Are there any lubes known to be OK on the plastic over the long term?
There are a few things you should keep in mind when lubricating a polymer lower. First, make sure to use a quality lubricant that is designed specifically for firearms. Many shooters prefer MIL-SPEC grease, but there are also many good brands of synthetic oil on the market.
Next, be sure to apply the lubricant sparingly. A little bit goes a long way, and it’s easy to over-lube a firearm. Excess lubricant can attract dust and dirt, which can lead to reliability problems. Finally, be sure to clean your firearm thoroughly after lubing it. All of the accumulated dirt and grease will need to be removed if you want your weapon to run smoothly.
If you follow these simple tips, you should have no problem lubricating your polymer lower. Thanks for the question!