My son has a BPS with a synthetic stock that is too long for him. While I have shortened several wooden stocks I have never done a synthetic stock. How is the recoil pad attached (no screws apparent)? How much is safe to cutoff. I need to remove about 1/2 inch. Thanks for any advice and instructions.

I can't speak for a BPS, but I've shortened several plastic stocks over the years. Let me hasten to add that I am not a gunsmith and this is how I did it. There may well be better ways.

First, most of the pads I've run into on syn. stocks are screwed into places molded for the screws in the butt of the stock. It's certainly possible that your BPS is glued on, however. Either way, you'll probably remove too much plastic for the screw holders to still work, if they are there. The only problem is, it is possible the BPS pad has screws and if you don't remove them you might hit them when you cut the stock.

Cutting stock is pretty straight forward, can be done any number of ways. I typically put masking tape in a double or triple layer around area to be cut, carefully mark the cut line by measuring from butt all the way around and cut with a finer tooth cross cut hand saw. A bandsaw or even a table saw would work, but the speed of the cut makes for a greater chance for error. Depending on what kind of saw you used and how good a cutter you are, you might have to flatten/square the cut with some sandpaper. Because of this, you might want to make you initial cut a 32nd or so shorter than you final measurement. You also might consider if you want to alter the pitch before starting the cuts. As in most things with gun work, a slower pace is usually better than faster.

Once cut, I make a wooden plug, roughly the size of the remaining opening. If there are remnants of the screw holders in the plastic stock, depending on where your new pad's holes are, you might have to relieve them with a dremel tool or similar, but probably not. The plug doesn't have to be an exact fit, just close enough for the epoxy to glue it in. It is fairly easy to shape one with a grinder or even a pocket knife. I'd use some wood that will take a decent screw. Walnut would be a good choice. Pine might be a bit soft but would probably work if you got some tight growth line wood. After getting plug more or less to shape, remembering that the stock tapers, so the plug has to taper a bit too, epoxy it in place. After it has cured, drill a hole for access to stock bolt. Alternatively, you could just cut plug in two before gluing but that would probably make holding and alignment before epoxying a bit more difficult. You want the plug to be flat/perpendicular with the edges of stock. Again, a bit of sanding might be necessary.

Then I'd get new pad, and position it, then drill guide/relief holes for pad screws in wooden plug and screw it on. This should be obvious, but the screw holes should be quite a bit smaller than the thread outside diameter. Typical is for the hole to be about size of shaft that thread comes off of, depending on how brittle wood is.

BTW, over the years, I've run into some pad screws which are the standard straight slot. I would suggest replacing them with similar Phillips. It makes getting them in and out a helluva lot easier.

Of course, you'll have to fit pad to butt but that is standard procedure in any stock shortening process. If you're in a rush, you can skip it. IMO a bigger pad spreads the recoil. It looks like hell, but it feels good when you shoot.

The description is harder than the process.