Saw one from Brownells that just replaces the top on the gas block and has two inch picatinny rails on each side but it was only for the older mini s. Just what I was looking for only need it for a 582 mini
The gas block takes a lot of abuse when cycling, I would not want a device attached direction to the "hammering" affect of the op rod. Have you thought about a UTG rail that will bolt directly to the barrel?
Note of warning: I tried that Brownells integrated gasblock/tacrails product, and the accuracy of my rifle went completely to hell. I could barely even zero the weapon any more. I have no idea why, and don't care as it didn't stay on the gun for very long (I gave it away, not feeling right asking for any money). YMMV.
Somewhere in the archives there is information about two different rails made just for the Mini. If anyone has access to the older posts and can find them, Please let me know because I'm also searching for a rail.
After searching fore rail attachments for my mini 14, and finding none, here is what I came up with.
I purchased UTG 3 7/8" picatinny rails from amazon for $10. I discarded the screws that came with them and purchased #8-32 zinc tee nuts and #8-32 stainless steel machine screws from home depot for $3.
After disassembling my mini 14 and taking out the steel reinforcing in the stock, I applied blue tape to the bottom of the fore grip to prevent marring the finish, and providing an area where I wouldn't mind putting light pencil marks to establish a center line and mark locations of holes. I then drilled out holes in the bottom of the fore-grip just behind the gas block to mount the rails stepping up the drill bit size to 3/16 to prevent tear out in the wood grain, and then finished by drilling from the inside out with a 13/64" drill bit to create a hole just 1/64" narrower than the tee nut to provide a tight fit and clean up the hole. The up shear action of the drill bit drilling from the inside out not only prevented tearing out the outside wood grain, but it actually cleaned it up to a splinter free hole.
After drilling the initial hole for the tee nut, as previously mentioned I stepped up the drill bits from small to large to prevent tear out, I used a forstner bit to drill a flat bottomed hole in the inside of the fore grip to countersink the tee nut the thickness of the head, which is only about 1/32" because the tee nut would prevent the steel reinforcing bar from properly fitting otherwise. After drilling the countersink and the rest of the holes until I got to my finally size of 13/64, I used front snips to cut off the spikes from the tee nut which normal sink into the wood to prevent the nut from twisting (I didn't want to risk splitting the wood in the stock, even with trying to drill a pilot for each one of the spurs to seat into) By simply drilling the hole 1/64" narrower than the tee nut, there was sufficient grip to keep the nut from twisting while trying to screw in the bolt.
One problem with mounting a flat rail on the bottom of the mini 14 wood fore grip, is that the fore grip is not flat. It curves up ever so slightly towards the gas block. To remedy this, I got a piece of dense 1/4" thick pipe wrap foam tape, stuck it to the bottom of the picatinny rail, and used a new razor knife to cut the foam to the width and length of the rail. I then drilled holes in the foam where the picatinny mount holes were, being carefully not to catch the bit on the foam and twist it up.
After drilling the holes in the foam, I mounted the rail to the mini 14 fore grip. First, I took off the blue tape I applied at the beginning. Then, I applied a little blue, semi-permanent loc-tite to the stainless steel bolt threads and mounted the rail to the gun. I tightened up the screw closer to the trigger where the fore grip is flatter, then installed the screw next to the gas block where the fore grip slightly curves up. The dense foam pipe tape did a perfect job of conforming to the fore grip and rail and providing a firm furring strip. The difference from one end of the rail to the other between the rail and the fore grip is only about 1/16" of an inch, but the foam did a great job of filling the gap to prevent the rail from bending and/or wiggling loose. Also, it would have looked mickey moused seeing light come through one side of the rail.
Oh, did I forget to mention I'm a custom wood worker ? This is a job I feel anyone can do with the right tools and attention to detail, but being a finish carpenter certainly helps. My brother, who is a plumber (that's where I found the dense foam pipe tape), I wouldn't trust to do this same job, only because his tendency isn't towards meticulousness. But, like I said, with the right tools and an attention to detail, you, too, can do this. When I figure out how to post pictures of it, I will. It really is a beautiful gun. A blued, wood stock Mini 14 is a good looking gun anyways, but this upgrade doesn't stick out at all as if it doesn't belong. It looks almost like it belongs on the gun, like it was a manufacturer's option. But I'll let you be the judge.
I just registered and haven't figured out how to post pics. If you'd like to see what I came up with just check out a link to my company website. i added a page not in the navigation with just pics of the gun. here's the link