Hamish wrote on Nov 21^st, 2017 at 6:08am:

. . . spelling mistakes in front of your eyes. . .

Seems to me "but if" is spelled correctly - it just appears to have been carelessly typed if "bit of" was intended, leading to confused readers. (I wondered perhaps "but if history" is a new scholarly pursuit, as in - ". . . but if the U.S. had adopted the Mosin . . .")

Errant spelling is often a product of the educational system and hence not the writer's fault. Proofing text for typing errors is a heap easier than spelling.

Poof indeed, deacon!  ;)