Real gunsmiths chime in.

[XP1K]

To the professionals out there, not the shade tree guys like myself, y'all tell me if I'm on the right track.

Some time ago I built myself my first rifle. Trued up my action to the best of my abilities and chambered my first barrel. It shoots pretty decent. Half moa is the norm with minimal load development, and it's shot a few in the. 3xx range.

The problem is, when I chambered it I got some reamer chatter toward the end of the chambering process, and I failed to notice it until I test fired it. It's very minimal, but you can feel it in the fired cases. And you can see it in the chamber now that it has a few hundred rounds on it. Probably more like 5-600.

But it shoots good so why mess with it? Well, #1 its not right, and it's bugged me since day one. And I think it's probably going to lead to erosion in the neck due to it not sealing like it should when fired. And #2, probably the main reason, I want to learn how to fix my mistake.

So here's where I'm at. Long ago, the smith that used to due my work for me, may he rest in peace, had told me he had one chatter one time. He had called brownells and was talking to them about it and they told him a process to follow to get it to clean up.

He said brownells told him to take a cotton/flannel cleaning patch and fold it in half and make a small cut with a pair of scissors in the middle, and to slide it over the reamer to the neck/shoulder junction and take a light cut. Repeat the process until it cleaned up. He said he only had to do it once. I forget the depth of cut he said he took.

So that's where I'm at. Am I headed down the right path ? What spindle speed should i run ? I'm here to learn, feel free to tell me if I'm screwing up or if there's another way I should go about it please let me know.

I already moved the shoulder, the breach face, and the bolt recess forward .062" and my witness mark on the barrel and reciever lined up perfect.

Also, I picked up a reamer stop off of LRH, and before I moved the shoulder and everything forward, I slid the reamer in and adjusted the stop to the breach face. Then I added .005" just to make sure I didn't go too deep.

Here's the setup.

 

[hlee]

I’m no gun smith. But, I’m a true believer in the adage of “if it ain’t broke, fix it until it is.”

 

[XP1K]

I’m no gun smith. But, I’m a true believer in the adage of “if it ain’t broke, fix it until it is.”

Fixing it won't make it shoot any worse.

 

[papershredder]

I'm no gunsmith. But having spent most of my adult life working in machine shops, sticking anything other than cutting oil between the tool and workpiece is dumb.

Here's some tips: Chatter is mostly caused by improper feeds & speeds and/or inadequate work piece & tool holding. Brand new, sharp tools are more prone to chatter if the above is not dialed in.

The amount of material you leave for the final cut will matter. Both too much or too little material can cause chatter. I'm not gonna go into detail explaining that, but make sure there is at least a good .005" - .010" worth of material for the reamer for a final cut.

You could try honing the reamer, but if you don't already have experience in doing that, then I don't recommend it. An alternative to honing would be to just obtain a junk or discount barrel and use it to practice a few times and the reamer will naturally dull up enough so it's less prone to chatter. Doing that will give you a chance to experiment with feeds & speeds and will let you know of any inadequacies in your set up.

Now all things said above is under the assumption that your lathe is up to task, solid foundation, no excessive vibrations from the motor or gears/pulleys, doesn't have a worn out spindle bearing, or worn out ways because any of those could also be a source of chatter.

 

[XP1K]

I'm no gunsmith. But having spent most of my adult life working in machine shops, sticking anything other than cutting oil between the tool and workpiece is dumb.

Here's some tips: Chatter is mostly caused by improper feeds & speeds and/or inadequate work piece & tool holding. Brand new, sharp tools are more prone to chatter if the above is not dialed in.

The amount of material you leave for the final cut will matter. Both too much or too little material can cause chatter. I'm not gonna go into detail explaining that, but make sure there is at least a good .005" - .010" worth of material for the reamer for a final cut.

You could try honing the reamer, but if you don't already have experience in doing that, then I don't recommend it. An alternative to honing would be to just obtain a junk or discount barrel and use it to practice a few times and the reamer will naturally dull up enough so it's less prone to chatter. Doing that will give you a chance to experiment with feeds & speeds and will let you know of any inadequacies in your set up.

Now all things said above is under the assumption that your lathe is up to task, solid foundation, no excessive vibrations from the motor or gears/pulleys, doesn't have a worn out spindle bearing, or worn out ways because any of those could also be a source of chatter.

Thanks for chiming in. Based on what you said above I'm going to say inadequate tool holding combined with the brand new reamer and my lack of experience is what got me the first time around. And quite possibly a machine that wasn't up to what I was asking of it.

This evening when I got home from work I went ahead with my original plan with the cleaning patch. Soaked everything in vipers venom cutting oil and made an .010" deep cut. You could feel the chatter in the reamer and then feel it smooth out as it cleaned up. I then stopped the machine pulled the reamer out and blew everything thing clean with air and inspected my work.

It looked to be going in the right direction so I repeated the process once more. This pass felt clean from the start. After that I took two more passes .020" at a time and finished with a final cut .003" deep. Final product came out nice.

Based on what you said about the depth of the final cut I will plan it out in the future where I have .005-.010" left at the end.

I assembled the rifle and test fired it and the brass was perfectly smooth now and the neck seems to have sealed off much better. As it should be.

 

[Smokin7s]

What is your machine? What speed were you chambering originally? Did you pre drill and bore the chamber before entering the reamer or did you raw dog it with a reamer all the way?