Borescope results?

[cdhknives]

I finally just dragged everything of decent quality out of my safe and ran the scope through them. Noveske, Wilson, Rock River, and Shilen AR's. None of them have *any* visible reamer marks, all are plain SS barrels. These 2 barrels gotta go back...this is ugly...

 

[LVLAaron]

These 2 barrels gotta go back...this is ugly...

100%

 

[Liljoebrshooter]

Every manufacture can build a substandard product and let it go out the door. How they handle the issue after the fact is what matters.
I bought a barrel from one of the BIG name manufacturers that you were mentioning earlier and it is the worst looking barrel I have ever chambered. I contacted them and actually got a phone call from the person I emailed. I was told that what I was seeing and measuring is perfectly fine and just shoot it. Needless to say I will never purchase another one from them.
Joe

 

[cdhknives]

A bit more info for the curious. After taking the bore pictures I posted, I shot 10 rounds through it and looked at the fouling. Almost solid copper plating the last half of the bore...except for about 1/2" back from the muzzle where the copper faded irregularly. Maybe the slight choke of a lapped barrel didn't go all the way to the muzzle?

So I cut an additional 1" off, down to 24" from originally 27.5". The results speak wonders...three consecutive 100 yard 5 shot 3/4" or less groups with a single flier that was probably my fault.

 

[Earl]

Bell mouthing at each end of a blank is normal. It is caused by the lap being unguided as it leaves the barrel. I always chop off the first inch and a half of the chamber end of the blank before I start. I typically cut my barrels to a finish length around 21 1/2 inches (6 PPC) so there is 4 to 6 inches of the muzzle end that ends up in the scrap bin. I have never seen a barrel that had a true bore! I go thru about 10 barrels a year (3 guns) and have been addicted to bench shooting for over 20 years, I chamber thru the headstock. Spider on the outside and a 6 jaw adjust tru chuck. I go back and forth between the chuck and the spider until the first 2 inches run true with a 50 millionths indicator. Sometimes when the chamber end is running true for the first 2 inches, the muzzle end runs out a quarter inch or more! Sometimes I clock them, most times I dont. Does not seem to make any difference after the scope is zeroed. I have both a Hawkeye and a Teslong borescope like what you used. I always clean the blank before I scope it. It is amazing how much oil and grit you can get out of a brand new blank. My experience is that just because you have a good blank from a reliable manufacturer and you do the perfect job of chambering, there is always the possibility that you end up with a stainless steel tomato stake. Some barrels just wont shoot competitively, (5 shot groups around .2 or less in good conditions is competitive) Looking at your groups, the one on the right shows powder charge or seating depth issues. (vertical) The one on the left shows that conditions were changing as you shot. One of the keys to accuracy is to have a reamer that works well with your bullet. I went thu 4 or 5 reamers before I found one that worked with my bullet. I got rid of the others. After a match or two, and the accuracy wanes, I set the barrel back 50 or 60 thou. Sometimes the barrel shoots better after setting it back than when it was new. Opinions on that vary but I believe the after a thousand rounds or so, the barrel is as "stress relived" as it ever will be.

I have several shooting buddies that use Shilen barrels exclusively. They love them. I have used a few with less than spectacular results. Shilen barrels are "button" rifled - a button is pulled thru the barrel to rifle it. I use mostly Kreiger barrels that are "cut" rifled. The alloy of the barrel, the reamer, the bullet, the powder and the "nut behind the bolt" seems to be keys to accuracy. I believe that John Kreiger retired so someone else is running that business now. Time will tell if their quality remains the same or if I will have to start over.

 

[Liljoebrshooter]

Where are you located Earl? Just wondering if we have crossed paths at a match.
Joe

 

[Earl]

I am in Phoenix. The closest to you that I have ever shot at match is St Louis or perhaps Kelbly's.

 

[Liljoebrshooter]

Huh. Been to st Louis a few times. Did pretty good there one year. Kelblys is one of my favorite places to shoot.
The wife and I are headed to Holton this weekend for the first match this year.
Joe

 

[Earl]

I used to go to the SS but got tired of waiting 3 hours between relays. Been to the Nationals several times at St Louis. My best shooting buddies are Hall of Famer's. Tough to beat them in a match but it does occasionally happen.

 

[cdhknives]

You BR guys... I'd love to try out that game, but for now have to content myself building a solidly sub MOA 7 lb hunting rifle or three that don't beat me up when I carry them all day! I have a trued up Rem 700 action in the safe that I hope to someday turn into a heavy varmint/light BR rifle, but not this year and not till I get a lot better with my lathe!