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cold bore shots

24 Apr 2015
@ 04:03 am (GMT)

john mitchell

I'm curious as to why in some calibers the first And sometimes the second shot are faster than subsequent rounds. It makes sense and is true normally that first cold bore rounds are slower. Anyone have a clue to this conundrum


24 Apr 2015
@ 08:44 pm (GMT)

Thomas Kitchen

Re: cold bore shots
hi john
im having two guess's here at this one.
first you might still have some lubricant in your barrel reducing drag that doesnt burn off until a few shots.
2nd guess is that with clean barrel you have no carbon in barrel after this builds you are reducing the size of bore creating more drag on bullet slowing it down.
25 Apr 2015
@ 09:13 pm (GMT)

Nathan Foster

Re: cold bore shots
Bang on.

Sometimes a bore will get faster if it fouls and tightens in tolerance, raising pressures and velocity

Other times, I note that drag can slow a bullet a down or as Thomas says- lube burns away and drag is increased.

It can go either way.

26 Apr 2015
@ 02:03 am (GMT)

john mitchell

Re: cold bore shots
Thanks Thomas and Nathan . I'm thinking the bore tightening might be what's going on . the barrels I'm shooting over the crony are prepped the same. But I'm just guessing. Thought it was interesting though and I've noted it before.


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