Gunsmithing what are these marks in my bore?

N

new_guy

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Minuteman
Apr 6, 2010
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USA
#1
Just sent this rifle out to be cut, crowned and threaded for a supressor. At a glance, the work appears to be top-notch. It was done by the manufacturer of the supressor.

If you look closely, you can see circular marks circumscribing the inside of the bore (the last 1/4".)

I've never seen this on a barrel that was cut and crowned. Then again, I've neve had one threaded for a supressor.

Are the two related?

What is it from?

Why is it there?

tool_marks2.jpg
 
#3
Re: what are these marks in my bore?

I can tell you those marks shouldn't be there. My guess is sandpaper or abrasive cloth being used where it shouldn't.
 
#4
Re: what are these marks in my bore?

I have done that before. When you polish a crown you have to be very careful. I used a foam sanding block and somehow did it. Not quite that deep, but same marks. It was on my first build, a 6BR and it has shot many groups in the .1's and a few under that.
 
#5
Re: what are these marks in my bore?

I would bet a piloted crowning tool was used and either the barrel wasn't indicated properly and the crowning tool aft of the movable pilot was hitting the barrel (especially if it is on only one side) or the movable pilot wasn't spinning.
 
#6
Re: what are these marks in my bore?

Instead of loosing time to think about what it is and how it came here, I would ask them to remove 1/4" in of the barrel to get it off.
Othervise You might loose hundreds of dollars in ammo trying back and forth thinking about why it's not shooting as good as before.
Somebody have made mistake and will surely fix if it you ask them

Håkan
 
#7
Re: what are these marks in my bore?

I may be wrong but I believe what we are all looking at is where the smith used a short piece of barrel to make a thread protector cap (albeit an ugly one). If this part screws off then you may have excellent threads and a perfect crown below. I do not see any external threads??? The lands of such a cap were removed to assure "no contact" of the bullet as it passes through the cap.

If I am wrong and this is your actual "crown" then you have a good reason to be concerned as others have stated. For your sake alone I hope I am right. Please let us know.
Thanks.
 
#8
Re: what are these marks in my bore?

A picture with the cap removed would be helpful. I don't understand the same pattern on top of the lands as well as in the grooves unless it is in the cap and he didn't relieve enought of the threads for clearence. What ever happened it violates rule #1 Don't do anything to make the phone ring.
 
#9
Re: what are these marks in my bore?

Thanks for the input. Here's a photo with the cap removed (and some lint.)

tool_marks3.jpg


Unfortunately, the marks are in the bore and not on the cap.

My initial reaction was that some sort of piloted tool had been used to cut or polish the crown. But I was really hoping that someone here had an illogical explanation that was related to supressors that I was not aware of.

I've sent the same photo to the owner of the company, and I'm sure he'll make it right. I do need to talk to him and make sure his gunsmith understands how to crown a barrel with a lathe though.
 
#11
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body">I would bet a piloted crowning tool was used and either the barrel wasn't indicated properly and the crowning tool aft of the movable pilot was hitting the barrel (especially if it is on only one side) or the movable pilot wasn't spinning. </div></div>


Initialy I thought the same thing, but the scratches wouldn't be in the grooves as well as on the lands if this was the case.
 
#13
Re: what are these marks in my bore?

i am betting a solid pilot crowning tool and swarf got between the pilot and the bore. hopefully the company makes it right for you. in my opinion, that should not have left the shop.
 
#15
Re: what are these marks in my bore?

Ouch. I was hoping I was right but no luck there. I am appalled that someone let that out the door without at least an "I'm sorry". I do not consider myself all that good at running the lathe but even I can do better than that. I originally thought we might be looking at a full face thread cap that also protects the muzzle face/crown area.

I would be seriously unpleased if I paid someone to do that. Heck, I'd still be unpleased if someone did that to my barrel for free. I hope they make it right for you.
 
#16
Re: what are these marks in my bore?

Thanks for the input.

Assuming I've lost faith in this outfit, who would you guys recommend to cut this mess off and start over?
 
#17
Re: what are these marks in my bore?

APA, Roscoe, take your pick, a lot of great smiths on this site that know how to properly cut/thread/crown a barrel.

But first, I would call and ask for a refund from the people that did that to your barrel.
 
#18
Re: what are these marks in my bore?

It may be hard to see but, the original bore is still in tact, unmarked. I used a piloted range rod to indicate the barrel in with but never let anything spin in the bore. You'll have to cut the last .500" or so off the end of your barrel and start over to get rid of those marks. If you’re careful when working on other peoples rifles, you can even save the original finish as shown here. This is the same type job you had done. Threaded 5/8x24 Class 3A with thread protector.

2vb7vaa.jpg
 
#19
Re: what are these marks in my bore?

Damnit William every time you post one of your pics you piss me off
wink.gif


I know you're starting to get a head the size of a huuuggeee melon but you sure take pride in your work!!!! I sure appreciate your taking the time to show what you are capable of. Just wished I wasn't on dialup so I could see all of it. Thanks.

Respectfully,
Dennis
 
#20
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rhys</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body">I would bet a piloted crowning tool was used and either the barrel wasn't indicated properly and the crowning tool aft of the movable pilot was hitting the barrel (especially if it is on only one side) or the movable pilot wasn't spinning. </div></div>


Initialy I thought the same thing, but the scratches wouldn't be in the grooves as well as on the lands if this was the case. </div></div>

You want to bet?
 
#21
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SDWhirlwind</div><div class="ubbcode-body">Damnit William every time you post one of your pics you piss me off
wink.gif


I know you're starting to get a head the size of a huuuggeee melon but you sure take pride in your work!!!! I sure appreciate your taking the time to show what you are capable of. Just wished I wasn't on dialup so I could see all of it. Thanks.

Respectfully,
Dennis </div></div>

Hell Dennis..........you can do it too if you want to.
 
#22
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: new_guy</div><div class="ubbcode-body">Just sent this rifle out to be cut, crowned and threaded for a supressor. At a glance, the work appears to be top-notch. It was done by the manufacturer of the supressor.

</div></div>

How is your confidence level in the suppresor.......the same outfit built it!!! . yikes
Dude,that is absolutely poor workmanship,and no quality control.
 
#23
Re: what are these marks in my bore?

Sub-par for sure. The ID has the groves as if it was turned but then the ID would be uniform and as it is not I would say it looks like the "smith" used something pretty abrasive to deburr his cuts. I think you need to re-crown that barrel or push for a new one. In short: they fucked you.
 
#24
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rhys</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body">I would bet a piloted crowning tool was used and either the barrel wasn't indicated properly and the crowning tool aft of the movable pilot was hitting the barrel (especially if it is on only one side) or the movable pilot wasn't spinning. </div></div>


Initialy I thought the same thing, but the scratches wouldn't be in the grooves as well as on the lands if this was the case. </div></div>

You want to bet? </div></div>


I used to use a piloted crowning tool on pistol barrels, and the top of the lands was the only place I got makrs like that. They are also the reason I stopped using that tooling. Just haven't seen a piloted crowning tool leave the scratches like that in the grooves.
 
#25
Re: what are these marks in my bore?

I bought a new savage tactical with the mcmillan stock some years back, it had the same marks in the bore. I noticed them at the gunshop when I picked it up, the owner of the store said dont worry about it or something like that, and gave me a hard time about wanting to return it although I havent even left the store. I took it home b/c it was paied for so I called savage and sent them pics before I shot it and they said there gunsmith reviewed the pics and said it would not hurt any thing. I reluctently broke the rifle in and started shooting it. It did ok about 1/2 moa but the marks bother me so bad I sent it back to savage. I talked to the "gunsmith" whial it was there and he said he could not see any thing but would look at it agan and call me back in a few days. Well 1 week later the rifle arrived back from savage with no return calls, or info in the box about the complaint. It had a 3 round target that measured about 5/8 in, I inspected the barrel and it was the same one. I called back and could not get any thing from them explaning what they determined except it met there accuracy requirements. I think you should give the gunsmith inquestion a chance to make it good, I hope you have better luck than me. I have not owned another savage sence. Good luck.
 
#26
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rhys</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rhys</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body">I would bet a piloted crowning tool was used and either the barrel wasn't indicated properly and the crowning tool aft of the movable pilot was hitting the barrel (especially if it is on only one side) or the movable pilot wasn't spinning. </div></div>


Initialy I thought the same thing, but the scratches wouldn't be in the grooves as well as on the lands if this was the case. </div></div>

You want to bet? </div></div>

I used to use a piloted crowning tool on pistol barrels, and the top of the lands was the only place I got makrs like that. They are also the reason I stopped using that tooling. Just haven't seen a piloted crowning tool leave the scratches like that in the grooves. </div></div>

I've seen a few of those and the piloted crowning tools from PTG, Clymer, and JGS are very good if one knows how to use them, no different then a piloted reamer that everyone uses to cut chambers.

It's very critical that the bore is running very true and you have a good reamer holder, if not you will have issues, same with a chamber reamer. It all comes down to how good ones set-up is.

In the OP's pic the land in that bore is almost, if not completely, cut down to the grove and the grove also got whacked in the processes. There was a problem with this set up and or the cutter used to make the crown.

Will it cause issues? Maybe, maybe not, but it would sure bug the hell out of me.
 
#27
Re: what are these marks in my bore?

Newguy,

Send it to me with funds for return shipping, approx $45 to $50, and I'll cut it off, crown and thread it 5/8x24 Class 2A or 3A, your choice, complete with a new thread protector.

No additional funds required.
 
#29
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Black Ops</div><div class="ubbcode-body">
Who is the outfit that threaded and protected your barrel New Guy ?

<span style="font-weight: bold">Mike
Tac Ops</span> </div></div>

+1
 
#30
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">Newguy,

Send it to me with funds for return shipping, approx $45 to $50, and I'll cut it off, crown and thread it 5/8x24 Class 2A or 3A, your choice, complete with a new thread protector.

No additional funds required. </div></div>


This is but 1 reason you will be doing my next build.....

Absolutely stand up guy and stand up work, kudos to you sir
 
#31
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">Newguy,

Send it to me with funds for return shipping, approx $45 to $50, and I'll cut it off, crown and thread it 5/8x24 Class 2A or 3A, your choice, complete with a new thread protector.

No additional funds required. </div></div>

In case anyone missed it, William just offered to fix it for the cost of return shipping!!!

New Guy, what more could you want?

Oh and +1 on the name of the outfit.
 
#32
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Black Ops</div><div class="ubbcode-body">
Who is the outfit that protected your barrel ?

<span style="font-weight: bold">Mike
Tac Ops</span> </div></div>

Looks like there wasnt much <span style="text-decoration: underline"><span style="font-weight: bold">"Protecting"</span></span> going on
wink.gif
 
#33
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">Newguy,

Send it to me with funds for return shipping, approx $45 to $50, and I'll cut it off, crown and thread it 5/8x24 Class 2A or 3A, your choice, complete with a new thread protector.

No additional funds required. </div></div>

Amazing! Kudos wnrosoce.
 
#35
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">Newguy,

Send it to me with funds for return shipping, approx $45 to $50, and I'll cut it off, crown and thread it 5/8x24 Class 2A or 3A, your choice, complete with a new thread protector.

No additional funds required. </div></div>

I'm sorry for the delayed reply, but I was out in the rain most of the day yesteday hunting hogs.

2.jpg


3.jpg


However, and more importantly... <span style="font-weight: bold">Thanks, William!</span>

That is a very generous offer, and one that I'll take you up on. This is my first venture down such a path, and guidance like yours is needed and greatly appreciated.

Rest asured that your generous gesture has more than earned my future business!

I'll phone you today to coordinate shipment of the rifle.

Thanks again, VERY much!!!

 
#37
Re: what are these marks in my bore?

Here is the response I got this morning from the company that did the work.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> That is normal with threading, and won't hamper your accuracy at all.

Because with suppressor use, you have to use a live center - to cut the threads.
This is a tapered plug that goes in the muzzle end of the barrel, the barrel is then turned in a lathe.

That is the only way to cut threads concentric with the bore.

So when he's done he hits it with some scotch-brite, to touch up any tool marks.

This makes sure you have a clean crown, with no burrs or deformities.

Your Rifle should shoot just as/or better than before you sent it to us.

He uses an 11 degree target crown, and it works.
</div></div>

Yes, I have seen the requests asking who did the work. I'm new here (this is my first post), and I really appreciate all of the help you guys have given (especially you, William).

I would really rather not say which manufacturer of supressors did the work. Better advice would be to ask more questions than I did when I blindly sent it to them thinking they knew what they were doing.

Thanks again for all of your help and comments.
 
#38
Re: what are these marks in my bore?

Look buddy, we try to take care of our members here, and one of the ways we do that is by telling the new guys which outfits to stay clear of. If we dont know who did this to your barrel, another poop shlub is going to end up in your situation. Not to mention that this outfit is trying to feed you bullshit and telling you what they did is normal, this is unacceptable. Please name the outfit.
 
#39
Re: what are these marks in my bore?

Kudos to you new guy on your ethical approach to not naming and shaming.

Not sure having read the reply that I would not be tempted to name who was NOT the can maker.

Then members would know who they can trust.
 
#40
Re: what are these marks in my bore?

I haven't seen this asked yet, but has the rifle been shot with these marks? If so, did it effect accuracy?

If not, I wouldn't worry about it (but that's me). If it did, then I see about getting it fixed.
 
#41
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> That is normal with threading, and won't hamper your accuracy at all.

Because with suppressor use, you have to use a live center - to cut the threads.
This is a tapered plug that goes in the muzzle end of the barrel, the barrel is then turned in a lathe.

That is the only way to cut threads concentric with the bore.

So when he's done he hits it with some scotch-brite, to touch up any tool marks.

This makes sure you have a clean crown, with no burrs or deformities.


</div></div>

With cautious respect to who ever wrote you that, I disagree.
You are showing pretty serious damage in the most unforgiving part of the entire barrel.

200,000 rpm and 55,000 p.s.i. come to a release point at the muzzle. The crowned area of the muzzle is the last thing controlling the bullet as it is released into free flight.

Most rifle smiths on this site would have a stroke at even a minor deformity around the crown. To see a full .500-.600" of damaged bore on your barrel would bring the entire train to a halt until that was addressed and all the vomit was cleaned from the shop floor.

Your bore shows the very thing that the business reply stated should not be there. "tool marks, burrs, deformities".

The entire bearing surface (lands AND grooves) are altered enough at that point that your engraved bullet jacket will be required to reshape again right before exit. Most probably will also loose any gas seal that was established 20 something inches earlier. I would encourage you to correspond further with the business and share with them that you believe they should re-visit their techniques. If, after thorough communication with them, they still insist that this result is acceptable and within their accepted QC, then you should then ask them if it is OK to post their name associated with those photos on a public internet forum. This would be free advertisement for them and show examples of their work. Fair enough. . . . . . .

I do not believe your rifle is ruined but I would not even go through the expense of shooting it until that is addressed. Even if your rifle shot tiny groups by some miracle of 7 pound, 8 ounce baby Jesus, it probably would not do it for long and would absolutely be subject to squirrel stampedes without notice.

In the mean time, get Roscoe to make fixy fixy and enjoy your rifle afterwards.

Good luck,
Terry
 
#42
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Terry Cross</div><div class="ubbcode-body">Even if your rifle shot tiny groups by some miracle of 7 pound, 8 ounce baby Jesus, it probably would not do it for long and would absolutely be subject to squirrel stampedes without notice.

In the mean time, get Roscoe to make fixy fixy and enjoy your rifle afterwards.
</div></div>

Not to get off topic, but those have got to be the two most entertaining sentences I've read on this site in some time.
 
#44
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: rth1800</div><div class="ubbcode-body">Anyone think of counterboring the muzzle beyond the damage? </div></div>

I understand where you are going with that thought and it is logical to ask.
Why cut away the new threads just to fix the bore? . . .

This is just me but the first thing I would consider is. . . . if they did that to the bore and think it's acceptable, wouldn't I be justified in wondering about the quality of thread job they did?

Even if counterboring the muzzle into a deep recess configuration and retaining the threads, I would not want to take any more support and rigidity away from the threaded structure responsible for retaining a 18 to 30 ounce suppressor. Looks like you are already at 5/8"-24 t.p.i. and to take even more material away would not be in my top list of responses.

Lastly, prior to ANY muzzle work, the bore would need to be properly zeroed in the lathe. Setting everything up so that the last 5" of bore is to min T.I.R. is 90% of the work. Once you have done that, it only makes sense to recut everything associated with that setup and bore geometry.

Just my opinion and that is based solely on my own experiences and preferences.






 
#45
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jasonk</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Terry Cross</div><div class="ubbcode-body">Even if your rifle shot tiny groups by some miracle of 7 pound, 8 ounce baby Jesus, it probably would not do it for long and would absolutely be subject to squirrel stampedes without notice.

In the mean time, get Roscoe to make fixy fixy and enjoy your rifle afterwards.
</div></div>

Not to get off topic, but those have got to be the two most entertaining sentences I've read on this site in some time. </div></div>

I have found that due to my Texas and Louisiana roots, people expect that type of language in all facets of my communication. I felt obligated to use those parallels especially after posting about RPM, PSI and other technical jargon.
If anyone fails to follow the intent of the post, I can futher elaborate using a different context, possibly from Alabama or North Carolina.
 
#47
Re: what are these marks in my bore?

I spoke to the OP today and he is shipping the rifle via Fed-X. His account so I told him N/C for shipping. He insisted on paying something so I told him to send two Asian Girls with the rifle if that'd make him happy and we'd call it even. One for me and one for TC
wink.gif
I hope mine can cook........if not, at least dance on a pole.

All BS aside, he seems like a good guy that was feed a plate full.

The threading job wasn’t performed by a Rifle Builder so you can all relax. It was threaded in a live center and Scotch Bright was the culprit that caused the marks in the bore. I'll chop off the first attempt and make the second one right.
 
#50
Re: what are these marks in my bore?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: wnroscoe</div><div class="ubbcode-body">I spoke to the OP today and he is shipping the rifle via Fed-X. His account so I told him N/C for shipping. He insisted on paying something so I told him to send two Asian Girls with the rifle if that'd make him happy and we'd call it even. One for me and one for TC
wink.gif
I hope mine can cook........if not, at least dance on a pole.

All BS aside, he seems like a good guy that was feed a plate full.

The threading job wasn’t performed by a Rifle Builder so you can all relax. It was threaded in a live center and Scotch Bright was the culprit that caused the marks in the bore. I'll chop off the first attempt and make the second one right.
</div></div>

Ya.. we know !!! it was threaded by the suppresor manufacture ( Class 2)....scary stuff there boys and girls. Hopefully the bullet will pass thru the can's bore and not out the side.
 
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