Determine when ogive touches lands

[Bigbubba]

So I read the article on precision reloading in the last issue of Calibre, which discussed the use of the Bullet comparator to measure the "cartridge base to ogive" or CBTO and use that as a length vs using the "cartridge overall length" or COAL.

OK, so I understand why that would be better and I understand how the bullet comparator would greatly help in setting up the seating die to achieve this.

What I need to know is the best way to determine when the bullet is touching the lands? So that the seating die can be set accordingly.

Any advice on a reliable way to do this?
Thanks

 

[silverfoxdj]

Google is your friend there are several more:

 

[667]

I use the Hornady tool...

http://m.hornady.com/store/Lock-N-Load-OAL-Gauge-Straight-1Each/

 

['Boo]

Any advice on a reliable way to do this?

This is what I use:

http://www.sinclairintl.com/reloadi...spx?avs|Manufacturer_1=sinclair+international

 

[Bigbubba]

Thank you for the helpful information you have all answered my question.

 

[Ganderite]

I seat the bullet long and coat the ogive with a Sharpie. Rifling marks show up clearly. Seat another one a bit deeper and repeat....

 

[cycbb486]

I use the method of seating the bullet long with normal neck tension. Close the bolt on it with the ejector removed , open the bolt and measure. Repeat a few times to confirm. When it comes to load developing there is only one way to seat the bullet, you cannot seat longer or it will push back into the case. So basically you have hard jam and you seat the bullet deeper into the case.

 

[LawrenceN]

I take a bullet and prepped casing. I lube the case neck and the ogive with a light grease and gently insert it into my rifle. I slowly close the bolt and then gently withdraw the round. Then I measure the overall cartridge length and I know how deep to seat the bullet so that it just kisses the lands. No special tools required.

 

[Magellann]

I use the method of seating the bullet long with normal neck tension. Close the bolt on it with the ejector removed , open the bolt and measure. Repeat a few times to confirm. When it comes to load developing there is only one way to seat the bullet, you cannot seat longer or it will push back into the case. So basically you have hard jam and you seat the bullet deeper into the case.

I have never had a need yet to check, other than the oal in the reloading manuals, but if I did I would most likely use your method.

 

[silverfoxdj]

I use the Hornady tool...

http://m.hornady.com/store/Lock-N-Load-OAL-Gauge-Straight-1Each/

Same here it works quite well

 

[Kryogen]

Hdy tool

 

[Sqr]

Insert a cleaning rod down the bore on a closed bolt, place a paper clip in the rod. Now insert a bullet of you choice and again insert the rod and place a second clip on the rod. Measure the distance between and you have max COAL. Back off a couple of grand as a starting point. Easy peasy.

 

[Kryogen]

Insert a cleaning rod down the bore on a closed bolt, place a paper clip in the rod. Now insert a bullet of you choice and again insert the rod and place a second clip on the rod. Measure the distance between and you have max COAL. Back off a couple of grand as a starting point. Easy peasy.

With a 50 mils imprecision

 

[mod7rem]

I take a fireformed case and full length resize it just enough that it closes in the chamber with some force. This crush fit on the case will keep the case head back against the bolt face without having to remove the ejector plunger. Then I take a hacksaw and split the case neck down to the neck/shoulder junction. You can squeeze the two halves of the neck together to get a little more tension if needed. Then seat a bullet into that case in the chamber by closing the bolt. Do it multiple times to verify. I found that if the neck tension is high, you can easily jam the bullet into the rifling .010" - .015" giving a misleading measurement.

 

[Kelly Timoffee]

This method , as I feel that fumbling around with loose necks and removed ejectors , cleaning rods ,etc is adding to many variables.

When the ink is rubbed off it is touching, not rubbed off not touching.

This with a comparator gets very consistent and accurate results.

I seat the bullet long and coat the ogive with a Sharpie. Rifling marks show up clearly. Seat another one a bit deeper and repeat....

 

[oneadam12]

This is what I use:

http://www.sinclairintl.com/reloadi...spx?avs|Manufacturer_1=sinclair+international

There are actually two surfaces on that caliper for measuring inside to outside.

 

[Viper26]

A good demo of the wooden dowel method
Use it to get the maximum COAL then measure the ogive with a comparator. Back off .015-.020 and you're there.

https: //www.youtube.com/watch?v=GmDi7v530Og

 

[PitBull1973]

I use my Type S die and seat a bullet long , chamber it and I get my jam length. Same measurement all the time

 

[waynewjw]

Steel rod from Home Depot and pkg of collars from Princess Auto. Slide rod down barrel on closed bolt and tighten top collar. The I drop 10 bullets only gently down the barrel, and slide the second collar down and tighten. Use calipers to measure the distance. I take the average of the 10 bullets, they can vary slightly in dimension. From there I calc 5/10/15/20 thousand and start loading. Cheap and fun to calculate out.