Gunsmithing First chamber job UPDATE

GasLight

GasLight

That Guy
Banned !
Full Member
Minuteman
May 2, 2008
1,962
13
Bozeman, MT
www.thevaultgunandloan.com
#1
Well, finally got my first chamber job done. Think it turned out pretty nice, just need to do some muzzle work now and then get the stock ready to roll, and I will be able to see how it shoots. Figured I would share because I have been trying to complete a rifle project for a couple years now, so I'm pretty stoked.

2aklmdh.jpg


20uac07.jpg
 
#3
Re: First chamber job

After I did the first one for myself, I began to question everyting and remeasured every single thing possible about 15 times before I pulled the trigger on it.

I have to say that it is quite gratifying to have done the work and see it shoot well.

Good luck and have fun shooting it!

Brian
 
#6
Re: First chamber job

good job. i am glad to see more people trying their own work like this. with the price and wait time of a barrel blank, the first few are definatly a bit nerve racking.
 
#8
Re: First chamber job

WTG the first one is the hardest, not gonna tell you how my first attempt turned out. Let us just say nothing like yours. Luckily I had enough shank to later turn my first into a shooter.
 
#9
Re: First chamber job

Give us the details man! This is freaking cool. What caliber is it? What reamer did you use? What are your plans for this rifle? Are you a gunsmith or a machinist? This is really neat and I have always wanted to try this myself. What was the hardest/ scariest part?
 
#10
Re: First chamber job

Sorry, realized this was a pretty limited post information wise. The barrel is a Rock (will finish at 26"), 1:10 twist. I used the .308 Bisley reamer from PTG. I am planning on shooting the 208 HPBT bullets from Hornady through it, not sure if I will have to throat it out yet or not. A machinist or gunsmith I am not. I plan to eventually branch out and do some local smithing, but I am not ready for that yet. More of a hobbiest right now.

As to the hardest/scariest part, I guess for me the hardest was dialing in the chamber length of the bore to zero runout. I had to use an extension to reach my rear spindle spider, so there was more flex in the tubing than in the barrel itself. I wasn't happy with it all the way because it wasn't dead perfect. At the throat I was less than .0001", but at the end of the breech it wasn't quite that good, it was still just under .0005", but I thought it should be better. Anyway, I pre-bored that section out conentric before running the reamer in, so it won't make a difference, I was just frustrated that I wasn't able to get it nuts all the way out. The scariest part for me was the last few thou of the chamber... at that point everything else is nuts, so you sure don't want to drive it in deep and have to re-touch the shoulder, face, and bolt recess again...

 
#11
Re: First chamber job

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: eddybo</div><div class="ubbcode-body">WTG the first one is the hardest, not gonna tell you how my first attempt turned out. Let us just say nothing like yours. Luckily I had enough shank to later turn my first into a shooter. </div></div>

Well, I have had my share of mishaps to this point. I messed up a shotgun barrel 2x trying to thread it for chokes... still haven't lived that one down yet. But I also made a couple reloading/hydro-form dies before this, so I had a good feel for it.

The biggest lesson that I learned so far, quality tooling and machinery make the biggest difference, I tried to limp by with cheap and shitty tooling, but by far the cleanest work came after I upgraded... Now I just need to work on getting better equipment.

Dave
 
#12
Re: First chamber job

Very cool. I'd be nervous as hell trying it myself but excited at the same time. This rifle will likely be the most satisfying shooter you have ever owned. I expect progress updated with a range report at the end. Congrats.
 
#13
Re: First chamber job

I drilled my first one too deep...lol

I just laid my reamer beside the drill bit and found a length where the bushing would be in the bore and the shoulder would touch. I did not account for the short body length of the case. One of those head slap moments. No harm no foul, I fixed it later.
 
#14
Re: First chamber job

It sure is a great feeling to get the first done!! I recently did my first chambering job that came out better than I had even hoped, every thing went smooth but putting that reamer in for the first time made my stomach turn over!
Pulling the trigger on it is a very good feeling and seals the deal on the addiction, I'm like a junky now, I'll be down at the pawn shop selling something to get money for my PT&G bill!
 
#20
Re: First chamber job

Excellent job! My friend and I are beginning the same endeavor! How did you gather your tenon, head space and barrel nose measurements? Did you take them directly off the front of the recoil lug or did you measure the recoil lug thickness then measure off the receiver then combine them?
 
#21
Re: First chamber job

for the tenon, I measured the depth of the action with the recoil lug pinned to it, I measured from the outside of the recoil lug to the front of the bolt lugs. I then <span style="text-decoration: line-through">added</span> subtracted .005" to this. I then turned the tenon down to that length at 1.062x" and then threaded it until the action threaded on. I then measured the bolt from the end of the nose to the front of the bolt lugs and then measured the diameter of the bolt nose. I opened the hole to .710" (.010" oversize) and bored the hole to the same depth as the measurement I made (I figured I already had calculated a .005" clearance into the tenon OAL). The headspace, I used a go gauge, and I just kept checking. I took the recoil lug off and measured the gap as I crept up on the proper headspace. Mine turned out to be ~.003" over minimum headspace. I could have corrected this with a minor cut on the shoulder, but to me on my first job, this is plenty good. The bold won't close on the no-go gauge with the action and barrel only being hand tight, I am guess I gain .001-.002" when I tighten it in the barrel vise.

That's the scoop! Good luck, it is awesome to have done this, well that is as long as it shoots like a dream.

Dave
 
#22
Re: First chamber job

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GasLight</div><div class="ubbcode-body">for the tenon, I measured the depth of the action with the recoil lug pinned to it, I measured from the outside of the recoil lug to the front of the bolt lugs. I then added .005" to this. I then turned the tenon down to that length at 1.062x" and then threaded it until the action threaded on. I then measured the bolt from the end of the nose to the front of the bolt lugs and then measured the diameter of the bolt nose. I opened the hole to .710" (.010" oversize) and bored the hole to the same depth as the measurement I made (I figured I already had calculated a .005" clearance into the tenon OAL). The headspace, I used a go gauge, and I just kept checking. I took the recoil lug off and measured the gap as I crept up on the proper headspace. Mine turned out to be ~.003" over minimum headspace. I could have corrected this with a minor cut on the shoulder, but to me on my first job, this is plenty good. The bold won't close on the no-go gauge with the action and barrel only being hand tight, I am guess I gain .001-.002" when I tighten it in the barrel vise.

That's the scoop! Good luck, it is awesome to have done this, well that is as long as it shoots like a dream.

Dave </div></div>

hey dave, i am sure you mean you subtracted .005" from the length from the recoil lug face to the bolt lug face. i personally like to shoot for .007"-.008" shorter than the measurement from the recoil lug face to bolt lug face when creating my tennon. this usually allows for .005"-.006" of clearance after the tennon stretches when torqued to the receiver. before i chamber, i double check that i do have .007"-.008" of clearance with the receiver threaded on hand tight.

308build21.jpg
 
#23
Re: First chamber job

blush.gif
yeah, I did mean subtract LOL...

I appreciate the input a ton!! I will be doing another barrel job in the not too distant future. I will definately be taking your advice on the .007-.008". I did make sure to check that the bolt could travel all the way forward until the handle contacted the receiver when it was all torqued up, just to double check I didn't leave it too short.
 
#25
Re: First chamber job

nice job, the first one is always the most nerve racking, took me 12 hours on my first one and I had cut up an old barrel and practiced all of the steps several times before I actually cut on the new barrel. A lot of fun and very satisfying when you pull the trigger the first time.
 
#27
Re: First chamber job

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sniperhandle</div><div class="ubbcode-body">Coming along nicely Gaslight, What kind of lathe are you using?</div></div>

My lathe is a LeBlond Regal it is a 13" x 18". It isn't ideally suited to this kind of work as the headstock from rear spindle to the front of my 4-jaw chuck measures right around 29". I can make it work obviously, but at some point I will be in the market for something more suitable.

Dave
 
#29
Re: First chamber job

That looks good! I also like to put a slight radius/chamfer on the entrance to the chamber so that the case necks don't catch on that edge.
 
#32
Re: First chamber job

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: butchlambert1</div><div class="ubbcode-body"> Looks good. My only comment is the chamfer is a little to large for my liking. I just barely break the edge. I don't want a lot of the cartridge web unsupported.
Butch</div></div>

The chamfer is bigger than I want, but there isn't too much of the chamber unsuported. I was just going to break the edge as you say, I had left the compound on 29.5°, so it looks big for the amount of chamber that is gone. If that makes sense.

Dave
 
#33
Re: First chamber job UPDATE

Here is the first shot:

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The range was busy, so I just shot a few times at steel, and had two of my boys shoot it. Will do further range report as I get the opportunity.

Thanks
 
#37
Re: First chamber job UPDATE

My lathe is a leblond regal 13x18. I just used some threading fluid and some tap magic. I pre-bored the chamber and didn't have to run the reamer in very far. I kept it clean and oiled while cutting, and the chamber appeared very nice, there was no need to polish or debur it that I could see anywhere.

Dave
 
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