Hello

I plan to install the ratchet castle nut. Is it still important to follow the torque specs or is a much less torque enough? The ratcheting system seems to hold it very secure.

I'm worried about twisting the lower receiver if I torque it to 40 ft. lbs because I only have the magwell vise block.

The installation guide is a bit vague, it just says: "Continue tightening until the buffer tube will not easily rotate when twisted with one hand. From slight buffer tube rotation to fully tightened will be about two clicks of the ratchet lock system."

Do I need a torque wrench?

In my experience with the PWS Ratchet System, overtightening leads to issues so I stopped using a torque wrench and everything has been holding just fine.

You won't twist the receiver torquing to 40 ft-lbs with a magwell block. That said, based on what you quoted of the installation instructions, sounds like you might not hit 40. Also, you should always have a torque wrench

I wish I could give you a better answer because I do use a torque wrench on a lot of things, but:

I use a magwell vice block, grease the threads, install everything hand-tight, put the buttstock on, and tighten to 1 ugga dugga while holding the stock. Then I check that the stock is straight, and try again if it isn’t. I’ve done a few PWS ratchetyy ones, and a few other types. I’ve got a high-use working gun that’s had one for 4 years and around 40k rounds with no issues related to that. Its also been dropped, etc.

I didn't torque mine to any spec. Went tight plus 1 without a vice. I'm at about 2500 on it and it's been flawless

I don't remember specifically, but I believe the instructions tell you to tighten it 2 clicks, and you're good.

I have the same system on my MK212.  I hand tightened the ring and it hasn’t moved one notch. I took it to a 500 round carbine class and held up amazingly