mos barebones.

[cupid04]

10a] Spanish agreement to deviate with one in the mountains. [6] ?I???A.

15a] Shoot kangaroo's head revealing goo. [sorry, no letters]

16a] Shot a duck about a very small distance. [sorry, no letters]

3d] Part of flight that has street gang bored we hear. [11] S???N?B?A?D.

[Lie-in King]

10a Si-err-a
15a Gun-k(angaroo)
16a Ammo - 'a o (duck)' (about) mm (millimetre)
3d Stringboard - st(reet) + ring (gang) + board = "bored" - "flight" as a staircase

[cupid04]

Thankyou very much Lie-in King.