..so long as you got the plastic seal between the gas tube and the barrel (at the transfer port....it's where the gas crosses from the bottom tube into the barrel) in place and it's not leaking gas when fired. I think you'd have noticed, they tend to squirt gas out at a notcable amount at each shot if it's mangled.
Usually the bolt handle screw wills tay put if you tighten down tightly...some use a thread locker, but it makes it a real pain in the rump to take that screw back out if it's ever needed.
Those "set screws" on the trigger: should be two little ones and a larger one at the bottom, along the back of the trigger guard (but hidden when in the stock). Top one adjusts the sear engagement. Middle one is the overtrtavel adjstment. LArger screw at the bottom adjusts the weight (it sets the trigger spring tension).
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Might want to adjust the trigger.
This isn't the only way, but it works for me.
Start with an empty rifle...no gas.
Take rifle back out of the stock.
Are going to need a small bladed screw driver. Thsoe adjustment screws tend to be a bit soft and easily buggered up..so take time to get a screwdriver that fits the slots with little slack (can use a cheap small screw driver, and adjust it with a fine file until it fits the slots without play).
There are two screws that hold the whole trigger unit to the gas tube. The rear one is in the way for adjusting the trigger screws, so remove it. (The end caps or the gas tube and action can be removed, but all the good parts inside are captured and won't come falling out).
Top screw adjusts the sear engagement..can see it's effects through a little window in the trigger housing. Small movments of the screw seem to have large effects on the sear engagement, so go slowly. Will cock the action, adjust a bit, dry fire, and repeat as you adjust. Want a crisp release, but not so razor fine that it can slip if the rifle is struck.
With the sear engagement adjusted, cock the action and adjust that middle screw in several turns. The rifle won't fire. Keep adjusting the overtravel screw out until the rifle does fire. Add a fraction of a turn out.
Can play with the bottom screw, which does change the spring tension on the trigger, but it doesn't seem to do a whole lot...and if backed out too far, tends to hit the inletting of the stock.
(Some folks will remove that coil spring and substitute a lighter one. The little spring that powers some ball point pens seem to be a favorite.)
Put it back together. Dry fire several times to test the trigger (esp. check that it resets correctly). Test it with the safety ON to be sure it won't fire..and that it won't fire by itself when set on safe...trigger pulled, then released...then safety truned off.
Usual advice is to cock the rifle, safety off, and bump the rifle butt plate on a crapeted floor. I'd advise you to take the butt plate off and bump it pretty hard (those butt plates can crack, we don't want to test them).
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Know it's a pain in the arse, but at this point I'd take it back out of the stock. Won't use a thread locking compound as those screws will need to be adjusted again some time in the future. Put a drop of paint (or nail polish...but don't take your wife's favorite color) to kind of hold them in place. Don't want all this work to just vibrate itself away.
