Thoughts on a long lead in a barrel

[geocodyrgia]

All, as I know there are a number of gunsmiths on the forum here, I would like to kindly ask for your input. I'm looking at project for reducing the wear in the throat of a barrel, but one of the limiting factors will be the requirement for not having rifling for the first 2-4". Essentially a long, non-tapered lead. I'm still investigating machining tolerances, obviously less is better, but if you have particular expectations you look for that input would be greatly appreciated as well.

So my question is: do you believe a bore diameter lead that is long enough to cover the area that becomes fire-cracked from hot/high pressure rounds would be detrimental to accuracy?

If accuracy in affected by a long lead and the lands/grooves really need to start in very close proximity to the ogive of the bullet as it's seated in the case, I will need to re-work my plans or at least make some changes to how it would be implemented.

Thank you all for any input!

 

[BallisticsGuy]

That's effectively just the pre-wearing out of a barrel. Excessively long jumps provide room for randomness and in my experience are detrimental to the accuracy potential of a rifle/load combo.

If you want longer barrel life: consider bore coatings like chrome lining or nitriding, reduce the operating pressures (which usually amounts to reduce the total amount of powder being burned with each shot), increase the time interval between shots.

 

[DUSTY NOGGIN]

i think you will erode faster .. due to speed while impacting lands

i also think having the bullet still exiting the mouth as the pressure in case is increasing .. allows a better brass seal .. while holding all power in area until powder fully ingnited


also potentially dangerous with low neck tension .. primer could push out to that 4" and leave with excessive ingition capacity .. secondary detonation .???

 

[FEENIX]

For what it is worth >>> https://bisonballistics.com/articles/an-introduction-to-rifle-chambers