Safe to tap a polymer lower?

[DSPLCD1]

I recently replaced the pistol grip on my S and W MP15/22, after a range day with heavy handling, I noticed the grip coming loose. Mr. Hercules decided to tighten it up a bit and felt it starting it to slip. Can I tap it for a larger bolt???
Thanks.

 

[Mr. Katanga]

You could but those poly lowers are a pain in the ass, ive learned my lesson on them and with aluminum stripped lowers going for 50-60 bucks thats your best bet, if your wanting to fix that one I would try using a heli coil, thats probably the strongest way to fix it and you can use the original bolt.

 

[FrankT]

You really put some pressure on it as I have changed a few out and never stripped one. I would replace the lower as stated above.

 

[ksenter]

You really put some pressure on it as I have changed a few out and never stripped one. I would replace the lower as stated above.

still serviceable, why replace? Its a non-integral part. If the grip fails, there's no issues, just not as useful. edit: Rear takedown pin may suffer however, didnt think of that initially.

Not gonna be able to drill and tap like metal as easily as the polymer will melt on ya quickly. Here's an idea or two for ya.
1. as stated, helicoil
2. plastic-weld
3. freeze the plastic before you drill
4. nutsert

give er hell and lets hear some results.

 

[DaSandmanCometh]

Here's how you fix this situation. You get a some threaded aluminum tube, drill out the hole in the lower to fit the tube. Mix you up some epoxy, scuf up the outside of the tube and glue the tube into the lower.

 

[CCHGN]

I second the JB weld. I'd shoot that in there and run the screw in and clamp it. Btw, what are you doing with a .22 to break it up?

 

[Cjones]

15-22 is not a standard lower and cannot be replaced other than factory

 

[FNHman]

Drill out hole with low speed in small increments use a depth stop if using a hand drill as the plastic tends to pull you in deeper, then helicoil.

 

[Mr. Katanga]

Just realized that it was a 15/22, yeah use the heli coil and take your time.

 

[DSPLCD1]

I second the JB weld. I'd shoot that in there and run the screw in and clamp it. Btw, what are you doing with a .22 to break it up?

Fitment wasn't 100% when I installed it. Will try the helicoil and post results.
Thanks for the advice everyone!!

 

[Calculated steps]

If your going use a helicoil you have tap the old hole out. just find the bolt to those threads do away with coil.