Useless Question

[REDLINE]

With a 10mm Auto 200gr XTP load that achieves 1250 FPS from a 4.5-5 inch barrel, how long would a barrel have to be at the point where the bullet never made it out of the barrel?

Just something I was thinking about for no intelligent reason and have yet to begin to know where to start with an answer.

[cmemiss]

I'm just a simple J-school/humanities major, but it seems to my simple mind that there are waaay too many variables to the question, i.e. barrel fit/friction, different powder used giving off differing gas volumes, and on and on.

[The_Shadow]

Well it will be a frictional coefficient that continues to act to slow the travel of the bullet.  Sort of like water n a fire hose.  We used to compensate for the friction of the water flowing in the hose, the gallonage flow rate and any fittings or appliances.   We also had to take in account the elevation +/-...

There is rotational drag and barrel friction as the bullet is being pushed by the gases and that expansion of gas will fall short faster.  Eventually the energy will run out at some point...where I have no clue!

[cmemiss]

Shadow,

Does 29.7 x D squared X Sq. Root of NP ring a bell.  If so, hello brother.

[The_Shadow]

Yes it does, brother.  I was just reading your Bio on the intro section! 

[REDLINE]

No doubt there would be a range of possible variables, different but the same as there are for what speed the same round will achieve through different 5" barrels from different manufacturers.

I'm just wondering loosely, as opposed to narrowing it down to the nearest inch or so from a given specific barrel.

Would 4' do it?  More?  Less?