Rifle Action Truing

[thestelster]

I’ll wait patiently for pictures, no rush

So it’s possibly a “headspace” issue? I was warned it’s a one shot approach to get right, or you can ruin parts. The barrel isn’t threaded where it mounts to the receiver, the barrel nut attaches the barrel to the receiver

@Chicken lights which firearm do you have, and what issues are you having?

 

[Chicken lights]

@Chicken lights which firearm do you have, and what issues are you having?

PM sent

 

[Susquatch]

I have a question about mounting a barrel to a receiver, but I only know enough to be dangerous.

If I’m correct in how I understand this- the receiver is slightly tapered where the barrel registers. There are shims that go between the receiver and the barrel

So the goal is to get the shim pack the correct measurement before tightening the barrel nut

Too little of shims, results in barrel damage, too many shims, too loose of a barrel and not seated correctly

Am I sort of on the right track, on how I understand things?

So it’s possibly a “headspace” issue? I was warned it’s a one shot approach to get right, or you can ruin parts. The barrel isn’t threaded where it mounts to the receiver, the barrel nut attaches the barrel to the receiver

Yes, it's all about headspace.

I agree with what @thestelster said.

Let me add that I think you are specifically talking about the Savage Barrel Nut but mixing in information you have heard about shouldered barrel designs (Remington, Winchester, etc). They are NOT the same. But the end result is.

With the savage, it's definitely not a one shot thing. But even the others are not one shot efforts. It's easy to test fit till you get it right.

A yahoo with a pipe wrench is a whole nuther matter.

The part between the barrel and receiver is called a recoil lug. It is not a shim. It transfers recoil forces from the barrelled action to the stock.

They do sell recoil lugs in different thicknesses that can be used to change the head spacing but that isn't generally the way to do it. Normally, the chamber is cut to the correct headspace when it is reamed. Sometimes with prechambered barrels, you can also cut the barrel shoulder a bit to accomplish the same thing with minimum machining. But again, this is not the preferred approach it's only done to facilitate using pre-fit barrels.

This might be one of those things best explained on the phone or hands on during a visit. A visit like that would make it all obvious.

 

[Chicken lights]

Yes, it's all about headspace.

I agree with what @thestelster said.

Let me add that I think you are specifically talking about the Savage Barrel Nut but mixing in information you have heard about shouldered barrel designs (Remington, Winchester, etc). They are NOT the same. But the end result is.

With the savage, it's definitely not a one shot thing. But even the others are not one shot efforts. It's easy to test fit till you get it right.

A yahoo with a pipe wrench is a whole nuther matter.

The part between the barrel and receiver is called a recoil lug. It is not a shim. It transfers recoil forces from the barrelled action to the stock.

They do sell recoil lugs in different thicknesses that can be used to change the head spacing but that isn't generally the way to do it. Normally, the chamber is cut to the correct headspace when it is reamed. Sometimes with prechambered barrels, you can also cut the barrel shoulder a bit to accomplish the same thing with minimum machining. But again, this is not the preferred approach it's only done to facilitate using pre-fit barrels.

This might be one of those things best explained on the phone or hands on during a visit. A visit like that would make it all obvious.

I’ll send a pic once I’m near the shop again. I’m not going down your way for a few weeks unfortunately

 

[Susquatch]

I’ll send a pic once I’m near the shop again. I’m not going down your way for a few weeks unfortunately

OK, no problem.

I'm not moving any time soon. A visit whenever you can make it will be fun!

 

[thestelster]

Waiting for the chambering.

I'm going to sign this......

Old enough to know a lot, learned enough that I still need to learn even more.

Here is one method of chambering rifle barrels. There are a myriad of methods and I've used quite a number of them. Use the method which is easiest for you and gives you the results you're after. You might have to use different methods for different situations. In this method the barrel is held in a spider and is centered with the 8 bolts, so that the bore of the barrel is running concentric and true with the axis of the lathe. The reamer is positioned against a dead center in the tailstock. The reamer is prevented from rotation by a tap wrench with one arm on the compound rest. The depth of cut is controlled by the tailstock wheel, and measured with the dial indicator against an arm attached to the quill of the tail stock. The reamer is held firmly against the dead centre with the left hand pulling rearward slightly.

 

[thestelster]

Here is how I hold the reamer backwards against the center.

 

[thestelster]

Oh, in case you're wondering about the blue glove. I don't like wearing gloves unless I absolutely have to. It removes all the sensation of doing precise work and holding small parts, especially holding small parts during cleaning in the Varsol tank. But considering I had carpal tunnel surgery last Thursday, and started working on Monday four days later....

 

[Chip Maker]

Ouch!

 

[Susquatch]

Oh, in case you're wondering about the blue glove. I don't like wearing gloves unless I absolutely have to. It removes all the sensation of doing precise work and holding small parts, especially holding small parts during cleaning in the Varsol tank. But considering I had carpal tunnel surgery last Thursday, and started working on Monday four days later....

And you are holding a Reamer back with that hand.....

Shouldn't you be in the house milking that for sympathy with your SWMBO?

 

[thestelster]

And you are holding a Reamer back with that hand.....

Shouldn't you be in the house milking that for sympathy with your SWMBO?

SWMBO? She wanted me to take it easy, but I can't sit around if there are things to do. In fact, I was on my hands and knees cleaning and scrubbing up the whole bathroom the day after surgery.

 

[Susquatch]

SWMBO? She wanted me to take it easy, but I can't sit around if there are things to do. In fact, I was on my hands and knees cleaning and scrubbing up the whole bathroom the day after surgery.

I wonder what your surgeon would have to say about that..... LOL!

 

[thestelster]

I wonder what your surgeon would have to say about that..... LOL!

Yeah, they usually just shake their heads. Especially when I did a half-ironman triathlon a year and a half after my hip replacement!

 

[Chicken lights]

Is threading a barrel muzzle a lathe operation or can you farm boy it with the right die?

(I’m sure you could point it on the lathe and finish it with a die, too)

 

[Susquatch]

Yeah, they usually just shake their heads. Especially when I did a half-ironman triathlon a year and a half after my hip replacement!

Something serious is the matter with me.

I must be attracted to friends like you......

A buddy of mine for 60 years is scheduled to have a heart valve replaced. He was told to avoid any activity that raised his heart rate or blood pressure. He is busy ignoring those orders totally.

You guys are both crazy.....

But I like you anyway!

 

[Susquatch]

Is threading a barrel muzzle a lathe operation or can you farm boy it with the right die?

(I’m sure you could point it on the lathe and finish it with a die, too)

In my opinion it's a lathe job beginning to end. But a little different than chambering or crowning because the brake must look good on the outside AND have a concentric bore. This is not simple. It means setting up the bores of both barrel and brake concentric with the spindle for boring, threading, and shouldering and then cutting the OD of the brake to be concentric with the OD of the barrel. Remember that very few barrels have an OD and an ID that are actually concentric with each other.

However, I'd be willing to bet that there are a gazillion brakes out there that were done without a lathe with gaps at the interface, crooked alignment, and big fat diameters to hide the mismatch. And I doubt that most shooters care.

 

[thestelster]

To get maximum recoil reduction from a muzzle brake, the bore of the muzzle brake should be between 0.015"-0.020" larger than bullet diameter. That's 0.0075-0.010" per side clearance before the bullet hits the bore of the muzzle brake over 2-3" brake length. That type of precision usually cannot be attained by a threading die. Now, some off the shelf muzzle brakes, or even factory ones, have the bore of the muzzle brake considerably larger than what I stated earlier....for liability reasons. But the larger the delta between bullet diameter and muzzle brake bore, the less effective it is, to the point where the brake is purely cosmetic.

 

[Chicken lights]

That makes sense, so it’s more than just cutting the threads, it’s about having the threads concentric to the centre of the barrel

 

[thestelster]

Yes!

 

[Susquatch]

To get maximum recoil reduction from a muzzle brake, the bore of the muzzle brake should be between 0.015"-0.020" larger than bullet diameter. That's 0.0075-0.010" per side clearance before the bullet hits the bore of the muzzle brake over 2-3" brake length. That type of precision usually cannot be attained by a threading die. Now, some off the shelf muzzle brakes, or even factory ones, have the bore of the muzzle brake considerably larger than what I stated earlier....for liability reasons. But the larger the delta between bullet diameter and muzzle brake bore, the less effective it is, to the point where the brake is purely cosmetic.

Darn good point!

I'd only add that full length concentricity and clearance also affects accuracy. Even though the brake doesn't touch the bullet, pressure differences affect the projectile and many claim it can introduce wobble and deteriorating accuracy.