BUIS question

[engineer151515]

I'm looking at a Midwest Industries (MI) BUIS for an M4A3 Bushmaster with the stock fixed front sight.

Would a SPLP (same plane low profile) BUIS work correctly or is their ERS (emergency rear sight) the correct choice? Other than one being a "low profile design", I'm not sure if there is a difference where one sight is used only with gas block front folding sights or whatnot.

Thanks

[Constructor]

The same plane sights are made to mount on a rail or gas block the same height as the receiver, all rear sights should be the same height.
If you plan to mount a front sight on a lower gas block then you need to buy the taller front sight.

[engineer151515]

This was helpful.
Thanks