If the crown of the gun is so important to accuracy. Why isn't cleaning it?

[Lavid2002]

If the crown of a gun is so important to accuracy why isnt it necessary to clean it? I know it IS important to clean it at home when cleaning the gun.....but why dont competition shooters wipe off the muzzle in between strings? If a very small nick can have an important effect on accuracy why doesnt the fouling that accumulates on the muzzle have a big effect on accuracy too?


I would think if this creates as big of a problem in real life as it does in theory I would have heard more about it....but I personally have never heard anything about this...or seen anyone do it.


Information?

-Dave

 

[Bud Helms]

Soot or powder deposits on the outside the bore on the face of the muzzle has nothing to do with the bullet exiting the barrel and doesn't affect accuracy. It's like a fingerprint on the scope. When the bore is swabbed at the range, that transition "edge" between the bore and the muzzle face is cleaned. That's all you need.

 

[Lavid2002]

If a scratch on the muzzle effects the gasses escaping from the muzzle and can deviate the bullet path why doesnt a soot deposit? I still dont understand why : / You are saying only the very very corner is important?

 

[Bud Helms]

The edge all the way around the muzzle where the bore transitions to the face of the barrel is the muzzle. Right where the rifling stops. A scratch on the face of the muzzle won't affect the bullet's path. A scratch that makes it down to the edge of the bore might. But it would have to be a really deep scratch. Defects like scratches that make it around the edge, i.e., over the lip into the bore, are the ones that will affect accuracy the most. There is no evidence other than, "I had one that did it", that a scratch on the face of the muzzle only, meaning that does not extend to the edge of the bore and that the bullet does not touch on the way out of the muzzle, has any affect on accuracy.

Precision shooters take many measures of precaution that have no real basis in known fact because their attitude is that every small preventive measure might make the difference in winning. This is one of them. A small nick or scratch in the muzzle face only is not known to affect accuracy.

Recessed muzzle crowning is to keep that edge of the bore, that last smidgeon of bore, out of harm's way, not the relatively thin area around the muzzle that represents the wall of the barrel.

A piece of metal curled up, protruding into the bullets path will probably affect accuracy. A scratch on the muzzle face, .15 inches away from the bore edge probably will not. A really deep gouge that extends into the bore edge and forms a channel for passage of gases might. Only shooting it will tell. But why take a chance? refinish the crown and know it is smooth and symmetrical.

 

[Lavid2002]

Got it...all this time I have been thinking the crown of the gun was the end of the barrel....
I.E.
Standard
Recessed target
Deep recess
11* target
Flat

But these are just kinds of muzzles? The crown on all these is identical because the crown is only the portion of the rifle where the bore ends and the muzzle begins? That very small corner....?

That seems legitimate that fouling wouldnt effect the accuracy then

 

[.308shooter]

QUOTE]The crown on all these is identical because the crown is only the portion of the rifle where the bore ends and the muzzle begins? That very small corner....?[/QUOTE]

True.

 

[Bud Helms]

Well, the crown is that area of barrel face between the actual edge of the bore and the outer thickness of the barrel at the muzzle end and its name is how it is finished (shaped). You listed different crowns. The muzzle end of the barrel is referred to generally as the muzzle, and the "crown" is a description of the shape in which "the muzzle" is finished. So you say you have a crowned muzzle. Notice that the crown name is a description of where the bore edge is with respect to the outer wall of the barrel.

recessed target crown: the bore edge is recessed in a flat-bottomed well whose bottom is displaced inward along the bore axis from a ledge left flush with the outer wall of the barrel, i.e., the well wall, and by the way, still has a slight bevel cut at the bore opening.

11* target crown: the bore line is at the apex of an 11 degree bevel from the outer wall of the barrel. The base of that cone is actually slightly smaller than the outer barrel diameter in order to leave ledge, not a sharp edge.

So the name tells you where the bore edge is with respect to the outer barrel edge. Some crown's combine these two and recess the 11 degree crown slightly. Some "crowns" are hardly noticeable, being a very slight bevel at the muzzle. There are several variations. You listed some of them. An uncrowned barrel is an unfinished barrel.

 

[tirod]

It's even simpler than all that. It's the last part of the rifling to touch the bullet that is important. The big flat part of the crown doesn't, but having a concentric shape at the proper angle helps.

When cleaning a barrel, the rod isn't supposed to go in at the muzzle to help protect that last fraction that the bullet is touched. It's why some armies use a pull through chain kit instead.

The gun crowd calls that area the muzzle, it does compose the whole end of the barrel, but the important part is just the corner, the last fraction of an inch that guides the bullet. Screw that up, and the gun will be off target at best, or useless at worst.

As for cleaning it, military rifles with flash hiders never really get clean until they are screwed off, which isn't allowed under operator maintenance. Then interesting things start to happen as the soldier attempts a white glove standard scraping around to remove the last piece of filthy evil carbon so he isn't further motivated by extra duty or on the spot physical training. It's a wonder the beat up POS carbines in basic qualify anyone at all - but they do.