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?

The reason they appear circular is because the bore is circular. Because it appears on the lands as well as in the grooves, I would say it was the result of something being forced into the muzzle. I would be for finding out. By the looks of the lands it appears to have caused some pretty heavy damag. Something that would have, should have, been felt at the time of occurrence.

They are definitely nasty looking.

I had it on a Colt 32 revolver that I had the barrel shortened on. It is where the "pilot" or "spigot" on the tool used to cut a crown on the muzzle has been inserted into the bore.

Methinks that your guy has put the barrel in a vice and inserted the pilot of the tool that cut the crown into the bore and then turned it.

Just like you insert a Lee Case Trimmer into a fired case. And turn it to trim the case. I think they have used a bigger version of one of those to cut your crown.

Ouch!

Now the proper way would have been to have put the barrel into a lathe and use a normal cutting or parting tool to cut the crown. So that nothing was inserted into the muzzle.

I would be more than a little unhappy. The only "quick fix" is to now counterbore the muzzle.

Personally having had them ruin the muzzle the first time why do you think that they can get it right the second time.

Is the maker of the suppressor a true gunsmith? Or just someone who makes mufflers for guns?

I think your guy may have lots of "die and tap" sets...but no lathe! Certainly no lathe was used to cut your crown.

ouch!

I thought some sort of piloted tool for the crown also, but I was really hoping that someone had an illogical explanation that was related to supressors that I was not aware of.

Unfortunately, the supressors are top-notch. Maybe the gunsmith was having a bad day? Either way, I've sent the owner an email and photo of the damage to the bore.

I'm sure he'll make it right.

Hopefully it is not going to have to be an SBR as well as supressed now, unless they want to buy that stamp for you.

Sorry to see this and hope it gets sorted out fast.

quote:

Originally posted by Charles_Helm:
Hopefully it is not going to have to be an SBR as well as supressed now, unless they want to buy that stamp for you.

It is close... but there's an extra inch there for a re-do.

quote:

Originally posted by new_guy:
It is close... but there's an extra inch there for a re-do.

That is cutting it close, as it were.

Good luck.

As smashed down as the lands are, I'll have to go with Westpac. I don't know why you would use a piloted tool for a crown. They need to be single tool cut with a very sharp tool.
Butch

Well, the barrel doesn't have to be cut off, you could simple drill it out and internally crown the bottom of the hole/end of barrel. That way you wouldn't lose any length if you don't want to.

Not to rain on your parade but the crown doesn't look too special either.

Stepchild

It wasn't done with a piloted tool. A pilot will only run on the bore, not the bore and the groove. It looks like someone drove an oversized alignment pin in the muzzle to dial in the bore. They need to go back to school. Also, if they machined a thread relief at the shoulder, someone will need to remove the entire thread tenon and redo. The axis of the suppressors need to be perfectly aligned with the bore to avoid bullet impacts and off axis gas play. Good luck!

I agree with counterboring with a very sharp tool. You will lose a little of the rifled bore but still maintain the profile outside. You will essentially have a very deep recessed crown.

I don't know if stability will cause a can strike or not on it. I am not familiar if can's allow for a jump or not.

ETA: To be honset the bullet has to jump now; it should only help to have a good sharp edge to jump the same distance.

Yep, The marks are not from a pilot when the crown was cut. You only see the marks from that on top of the lands.

You know what's really pitiful? Krieger crowns their barrels with a piloted tool and leaves marks on the lands. As much as I love their barrels, I wouldn't let them finish one for me for free.

Agreed, but the marking are on the grooves as well as the lands. If a pilot was used, that damage should only be on the surface of the lands. That implies that a undersize pilot was used with a shim wrapping to bring it to a diameter. Either (1) they used a pilot pin in the tail stock and galled the lands as the bore rotated around the shim, or (2) they did use a hand tool with a shim wrapping with the same result. A terrible crown. Frankly, it should NEVER have passed out inspection.

Cure is as suggested, counterbore to the clean area and have a recessed square face crown.

as kim said but HAVE IT DONE SOMEWHERE ELSE..... that's about as screwed up as i've seen a NEW CROWN........

Top notch???

That surface finish on the crown is crap let alone the pilot grove he cut in your bore.

Brownells sells a "no lathe crown cutter"
Guess what he used??
And it's my guess it was the pilot but with the added grit of the chips getting in between the bore and pilot swirling around it would then mark the lands and groves. That will happen when the barrel is clamped in a vise vertically and gravity carries the chips into the bore.

You nailed it. Chips and the hand crown cutter.

The barrel could be set back up.
Dailed in with a 4 jaw. bore out the crappy part.
face the end of the lands off at 11degrees from perp.
Double check the the edge of the lands for burrs with a q-tip.
Polish the end while it's set up.
I can't believe they let that go.
timan

They polished your crown with some 100 grit paper and in the process, stuck it into the bore for good measure. I have no stake either way in this, but it looks like simple poor workmanship.

Looks to me like the barrel turned while it was chucked up.

Terry

Hate to agree with TC1 but this is certianly what it looks like to me----going to have to shorten the barrel a bit.....

quote:

Originally posted by dpcd:
They polished your crown with some 100 grit paper and in the process, stuck it into the bore for good measure. I have no stake either way in this, but it looks like simple poor workmanship.

+1

James

Here is the reply I got back from the supressor mfg this morning - after I sent them the photo above.

quote:

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.

quote:

Originally posted by new_guy:
Here is the reply I got back from the supressor mfg this morning - after I sent them the photo above.

quote:

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.

Well he's wrong.
It's not the only way to machine threads on a barrel. A center is not needed. You can set the barrel up in a four jaw chuck indicate the bore and machine your threads.
Its the same as machining the breach end.
Using a center is just lazy.

Chris,
The guy is full of shit!
Butch

Chris, "I" would drive to Ennis, and have that shop dp it right.

They have crowned more than a couple of barrels. They are almost in your backyard.

Keith

I just cut 8" off my Mousin Nagant 91/30 rifle. I used a hacksaw and filed the end of the barrel until it appeared square and draw filed it until it looked good. I chucked up a stove bolt (slotted machine screw) in my Makita drill and made a paste out of clenser (I didn't have any valve grinding compound) and used that to crown the muzzle in the area of the lands and groves. I did this until I had no wire edges and then ran a brush and patch through the bore and headed for the range. Accuracy was great, and a big improvement over the original barrel. (My barrel should have been counter bored years ago but it wasn't.)

Please keep in mind that I didn't take the barrel out of the action nor remove the stock or scope.... I just rested the rifle on a cardboard box and cut away. I can honestly say that the work I did looks better than your pictures, probably cost a lot less, had no down time and turned out OK. Yes, it is easy to take a hacksaw and file to an $80 rifle and I would have second thoughts attacking a "good" rifle but then again, perhaps not.

If a gunsmith did to my rifle what they did to yours, I would be upset. If I did it to myself, I would cut some off and try again.

Only a hack would let a barrel leave his shop with a bore looking like that! And then try to justify the damage with such a line of bullshit! What company is it so I can steer my suppressor customers clear of it?

I think it's from a piloted crowning tool, and the slob that did the work didn't bother to clean off chips from the pilot every few turns as it was being cut. A live center should spin with the barrel, not spin IN the barrel!

quote:

Originally posted by butchlambert:
Chris,
The guy is full of shit!
Butch

RIGHT! Only a fool or a liar would send a reply like that.

Here's a suggestion for correction. I had an original Savage 1895 (yes, 1895 not 1899) lever rifle in 303 Savage that keyholed every bullet. I used a 30-06 reamer with no throat to counterbore the muzzle back about 1/4" and the rifle began putting them all touching at 50 yds. HANDHELD reamer and no deburring afterwards except for several passes with an oversize bronze brush. I was prepared to fab a long lap to reach down into the counterbore to lap the bore's edge but it wasn't necessary.

Just food for thought.
Regards, Joe

quote:

Originally posted by xs headspace:
I think it's from a piloted crowning tool, and the slob that did the work didn't bother to clean off chips from the pilot every few turns as it was being cut. A live center should spin with the barrel, not spin IN the barrel!

Exactly!

Ask the suppressor manufacturer to explain how a live center works. Any answer other than that highlighted above and they are full of crap.

OH NO! The guy put an 11 degree crown in the bore not on the face of the muzzle! I see it now! Ass backwards. Barrel needs to be faced off, recrowned, and threaded on the outside for the suppressor.

William Roscoe of Louisiana Precision Rifles saw my post and said to send it to him, and he would fix it.

He received the barreled action at 4:09pm this afternoon. At 8:00 pm the same day, he had these photos.









THAT is service well above and beyond!

Now that looks good.

Man, that first guy, what a hack.