• This Forum is for adults 18 years of age or over. By continuing to use this Forum you are confirming that you are 18 or older. No content shall be viewed by any person under 18 in California.

Indicating Barrels to chamber

FWIW
I just chambered a 223rem for a BAT action. I don't have a core drill for 5.56 so I drilled and did a two stepped bore to true the hole. Maybe .350" deep as I just free handed the feed. Just finished the chamber. I use a pusher which lets the reamer find its own path. I cut the last pass and for the hell of it I measured the runout on the reamer shank. This is 4.400" away from a snug fitting bushing. It ran .0002" TIR. I never cleaned the chamber out, just let the coolant flush it out. The runout could be caused from left over crud from cutting the chamber.
Edit; I dialed the throat in and checked the runout just inside the breech. It went from a few tenths in the throat to .0017"TIR about .500" in. Total distance between point maybe 2"

That's pretty good huh?

Interesting idea checking runout on the reamer while it is sticking out.
 
There is a machine shop that will do an occasional job for me. They only make small parts. Some of them are really small.

I once asked the owner about tolerances. He said his machines could hold tolerances to a few tenths.

It surprises me that most of the machines used for Gunsmithing are more precise than his.
 
There is a machine shop that will do an occasional job for me. They only make small parts. Some of them are really small.

I once asked the owner about tolerances. He said his machines could hold tolerances to a few tenths.

It surprises me that most of the machines used for Gunsmithing are more precise than his.
Holding parts to a tolerance is different than how much runout a bearing has. If your bearings have no measurable runout, you can dial in a part very very well. Pushing in a reamer is a very low force operation and does not test the rigidity of the machine. And its a form tool which means it will cut the chamber to size so long as you dont influence it. Turning a batch of parts to a specific OD would be a very different question, and likely what he meant when you asked him. Tool wear, machine flex, tool changes, temps, and other things all come into play when running a batch of parts. Its a very different thing. For what we do, we dont need to repeat 1000 parts, we do one job at a time and we dont load our machines, its light work. I wouldnt own a lathe that had .0001" tir in the bearings.
 
Last edited:
One other thing I noticed on my first 223 barrel (5r) is that it’s also noticable harder to get a small bore diameter dialed in than a 243 or 264. There just isn’t as much room on the grooves or lands and the radius of bore changes faster as well. I would say it took me 2x as longer than others I have done.
 
One other thing I noticed on my first 223 barrel (5r) is that it’s also noticable harder to get a small bore diameter dialed in than a 243 or 264. There just isn’t as much room on the grooves or lands and the radius of bore changes faster as well. I would say it took me 2x as longer than others I have done.
You gotta get juuuust the right angle so that the other side of the bore doesnt hit the stylus back toward the indicator. Did a 17cal yesterday and it was tuff
 
Yes and a 13
But do you have one that is fire-plug red?

Mk9Xr0LfY_lA4GtjoN2_LClnlUJU3p7kDpK9O1XWEECyGM3YRrl9PJABeFZqNW5SCPvhqxoMXqhGNYWqM2vkjI4JjXBwLp_SVfTKCcnrzG7aXCQz9o-U0lQ1hjfQNM_j2_Tbr8hLOecZOEKtZ8Do36ZAA25TR2dCRq81y3l3tExggqyKp5uAZ4O9emOp7hUARrdbC6biADberiTtcOjc9g0Wl-tIJNuazIF1-Ly98l555eEccE9-1JZbg3uQlR2dCszb_RqMF9EhFv6fEZhy3EJ59gjUDc6ihKEJkfehtK-jW5BL1AvD6sv8as1nDOPLBGoWDrgI0pO0KG8oO926ymDrzbGNlRqXuEHc-L8XTTJJqheKBU8ExQgZqpP4244WMmmYfQKMKobItgpwbdgSQxO4IrYf-7L1elenlByjKylhmTzmYKeysUJ4VYCvLS2ftx6Ca7z9JO1ZbsEl2QwdqCOu1iU4dkuuAHmwoTarLf_E-7wSqTyWWEHlybaG-KRrOpGxDngUHScwemJjG4Loep90ZMy5Hm3kYPWPLsyZdtLERlWs0O7ZuHpeMY-XjY-j9Vw0HZFXY1SXcpJg2vs10HqPBniPR4Ea3706cirX7Z4Sni-VJfRz5j1ZiDf5mlR3DBfcG1B_XzNEwccsCodsc7JuE5Gm28_WaZUr5hnnKwDIbWvYuLbHhUS25Y9UCV4=w1139-h824-no
 
For those like me who haven't done a lot of barrels yet, I thought it might be helpful to share some videos of what my my chambers have been looking like. I've only done 6 barrels total now - 3 on the lathe of a real gunsmith who was willing to talk me through and now 3 on my own (a used grizzly 0750G with a DRO).

I've been documenting what my chambers are turning out like thanks to the $50 teslong and then will keep track of what they're shooting like to see if there is any obvious correlation. As mentioned earlier in the thread, I'm surprised what some look like that still shoot (maybe not benchrest standards) but pretty darn well.

I decided to clean and then chamber a used up barrel as my first test run on the new lathe after lots of adjusting and test cuts to be mostly happy with its form and function. The neat part about chambering a clapped out barrel is you can really see where you are taking metal from in the freebore and lands.


After doing that one (which I never shot) I was happy enough with the results that I did my first match barrel in 6 creed. It was a 5R and you can see what I think is a little deflection on this one due to 5R rifling. The edge of the lands all look good but in between them you can see that half-moon looking pattern.


Happy to report that 50 rounds in its producing .6 moa 10 shot groups at 900 yards from a harris bipod and rear squeeze bag. I don't have benchrest equipment so could be the gunsmith, the shooter, or the harris and squeeze bag at this point - I have no idea. But groups like that are more than good enough for my game.

Top right was an old barrel I chambered on the gunsmith's lathe, bottom was my first chamber on my lathe (shown above), left group was a buddy who apparently doesn't know what "left" target means, but thankfully can't call wind.

IMG_0997.jpg

Hope those are interesting to someone - if any of you pro's take the time to wade through 5 mintues of chamber video, I'm always open to suggestions if you see something that looks funny or how to improve anything about it.
 
For those like me who haven't done a lot of barrels yet, I thought it might be helpful to share some videos of what my my chambers have been looking like. I've only done 6 barrels total now - 3 on the lathe of a real gunsmith who was willing to talk me through and now 3 on my own (a used grizzly 0750G with a DRO).

I've been documenting what my chambers are turning out like thanks to the $50 teslong and then will keep track of what they're shooting like to see if there is any obvious correlation. As mentioned earlier in the thread, I'm surprised what some look like that still shoot (maybe not benchrest standards) but pretty darn well.

I decided to clean and then chamber a used up barrel as my first test run on the new lathe after lots of adjusting and test cuts to be mostly happy with its form and function. The neat part about chambering a clapped out barrel is you can really see where you are taking metal from in the freebore and lands.


After doing that one (which I never shot) I was happy enough with the results that I did my first match barrel in 6 creed. It was a 5R and you can see what I think is a little deflection on this one due to 5R rifling. The edge of the lands all look good but in between them you can see that half-moon looking pattern.


Happy to report that 50 rounds in its producing .6 moa 10 shot groups at 900 yards from a harris bipod and rear squeeze bag. I don't have benchrest equipment so could be the gunsmith, the shooter, or the harris and squeeze bag at this point - I have no idea. But groups like that are more than good enough for my game.

Top right was an old barrel I chambered on the gunsmith's lathe, bottom was my first chamber on my lathe (shown above), left group was a buddy who apparently doesn't know what "left" target means, but thankfully can't call wind.

View attachment 1234974

Hope those are interesting to someone - if any of you pro's take the time to wade through 5 mintues of chamber video, I'm always open to suggestions if you see something that looks funny or how to improve anything about it.

I would find it very hard to believe the chambers shown in your video would be the limiting factor in your groups.

Those look pretty darn incredible to me.
 

Upgrades & Donations

This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.


Click Upgrade Membership Button ABOVE to get Gold or Silver Status.

You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.


To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.

Forum statistics

Threads
165,872
Messages
2,205,142
Members
79,175
Latest member
rlk99
Back
Top