I would like to replace the original fixed stock with the Magpul MOE Fixed Carbine Stock - MIL-SPEC version but was wondering how I go about removing the old stock pin holding it in place? Do I need to drill it out and if so, what size drill bit should I use? I don’t want to drill the hole too big to install the Magpul stock. Any information you can provide would be greatly appreciated.

I'm not overly familiar with CA compliant stock but you may have to back off the castle nut and unscrew the entire assembly to make the switch.

I think you can use your existing buffer tube on the fixed stock so you probably don't have to mess with the castle nut. Since I don't live in CA and I'm not sure how they fix the stock, I'm guessing you'll need to drill out the pins on the stock to be able to slide it off. I'm sure another CA resident here can confirm.

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Still carrying my S&W 642

That fixed carbine stock model is new to California as of 1 Jan 2017. Prior to that date, the only difference between Ca. and non-Ca. Sport II's was that ours had the "bullet button".

Have seen reports that S&W used a non-standard length buffer tube in those states where a fixed stock was required. If that is the case, good chance they did the same here. My best suggestion is to contact S&W customer service and find out what you can there.

One thing to take into consideration with the Magpul FCS is the length of pull. The stock length of pull with the fcs is 12.25". They do have an extended pad that also fits the prs stock. It adds another 1/2 inch to the length of pull.

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Peace was my Profession