Head space and lands

[Jmort1754]

What's the best device to measure these

Precision mic from rcbs
Hornady
?

 

[OldGrayJB]

This is the method that I use to find lands. Neither of the tools you mentioned are required.

 

[Harvey_NW]

This is the method that I use to find lands. Neither of the tools you mentioned are required.

He used the lands to seat the bullet to an unknown depth of jam, and then backed it off .022" and called it good. Lol.

What's the best device to measure these

For finding the lands the best way without tools is to strip the bolt and use Alex Wheelers method of feel. Or I prefer the Frankford Arsenal kit that attaches to a cleaning rod and measures from the bolt face to the tip of bullet touching the lands. Seat a bullet to the measured length, and you'll need a comparator and bullet insert to measure to measure CBTO. That is touching the lands.

For headspace you can add layers of Scotch tape to the head of an unfired or resized case until you get resistance on bolt close, then you'll need a comparator with the correct bump gauge to measure case head to datum. Scotch tape is .002" thick, so the measurement should be within .001" on the measurement when you get resistance.

 

[Blackdog317]

I use the Hornady OAL gauge with good results (to find the Lands).

Lock-N-Load® O.A.L. Gauges & Modified Cases - Hornady Manufacturing, Inc

Lock-N-Load® O.A.L. Gauges Regulating seating depth and the resulting jump to the rifling is widely regarded as fundamental to improved accuracy. A few thousandths of an inch change between the bullet and the rifling can make the difference be...

www.hornady.com

 

[SloppyJ]

+1 on the hornady gauges. You're going to want to pick up both the headspace and bullet comparator set. I was using them both last night.

 

[Dmoua]

He used the lands to seat the bullet to an unknown depth of jam, and then backed it off .022" and called it good. Lol.


For finding the lands the best way without tools is to strip the bolt and use Alex Wheelers method of feel. Or I prefer the Frankford Arsenal kit that attaches to a cleaning rod and measures from the bolt face to the tip of bullet touching the lands. Seat a bullet to the measured length, and you'll need a comparator and bullet insert to measure to measure CBTO. That is touching the lands.

For headspace you can add layers of Scotch tape to the head of an unfired or resized case until you get resistance on bolt close, then you'll need a comparator with the correct bump gauge to measure case head to datum. Scotch tape is .002" thick, so the measurement should be within .001" on the measurement when you get resistance.

I mean Eric Cortina is a F-Class Southwest National winner and F-Class world champion.

I have used the Hornady tool to find the lands in the past. If you’re limited to magazine length then it doesn’t really matter where your lands are.

I now start at jam-0.020 and work my way back.

 

[SloppyJ]

I mean Eric Cortina is a F-Class Southwest National winner and F-Class world champion.

I have used the Hornady tool to find the lands in the past. If you’re limited to magazine length then it doesn’t really matter where your lands are.

I now start at jam-0.020 and work my way back.

Always wondered how someone defined "Jam"? I define it by where it pulls the bullet out of my case gauge and I have to pound my rifle on the ground or stick a cleaning rod down the muzzle to get it out.

 

[Harvey_NW]

Always wondered how someone defined "Jam"? I define it by where it pulls the bullet out of my case gauge and I have to pound my rifle on the ground or stick a cleaning rod down the muzzle to get it out.

I define jam as anything past touch where the projectile actually starts to engage the leade, and the lands start to engrave into the jacket. Neck tension plays a factor in this because you'll be able to jam a bullet with .005" neck tension much more than one with .001". But these are all measurable dimensions, so the method of seating a bullet with the bolt and then backing it off .022" to "make it easy" is comical to me, regardless of his accomplishments. He also takes gunsmithing advice from Alex Wheeler, who's method I mentioned above.

 

[Go West Old Man]

He used the lands to seat the bullet to an unknown depth of jam, and then backed it off .022" and called it good. Lol.

As is the case with methods & opinions, there’s probably several good ways to accomplish this goal…arriving at a seating depth for your load that shoots best.

You’re incorrect in saying that he “backed it off .22and called it good”. More to it than that. His premise and method is to find Jam , a measured/measurable point where you will stick a bullet, as a starting point to stay away from as you incrementally increase seating depths for testing. Starting at Jam -.020 , a point where you will not stick a bullet, and increasing seating depths as Cortina describes .003 at a time I think isn’t very practical for conserving powder & bullets for hunting load, development /testing but it will eventually get you to a satisfactory seating depth that shoots well if you’re inclined to do this.

Again, more than one way to do things. @Jmort1754 , Formidilosus thread on load development is very informative.

 

[Harvey_NW]

You’re incorrect in saying that he “backed it off .22and called it good”. More to it than that.

Did you even watch the video? 4 min 20 sec, "I'm gonna subtract 20, no 22, so we're gonna go to 2.140 just to make it easy". Literally exactly what he did.

His premise and method is to find Jam , a measured/measurable point where you will stick a bullet, as a starting point to stay away from as you incrementally increase seating depths for testing. Starting at Jam -.020 , a point where you will not stick a bullet,

Except he waxed it so it purposely wouldn't stick, and then threw out an arbitrary number ("twenty two, just to make it easy") to subtract from and be safe from sticking a bullet. That is not a measurement to the lands that the OP asked for.

and increasing seating depths as Cortina describes .003 at a time I think isn’t very practical for conserving powder & bullets for hunting load, development /testing but it will eventually get you to a satisfactory seating depth that shoots well if you’re inclined to do this.

No it won't.

 

[Wrench]

I use super glue and seat the bullet using the lands. Leave it for a few minutes. If you had a light pressure it'll glue up nice. No jam but contact.

Headspace is a fired case measured to the datum at the shoulder.

 

[wind gypsy]

Measuring "headspace" isn't anything i've ever done in relation to reloading. Measuring to a case shoulder datum, sure.

I use the hornady tool and comparators. There are methods that are more accurate but I highly doubt there is any benefit for my uses by being more accurate than the hornady tools get me.

 

[N2TRKYS]

I don’t care about distance to the lands. However, a pencil, your bullet of choice, and your cleaning rod is all you’ll need to make that measurement.

 

[Go West Old Man]

Did you even watch the video? 4 min 20 sec, "I'm gonna subtract 20, no 22, so we're gonna go to 2.140 just to make it easy". Literally exactly what he did.


Except he waxed it so it purposely wouldn't stick, and then threw out an arbitrary number ("twenty two, just to make it easy") to subtract from and be safe from sticking a bullet. That is not a measurement to the lands that the OP asked for.


No it won't.

I have watched the “Chasing the Lands….” and fully understand what he describes. Like I said, there’s more than one way to accomplish the same thing, and I never said Cortina is the best or only way nor did I disparage any method used by others.

So, on another idea, how are you with just skipping all the above methods, skipping distance measurements to the lands, and just seating to magazine length & see if it shoots for a hunting load? It’ll either shoot/group well or it won’t. Right?

 

[wind gypsy]

I have watched the “Chasing the Lands….” and fully understand what he describes. Like I said, there’s more than one way to accomplish the same thing, and I never said Cortina is the best or only way nor did I disparage any method used by others.

So, on another idea, how are you with just skipping all the above methods, skipping distance measurements to the lands, and just seating to magazine length & see if it shoots for a hunting load? It’ll either shoot/group well or it won’t. Right?

Just seating to magazine length is going to result in bullets jammed into the lands in lots of cases. In the cases where it isn't, there isn't much reason to start anywhere besides at mag length unless of course one thinks they need to chase lands.

 

[TaperPin]

I’m all for companies selling stuff, but to find the lands it doesn’t cost anything. Fire a case and back the sizing die out a full turn and seat a bullet. The case is maxed out in the chamber and can’t move - the ejector can’t push it in any further and it’s definitely not flopping around in there.

Use a candle to smoke the bullet and chamber it. Lands show up quite plainly in the candle soot - adjust the bullet in and re blacken the bullet until there is the faintest mark of all the lands. This gets you within .001“ to .002” or so. Just keep in mind that seating dies change depth about .036” per revolution, so it doesnt take much of a turn once you’re close.

Rarely does a gun writer even mention this now, but man do they encourage some of the craziest tools.

As for Cortina, he doesn’t want you to tune loads with seating depth like all benchrest and f class guys do, but rather he want to sell you a tuner for your barrel. His podcast is about selling things - he’s in a business and the people he interviews are in businesses.

 

[Gila]

Just seating to magazine length is going to result in bullets jammed into the lands in lots of cases. In the cases where it isn't, there isn't much reason to start anywhere besides at mag length unless of course one thinks they need to chase lands.

That could very well be the case with some cartridges. Although, some long action cartridges can exceed the magazine length if hand-loading heavy VLDs. The 300 win mag is a good example. Need about 3.6+ to load up 230 Bergers. Should always check the free-bore so the bullet won’t jam if you are going to hand-load for that rifle. Should always check CBTO at the jam point. What I consider jam is OGIVE contact with the lands. You only have to do it once and that CBTO measurement is good for your rifle/barrel.

The process is so simple a caveman can do it. I put sizing wax on the bullet OGIVE. Doesn’t take much neck tension, just enough to keep the bullet from easily moving in the case. Close the bolt and carefully extract the dummy round. Use the bullet comparator to measure CBTO to the lands contact. I do it three times and the measurement should be the same. I subtract .015” from the CBTO to lands and use that as my final CBTO for all bullets. I put neck tension on a dummy round and make sure the bolt closes easily. The measurement won’t change for the life of the barrel.

 

[Harvey_NW]

So, on another idea, how are you with just skipping all the above methods, skipping distance measurements to the lands, and just seating to magazine length & see if it shoots for a hunting load? It’ll either shoot/group well or it won’t. Right?

Depending on the mag setup it is a good idea to see where the lands are for safety concern depending upon your loading procedure, but on something like a Tikka with a known mag limitation for certain cartridges it's a safe bet you're jumping at mag length. My personal preference is to seat bottom edge of bearing surface to neck/shoulder junction, and test the combo. IME that is the consensus, it either shoots well, or it doesn't. Dropping the powder charge can improve dispersion, but it may not be enough. If it's not acceptable then I'll swap bullet or powder and retry.

 

[Gila]

I’m all for companies selling stuff, but to find the lands it doesn’t cost anything. Fire a case and back the sizing die out a full turn and seat a bullet. The case is maxed out in the chamber and can’t move - the ejector can’t push it in any further and it’s definitely not flopping around in there.

Use a candle to smoke the bullet and chamber it. Lands show up quite plainly in the candle soot - adjust the bullet in and re blacken the bullet until there is the faintest mark of all the lands. This gets you within .001“ to .002” or so. Just keep in mind that seating dies change depth about .036” per revolution, so it doesnt take much of a turn once you’re close.

Rarely does a gun writer even mention this now, but man do they encourage some of the craziest tools.

As for Cortina, he doesn’t want you to tune loads with seating depth like all benchrest and f class guys do, but rather he want to sell you a tuner for your barrel. His podcast is about selling things - he’s in a business and the people he interviews are in businesses.

Eric has always tuned loads with seating depth. He recommends seating the bullet .020” from jam (lands contact) and then working up your loads. Once loads are worked up then he goes for the “accuracy node”. He moves in at .003” increments and fires groups until he reaches the middle of a “plateau”. Someone said somewhere that he very seldom moves more than .009” to reach the node but don’t remember the who or when, so can’t verify that. Personally, for my hunting guns and how I shoot that is too much effort and money spent for little gain.

 

[Gila]

For my Tikka 300 win mag (the barrel has a giraffe throat like many production guns) I just load shorter conventional bullets (Accubonds, Gamechangers) at SAAMI COAL of 3.34”. That is the same max length for all 300 win mag factory ammunition. The Tikka mag maxes out at 3.37” COAL.