Your critiques please

[cast1]

You guys please evaluate my process.

I start with the action. 1/2” mandrel in Gretan raceway bushings. Dial in using a fixture I plagiarized from Mike Bryant. Touch up the action face, integral lugs, chase the threads. True the bolt in a labounty. Get it to do this:

Set my barrel up, do tenon, drill, prebore, ream. Get this:

Check the squareness of my action to barrel:

You guys please point out any errors in thought or execution. Thanks in advance for your input.

 

[STS]

That's nice looking work. The only issue I see is you are checking the lug contact without the trigger in place. Unless your bolt is a custom bolt sized to the bore of the action or you have sleeved the Remington bolt, the mainspring will push against the trigger sear and lift the back of the bolt enough to unseat the top bolt lug.

 

[DaveTooley]

Explain to me how you align the bolt axially in the Labounty fixture.

 

[shortgrass]

After all is assembled and you took it to the range, did the results of your work meet or exceed your expectations? If it did, you did nothing wrong. Where have the 'free thinkers and 'problem solvers' gone?

 

[cast1]

Explain to me how you align the bolt axially in the Labounty fixture.

Hey Dave! You can’t. I’ve used the viper fixture to date, but the labounty is much more rigid in my lathe. Interestingly, when I get the bolt head dialed in in the labounty, the fixture is not concentric, but when I run an indicator down the length of it, the fixture is within a tenth or two of parallel to the axis of the lathe. If the v in the fixture is parallel with the outside surface and it should be, it should do a good enough job providing axial alignment of the bolt. Remington bolts are far from concentric anyway and I wonder if indicating two points .75” behind the bolt head is anywhere near a representation of what’s happening at the rear of the raceway. That’s what I tell myself anyway. It’s my hope that on a non sleeved remmy, there’s enough slop to compensate for it. It’s all kind of out the window when the sear pushes up on the rear of the bolt anyway, right? At least that’s what Vaughn’s book says. Do you use a steady for bolts?

 

[cast1]

After all is assembled and you took it to the range, did the results of your work meet or exceed your expectations? If it did, you did nothing wrong. Where have the 'free thinkers and 'problem solvers' gone?

So far it has. I build for PRS type rifles and everything I’ve done to date will shoot sub half off a bipod and rear bag with multiple types of factory ammo. That’s what I’m looking for. I realize my game is Baja and yours is Formula One lol, but I always want to learn. Maybe I’ll try BR someday.

 

[cast1]

That's nice looking work. The only issue I see is you are checking the lug contact without the trigger in place. Unless your bolt is a custom bolt sized to the bore of the action or you have sleeved the Remington bolt, the mainspring will push against the trigger sear and lift the back of the bolt enough to unseat the top bolt lug.

Thanks for the reply. If I checked that with a trigger group in and it was off, is any way other than removing material from the back of the bottom lug to fix it? Thanks again. Awesome to have you guys as a resource.

 

[STS]

Thanks for the reply. If I checked that with a trigger group in and it was off, is any way other than removing material from the back of the bottom lug to fix it? Thanks again. Awesome to have you guys as a resource.

Nope, the only way to prevent that is to tighten up the tolerances between the bolt and receiver bore to the point that the bolt can't be displaced upward. If you take steel off the bottom lug to the point that the top lug will touch you have assured yourself of two things. The bolt face will not be perpendicular to the bore and the bolt will be off axis to the receiver. Both of which are exactly opposite of the purpose of truing and action. Guys who try to do their rifle a favor by "lapping the lugs to 100% contact" have really shot themselves in the foot and damaged the action to some extent. To correct an action that has been lapped into a crooked state takes more steel removal than a virgin action in most cases.

 

[cast1]

Nope, the only way to prevent that is to tighten up the tolerances between the bolt and receiver bore to the point that the bolt can't be displaced upward. If you take steel off the bottom lug to the point that the top lug will touch you have assured yourself of two things. The bolt face will not be perpendicular to the bore and the bolt will be off axis to the receiver. Both of which are exactly opposite of the purpose of truing and action. Guys who try to do their rifle a favor by "lapping the lugs to 100% contact" have really shot themselves in the foot and damaged the action to some extent. To correct an action that has been lapped into a crooked state takes more steel removal than a virgin action in most cases.

That’s kind of what I figured. There’s a process described in Vaughn’s book but it involves actually cutting the bolt face at an angle to compensate for bolt cant. I’ll probably eventually learn to sleeve ‘em.

 

[STS]

It's not difficult to do. I use old Remington barrels to make the sleeves. I would advise practicing on a blank piece of steel to simulate the bolt before diving in on the real thing. It takes a bit of measurement manipulation to get the sleeves to come out right since you have to split them and loose some diameter. I scribe lines with a pointed cutter in the side of the sleeve while still in the lathe so I make sure I have a perfectly straight lines that are 180 degrees opposite. Split them with a Dremel abrasive cutter and tidy up the ends. Make sure there is a small radius on the ends of the sleeves in the lathe. It's mech easier to do it there than on the bolt. I turn the bolt .005 under ID of the sleeve to allow for adhesive. Turn the bolt and stick the sleeves on with a hose clamp and leave it all in the same lathe set up 24 hours and turn/polish to final diameter. Nothing to it really.

 

[DaveTooley]

That's nice looking work. The only issue I see is you are checking the lug contact without the trigger in place. Unless your bolt is a custom bolt sized to the bore of the action or you have sleeved the Remington bolt, the mainspring will push against the trigger sear and lift the back of the bolt enough to unseat the top bolt lug.

 

[DaveTooley]

Anyone ever consider that on a repeater the top round in the magazine exerts upward pressure on the bolt as well as the trigger?

 

[STS]

Anyone ever consider that on a repeater the top round in the magazine exerts upward pressure on the bolt as well as the trigger?

You are correct.

 

[carlsbad]

Explain to me how you align the bolt axially in the Labounty fixture.

Dave,
I understand the limitations of the labounty. I've gone away from it myself. What is your preferred setup for truing a bolt?

--Jerry

 

[Roeder]

That’s kind of what I figured. There’s a process described in Vaughn’s book but it involves actually cutting the bolt face at an angle to compensate for bolt cant. I’ll probably eventually learn to sleeve ‘em.

I'll try to tread lightly here because Mr. Vaughn is not available to defend his conclusions. I would not advise anyone to follow his recommendations in the area of lapping bolt lugs or fitting barrel threads. His book is an interesting read but I do not know of a single top level smith that uses his ideas.

 

[ab_bentley]

I’ll probably eventually learn to sleeve ‘em.

Or dovetail.

 

[cast1]

I agree. An interesting read but I really do wish he had used a custom action and a more accurate cartridge to test his theories.

Alex, so you use a steady then? Could you post a picture of your setup or pm one to me? Thank you all very much.

 

[DaveTooley]

Dave,
I understand the limitations of the labounty. I've gone away from it myself. What is your preferred setup for truing a bolt?

--Jerry

I have a chuck that runs very true axially. I have threaded mandrels I screw into the rear of the bolt. Hold the bolt in the chuck and I take a clean up cut on the mandrel. Swap ends and hold the nose in a 3 jaw chuck in the tailstock. A very light cut on the back of the lugs and that's done. For the bolt face I use Manson's screw in receiver guide with bolt face specific carbide cutters. I used to use the mandrel, hold the nose with a center in the firing pin hole and move the chuck until the sides were parallel but to many bolts are banana shaped so it was a bunch of work that had compromises built in. I figured why waste time considering all the compromises so I went to using a chuck in the tailstock.

 

[GenePoole]

I use a 5C collet. Can't beat it for ease and accuracy. Of course you can't do it with the handle attached, but surely you intend to rework the handle anyway, right?

 

[cast1]

I use a 5C collet. Can't beat it for ease and accuracy. Of course you can't do it with the handle attached, but surely you intend to rework the handle anyway, right?

Lol eventually!