel mount like this :

Ultimaks and accessory rails on the stocks of all these:

As far as using the short rail that you already have, it's 4 screws just like a gas block right ? You're just replacing two of them.
Tighten all 4 in an X pattern just like you are tightening the factory gas block.

 

 

The most important thing to know when tightening the gas block to the correct torque, is tightening them evenly. The gap should be the same on both sides for the entire length. You can see in this pic how it is uneven. I have found that even the slightest bit can affect accuracy. You can use a pair of calipers to measure the gap.

 

Yes, this too ^^^^^^.
Sometimes my mind isn't in gear yet at 3:30 AM.

I understand that obvious unevenness is not good. I've always eyeballed the gap, never measured.
Seems to work as my 30 does close to MOA with good bullets like the SST in a handload, or the Silver Bear factory ammo.
My friend Curt, a forum number here, has shot a few 3 shot groups at 200 yards with cheap factory Brown Bear in his 14 that were nickel size. Coyotes don't stand a chance.
Dang, Curt, we need to get back to that area, 1200-1400 yard shooting if you want to shoot that far.

I don't believe Curt gets out the calipers to measure the gap either and he's the best shot with a Mini I've seen.
You can measure if you want, but "eyeballing" the gap is fine.

Where I see a need for a tool is having an inch pound torque wrench like the Wheeler or similar.
But for the first 20 years of Mini use ( bought my first Mini -14 in 1980 after Army service), I just tightened the gas block by "feel". I used the short end of the Allen wrench to hold onto and once it became uncomfortable on my fingers I stopped.
After I got my torque driver about 6 years ago, I used it to check my "by feel" torque, and it was right at 30 in. lbs. Not too bad for a guess.
But these days 25 in lb. results in tighter groups, for me anyway.

 

Yes, eyeballing the gap front to back works, but the calipers help when comparing the right side to the left side. And my eyes suck. Lol. Either way, I feel it is an important step that is often overlooked.

 

Feeler gauges instead of calipers.
So, I guess my question is…why does the torque on the gas block effect the accuracy so much?
Barrel harmonics?
Amount of gas getting by?
Rigidness of the assembly?

along that thought, do the barrel stiffeners work on the 580 series of Minis? Or did the heavier barrels take care of that?

 

As per Mfr of AccuStrut, the dual clamp AccuStrut "may" improve later heavy-barrel Mini-14s--or may not: Thick Barrel Results Since all Mini-30s had heavier barrel profiles than did the early Mini-14s, I would guess that the result of installing AccuStrut onto a Mini-30 would be similar to result of installing onto a heavy barrel Mini-14.

Perhaps a Mini-30 expert cam chime in.

 

Thank you for your thoughtful and detailed response. I have included photo of my rifle. I have a Samson Hannibal rail and Burris Scout scope. I find that the with the scope, either the turrets or the QD scope mounts interfere with the any accessory mounting along the side of the Hannibal. The QD swivel looks like it will mount okay.

I actually got that add OEM Ruger picatinny tail in order to mount a Harris bipod. That is the primary use for it. Do you feel that I would be better served by removing that, reinstalling the original lower half of the gas block? It is difficult to describe but the way that rail installs is two screws underneath it that you have to tighten first and two long screws that secure the rail to the barrel. I do have a proper torque wrench in order to assure an even tightening.

 

Barrel harmonics.
I figured that since the Mini shot better with lighter screw torque, it should stand to reason that Minis would shoot best if allowed to "run naked", without any gas block, or bipod or sling pressure.

But we wouldn't have much of a semi-auto without the gas block there.

I tried the screw torque thing on a 10/22 International I got a few years ago.
With a little experimentation I found that I could really shrink groups with any ammo I tried by finding the stock screw torque it liked.
Cheaper stuff like Federal Automatch and Rem Goldens only had one sweet spot, and that was on the lower end of the scale, 12 to 14 in.lbs.
Better ammo like several brands of Subsonics and Match ammo usually have several sweet spots, like 14, 16 and 18 in.lbs.
The better quality ammo doesn't need as much help as the bulk stuff.

Then last year I got a Ruger American in .22 mag. I found that the lower stock screw torques were better with the heavier bullets from 40 to 50 grain.
The 30 and 33 grain zippy JHPs liked higher torque better.

I talked about this on a few rimfirecentral threads, and a few understand and said they found similar improvement by tickling their screw torque, but a few said no way that the stock screw can help groups and change harmonics.
I showed them targets where I went up 1 in.lb. at a time, and there was definitely a sweet spot. I hate it when someone tells me to not believe my own eyes 👀.

I had doubts that tightening the stock screws on a bolt action that had a really free floating barrel would do anything.
It does help, just not as much as a barrel that has contact with the fore end.
It seems that the torque of the action in the stock can be tweaked for the better as well.

 

So, I have Two basic questions now after having started this thread. First, is tightening in an X pattern crucial? As you can see by the photo, the Picatinny rail that I have installed at the front of the foregrip is held in place by 2 screws that secure it to the lower half of the gas block and are long enough engage with the upper half of the gas block. Thus, when you install it you have to tighten the two of the original gas block screws (the ones closest to the foregrip), slide the Picatinny rail in place and install the other two screws for the rail / gas block. This prevents tightening in an X pattern. The second question relates to potential accuracy problems I may be introducing with using the Picatinny rail as a bipod mount location. Am I introducing a whole other set of variables by mounting the bipod there?

 

I don't think the bipod use will flex your gas block or anything.
If the rail stuck way out that would put a lot of leverage on the mount and gas block.
You should be fine.

What I don't like to see are those bipod and swivel mounts that clamp to the barrel in front of the block.
Not good on the Mini platform to clamp more stuff directly on a barrel that would prefer to "run naked" if it could.

Better yet would be to put the bipod on a short piece of rail screwed onto the bottom of the stock.