The 15-22 has a 10” handguard. I’ve found this sufficient for even a c-clamp style grip. If not, the barrel nut swap and hand guard of your choice is relatively inexpensive.

I’ve looked at the kriss and although tempted, decided that you can’t beat a 15-22 for a .22lr dedicated rifle when it comes to price, customization, magazines and reliability. If I wanted an all metal AR-22 trainer, I’d buy a CMMG conversion bolt and mags or PSA upper for my AR-15.

Thanks for your take.