Gunsmithing Evaluate this chambering setup

[cast1]

To date, I've used range rods with two indicators for dialing in a barrel. I've turned out a couple sub half moa rifles like this but I've always been troubled at the fact that I could never get the same reading twice when I would remove and reinstall a range rod. Also, if i put a long stem indicator up where the throat would be, they always would read off by 2-4 tenths. So, I tried a method that's an amalgamation of the reading I've done on what the benchrest guys do. I started with a range rod to get close, then put the tip of my indicator right where my adjustment screws are and dialed that in as closely as I could see. Then, I buried the indicator and used the spider to dial that section in. Then, I double checked the area where the throat would wind up and it was still running as true as I can read on a half thousandth indicator. Muzzle just happens to be turning as true as my eye can see, not that I would care. Here is a video:

<iframe width="853" height="480" src="https://www.youtube.com/embed/9Nj6NxNkXxw?rel=0&controls=0&showinfo=0" frameborder="0" allowfullscreen></iframe>

 

[Supersubes]

I'm pretty new to doing my own barrels but that's very similar to what I do. Im using a 6 jaw which clamps the barrel via a steel ring. So I dial in that area first, like you do under your adjustment screws. I dont use the range rod at all. Obviously range rods work, but ive found they never go back to the same place twice, no matter what I do to dress the edge where the taper engages.


edited: Just watched your vid. That thing is dialed! Great job!

 

[ugsly308]

Like you i started years ago with range rods, then went to using a long stem indicator and never looked back. Have you checked to see if you have any runout afterwards also? Im using a floating pusher to drive the reamer after I prebore. Works well for me and everything shoots very well. Im not sure how rigid that spider in your 4 jaw is, you get any chatter when cutting?

Casey

 

[cast1]

I don't get any chatter. It's a good and solid setup but adds a little to the length. I managed to find a camlock faceplate so I can put a spider on the front to shorten it up.

 

[skeetlee]

I like to indicate at the throat and them a little ways in front of the throat. I pre bore everything behind the throat true to the throat so now i have a large section running true. I use my long stem for the throat and a grizzly rod 2 inches out on front of the throat. I too get everything close with a range rod before i get picky. my chambers are always .0002 or under when finished. Oh, o like to use and end mill to hog out material so i can get my indicator in farther after i get running true with the range rod. once im happy i bore out to .014 under the neck shoulder junction of my reamer. Lee
Lee Gardner Precision

 

[hero's machine]

I've tried a bunch of methods, made some really slick apparatuses to measure the bore..... but then I moved to just using measuring tools to measure with and my post reaming numbers are running as good or better than I'm reading on the lands. I've gone back and checked my indicators with the other gadgets and they run pretty good....but it's just the possibility of tolerance stacking that makes me look for the least potential.

 

[Mr.Tacticool]

Since all other TV gunsmiths are doing jail time i now rely on this Mastergunsmith for my smiting ideas .LOL neva been done befo

 

[hero's machine]

Since all other TV gunsmiths are doing jail time i now rely on this Mastergunsmith for my smiting ideas .LOL neva been done befo

Ho li chit. That's a dandy.

 

[Red_SC]

I like to indicate at the throat and them a little ways in front of the throat.
Lee
Lee Gardner Precision

I do the same, I typically put the barrel in with about 2.5" of stickout so that my Interapid will just reach to the chuck. Then I indicate that point and another point just inside the barrel. I do use Grizzly rods occasionally, but don't use taper rods.

Hey Lee, I don't recall noticing your last name before. My dentist is also named Lee Gardner, and he does great 1911 work on the side, lol.

Jamie
Ogburn Combat Development

 

[Danny1788]

I like to indicate at the throat and them a little ways in front of the throat. I pre bore everything behind the throat true to the throat so now i have a large section running true. I use my long stem for the throat and a grizzly rod 2 inches out on front of the throat. I too get everything close with a range rod before i get picky. my chambers are always .0002 or under when finished. Oh, o like to use and end mill to hog out material so i can get my indicator in farther after i get running true with the range rod. once im happy i bore out to .014 under the neck shoulder junction of my reamer. Lee
Lee Gardner Precision

Lee are you taper boring to the case taper or just strait .014" under sized from the neck shoulder junction and then running the reamer in?