Gunsmithing Expert opinion wanted on New barrel freebore (pic)

[2aBaC̶a̶]

Long story short I ordered two prefit barrels of different calibers from a prominent barrel manufacturer. Waited the 4 months. I had to send one back for having almost no freebore as in the lands extended to the chamber. They claimed it was fine but they extended it for longer bullets.

Second one I scoped and looks questionable as lands extend to the chamber on only one side and leave light marks on a round colored with sharpie. I hate to be that guy calling again with another freebore issue. Should the bullet touch the freebore at any spot? Am i being paranoid?

In your opinion would you try it or send it back?

 

[LRI]

Shoot it. Bullets always tell the truth.

 

[Mordamer]

I would want to send it back.

If you are willing to shoot it, it might still shoot great.

 

[whatsupdoc]

Chamber looks like it is not concentric with bore. I have seen worse. I would shoot it and go from there.
To me that shows the shop has lax QC.

 

[Praeger]

Your borescope lens likely is a wide field of view and if not centered in the bore will make the lands on one side appear longer than the side the scope is closer to. Move the borescope around, or wrap tape around the borescope head so it has less clearance to the lands and check again.

 

[2aBaC̶a̶]

Yes, It took a minute to orientate the camera in a way to capture the true perspective. It is exactly how it appears. Lands to the second shoulder on one side and not the other.

 

[Krob95]

You paid them good money for complete barrel. Not some half ass chambering. I’d send it back so they can make it right if it was me.

 

[MachoMan]

Well at least he had it close enough not to have a step in it.

 

[Vodak]

There's going to be a lot of pissed of barrel makers now that everyone's able to buy a cheap video bore scope.

Not knowing the maker and the cost I'm not trying to defend them in any way, but there are a few things I would consider. Bores are not straight. They get them pretty close, but they're never perfect. Its why it's a good idea to turn a barrel to length before you contour it. A classmate of mine in school decided he wanted to shorten a barrel he was turning after he had contoured it. Took several inches off the muzzle, and found his bore to be about .010" off center. Easily visible to the naked eye. Not a top quality barrel in that case, but still. That tube may have something similar going on. The barrel maker may have done everything right, indicated the bore, dialed it all in, and just past the rod it may bend a couple of thousandths.
Could be a hard spot in the barrel. Floating reamer hits hard spot half way in, ends up a couple of thousandths off line at the end. Or maybe the button or rifling cutter deflected off of it and left a tight spot on side that's cut clean.
I would call the maker, tell them what you found, and see what their policy is for returning a fired barrel. If they're open to it start load development. If it shoots, keep it. It's going to have burned the rest of that throat smooth in a few hundred rounds anyway.

 

[Edds]

Shoot it. Bullets always tell the truth.

Do the barrels you chamber look like that?

 

[LRI]

Do the barrels you chamber look like that?

Honestly? Couldn't tell you. I rarely look down one anymore as my eyes are slowly going to shit and I've never owned a borescope. never needed to.

I'll share this just for perspective. Tammy Forester was a 92 Atlanta Games Silver Medalist. Her rifle had a bulge from a squib load. You could literally feel it jump from 22 to "something" and back to 22 again when you ran a patch down it. That barrel held multiple national, world, and international event wins.

My only point is that borescopes have their place sure, but the bullet always tells the truth and 99/100 barrel makers are going to tell you the same thing: Go shoot it. If it sucks, send it in, if it runs the number and doesn't copper coat the bore in 5 rounds, then it's not broke.

 

[chase723]

Free +P

 

[1moaoff]

Honestly? Couldn't tell you. I rarely look down one anymore as my eyes are slowly going to shit and I've never owned a borescope. never needed to.

I'll share this just for perspective. Tammy Forester was a 92 Atlanta Games Silver Medalist. Her rifle had a bulge from a squib load. You could literally feel it jump from 22 to "something" and back to 22 again when you ran a patch down it. That barrel held multiple national, world, and international event wins.

My only point is that borescopes have their place sure, but the bullet always tells the truth and 99/100 barrel makers are going to tell you the same thing: Go shoot it. If it sucks, send it in, if it runs the number and doesn't copper coat the bore in 5 rounds, then it's not broke.

Should be mandatory reading. Then require signature acknowledgement before asking borescope questions.

 

[Vodak]

••• sarcasm ••• Well she probably would have won the gold with a decent barrel!

 

[arob]

While Chad has a good point of letting the barrel tell you if it will shoot or not, that was a poor attempt to get the throat straight. Things happen, it may not be a normal thing for the shop that did the work, but I would say a custom fit barrel should be much better. Factory barrel....not a big deal, custom barrel.....pretty poor.

 

[2aBaC̶a̶]

While Chad has a good point of letting the barrel tell you if it will shoot or not, that was a poor attempt to get the throat straight. Things happen, it may not be a normal thing for the shop that did the work, but I would say a custom fit barrel should be much better. Factory barrel....not a big deal, custom barrel.....pretty poor.

It's a custom prefit from a well known barrel manufacturer. all they do is barrels. These are my first two custom barrels for my first custom action. I'm a little disappointed.
Here is the first. A 6.5 prc. You can see its almost straight and most of the lands make it to the chamber, also the copper rub marks from me trying to "find the lands". I found them and they start at the case mouth. This is the one i sent back and they "fixed". I will say customer service was great and they had it back to me in a week.

 

[Steel head]

Yes, It took a minute to orientate the camera in a way to capture the true perspective. It is exactly how it appears. Lands to the second shoulder on one side and not the other.

My first and second Shilen prefit was almost identical in the throat.
Both shot excellent to amazing and lasted a long time.
I’d say acceptable on a$400 barrel.

Honestly I’d be a bit miffed if I got that on a $700+ barrel but LRI does bring up some good points.

 

[MachoMan]

I hope this don’t get taken the wrong way but! You starting to see this a lot from guys that ran out and bought a CNC machine to do there chambering work on. They run out and purchase a very expensive machine and then realize they have to run a lot of barrels to pay for it. What happens ? Well it becomes a task to make productivity greater than setup and Quality. You can see some do not have proper setup built into there CNC Pre Fit Barrel business. It’s all in Setup even on a CNC.

 

[Supersubes]

The surface finish looks nice, but what a shame to have a crooked chamber. I wouldn’t put up with that, but that’s just me.

 

[2aBaC̶a̶]

My first and second Shilen prefit was almost identical in the throat.
Both shot excellent to amazing and lasted a long time.
I’d say acceptable on a$400 barrel.

Honestly I’d be a bit miffed if I got that on a $700+ barrel but LRI does bring up some good points.

If it was only looks I wouldn't even bring it up. The issue is that the bullet rubs on one side of the freebore when clambering. I'm going to give it a shot. If it shoots, then great. If there are any issues it's going back.

At least this barrel chambers. The first one I had to bury the bullet ogive in the case mouth to get it to chamber.

 

[lawrence97]

You already had one barrel that was chambered out of spec from this outfit. Why trust them a second time?
You are having doubts about this barrel and it will always be in the back of your mind. Send it back to them while it’s new and unfired. Get your money back and have a gunsmith chamber a barrel specific to your action and not some prefit that’s mass produced.

 

[cast1]

Would be interesting to know if your builder is using a throating reamer or a fully formed finishing reamer. There is no real way to mess up free bore otherwise without an improperly ground reamer.

There is some evidence of reamer chatter in your first pic. Very common with 5r rifling. I prefer 4 or 6 groove barrels for this reason. Reamer edge runs up on the unopposed, ramped land and gets pushed over to the opposing groove and takes that little scallop out that you can see in your picture. That being said, the first creedmoor I chambered was my own match rifle and it’s lousy with the same phenomenon. It’s an easy sub quarter MOA gun with boxed ammo. Had that been your barrel and you sent it back to me you would have missed out on a great shooter. I may have screwed it up trying to fix a problem that never needed attention in the first place.

Chad is right. Go shoot and worry less about how the sausage is made. Theres a picture out there from Alex Wheeler of a tenon on a 6BRA that looks like a 15 year old did it on a harbor freight lathe during an intro to machining weekend course. It’s a world record barrel. Pretty doesn't mean perfect and ugly ain’t always bad.

 

[cast1]

Also, you’d almost have to try to throat a barrel so badly eccentric to cause a bullet to rub one side of the freebore. That would move from neglect to sabotage lol. Most likely you’re getting scratches during mag feeding.

 

[Supersubes]

Would be interesting to know if your builder is using a throating reamer or a fully formed finishing reamer. There is no real way to mess up free bore otherwise without an improperly ground reamer.

There is some evidence of reamer chatter in your first pic. Very common with 5r rifling. I prefer 4 or 6 groove barrels for this reason. Reamer edge runs up on the unopposed, ramped land and gets pushed over to the opposing groove and takes that little scallop out that you can see in your picture. That being said, the first creedmoor I chambered was my own match rifle and it’s lousy with the same phenomenon. It’s an easy sub quarter MOA gun with boxed ammo. Had that been your barrel and you sent it back to me you would have missed out on a great shooter. I may have screwed it up trying to fix a problem that never needed attention in the first place.

Chad is right. Go shoot and worry less about how the sausage is made. Theres a picture out there from Alex Wheeler of a tenon on a 6BRA that looks like a 15 year old did it on a harbor freight lathe during an intro to machining weekend course. It’s a world record barrel. Pretty doesn't mean perfect and ugly ain’t always bad.

I don’t think there’s a chatter there. The “scallop” appears to me to be the corner of the land/groove that’s not getting cleaned up. Note How the land/groove at 1 and 5 o’clock or almost identical, and the 3 o’clock land/groove, is least touched. Reamer is cutting more at the 9 o’clock.

So little material is being removed at the leade, I’d be shocked if that would be sufficient to push the reamer around. Just my experience and observation.

 

[2aBaC̶a̶]

Also, you’d almost have to try to throat a barrel so badly eccentric to cause a bullet to rub one side of the freebore. That would move from neglect to sabotage lol. Most likely you’re getting scratches during mag feeding.

I can feel it if I load the round on a stripped bolt or using the Hornady OAL tool. Using the tool I have to forcibly push past it to reach a hard stop at the actual lands. Thats when I first noticed.

It could be nothing or it could be something. I have plans to shoot it this week so that will be the deciding factor.

 

[Ledzep]

Maybe looking at .0005-.0015" off center.

Probably hammers. Which begs the question, did you buy it to shoot tight groups or to be machined perfectly?

Put 700 rounds on it and you won't be able to see the uneven rifling start.

 

[Supersubes]

Maybe looking at .0005-.0015" off center.

Probably hammers. Which begs the question, did you buy it to shoot tight groups or to be machined perfectly?

Put 700 rounds on it and you won't be able to see the uneven rifling start.

Both, people pay for both.

 

[Vodak]

That's true, but I have a feeling if makers were to start chucking every tube they chamber that's a little off center we'd all be paying a lot more. I don't know, I've never owned a bore scope, maybe this significantly worse than other barrels in the same price range. I do know from chambering some barrels myself and doing a fair amount of work as a machinist that this is a particularly hard sort of tolerance to control.

 

[Edds]

I once got caught in a surprise hail storm in my 30 day old new Ford pickup. The windshield was broken and there wasn't a spot on the hood, top, or bed rails you could put your fist on that didn't have a dent on it. The Insurance adjuster said "did you buy that thing to drive or look at? We will put a new windshield in it and you should be happy".

 

[Steel head]

Maybe looking at .0005-.0015" off center.

Probably hammers. Which begs the question, did you buy it to shoot tight groups or to be machined perfectly?

depends on how much coin I’m paying.
Various sub $450 chambered button barrels as long as it shoots I’m GTG.
If I’m shelling out $300-400 for a cut blank and another $300-400 to machine it I want the whole shabang

Both, people pay for both.

This.

 

[Supersubes]

That's true, but I have a feeling if makers were to start chucking every tube they chamber that's a little off center we'd all be paying a lot more. I don't know, I've never owned a bore scope, maybe this significantly worse than other barrels in the same price range. I do know from chambering some barrels myself and doing a fair amount of work as a machinist that this is a particularly hard sort of tolerance to control.

Had the barrel been dialed in properly to begin with, this wouldn’t have been an issue. The resulting chamber would have been coaxial with the bore. Why would you say this tolerance is hard to control?

 

[Ledzep]

I once got caught in a surprise hail storm in my 30 day old new Ford pickup. The windshield was broken and there wasn't a spot on the hood, top, or bed rails you could put your fist on that didn't have a dent on it. The Insurance adjuster said "did you buy that thing to drive or look at? We will put a new windshield in it and you should be happy".

Okay now imagine instead of obvious exterior damage, you stuck a scope through your drain pan and saw where they machined a bearing journal further up one side of the counterweight than the other.

ETA: I get it, you want it to be done right-- and I'm not making excuses for the smith, but I think most people don't want to pay what it really costs to guarantee <.0005" precision.

 

[Edds]

Okay now imagine instead of obvious exterior damage, you stuck a scope through your drain pan and saw where they machined a bearing journal further up one side of the counterweight than the other.

ETA: I get it, you want it to be done right-- and I'm not making excuses for the smith, but I think most people don't want to pay what it really costs to guarantee <.0005" precision.

How much does it cost?

 

[Supersubes]

Okay now imagine instead of obvious exterior damage, you stuck a scope through your drain pan and saw where they machined a bearing journal further up one side of the counterweight than the other.

ETA: I get it, you want it to be done right-- and I'm not making excuses for the smith, but I think most people don't want to pay what it really costs to guarantee <.0005" precision.

I wouldn’t even think of sticking a reamer in a barrel that was running out .0005.

 

[Steel head]

I wouldn’t even think of sticking a reamer in a barrel that was running out .0005.

Out of curiosity how long does it take to dial in a barrel?

 

[Supersubes]

Out of curiosity how long does it take to dial in a barrel?

It depends, some days you get right on it, and some days you chase it. 30 minutes is about average. Getting it to .0005 is easy. Getting it to .0001 is what takes all the time.

 

[Steel head]

It depends, some days you get right on it, and some days you chase it. 30 minutes is about average. Getting it to .0005 is easy. Getting it to .0001 is what takes all the time.

I’ve indicated parts in a 4 jaw and had a similar experience.
Sometimes it falls into place and others you feel retarded.
I wasn’t going for .0001 though.

 

[Supersubes]

I’ve indicated parts in a 4 jaw and had a similar experience.
Sometimes it falls into place and others you feel retarded.
I wasn’t going for .0001 though.

I started with a 4 jaw independent. Tedious for sure. Now I use 6 jaw set-tru style chucks. Makes thinks easier, but blowing past the dial-in happens a lot when you’re going for small numbers.

 

[Mordamer]

It depends, some days you get right on it, and some days you chase it. 30 minutes is about average. Getting it to .0005 is easy. Getting it to .0001 is what takes all the time.

What indicator are you using to dial in the throat area to .0001"?

 

[MachoMan]

That's true, but I have a feeling if makers were to start chucking every tube they chamber that's a little off center we'd all be paying a lot more. I don't know, I've never owned a bore scope, maybe this significantly worse than other barrels in the same price range. I do know from chambering some barrels myself and doing a fair amount of work as a machinist that this is a particularly hard sort of tolerance to control.

Well then they got what they paid for. Cheap is cheap. It’s like racing. If u bitch about the cost u don’t need to do it. Any good chamber job should be indicated and checked.[/QUOTE]
What u are seeing in this chamber is not totally radial alignment it’s co axial. The bore wasn’t straight with his rifling through the throat to the chamber area. U can’t just indicate it for runout alone.

 

[Supersubes]

What indicator are you using to dial in the throat area to .0001"?

A long stemmed intrepid to direct dial or a grizzly rod and a standard intrepid.

 

[cast1]

I stand corrected. Pics don’t look like anything bad but I took time to watch the video. That ain’t right.

 

[cast1]

This is what you should see on every barrel you chamber. It shows the runout just into the lands, forward of the lands, and rear of the chamber.



I would see if I could get a refund on that piece in the video. Unless there’s something in the video that makes it look off, that mess is totally uncalled for. I would agree with what has been said here about some high volume shops. It takes a lot of chambers to pay for a Haas TL-2.

 

[MachoMan]

Everytime!

 

[Rubicon Precision]

This is what you should see on every barrel you chamber. It shows the runout just into the lands, forward of the lands, and rear of the chamber.



I would see if I could get a refund on that piece in the video. Unless there’s something in the video that makes it look off, that mess is totally uncalled for. I would agree with what has been said here about some high volume shops. It takes a lot of chambers to pay for a Haas TL-2.

You can see that on an indicator then see something completely different with a borescope. DTIs have error, especially long stems being side loaded. Then you have the diameter of the ball point that can ride over features in the bore, that can easily be seen with a scope.

 

[Supersubes]

You can see that on an indicator then see something completely different with a borescope. DTIs have error, especially long stems being side loaded. Then you have the diameter of the ball point that can ride over features in the bore, that can easily be seen with a scope.

I’ve used the long stemmed quite a bit. They seem to repeat very well. They do leave a mark on the lands, but it’s only disrupting the lay of the lapping. Never picks anything up during firing. One thing I’m certain of. I’ve never produced a chamber as off axis as the OP’s. I scope everything, and I’ve never been able to detect even the slightest runout.

 

[cast1]

I wonder if this job was dialed in at the muzzle and breech end and happened to be a very banana shaped bore?

 

[Ledzep]

I'd guess it wasn't dialed in, or was dialed in quickly in one position. I don't get too anal with my personal barrels. I use a long stem indicator and get it dead nuts under the jaws and within .001" on the breech end. I've also scoped many of them and never seen off-centerness. I don't have the capacity to measure .0001" reliably so to answer the question of "how much does it cost" to guarantee .0005" positional accuracy, it starts with measuring resolution well below .0005". It probably ends with Swiss turn machine for electrodes for a sinker EDM that has room for barrels and the ability to align axially and positionally.

 

[Vodak]

Had the barrel been dialed in properly to begin with, this wouldn’t have been an issue. The resulting chamber would have been coaxial with the bore. Why would you say this tolerance is hard to control?

Deep hole, small diameter drilling is hard to keep perfectly straight. Even over a 2.5-3" section like were looking at in a chamber. Follow that up with the reamer being fed into an interrupted cut going through the lands and grooves, the possibility of varying hardness in the steel, residual stresses, difficult chip clearing compared to an external cut, run-out in the lathe, etc. It's just a lot of factors to try to control. Not saying it cannot be done, just that it takes a lot more effort and tooling investment than I expect the average gunsmith, and possibly even barrel makers are willing or able to expend. Someone like you (Supersubes) obviously has put the investment and effort into it, but I think you're probably ahead of the curve.

Again, I'm not trying to excuse the Mfg's work here. The fact that the OP had to send the other bbl back because it had no freebore before the leade at all clearly shows they are lacking in the QC department. Just saying that there are probably a lot more barrels in circulation that have a similar degree of misalignment, and shoot great, than we probably expect. Different people have different opinions on what price range dictates what quality tier of barrel falls where. The OP has not disclosed who's barrels these are, or at what price range. (And I don't think they need to.) If this is a $6-700 dollar "name brand" barrel I would expect a higher standard than a $300 dollar "name brand" barrel. But both of those could fall into a range that is above what the average (compared to the kind of person on a forum like this) shooter would consider to be a "match grade" barrel.

 

[ugsly308]

I see that on a lot of prefits that come thru and also on some other shops that chamber and they all shoot extremely well. A borescope can be a very useful tool but you need to know what to pay attention too. I'd shoot it and see what the target says.

Casey