Warbird Information Exchange

Didn't they usually adjust the fire to converge at a certain distance and if so what was the usual distance?

I think I've read that the usual convergence (and sight-in) distance was around 300 yards but some pilots preferred other distances.

And some didn't like the rounds converging and preferred them shooting straight ahead.

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Daviemax
Researcher of Post-War B-17 History
Maintains database of B-17s used from 46- on.

Thanks for the replies. I had wondered if there was an allowance for personal pilot preference or if the distance was mandated by military regs. I have to wonder how any aligning of the guns was done when the need arose on board a carrier.

You can use a reduced range target and boresight. Since the ballistics are well known, and it's pretty simple to figure, if the bullet hits here at 30yds, it should hit here at 300,
I have also read of pilots asking pairs of guns to be set to different convergences. Say, one pair at 325yds, one pair at 300 and one at 275 to give a larger 'beaten area' on softer targets.


Another issue is dissimilar ballistics on aircraft with mixed cannon and MG armament. 20X110 and .50BMG have roughly similar trajectories, but the German MK108 lobbed a shell in a rainbow-like arc compared to the 13 or 15mm guns.

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Lest Hero-worship raise it's head and cloud our vision, remember that World War II was fought and won by the same sort of twenty-something punks we wouldn't let our daughters date.