finding the lands

[Dusty Stevens]

Sorry the black thing is a seating die

 

[Dusty Stevens]

No i made it all From barrel stubs. The black piece is a barrel stub thats chambered short then melonited. The base is adjustable inside for a perfect fit no matter what bump you have. The top has a stem kinda like a wilson with very fine clicks like .00025 i cant remember exactly. Its the only one i ever did for good reason. Zoom in you can see my name on it. Shouldnt have posted it really.

 

[searcher]

Do we really need to find the lands to the .001 of an inch or do we really just need a datum to start our seating test from. i know many have an unreasonable fear of jaming bullets but on my target rifles i always start load development jammed .010 or .020. That distance to the lands is a moving target anyway.

i use the stoney point and after years of practice can get consistent measurements easily to .002 or .003. My thoughts are that is plenty good for a starting point. I find that with a new barrel after 100 or 200 rounds with a well broken in throat that measurement is quite different and than it settles down.

I believe knowing for sure you are off or in the lands and maintaining a reference point is what is important. Granted, you want to know fairly close as to where you are - as the pressure spike needs to be anticipated when going deep - and you also want to know you are clear of the lands by at least .003" once out. Whether you are .002" or .005" off one way or the other matters little - it is how the gun reacts to the position you are in and making adjustments from your reference point.

 

[KenOath]

Looks like I’m in the minority here but I don’t have any problems finding a consistent lands measurement with the Hornady tool and Sinclair Stainless Steel insert, can always get within a couple thou... use to double check with the striped out bolt method but was always so close I stopped... the only exception with the Hornady tool method is it’s hard to get consistent measurements for 5R rifling, for 5R I use the stripped bolt method. Just my 2cents...

 

[Dusty Stevens]

That video that @Alex Wheeler posted is the quickest and most repeatable method not to mention the cheapest. It works on any case, any bullet anytime no matter the freebore or wear. Im glad he took the time to unselfishly make it

 

[KenOath]

That video that @Alex Wheeler posted is the quickest and most repeatable method not to mention the cheapest. It works on any case, any bullet anytime no matter the freebore or wear. Im glad he took the time to unselfishly make it

Yep the Alex Wheeler method is what I’m referring to when I say stripped out bolt method, great vid I’m glad he shared it also..

 

[Drop Port]

Looks like I’m in the minority here but I don’t have any problems finding a consistent lands measurement with the Hornady tool and Sinclair Stainless Steel insert, can always get within a couple thou... use to double check with the striped out bolt method but was always so close I stopped... the only exception with the Hornady tool method is it’s hard to get consistent measurements for 5R rifling, for 5R I use the stripped bolt method. Just my 2cents...

5/16x36 tap, thread you own fire formed case and stand the rifle vertical you can feel the weight of the bullet and feel the touch, very consistent.

 

[KenOath]

5/16x36 tap, thread you own fire formed case and stand the rifle vertical you can feel the weight of the bullet and feel the touch, very consistent.

Yep I get my smith to thread my fired cases, then I size the body and shoulder like I normally would for that chamber and good to go...I haven’t tried standing the rifle vertically but will give it a try. Cheers

 

[KenOath]

I


my new chamber was a little tricky at first, but now it's no problem getting a repetitive number that I call lands.

yes , mine took about 75 rounds to get the rough off , now 107 smk slide right in and stop plus or minus.001-2 I write that CBTO number on the box as well as BBTO that's my benchmark for my ladder test and seating depth.
As I mentioned earlier after dbl checking a new box (with the same lot number) they weigh the same BBTO was the same but my rifle said nope! Not the same..
I set them aside for future study.
J

Just takes a little practice to get a feel for it.. but I did find it good to check my numbers with the Wheeler method.

 

[Alex Wheeler]

Stripped bolt method would be a good name for it. I did not come up with it, just made the video. One thing I wish I would have mentioned is it should be done with a straight round. Spin it on a concentricity gauge. If theres runout in the round the bullet will drag in the freebore and you will never get rid of the last little bit of faint click. I recommend watching the rifling marks at the same time. If the marks go away at the same time as the click you know your there!

 

[cptjack]

what is a shooter do when in a 700 rem ,the lands are so far forward that about 1/3 bullet dia is in case

 

[Tim Singleton]

Just have to shoot it with 1/3 of the bullet in the case. Until time for a new barrel. It may shoot great

 

[KenOath]

what is a shooter do when in a 700 rem ,the lands are so far forward that about 1/3 bullet dia is in case

Use a longer heavier bullet...

 

[searcher]

what is a shooter do when in a 700 rem ,the lands are so far forward that about 1/3 bullet dia is in case

That is a situation where jambing the bullet with a soft seat or deeper often works very well. The further out a bullet sits inside the neck - the harder it usually is to attain great concentricity. Jambing helps to center the bullet in the bore. You don't run into doughnuts as a rule, either. Still - seated way out can still be VERY accurate even when off the lands. I have a Sako 6ppc that likes a discontinued 62 grain bullet that sits close to half way out the neck. Tack driver. The problem comes up when you are chasing the lands with such a bullet. Eventually you have to jamb the bullet or face having not enough neck to properly support the bullet in a concentric position otherwise.

 

[Kracken McGraw]

Use a longer heavier bullet...

The Sierra #2150 pro hunter is a good example of this in .308 bullets.