Measuring distance to lands of rifle

[engelwood]

Hey guys,

Just wanting to pick some brains here. Say that you have the bullet that you want to use and although you don't have a tool to measure distance to lands, you still want to know COAL of the load to get the desired distance off the lands that you are looking for. How do you determine what you want your length to be? Here is what I did... I found that I was getting some inconsistency at the range during barrel break in and figured that the bullet was "jumping" further than I wanted it to as I had only loaded up bullets at the "max" COAL stated in reloading manuals. After thinking about it I'm shooting a completely custom rifle that is throated for longer bullets such as the Berger VLD's. I attempted to measure the COAL of what my bullet would need to be to sit right on the lands by taking a spent cartridge, pinching down one small section of the neck so it would hold the bullet stiffly, but would allow the bullet to slide back in the cartridge as the bolt carried forward and the bullet pushed up against the lands. When I pulled the cartridge and bullet out, I measured the COAL to find that I was jumping the bullet way more than what would be considered reasonable. I did this method, starting over each time a total of 4 times. What I found was that each time I varied in measurement less than .010. I have determined that I think this is a reasonable way to measure what I need my COAL to be to sit say .010 or .020 off the lands. Thoughts on this process and anything that I may have overlooked?

Thanks

[Jingles]

What I did for measuring OAL was close bolt with nothing in Chamber.
Insert cleaning rod in muzzle mark on cleaning rod where end of barrel is once cleaning rod had come in contact with the bolt face
Pull out the cleaning rod 4 to 6 inches.
Insert JUST the bullet you want to load into the chamber.
GENTLY push cleaning rod back into barrel until it contacts the bullet
Mark on the cleaning rod the end of barrel.
Measure the distance between the 2 marks and you'll have your OAL.

Be sure to tap out the bullet before going hunting

[fastdam]

Engelwood, i do it just like you explained and it works good for me.

[wsmnut]

Hey guys,

Just wanting to pick some brains here. Say that you have the bullet that you want to use and although you don't have a tool to measure distance to lands, you still want to know COAL of the load to get the desired distance off the lands that you are looking for. How do you determine what you want your length to be? Here is what I did... I found that I was getting some inconsistency at the range during barrel break in and figured that the bullet was "jumping" further than I wanted it to as I had only loaded up bullets at the "max" COAL stated in reloading manuals. After thinking about it I'm shooting a completely custom rifle that is throated for longer bullets such as the Berger VLD's. I attempted to measure the COAL of what my bullet would need to be to sit right on the lands by taking a spent cartridge, pinching down one small section of the neck so it would hold the bullet stiffly, but would allow the bullet to slide back in the cartridge as the bolt carried forward and the bullet pushed up against the lands. When I pulled the cartridge and bullet out, I measured the COAL to find that I was jumping the bullet way more than what would be considered reasonable. I did this method, starting over each time a total of 4 times. What I found was that each time I varied in measurement less than .010. I have determined that I think this is a reasonable way to measure what I need my COAL to be to sit say .010 or .020 off the lands. Thoughts on this process and anything that I may have overlooked?

Thanks


Are you using a comparator to measure length?  Lots of bullets vary in length, so measuring using the tip of the bullet is going to be inconsistent.  I strongly suggest getting some type of bullet comparator, which will let you measure to the bullet ogive.

Wsmnut

[Greenhorn]

You can also slightly seat a new bullet in an already fired but not resized, piece of brass and then close the bolt on it.  It should push the bullet back into the brass and you will end up with the longest o.a.l. possible and then figure from there.

[Fl0und3rz]

Good description.

This is another pretty good write-up using a cleaning rod, cleaning rod stops, and calipers.

http://wildernessmeans.com/articles/hand-loading/hand-loading-for-long-range/rilflings

You can make a case for checking COAL by neck sizing a case shot in the rifle you wish to check.

[andersonjk4]

I've tried both of these methods and I found the method using a fired brass pinching the neck slightly works well.  The cleaning rod method works good too but I feel like I got more accurate results with the brass in the chamber. 

As said above a comparator will go a long ways in telling you your COAL more accurately.

Another tip for when you are putting your bullet into the fired brass is to color the bullet with a sharpie or smoke it before you run it through the chamber.  This will tell you if the lands are grabbing the bullet and pulling it back out a little.  I have found that a lot of the time the bullets will be stuck in the lands and pull out a little when the bolt is opened.  This will make your COAL measurement longer than it really is. 

 

[BULLBLASTER]

  I have also loaded a dummy round extra long and seated. 003-.005 deeper until it chambers easily. With a combination of.all these I have developed a load. Sometimes the magazine lenght of a hunting rifle is a limiting factor. In my 300 rum I am still 0.09 off the lands with 215 grain Berger's after installation of a 3.82 magazine. It shoots 1/2 moa when I do my part. There is an artical on Berger's website about seating depth tests. Look it up and read it it helps.a ton.