barrel crown

[billy]

Will having a crown reworked on a rifle help even if it was not hurt?

[Dolph26]

I don't know much about the issue, hence my question about the ding on the crown of my rifle, but in doing research on the internet it seems that the crown can have hairline cracks or be off-center even in brand new rifles.  If the rifle will not shoot as it should, most gunsmiths that I have researched will go straight to the crown and re-do it, making sure that it is uniform as it should be.  Like I said, this info is just from what I've researched on the internet, I am certainly not a gunsmith!  The crown is apparently very, very important for accuracy and gunsmiths do not consider re-crowning a muzzle to be a large or difficult job.  Hope this helps.

[7mm MAGNUM]

The crown on a weapon is one of the most important things.

An uneven, or damaged crown will allow the high-pressure gasses pushing the projectile down the barrel to escape unevenly. At the moment the projectile leaves the bore, this will push the rear of the projectile in the direction of the escaping gasses. Furthermore the portion of the bore still in contact with the projectile will cause drag which will add to the affect of the gasses.

ANY deviation in the shape of the crown will cause this to happen with varying degrees of severity.

[gunnut69]

The termius or the very end of the rifling is the important part.  Dings on the out edges of the crown are unsightly but if the ends of the lands and grooves are not damaged there is little to worry about.  The last inch or so of the bore including the terminus is the last part to touch a bullet and can have a very detrimental effect on accuracy.  I once bought a M99 savage in 250-3000 that was advertised as 'has an excellant bore'.  It did, except for the last inch.  The 99's are comonly cleaned from the muzzle and an aluminum jointed rod had done it work.  The muzzle was funneled.  Crown looked just fine and if you looked into the bore it also looked fine.  If a strong light was shined against the inside of the bore from the muzzle the lack of rifling became readily apparent.  I returned it and bought a takedown featherweight.  No wear and will shoot under an inch all day..  The fractures spoken of were actually chips.  I've only seen them in button rifled barrels and only at the muzzle..  I believe the are caused by the metals work hardened state and the concussion of the muzzle blast but that's just a hypothesis..  I have never seen them on a cut rifled barrel..nor have I found a forged barrel so damaged.  That I can't really explain except that perhaps because of the huge amounts of stress stored in a forge barrel, they factories do a more thorough job of stress relieving them and eliminate another problem at the same time.  Also it may be that the culprit for the flaking is the boundary between the differing hardness levels.  The bore being the hardest and the remainder of the barrel less hardened.  This boundary may for the edge of the flake?  If a rifle starts shooting poorly it is one of the things I check first.  A quick refresh of the terminus cut on the crown will remove the fractures and clean up the muzzle..  Look at the very end of the bore with at least 10X magnification and a strong direct light.. and from a 45 degree angle from the bore line.