Finding the lands, help

[Shootin4fun]

Why wouldn't he ?
I like to know for every gun I have and every different bullet.
It doesn't make sense to not know as a reloader in my opinion.

See Eric Cortina videos on YT..."stop chasing the lands!" And others. Really what he's saying is sure, find them to avoid being in the jam. That's all. The abosolute number is only important as a starting reference point. After that, just start moving from the reference point and measure only the depth and tract your results. The accuracy Nodes for seating depth are like powder charges and are sinusoidal. He says adjust in .003 increments. I have been doing .005.

Cortina shot a 1.5" group at 1K yards. He knows what he's talking about.

Recently saw his videos and I got back to a rifle that was very accurate but my accurate load seemed to have fallen apart....I realized I probably shot over 1200 rounds though it and there was erosion. Measure to the lands. Sure enough, about .008 deeper now. I started experimenting as Eric says, and I planned on going longer in steps but accidentally made a 5 round batch .005 shorter, not longer. I cursed when I realized what I'd done...oh well make some longer too. Shot them. The shorter ones got the gun back to shooting better than I can. Ones .005 and .008 longer didn't get it back to the accuracy node.
Also, Eric states that .010 erosion does not mean matching the change in either direction does not necessarily get you back the an accuracy node.

So it's not that you don't need to find the lands at all, it's just a reference starting point.

Also, back to the OPs original question, if you don't fire the brass to actual headspace with the case base in contact with the bolt face, the measurement is off. So I no advantage to finding the measurement to the lands when not yet attached to the receiver other than just for OCD record keeping.

 

[Trm82]

See Eric Cortina videos on YT..."stop chasing the lands!" And others. Really what he's saying is sure, find them to avoid being in the jam. That's all. The abosolute number is only important as a starting reference point. After that, just start moving from the reference point and measure only the depth and tract your results. The accuracy Nodes for seating depth are like powder charges and are sinusoidal. He says adjust in .003 increments. I have been doing .005.

Cortina shot a 1.5" group at 1K yards. He knows what he's talking about.

Recently saw his videos and I got back to a rifle that was very accurate but my accurate load seemed to have fallen apart....I realized I probably shot over 1200 rounds though it and there was erosion. Measure to the lands. Sure enough, about .008 deeper now. I started experimenting as Eric says, and I planned on going longer in steps but accidentally made a 5 round batch .005 shorter, not longer. I cursed when I realized what I'd done...oh well make some longer too. Shot them. The shorter ones got the gun back to shooting better than I can. Ones .005 and .008 longer didn't get it back to the accuracy node.
Also, Eric states that .010 erosion does not mean matching the change in either direction does not necessarily get you back the an accuracy node.

So it's not that you don't need to find the lands at all, it's just a reference starting point.

Also, back to the OPs original question, if you don't fire the brass to actual headspace with the case base in contact with the bolt face, the measurement is off. So I no advantage to finding the measurement to the lands when not yet attached to the receiver other than just for OCD record keeping.

Don't do it if you don't want to that's fine !!
I have tools to do it and it takes 2 minutes to do so I'll keep doing it.

 

[spladi]

Don't do it if you don't want to that's fine !!
I have tools to do it and it takes 2 minutes to do so I'll keep doing it.

There is a certain amount of voodoo and swagging in the shooting and reloading world of fun. I maintain my jump or jam as the barrel wears and likely will continue.

 

[Alex Wheeler]

Scroll down the page, my video on finding the lands. Its important to know where they are and how they move. Anyone telling you its not is wrong. https://www.wheeleraccuracy.com/videos

 

[RockyMtnUT]

"Where they are and how they move." Which of the two is more important if you had to pick just one?

 

[Alex Wheeler]

Once you learn a cartridge and bullet you will have a very good idea of where to seat the bullet when you start load development. You at least want to be close when you start testing powder charges. So knowing where they are is critical to me for load work. Keeping track of them is so easy and will give you a clue as to when to re test your seating depth if accuracy is falling off. Its just to easy to do this to not do it.

 

[Shootin4fun]

Don't do it if you don't want to that's fine !!
I have tools to do it and it takes 2 minutes to do so I'll keep doing it.

Yes, we'll all keep doing it. I think Cortina's point is more sematic and that it's not that you don't make adjustments when the lands have receded, but that the absolute amount they change does not directly correlated to the seating change you need to make. .010 of erosion does not automatically equal .010 less depth. Of course we need to measure it to see where to start at the beginning, but for a given bullet, after that you almost wouldn't need to measure but instead could just make graduated depths and see where your new accuracy node is. In other words, the proof is in the paper, not an absolute number adjustment.

 

[Shootin4fun]

Once you learn a cartridge and bullet you will have a very good idea of where to seat the bullet when you start load development. You at least want to be close when you start testing powder charges. So knowing where they are is critical to me for load work. Keeping track of them is so easy and will give you a clue as to when to re test your seating depth if accuracy is falling off. Its just to easy to do this to not do it.

Exactly.

 

[Donneric]

Is this possible to do without a bushing die?