m4 ramped uppers on

[tornado45]

I have two lowers one is a sp-1 and the other is h-bar sporter match.
Any issures with putting a upper that has the m4 feedramp type barrel.
I know i need the off set pin for the sp-1.
Any info would be appreciated
Thank youTornado45

 

[dangertree]

M4 barrel extension + M4 ramped upper = go
M4 barrel extension + regular upper = go
Rifle barrel extension + m4 ramped upper = no go

Hope that helps.