I posted on here a while back about the horrible condition of my new TC Venture barrel. I sent it in and they sent me a new rifle. Now there's something off. The crown looked cut off center so I decided to measure from the grooves to the outside of the barrel, avoiding the lands. I got a difference of 14 thousandths . Is it normal for a bore to be this far off center. I'm worried the uneven cut of the crown to the bore might cause issues.

I did take it out and shot it. I was able to get two shots touching and always one shot way off. It didn't depend on the sequence of shots but it was always one way off with 2 touching. The action screws and scope mounts are tight. I'm using a leupold fx-3 6×42

Should I send it back to TC a 2nd time?

Just shoot it.

I would suggest finding a more accurate method to measure.

Such things are not unusual. As Nordic says, "Just shoot it."

If you look at the chamfer at the crown, it appears it is not concentric with the bore. That would be my concern.

Jim, That may be , to a certain extent, a matter of perspective; if you look at the angle at which the photo was taken.
Not an uncommon occurence and this is far from a worst case. Regards Bill

Actually the bore has a .007 runout which isn't unheard of. A bit much for my taste but like someone said above, just shoot it and see how it shoots. Probably OK.

I would, and can, do this; re-crown it with a 90 degree recessed crown, with no chamfer, just to make sure. But the crown is not what is making the third bullet go out of the group.
Clean it and use some diamond compound to smooth out the bore.
Shoot it.
Barrels are only concentric at both ends; you have no idea how crooked they sometimes are. Don't worry about it.

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Its not the bore that's out. Its the outside of the barrel that is out. Instead of doing a lot of lathe and hand polishing these days, most gun manufacturers centerless grind their barrels or polish them with barrel spinners. As a result the hole often comes out not exactly in the center. In a hunting rifle it's really no big deal. Almost all barrels on hunting rifles today are out .002 to .010 inch. Anyone who suffers installing muzzle brakes will know exactly what I'm talking about. It's no big deal and in this day and age it's considered normal on production rifles. I even see it on Coopers and other high end production stuff. Just about everyone worth his salt these days crowns with piloted crowning reamers because they make so much nicer crowns and the crown is always true to the bore so you don't have to worry about the crown being off either.

At least it isn't like this:

Marlin 444 XLR - Good side


Marlin 444 XLR - Bad side


That's not an optical illusion. Somehow, on cut rifling, they got one side nice and clean and deep, and the other side was barely there.

They replaced the barrel and the rifle really shoots well. Actually, the barrel as it was didn't shoot badly, but I was concerned about how long that would last.

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I wish that I had a digital camera and took the time to take pictures of everything years ago Jon. I have seen some pretty crazy stuff over 35 years of full time gunsmithing. Here are a couple cute ones that make one go "HUUMMM ? ! ? !"

This first one is a cut Parker Hale rifled barrel with odd width grooves. Now what the fawk happened there?

Gunsmith Rod Henrickson 02811 by Rod Henrickson, on Flickr


This one is a modern made cut rifled barrel "I won't say who made it" but it is unique in that it has (Double step, really rough, Buttress, Ratchet Rifling.) This barrel actually came to me for installation. I squinted through it and for a second I thought I might have just gotten off a 4 month drunk.

ted simmons1 by Rod Henrickson, on Flickr

Yup. Shit does happen !

I like that Parker Hale barrel. At least it appears that the lands are the same width and the grooves are symmetrical.

That other one - to paraphrase the old science fiction writer, E.E. "Doc" Smith - "I could eat a handful of iron filings and PUKE a better barrel than that!"

I appreciate your posts and the experience and knowledge you bring to the forum. I have read some of what you've written in the past....elsewhere....and while I understand why you don't post there any more, it's their loss, imo.

quote:

Originally posted by JLarsson:
I like that Parker Hale barrel. At least it appears that the lands are the same width and the grooves are symmetrical.

That other one - to paraphrase the old science fiction writer, E.E. "Doc" Smith - "I could eat a handful of iron filings and PUKE a better barrel than that!"

I appreciate your posts and the experience and knowledge you bring to the forum. I have read some of what you've written in the past....elsewhere....and while I understand why you don't post there any more, it's their loss, imo.

Yup, some days you have to wonder what corner quality control is napping in. As to the other. The net is a big place and there is lots of room for everyone to play in. LOL

I saw a Rem 700 in .22-250 many years ago on which the bore was so out-of-center at the muzzle that you could measure it with a carpenter's tape.

The main problem with an out-of-center bore is that the barrel will heat unevenly and begin to bend.

You ask if it is normal. Yes it is for T C barrels! I build and install muzzle brakes on TC guns quite often. Mostly in 35 Whelen. The bores are ALWAYS off center for the reason Speerchucker said. I always have to do a little fudging on the OD of the brake to make thing look right. The bore of the brake MUST be concentric with the barrel bore or accuracy will suffer.

I have a Remington 700 in 7mmRM that has a crown just like that. I haven't measured it but it is off center almost the same amount. It shoots great with just about any load. I once shot up a bunch of boxes I had loaded with different bullet weights that only had 2 or 3 rounds left in each box as I was going to go with one load. The bullet weights ranged from 139, 140, 154 up to 160 and all of them went into one group that was not over an 1.25". Go figure.

I'm going to play around with it as you all have suggested. If it's grouping two shots together, I just need to figure out what's causing the flyer and fix that. then it will be a sub moa gun.
I did notice the end of the stock could flex and touch one side of the barrel with very little pressure applied. I took the stock off, bedded the webbing in the forarm, and sanded the barrel channel open more. Hopefully that was the problem and that flyer will disappear.

The flyer sometimes happens on the 1,2, or 3rd shot. when groups are tight, the flyer is off about 1-2 inches. When groups open up, the flyer spreads further away by the same degree.

Rod,
Those P-H barrels with the different width grooves are two groove, surplus barrels in which two more grooves have been cut. The cutter head was guided by the original grooves. If you look closely, you can usually see the difference in tool marks and, often, the diameter is a little different. The part that always bothered me was that the stupid things often shot better than good-looking barrels on which I had spent considerable time and money. Regards, Bill

quote:

Originally posted by Bill Leeper:
Rod,
Those P-H barrels with the different width grooves are two groove, surplus barrels in which two more grooves have been cut. The cutter head was guided by the original grooves. If you look closely, you can usually see the difference in tool marks and, often, the diameter is a little different. The part that always bothered me was that the stupid things often shot better than good-looking barrels on which I had spent considerable time and money. Regards, Bill

Bill that is an interesting bit of information, thanks for posting!

I took it back out and shot it. I'm getting pretty consistent sub-MOA groups, with a variety of loads, the flyer seemed to disappear after opening the barrel channel.

I did make an elevation and windage adjustment and all of a sudden the groups opened up from 0.82" to 2.75" and they slowly settle back down.
My scope did have water under the turret caps from the factory and there is a little slop in the adjustment knobs. I think I'm going to send it into Leupold just to be sure

quote:

Originally posted by Bill Leeper:
Rod,
Those P-H barrels with the different width grooves are two groove, surplus barrels in which two more grooves have been cut. The cutter head was guided by the original grooves. If you look closely, you can usually see the difference in tool marks and, often, the diameter is a little different. The part that always bothered me was that the stupid things often shot better than good-looking barrels on which I had spent considerable time and money. Regards, Bill

That would explain a lot Billy. I never did mic it to see what the actual bore and groove diameter was and I don't remember what caliber it was. It certainly looks like a 30 caliber in the pictures, but then again all black bears are 1000 pounds in pictures too! I thought it odd so I took some pictures. I assume then they would have been .311 bores ? Or were they cannibalized from some other contract?

I believe they were all 30's and may have come from a contract for Springfields. Maybe the same source from whence came all the Springfield bolts in the Midland rifles. You remember those, right? The Springfield bolt in a half-Springfield, half- Mauser receiver.
Anyway, all of the barrels like this that I saw were 30/06's. Regards, Bill

Ah yes. The dreaded Midland 2100. Well, I guess they were a better gun than the Savage 110 series. Never could shoot the 110s all that well. Damned bag limits the vision too much.

But yes. They probably would have been left over or reclaimed 1903a3 barrels. The 1903 chamber area was about 1.145 and the thread was 1.04 so all they would have had to have done was knock off the cone breach and a couple of threads and then cut on the 1.10 thread extension of the large ring 98.

Well, figured, I'd give an update. I decided not to worry about the bore not being centered in the barrel after I shot this group with a fixed 6 power scope.

Wow, that is terrible; 3 shots in the Elk's eyeball, and the 4th, you will have to shoot for the brain. Just goes to show everyone that looks aren't everything.

quote:

Originally posted by dpcd:
Wow, that is terrible; 3 shots in the Elk's eyeball, and the 4th, you will have to shoot for the brain. Just goes to show everyone that looks aren't everything.

All I have to say is: "YEAH, BUT !"

So there.

Yeah, the 2nd shot I pulled and then got back on track with the 3rd and 4th shot.