Muzzle threading question

[Spike A]

So I’ve recently delved into the suppressor world and with that want a few of my barrels threaded, already having a lathe started to read and figure a few things out, I made an outboard spider, made some brass rod inserts to go in my 4 jaw so I’ve got full adjustability … now I purchased a long stem indicator to reach In the bore a few inches, apx where the 4 jaw is, then move to end of barrel and adjust outboard spider and move back and forth a few times till the last one doesn’t effect the other, so here is where my question is

When I have what I think the last few inches of barrel straight.. … seems like the action end is wobbling ( so far I have tried a 22 lr and a 22 mag and a 223, all factory rifles as my customs are already threaded)

Is this normal?

 

[WSnyder]

Is this normal?

Yes. Rifle bores are not straight.

 

[SKWERLZ]

Yes. Rifle bores are not straight.

This^^^^^

A question I have is if you were to just dial in both ends like between two centers could bore curve be enough to risk baffle strikes?

 

[Spike A]

Yes. Rifle bores are not straight.

Right it just seems like more then I was expecting is all…

 

[LVLAaron]

Yep. That's how it be.

Set your lathe to a low speed and look down the bore. You'll see how crooked and twisty some barrels can be.

 

[urbanrifleman]

Put the barrel on the live center. Once you have the bore on center clean up the od.

Dialing in for a muzzle thread job just seems silly. I'll take a mechanic center every time.

 

[SKWERLZ]

Right it just seems like more then I was expecting is all…

I remember the the first time I dialed in the bore you did and being kinda worried, then the internet professors explained it.
I have a 338 barrel with a bore like a amusement ride and it’s a good shooter.

 

[LVLAaron]

Put the barrel on the live center. Once you have the bore on center clean up the od.

Dialing in for a muzzle thread job just seems silly. I'll take a mechanic center every time.

I want my crown and threads concentric to the bore at the end of the barrel. I dont want a baffle strike.

 

[urbanrifleman]

I want my crown and threads concentric to the bore at the end of the barrel. I dont want a baffle strike.

If you have a barrel so crooked you can't center it on a live center and cut threads on center, get a new barrel.

 

[Spike A]

So far I’ve only tinkered with factory stuff, near as I can tell the bore is centered in the suppressor … going to work on my first non factory either today or tomorrow … curious to see what that looks like

 

[LVLAaron]

So far I’ve only tinkered with factory stuff, near as I can tell the bore is centered in the suppressor … going to work on my first non factory either today or tomorrow … curious to see what that looks like

Keep doing what you're doing.

 

[DaveTooley]

Worrying about the last few inches of the barrel is the wrong approach. How long is the bearing surface of the bullet? That distance/hole, which is very short, needs to be concentric with the treads. As far as axial alignment we want perfection but it's not as critical as some make it out to be. How can we measure misalignment in that short a distance? I've threaded a lot of factory barreled actions and lets just say I improvised a lot of the setups because I don't remove the barrel. Never had a problem.
YMMV

 

[jackieschmidt]

Keep doing what you're doing.

^^^^^^^^

 

[Carl S]

There are different ways of setting up for muzzle threading .through the head stock,three point steady,between centres.etc.i thread quite alot of factory barrels,shortening them aswell.some barrels I remove some I don't.some suppressors i fit don't give you much clearance on the bullet so you've got to make sure that shoulder is square to the bore.ive never had a problem or a unhappy customer. .keeping everything square and true to bore doesn't make the phone ring.

 

[skeetlee]

I can’t say this is so in your case but if your bore is too crooked be careful of getting a baffle strike. Sounds like your issue is on the other end I do threads for cans a bit different in my shop especially on really crooked barrels. I have special made ground rods that are 10” long and in .0004 increments. Expensive to have made but they work well for this application. I hate dialing in with rods but I wanna be sure that the bullet isn’t gonna strike anything. All barrels have run out. Some just worst than others.

 

[LVLAaron]

Who makes those rods for ya?

 

[urbanrifleman]

Worrying about the last few inches of the barrel is the wrong approach.

Maybe I'm wrong but it seems like all of the techniques in recent times only worry about the last few inches of the barrel.

 

[LVLAaron]

For the muzzle end I dial the end... and 1.3 inches inboard. To Daves point, there isn't going to be a ton of bore variation at the end of the barrel... and only the last little bit matters.

As opposed to dialing a chamber.... where the bullet meets the lands can be 3-4 inches from the breech, and a lot more can happen.. if you're only dialing on the very tip of the breech

 

[DaveTooley]

Maybe I'm wrong but it seems like all of the techniques in recent times only worry about the last few inches of the barrel.

On the chamber end we have the length of the loaded round. Base to ogive to align.
On the muzzle we have the length of the bearing surface of the bullet to align.
6MM Berger 105 hybrid bearing surface .342"
30 cal Berger 185 Juggernaut bearing surface .336"

There is no common sense explanation that can validate the barrel having influence on the bullet AFTER the bullet has passes that point. So dial in the chamber end and the muzzle and go to work.

 

[sdean]

On the chamber end we have the length of the loaded round. Base to ogive to align.
On the muzzle we have the length of the bearing surface of the bullet to align.
6MM Berger 105 hybrid bearing surface .342"
30 cal Berger 185 Juggernaut bearing surface .336"

There is no common sense explanation that can validate the barrel having influence on the bullet AFTER the bullet has passes that point. So dial in the chamber end and the muzzle and go to work.

After that correct statement, this thread should be finished.