Best method for determining distance to lands?

[tsu45]

Assuming a brand new rifle, what is y’all favorite method for measuring the distance to the lands?

I have the Hornady equipment to do this, but no fired brass to compare base to shoulder length difference between the fired case and the modified case.

I’m always looking for new ways to shave extra consumables out of the load workup process.

Anybody tried this method? I would have to figure out how to disasssemble the TL3 bolt:

 

[Skunkworx]

I use Alex Wheelers method, words great. Better than the Hornady tool in my opinion.

 

[tsu45]

I use Alex Wheelers method, words great. Better than the Hornady tool in my opinion.

Do you happen to have a tl3? It has a mechanical ejector so I’m gussing I just need to remove the firing pin.

 

[Sig Marine]

You are correct. Just remove the firing pin assembly and slide the bullet/case combination under the extractor and slowly close the bolt.

 

[Skunkworx]

I did it with my rem700. You’ll have to remove the striker assembly if you’re going to try the wheeler method. The ejector shouldn’t make a difference with your action.

 

[Yondering]

My preferred method is very different than the video, and doesn't require any disassembly of the gun but is at least as accurate IMO. The only special equipment needed is some sort of collar on your cleaning rod that can be locked in place.

I close the bolt and run the cleaning rod in from the muzzle with a flat-tipped brass jag. With the jag against the bolt face, lock the collar on the rod right up against the muzzle.

Then, to measure distance to the lands for a bullet, seat a dummy round long so the bolt won't close. It doesn't matter how long, but you shouldn't be able to cam the bolt down. Hold the bolt in place by hand so the bullet is pushed against the lands gently; you can use rubber bands if preferred, but don't force the bullet into the lands hard.

Now run the cleaning rod back in so the jag touches the bullet tip, and measure with calipers between the muzzle and the collar; that's your OAL to the lands for that bullet. At that point I like to seat the dummy round deeper to match that measurement, and keep it in the die box for reference. Once I have that, I prefer to use a base to ogive measurement from that dummy instead of OAL.

 

[Mike Casselton]

I like to use a barrel stub with the reamer ran in where the shoulder begins.
Insert a cartridge that has been fired in your chamber, partially neck sized only, with your chosen bullet.

If you can rotate the cartridge, it's touching. Move the bullet inward until you can rotate.
The stub will leave marks on the bullet from land contact so you will know how far to move it.

 

[Sheldon N]

Anybody tried this method? I would have to figure out how to disasssemble the TL3 bolt:

TL3 bolt has a mechanical ejector and a quick disconnect firing pin assembly. It takes just seconds to pull the firing pin, then you can slide a piece of brass under the extractor and have a zero resistance bolt close. It's probably the easiest action out there to use the Wheeler method above.

Couple tips... makes sure the brass is sized enough to get a zero effort bolt close before you start, do it on a clean barrel so carbon/gunk doesn't influence the readings, make sure the brass and load is reasonably concentric. Crooked ammo will give you a false reading.

 

[Sheldon N]

Regarding how the TL3 bolt comes apart, see this video starting at 3:40

 

[Bradu]

Out of curiosity how much difference in the measurements are you looking at between this method and a hornady gauge?

 

[Sheldon N]

Out of curiosity how much difference in the measurements are you looking at between this method and a hornady gauge?

My experience with the Hornady gauge is that you can get a couple different numbers. There's the hard jam into the lands number which is very consistent and repeatable. Then there's the soft touch the lands number where you push a bullet back forth with a cleaning rod, trying to find where the bullet first encounters resistance. This "touch" number is usually 5-15 thousandths back from the hard jam, and is a bit more difficult to get repeatable readings with. The Wheeler method matches up roughly the same as the soft touch number with the Hornady gauge, but is a more exact and repeatable method.

Sometimes I use the Wheeler method, sometimes I use the Hornady gauge and just hard jam the bullet, then back off 30 thou knowing that will put me in the ballpark of 10-20 thou from touching the lands.

 

[Bradu]

I will have to try it to see how much difference I come up with. I've been happy with how my reloads shoot using the hornady gauge but I am always willing to try better ways.

 

[Dai Bando]

The Wheeler vid is great because you know exactly where you're throat is.

You can jam or jump from there precisely.

Hornady gauge, not so much.

 

[OzzyO20]

If someone wanted to do the wheeler method with a Accuracy International, would you only need to remove the firing pin assembly or would you have to disassemble the bolt as well?

 

[RickyRodney]

My experience with the Hornady gauge is that you can get a couple different numbers. There's the hard jam into the lands number which is very consistent and repeatable. Then there's the soft touch the lands number where you push a bullet back forth with a cleaning rod, trying to find where the bullet first encounters resistance. This "touch" number is usually 5-15 thousandths back from the hard jam, and is a bit more difficult to get repeatable readings with. The Wheeler method matches up roughly the same as the soft touch number with the Hornady gauge, but is a more exact and repeatable method.

Sometimes I use the Wheeler method, sometimes I use the Hornady gauge and just hard jam the bullet, then back off 30 thou knowing that will put me in the ballpark of 10-20 thou from touching the lands.

This is an awesome thread and response. I had similar results when I got my hornady gauge. My measurements were not that consistent and it became really hard to use my micrometer die as a new reloader it was confusing. I also plan to attempt to try the cleaning rod method however, I worry that mashing the bullet tip to get it out of the land may obscure the results or using the calipers against the collar.

 

[Yondering]

I also plan to attempt to try the cleaning rod method however, I worry that mashing the bullet tip to get it out of the land may obscure the results or using the calipers against the collar.

That's definitely a consideration, with two things to do about it -

1 - Don't jam the bullet into the lands, just press it lightly and hold in place. Don't push on it any harder than you'd push on your eyeball.
2 - Run the cleaning rod gently up to the bullet when taking your measurement, not carelessly like I've done sometimes. Definitely don't put the cleaning rod halfway in the bore and just point it upright; tips definitely get dented and it affects the results.

However, if you do dent a tip, it doesn't matter as long as you're measuring base to ogive instead of bast to tip. That ogive is the important dimension anyway for everything except mag constraints.

As for the accuracy of the calipers against the collar - if you're moderately competent you should be able to get within a couple thousandths or better. It's a pretty precise method, without the "adjust die, check again" system of most other methods.

 

[Bradu]

I leave the jag off and it doesn't touch the tip of the bullet anyways. It works very well.

 

[PinesAndProjectiles]

I use the Sinclair tool, found at the link below. No more modified cases, and my results are much more consistant.

https://www.sinclairintl.com/reload...lair-bullet-seating-depth-tool-prod35491.aspx

 

[918v]

The best way to measure distance to lands is by using a slit case. A slit case holds the bullet hard enough not to move but easy enough so it is not engraved by the rifling.

 

[Yondering]

I leave the jag off and it doesn't touch the tip of the bullet anyways. It works very well.

No, that doesn't give you a correct measurement, if the end of your cleaning rod is threaded. You need the end of the rod to contact the bolt face, and then the tip of the bullet, but with a hollow threaded end it can either fit over the tip of the bullet, or miss it off to one side. Then your measurement is not OAL, it's to some unknown point partway down the bullet nose.

You need it to touch the tip of the bullet, otherwise this method does not work.

 

[Yondering]

The best way to measure distance to lands is by using a slit case. A slit case holds the bullet hard enough not to move but easy enough so it is not engraved by the rifling.

I used to do that too, but results were often inconsistent and very sensitive to tension on the case. Often as the case is extracted, the bullet gets pulled back out a little bit, giving a false measurement.

 

[Bradu]

No, that doesn't give you a correct measurement, if the end of your cleaning rod is threaded. You need the end of the rod to contact the bolt face, and then the tip of the bullet, but with a hollow threaded end it can either fit over the tip of the bullet, or miss it off to one side. Then your measurement is not OAL, it's to some unknown point partway down the bullet nose.

You need it to touch the tip of the bullet, otherwise this method does not work.

My answer was in response to this quote not the method you are describing "My experience with the Hornady gauge is that you can get a couple different numbers. There's the hard jam into the lands number which is very consistent and repeatable. Then there's the soft touch the lands number where you push a bullet back forth with a cleaning rod, trying to find where the bullet first encounters resistance."

I use the oal gauge and the cleaning rod is to push the bullet back out if it gets pushed into the lands too hard.

 

[Milo 2.5]

I prefer the Hornady OAL tool and modified cases. It's more expensive but quicker and easier, may not be as exact though. To me this is just a baseline measurement, I am going to fine tune my seat depth anyway.

 

[918v]

I used to do that too, but results were often inconsistent and very sensitive to tension on the case. Often as the case is extracted, the bullet gets pulled back out a little bit, giving a false measurement.

You push out the round with a cleaning rod, not extract it with the bolt.

 

[SONIC SAAMI]

video shows a good way to get it done.
,,plastigauge between head of the case and bolt face will give you the headspace of that case in that chamber.

 

[Yondering]

You push out the round with a cleaning rod, not extract it with the bolt.

That works on some rifles if you can remove the extractor, but not others. Hard to do on a 700 for example. There are easier and more reliable methods of taking this measurement.

 

[Skimafia]

I have tried the cleaning rod method and the method listed above. I removed the ejector pin from the bolt of the stiller action and found that incrementally pressing the bullet shorter in my press was tedious. Mainly because I didnt have a micrometer seating die.
When I tried the cleaning rod method I used 2 delrin stops rather than 1. I think using 2 allowed error in my measurements.
I sold that rifle and have an AI AT. I will try the cleaning rod method again. I don't want to strip the bolt to try the other way.
I wonder if there is an easier way considering the barrel can be removed. Anyone with an AT tried anything different?

 

[_Raining]

I have the Hornady gauge and I am getting shorter distance to lands vs the Wheeler method. This is because I don't have the means to drill and tap a fire-formed case so I use the Hornady premade cases which have a shorter distance from base to shoulder datum.

I use the Hornady gauge to get a rough estimate them load about 20 thou longer and use that as my starting point for the Wheeler method.

 

[OzzyO20]

I have tried the cleaning rod method and the method listed above. I removed the ejector pin from the bolt of the stiller action and found that incrementally pressing the bullet shorter in my press was tedious. Mainly because I didnt have a micrometer seating die.
When I tried the cleaning rod method I used 2 delrin stops rather than 1. I think using 2 allowed error in my measurements.
I sold that rifle and have an AI AT. I will try the cleaning rod method again. I don't want to strip the bolt to try the other way.
I wonder if there is an easier way considering the barrel can be removed. Anyone with an AT tried anything different?

I'm in the same boat. I don't feel like stripping down my AI bolt if I can avoid it. I've tried the Hornady OAL tool, and I too get different numbers. I try and do 10 measurements and kind of average them out then subtract 0.020" for my CBTO. Has worked so far but I haven't played with seating depth.

What's hilarious is one of the main reasons I got an AT was because my smith retired and I didn't want the hassle of sending the gun off for new barrels. It never once occurred to me to do that to measure the chamber. This is a excellent idea if it works. I'll ask in the AI thread and tag you.

 

[918v]

That works on some rifles if you can remove the extractor, but not others. Hard to do on a 700 for example. There are easier and more reliable methods of taking this measurement.

It works on all rifles because you you don’t use the bolt at all.

 

[Skimafia]

I'm in the same boat. I don't feel like stripping down my AI bolt if I can avoid it. I've tried the Hornady OAL tool, and I too get different numbers. I try and do 10 measurements and kind of average them out then subtract 0.020" for my CBTO. Has worked so far but I haven't played with seating depth.

What's hilarious is one of the main reasons I got an AT was because my smith retired and I didn't want the hassle of sending the gun off for new barrels. It never once occurred to me to do that to measure the chamber. This is a excellent idea if it works. I'll ask in the AI thread and tag you.

Maybe what I will do is pull the barrel, grab a bullet and put the barrel in a vice muzzle down. I will drop the bullet in the chamber end of the barrel. You would assume it would stop at the lands. Use a calibrated stick from the muzzle end and touch the back of the bullet. Modify the cleaning rod idea and use a cleaning rod stop to take a depth reading from the chamber end to the back of the bullet. Measure how far the rod went in. Next, take a resized case and drop it in the chamber. Measure how much of the bottom of the case is exposed from the barrel end. Add the amount of cleaning rod length to the amount of exposed case, and that should be the depth to load a dummy round.

 

[christopher.dow]

i just did this last night and loaded up 50 Nosler 140 RDFs. My previous attempts with the Sinclair gauge were WAY off, and the groups showed that. I finally got the RDFs to group worth a damn. The firing pin assembly must be removed from the TL3 for this method to work.

 

[tsu45]

i just did this last night and loaded up 50 Nosler 140 RDFs. My previous attempts with the Sinclair gauge were WAY off, and the groups showed that. I finally got the RDFs to group worth a damn. The firing pin assembly must be removed from the TL3 for this method to work.

Did it this afternoon with the RDFs as well. Pretty easy.