rail options for a g&P 14.5 inch

[harry66]

hi guys,

im after a new free float rail i like the 12.5inch madbull mk18s but they are alot of money and might stick out to short on my 14.5 carbine outer barrel.

can anyone suggest a cheaper alternative to switching rail systems as ive seen replicas around for under £50 new

any advice would be great thanks