I realized that the title of this thread may have been misleading, as the OP did not explain HOW to replace the gas block. Since we can't turn to Ruger for the procedure (they don't want us mess'n with the block), we have to rely on our common sense...God help us...
Anyway, it's not a daunting procedure. Here's how I've done it...Disassembly is self-explanatory. Just use the right size Allen wrench. The most difficult part of the gas block reassembly, at least for me, is making certain that the gas port bushing is properly seated in the shallow depression (port) on the underside of the barrell. I find it easiest to involve my wife, thereby qualifying my gun tinkering as a legitimate family activity. Using both hands on the block, I slide it into place until I feel the bushing move into its proper position on the barrell. There isn't much play there, so it's either in place or it isn't. I hold it there with thumb pressure against the barrell while my wife snugs up the 4 screws well enough to hold it in place. I then torque the screws in a rotating sequence, keeping an eye for a consistent air gap between the upper & lower halves of the block. I use a torque screwdriver set to 28 lbs. of torque, although I don't believe it has to be 28 lbs. exactly, just a consistent tension on all 4 screws is important. It's worked for me.
You'll know right away if you got it right or wrong. Either the rifle will cycle properly and eject the casing when you fire it, or it will behave like a bolt action and cause you to cycle manually. Here's one more thing you can do as a check after it's assembled. Take a short section (maybe 6-8 inches) of automotive rubber fuel line from your garage shelf and slip it over the end of the exposed gas pipe (stock obviously is off & slide assembly removed). You should be able to blow gently through it and hear the air flowing into the barrell. If your face turns red during this part of the process because you can't get air to flow, something is wrong...start over. I keep that little section of fuel line handy for when I clean my Mini's. A quick blast of compressed air through the gas pipe will ensure that the gas system is clear of obstructions or build-up.
Last edited by KMO; 04-20-2010 at 02:10 PM.