Originally Posted by FullClip
Check out page 10 of your owners manaul:
Through our testing, Smith & Wesson has also found that there
are several brands and types of .22LR ammunition that do not
perform consistently or reliably. Consequently, Smith & Wesson
DOES NOT RECOMMEND that the following brands or types of
.22LR ammunition be used in your M&P15-22 rifle:
• Remington Golden Bullet • Remington Thunderbolt
• Remington Target 22 • Winchester Wildcat
• Any and all sub-sonic brands and types
They specifically tell you not to use sub-sonic ammo. bet they will fix it anyway, but if I were the warranty manager, things would be different.
You'd never know what somebody was shooting, unless they told you.