SP1 lower?

[Sniperfox]

Does anyone have any info as to whether a Colt SP1 lower will mate up with one of the M4 type or carbine type uppers that are on the market today? Such as Bushmaster or newer Colts?

[warlord]

Does anyone have any info as to whether a Colt SP1 lower will mate up with one of the M4 type or carbine type uppers that are on the market today? Such as Bushmaster or newer Colts?
Yes as long as it is a small pin, or you are going to need a converson pin from Bush master for the LG front pivot pin hole.