muzzle run-out is it a prob?

[Salkehatchie]

OK.  Got  a technical question. 

Muzzle run-out.  Just got a barrel for a smooth bore in last night and to my amazement it had muzzle run out.  Have never seen this before.  Appears as if the barrel walls are thinner on one side too.  And, the thin side is on the NE corner of the muzzle when looking down the barrel.

What affect if any will this have on my accuracy?

I would never have noticed it, it is slight - except that the crowning is slightly off.


Thanks!

[P.Bigham]

 I dont think it would affect the accruracy. But your sights might be off to account for the run out. I would send it back.

[keweenaw]

Not a problem but no excuse for it being sent to you that way, send it back.

Tom

[northmn]

To work well any runout should be on the top or borrom so it shoots high or low.  We used to do that with the old Douglas barrels.

DP

[Salkehatchie]

Thanks, unfortunately what I thought.  Darn.  Wanted to send this to my guy before Xmas. Now, do not know if it will make it. Oh well.

[wmrike]

I got a barrel from Dixie about 35-40 years ago.  The bore was centered at one end but badly off-center at the other.  Additionally, the barrel had three prominent bends.  The nice folks at Dixie wouldn't take it back.  Unhappy but undaunted, I got two of the bends out, but the third was about four inches from the off-center end of the barrel and I couldn't get enough leverage to remove it out.  I breeched the off-center end and set the plug so that the top flat dropped to the rear, and then built a rifle around it.  It was never a favorite rifle, but it has always seemed to shoot acceptably.

[Pete G.]

I have always wondered just how much difference a truly straight barrel makes. Seems like as long as the muzzle end was relativly free of deformity that it would be OK. I have seen a picture of a German experimental rifle the had a 90 degree bend that was designed for shooting around corners. The caption said that the rifle was sucessful, but impractical.

[Benedict]

A round ball gun does not have to be straight.  The sights have to line up with the last few inches to work.  Having said that, it seems to me that the best bet in this case would be to send the barrel back.

Bruce

[Dphariss]

I have always wondered just how much difference a truly straight barrel makes. Seems like as long as the muzzle end was relativly free of deformity that it would be OK. I have seen a picture of a German experimental rifle the had a 90 degree bend that was designed for shooting around corners. The caption said that the rifle was sucessful, but impractical.

Successful is a relative term when talking of the shooting around corners thing. Yes the bullets came out but thats about all that could be said about it. In use the outside of the curve tended to wear through.

Barrels that gave crooked or off center bores will not shoot as well as one with a straight, centered bore.
Compared to modern high power competition barrels some ML barrels seem like they were made by a HS shop class. Actually this can be said of *some* barrels by big names like Douglas too.
Barrel makers may take offense if they want but in your hearts you know what I am taking about. There are a lot of "no name" (and otherwise) barrels out there that are pure junk but some still shoot "OK".
I have had 3 out of the past 10-11 guns I have made. One was a Douglas BL barrel. One was a "no name" SB from TOW and one was from a maker who should have known better. It was not a Getz so Don need not take offense.

Dan

[northmn]

Most of the time the Douglas barrels shot very well, even those with a little run-out.  You put the Douglas stamp up or down.  I believe they had a theory about bore following grain (marketing anyway)  Others drilled the hole then milled them to center.  Problem was that sometimes the runout was not so well marked.  One Douglas I had lacked target accuracy because the runout was marked wrong as it came out on a edge and not a flat.  It shot slightly to one side at 25 yards and to the other side at 100 with a 50-75 yard sight in.  It was acceptable for casual use. Most of the new ones don't do that.

DP

[t.caster]

The guy who taught me showed the importance of mikeing (err, calipering) the runout on both ends! It wasn't always as marked back then. I still wouldn't trust it....I measure everything! Put the runout side (breech end) down and u will need a tall front sight, cause it will shoot high, but not bad. I did one with the runout up and the front sight ended up being about a 1/16" high! It sits in the closet gathering dust! That was a GM replacement for a Douglass barrel I never liked!

I think Douglass shipped out EVERYTHING they made. Sure they marked it with plusses +++ to indicate premium or not, so you knew what you were getting, kinda. But they even had double cut rifling at the muzzle that needed to be cut off. I have a couple cut-off pieces 2" long, around still. They had trouble indexing there rifling cutters, but they sold them anyway. Thank God you don't see that these days. Do we?

[RobertS]

So when you get a new barrel, should you check it for runout with a caliper?  Would you measure the distance between the bore and each of the side flats on all 8 sides at both ends?  How much runout is acceptable?  Maybe I am making a mountain out of a molehill, but I'm curious now what you guys do that know what you are doing!  THANKS!

[Stophel]

Barrels now are generally drilled in the blank and then the barrel is profiled with the barrel centered in the machine by the bore (so I'm told), so theoretically, you're not going to have "run out" anymore.

I HAVE seen some smoothbores that appear to have a slight amount of run out (I think my eyes can detect a discrepancy of as little as .001").  Unless your run out is really extreme, I can't see it mattering.   It doesn't mean the bore is crooked, it means the outside is milled off center.

[B Shipman]

As the boys have intimated, what Douglas used to do was take a piece of already formed octagon and try to drill a 44 in. hole thru it and come out on the center at the other side.


Clearly, the Douglas holes were just as straight as a "premium" barrels today. Today and on some barrels then, the barrel was set upon centers and ground or milled so the bore was on center fore and aft. And clearly this has no affect on accuracy.

Smoothbores, since they are tapered, tend to shoot high unless you use a very high front sight.  Put the thin spot on the bottom and have a better looking bead at the muzzle.

Note. Solder your lugs on up front at least. Don't try dovetails here.

[Dphariss]

So when you get a new barrel, should you check it for runout with a caliper?  Would you measure the distance between the bore and each of the side flats on all 8 sides at both ends?  How much runout is acceptable?  Maybe I am making a mountain out of a molehill, but I'm curious now what you guys do that know what you are doing!  THANKS!

You should also slug it for uniformity of bore dimensions.

I don't know about Douglas ML barrels but they sell several grades of BL barrels and some are pretty grim.

Dan