a friend of mine whos father is a gunsmith is verrrrry peticular about how he finishes a crown. the idea is that the bullet must leave the barrel and not have contact on one side more than another or else accuracy will be off. how can you tell if you have a bad crown? does this only apply to smaller bores??? he said that way too many barrels are sloppy at the end...

He is right, a barrel isnt precise if the crowning isnt done properly, the bullet will not go well,and you will get bad accuracy as the result of that.

A bad crown or a poorly executed crown can definately effect accuracy, depending on how bad or good the job was done. That said, I can tell you that I have "recrowned" barrels with a machinist's square, a hacksaw, files, and rotary stones in a drill motor. Some shot better, some the same, but never worse. Your results may vary.

I'll see if I can dig the data up, but the test to which I refere the barrels were rough cut with a saw at different angles and the repeatability suffered little. Point of impact may have varied from one cut of the barrel to the next. Like I said , I'll try to find it. roger

Someone, in Precision Shooting magazine, did an article about crowns. He cut the barrels with a hacksaw, lightly deburred them and shot them. Accuracy did not suffer but, point of impact changed radically.

I sent out a 30BR on a hart action I chambered the other day. Customer put it all together and wouldn't shoot under 1/2 inch. Needless to say he wasn't very happy with the gun or me. Everything looked perfect chamber had practically zero run out. I was pretty upset with myself and probably lost the gentlemans buisness. Anyway he noticed the burn pattern wasn't even on the crown and had a local gunsmith recrown it and it went to shooting in the .1's I don't know what happened but it is a perfect example of how important the crown is.

I don't think so, but there are MANY others here who do. My experiments reflect the same as Saeed's.
Saeed's Experiment

larrys, thanks for posting that link, I was just going to recommend that Boom Stick look at that, it will really make you wonder about the 'crown must be perfect' theorems......

I like mine to be better than what Saeed did to that barrel though!

I guess the subject of barrel crowns and accuracy is like everything else - it all depends. If accuracy means 1 MOA then you can probably get away with a pretty ratty looking crown. On the other hand if accuracy means .1 MOA you will not tolerate anything less than perfect. Many Benchrest shooters re-crown almost as often as they change their shorts. Nuff said??

Ray

After my first el;ephant hunt with my 458 Lott I saw a real drop in accuracy. It went from sub 1" groups at 100 yds to 1 3/4" groups. A local gunsmith noticed a dent in the crown area and he recrowned it. Aparently one of the trackers somehow dented the crown end of the barrel. It then started shooting better than it did originaly.

465H&H

Never have seen the gun that wouldn't group better after machining a clean, square crown. Harold Vaughn covered the subject fairly well in his book "Rifle Accuracy Facts".

Logic would dictate that a nice clean crown should shoot better, but I've had results that support both positions.

I once had a .22 WMR that had a crown that looked like it had been chewed off by a beaver - but it was very, very accurate. I figured I could improve it, so I had my 'smith clean it up. It shot exactly the same.

I also had a fine shooting .270 that acquired a very small nick on the crown. Accuracy went right out the window, but was regained by cleaning up the crown.

Sometimes I think guns are harder to figure out than women.....good ones are always good, and bad ones just cost you money.

The crown is the last thing the bullet touches as it is launched from the barrel. If it is not "perfect" accuracy will suffer. "Perfect" has nothing to do with looks. It can look great but if there is the slightest imperfection it will not be accurate. It can look like shit but if it gives the bullet an undisturbed launch it will be as accurate as your load permits.

I TOTALLY agree,it definately is a very important part of all the factors involved in accuracy of a firearm. And i am just as fussy with the crown as headspace and everything else. VAN

quote:

will a bad crown job affect accuracy???

yes, without a doubt.
jeffe

yes very much so,exiting gases must be as close too perfect as can be,big to small bores they all are affected the same way. regards jjmp