Best way to measure distance to lands?

[RidgeRebel]

Hey Guys,

I trying to load for my 7mm WSM and I am loading 168 VLD's. I am trying to follow Burger's advice to try different seating depths. But it's not working like I thought. I was just seating the bullets enough to get them into the action and then closing the action on them to seat the bullet the rest of the way. Then I would measure the c.o.l. and set the bullet back another .010. But I cant measure the c.o.l. and make sure the rounds are consistent because there is too much variance in the length of the bullets. I know there's got to be another way. Any advice would be aprreciated.

 

[jyd]

Re: Best way to measure distance to lands?

you need a pair of calipers
stoney point guage
bullet comparator and bushing for you caliber
I'm sure midway has it.
Its real simple once you get it figured out.

 

[WRM]

Re: Best way to measure distance to lands?

Take a fired case, and slightly dent the neck (I "bite" it). Seat a bullet long, chamber, and carefully remove it. Measure OAL being sure not to push the bullet farther down into the neck. Repeat a few times to make sure you get a consistent measurement. This is where that particular bullet is just touching the lands. When you set your seating die, use that same bullet, as ogive to tip may vary. Work your plus/minus based on that seating die setting.

(Edited to add) If you use new or resized brass, you're probably pushing the bullet into the lands due to the increased neck tension. You need something just tight enough to hold it, but not force it into the rifling.

Good luck,

Bill

 

[Weaselthis]

Re: Best way to measure distance to lands?

Start here:
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1699588#Post1699588
Read all 5 of his posts on the subject. You'll be better off for it. Get the OAL gauges, etc. Good luck.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: elksniper</div><div class="ubbcode-body">Hey Guys,

I trying to load for my 7mm WSM and I am loading 168 VLD's. I am trying to follow Burger's advice to try different seating depths. But it's not working like I thought. I was just seating the bullets enough to get them into the action and then closing the action on them to seat the bullet the rest of the way. Then I would measure the c.o.l. and set the bullet back another .010. But I cant measure the c.o.l. and make sure the rounds are consistent because there is too much variance in the length of the bullets. I know there's got to be another way. Any advice would be aprreciated. </div></div>

 

[head2h2o]

Re: Best way to measure distance to lands?

Sinclair makes the tools to do this with as well. Hornady makes a different system that has a small rod that you use to check it that requires modified cases that will fit in the chamber. You can then measure with a pair of calipers. I prefer just pushing a slightly seated round into the lands and taking a measurement with the comparator.

 

[rcamuglia]

Re: Best way to measure distance to lands?

You can do it well with your cleaning rod, 2 rod stops, and a set of calipers.

With the bolt in the gun and both rod stops on the cleaning rod, run the rod down the muzzle till it touches the back of the bolt.

With the tip of the rod in contact with the bolt, slide both rod stops down the rod till they are flush with the muzzle. Tighten the outermost stop.

Remove the cleaning rod, remove the bolt and drop the bullet you are trying to find the MOAL for into the chamber til it snugs into the lands. Set your rifle on a bench with the bipod in use. Use a pencil or other object like that to push the bullet into the lands and hold it there with your finger.

Run the rod back down the barrel a second time gently till the tip of the rod makes contact with the tip of the bullet. Slide the loose stop down till it makes contact flush with the muzzle.

Measure between the two rod stops and that is your MOAL for that bullet. Do this process a couple of more times with the same bullet to confirm and get consistent readings.

Use that exact bullet for the first case you seat a bullet in. Use a comparator to get a measurement of MOAL with the comparator. Adjust your OAL from there for your test loads...

 

[Fuzzball]

Re: Best way to measure distance to lands?

There are several ways to determine max OAL to the lands, cheap to costly. They all work, they all require a deft touch. I suppose we all have a favorite but I don't think anyone could honestly say his prefered method is "best." And, truth be told, it's really not as critical to get it precisely right to the last thou as some believe.

I have most of the commercial tools but I prefer the "cleaning rod" method described above.

 

[6.5x61Super]

Re: Best way to measure distance to lands?

Stoney point or Hornady's OAL gauges.

Get a modified case....take at least 5 measurements with a "known" bullet that is representative of the bullets you will be loading.

What is "representative"...well if you don't have a CONSISTENT base-to-ogive measurement...all bets are off....I have seen bullets vary by as much as 0.013" in base-to-ogive measurements.

So far the Lapua Scenars have been showing deviations less than +/- 0.001".

 

[djtjr]

Re: Best way to measure distance to lands?

Sinclair gauge is great

 

[wyosniper]

Re: Best way to measure distance to lands?

I have the hornady one it works great.

 

[Tripwire]

Re: Best way to measure distance to lands?

Magic Marker.

Witness marks can't lie....

 

[thefitter]

Re: Best way to measure distance to lands?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">Magic Marker.

Witness marks can't lie.... </div></div>

Detail your technique, please.

 

[Tripwire]

Re: Best way to measure distance to lands?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: thefitter</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">Magic Marker.

Witness marks can't lie.... </div></div>

Detail your technique, please. </div></div>

Seriously?

The only a little more old school than magic marker is candle soot.......

 

[thefitter]

Re: Best way to measure distance to lands?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: thefitter</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">Magic Marker.

Witness marks can't lie.... </div></div>

Detail your technique, please. </div></div>

Seriously?

The only a little more old school than magic marker is candle soot....... </div></div>

OK... detail your technique, please Grandpa.

 

[Tripwire]

Re: Best way to measure distance to lands?

Grandpa?

Too funny.....

Seat a bullet too long in a sized dummy case, paint the ogive where you expect the rifling to make contact. Attempt to chamber the dummy but don't force anything, extract. You'll see where the rifling touched because it will rub off the marker. How many ever lands you have will show as evenly spaced bright spots, about .030" or .040" long on most everything I've ever done.

Seat the bullet a little more (a micrometer seater sie is pretty handy for keeping track of what you're doing) repaint with marker, make another attempt to chamber.

Repeat the above until the dummy round just chambers, you're close. The same amount of rifling should still be showing, and if the bolt closes with only slight resistance then I'd consider that "jammed in the lands".

At this point you concentrate on seating deeper in smaller increments until the rifing marks are just barely visable.

Go from there wherever you want to. I usually consider that point as touching the lands, and base all other measurements off of that "max" COAL via comparator/bullet ogive.

Takes a few minutes, but ain't hard to do....and is cheaper than buying another gadget.

 

[thefitter]

Re: Best way to measure distance to lands?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Tripwire</div><div class="ubbcode-body">Grandpa?

Too funny.....

Seat a bullet too long in a sized dummy case, paint the ogive where you expect the rifling to make contact. Attempt to chamber the dummy but don't force anything, extract. You'll see where the rifling touched because it will rub off the marker. How many ever lands you have will show as evenly spaced bright spots, about .030" or .040" long on most everything I've ever done.

Seat the bullet a little more (a micrometer seater sie is pretty handy for keeping track of what you're doing) repaint with marker, make another attempt to chamber.

Repeat the above until the dummy round just chambers, you're close. The same amount of rifling should still be showing, and if the bolt closes with only slight resistance then I'd consider that "jammed in the lands".

At this point you concentrate on seating deeper in smaller increments until the rifing marks are just barely visable.

Go from there wherever you want to. I usually consider that point as touching the lands, and base all other measurements off of that "max" COAL via comparator/bullet ogive.

Takes a few minutes, but ain't hard to do....and is cheaper than buying another gadget. </div></div>

Thanks I'm going to give that a try and compare my findings to the Hornady tool and the split case method.

Do you ever get stuck in the rifling?

 

[Leaddog]

Re: Best way to measure distance to lands?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: thefitter</div><div class="ubbcode-body">Do you ever get stuck in the rifling?</div></div>

A reason to have a 30" long, .250" diameter wooden dowel handy. Better and safer than a cleaning rod, especially one with exposed threads.

 

[Tripwire]

Re: Best way to measure distance to lands?

Nope...ain't hard to know when to stop pushin' to avoid such things.

 

[jbell]

Re: Best way to measure distance to lands?

I have to agree with Tripwire. I have tried all tools I can find Sinclair, Stoney Point, RCBS, and the method described above is the most repeatiable. I still have the other tools and try them from time to time but always go back to the "witness mark" method. You may want to remove the ejector from the bolt to get the most out of it, but its not necessary.