This rail is badass! Lost all SLR Hand-guards! The hard part is deciding on which unit is gonna work best for you! I run this baby over a 5.5 9mm barrel on my colt pattern QuarterCircle10 sub gun build! & I topped off the barrel with a KAK slim-9mm can which looks awesome poking out the end of my SLR-Rifle Works 7" Solo Series Handguard!!!! Well worth the cash! Only regret is not buying the additional cerakoting finish! Already ordered my 4.25 slr rail for my qc10 40s&w build!