Re: [CAD_CAM_EDM_DRO] Re: Stainless tubing/gun drill

I presume you are a gunsmith too? If you have a good eye, you CAN simply
look down the bore and SEE if the barrel is straight or not. All you have
to do is look at the grooves. If they aren't concentric with the entry and
exit holes, the barrel in bent.

At any rate, I might like to point out (as we learned in school)...what
difference does a minor amount of non-straightness cause? None! Why?
Well, all things being equal with each shot(angle of elevation, point of
aim, etc.), as far as the bullets coming out of the barrel are concerned,
the bullets will have the same point of impact because the direction of the
bullet leaving the bore will not change from shot to shot.

BTW...a tip most gunsmiths won't tell you is bent barrels can be
straightened...sometimes just by whacking the barrel on the edge of a table.
I even saw this demonstrated.

If you really want those bores straight, devise a means of putting the
barrel liner in tension as was done on the Take down revolvers with
interchangeable barrels. This idea existed long before it was "invented"
(put on the market).

Smoke

> Hi,

> Does anyone know how to inspect/measure the straightness of a bore
> such as a barrel?
> I dont want to make guns, but i do make precision carbon fibre tubes
> on the inside of honed steel tubes.
> After a lot of expensive trial and error I can mould smaller sizes
> straight to 1 in 20,000 (e.g. at 47.6mm dia. i get max 0.1mm bow over
> 2metres).
> On larger sizes, say 130 mm x 3500 mm long I cant afford the trial
> and error.
> someone once told me of an optical technique (you can tell by looking
> at them, he said), any thoughts.
> regards
> Steve
>
>