This mod does little or nothing by way of performance-in some cases it decreases range while increasing accuracy; it is meant to be a purely cosmetic mod.
Step 1:First you need the front gun from a Longshot and the barrel from a Recon.
Step 2: Take both apart, remove the barrel of the Longshot, and replace the Recon barrel with it.
Step 3: Use some hot glue to hold it in place, then put the body back together.
Step 4: Take the two front pieces of the barrel, and using a dremel tool carefully shave away the little piece at the end.
Step 5: Put everything back together and your done!