While I agree WHOLEHEARTEDLY to the general message of the post, there may be a bit of miscommunication here. MGL 131 and 129C (not 131L) pertain to Appleseed and the nonlicensed use/possession of firearms and ammunition at a range for purposes of instruction, marksmanship, competition, etc. Section 131L has to do with "safe storage" law. The changes made to subsections b, c and d of 131L basically increase the existing penalties.
I'm unaware of any changes in H4121 that would affect the relevant portions of supervised furnishing firearms to minors (and other nonlicensed individuals such as non-residents who don't possess a non-resident LTC/FID).
That said, the bill itself contains certain sections- 131L amendments included- that affect all of us. In my opinion, the number one factor is that like the 1998 Chapter 180 legislation, this bill is going to contribute to a significant decrease in gunowners across the state. That is contrary to our goal of increasing ownership and marksmanship among our students and it WILL affect Appleseed. Barring unforeseen problems at work, I will be at the State House on Wednesday and I suggest anyone else who can make it, arrange to speak with your legislators. If you can't make it- you know what to do. Call, write, and get everyone else you know to do the same.