Establishing Bullet Seating Depth

[timberelk]

After much research and reading I decided to attempt to locate my lands...

I took once fired brass, inserted a new 140 grain Nosler BT, removed my firing pin from the bolt and chambered the dummy round. I did it several times and each time I was with .001-.003 when using the Hornady bullet comparator so I believe my method worked.

This resulted in a COAL of 2.903". The Nosler book says the COAL they used was 2.880". I was thinking about setting the bullet off the lands about .020" which results in a COAL of 2.883"

So I'm .080" longer than the Nosler loading book... is that too long? Does it not matter as long as it works in my gun? This will be hunting ammo so should I back the bullet off the lands by more than .020"? Maybe .030"? Or .040"?

Thanks for helping a newbie!

 

[26Reload]

While I was working up a load in my 65284 norma I consulted Nosler too....
What the tech told me....the lenght they say in the book for coal is the lenght of the cartridge they shot in their testing rifles...
So that would make you only over their coal.... .003"...

 

[26Reload]

Also...was told accubonds and ballistic tips can be close to lands... but the lrab need a minimum of .050...because the forward portion on the lrab bullet is much softer it might deform more closer to,the lands....but the others are harder and can take the pressure better...
At that short of difference how can that be....

 

[timberelk]

Did they recommend how close to set the BT off the lands?

Also...was told accubonds and ballistic tips can be close to lands... but the lrab need a minimum of .050...because the forward portion on the lrab bullet is much softer it might deform more closer to,the lands....but the others are harder and can take the pressure better...
At that short of difference how can that be....

 

[dok7mm]

To find the correct, or most accurate, seating depth, you'll need to test at different lengths for your rifle/bullet combo. I would suggest you start at your magazine length with a starting load, if you have sufficient bullet in the neck (at least .264").

Shoot a 3 shot group, seat deeper by .005" or .010", shoot another group and so on until you find a tight group. You can tweak it, either up or down, with your final load. A BT bullet should show accurate seating depth between .010" jump and . 030" jump and be easier to find than a secant ogive, like a vld.

Alex Wheeler posted a very good video here, on how to find your true base to ogive length. You pulled the FP, but did not mention pulling the ejector.

 

[L.Sherm]

I would go off of what you came up with, you don't know what reamer nosler used. I never pay attention to what manuals use as COAL i find the lands myself and go off that as long as the mag box allows it. I like to start .005 off and work backwards there only one way to go. I don't jam my hunting rifles my sage rat stuff different story if it likes it.

 

[timberelk]

To find the correct, or most accurate, seating depth, you'll need to test at different lengths for your rifle/bullet combo. I would suggest you start at your magazine length with a starting load, if you have sufficient bullet in the neck (at least .264").

Shoot a 3 shot group, seat deeper by .005" or .010", shoot another group and so on until you find a tight group. You can tweak it, either up or down, with your final load. A BT bullet should show accurate seating depth between .010" jump and . 030" jump and be easier to find than a secant ogive, like a vld.

Alex Wheeler posted a very good video here, on how to find your true base to ogive length. You pulled the FP, but did not mention pulling the ejector.

I pulled the firing pin but do not know how to pull the ejector. I've searched all over and have yet to find out how to remove the ejector

 

[dok7mm]

I pulled the firing pin but do not know how to pull the ejector. I've searched all over and have yet to find out how to remove the ejector

There is a roll pin on the bolt body, near the ejector on a 700 style bolt. You drive out the roll pin, while retaining the ejector & spring under pressure, so it doesn't fly off. Pull the ejector and spring. It is easier if you have the proper tools available from Brownells.

 

[dok7mm]

Timberelk, I reread your first post and if I read it correctly, you jammed the bullet into the lands. What you are looking for is the measurement where your bullet is free of the lands by .001".

If you can't find the video here, Google Alex Wheeler and go to his video section. Seeing it will make things clearer to you. You can also mark the ogive with black pen and see the lands on your bullet. Keep seating deeper, until the lands are not marking it. Remember, you have to do this with each style/weight of bullet you want to shoot. Keep good notes. Good Luck.

 

[26Reload]

I didn't get any suggestions as to any other measurements for seating other than their book.....policy...
While working with my rem 700 65284 I did pull the firing pin and the ejector....it is good to do for YOUR experience...thus you will know how to do it for every gun you have....I did measurements for 6 or 7 different bullets...just keep good records...
I recently did my 7rum and touch was at 3.999"...max box lenght of 3.6750"....I settled at 3.665"...just enough to clear when running the cartridge up the rails....I know that weatherby jumps a lot...I am curious if that is too much jump?

 

[timberelk]

I didn't get any suggestions as to any other measurements for seating other than their book.....policy...
While working with my rem 700 65284 I did pull the firing pin and the ejector....it is good to do for YOUR experience...thus you will know how to do it for every gun you have....I did measurements for 6 or 7 different bullets...just keep good records...
I recently did my 7rum and touch was at 3.999"...max box lenght of 3.6750"....I settled at 3.665"...just enough to clear when running the cartridge up the rails....I know that weatherby jumps a lot...I am curious if that is too much jump?

How difficult is it to pull the ejector? Is there any videos that show how it's done?

 

[26Reload]

I had a small nail that fit the retaining pin..just file off the point so you hit the entire pin...push the ejector in and push the pin out at the same time..and the remove your pin removal tool...
Remember there is a spring inside there..and keep the ejector covered until tension is gone....or the ejector and spring could be gone.......then while you have it out do a good cleaning on the spring and ejector and clean the holes in the bolt....you do this once and it becomes a zero on a ten scale....

 

[N2TRKYS]

Why are y'all pulling ejectors when measuring COAL?

 

[Engineering101]

timberelk

What you did will work fine to establish the max COAL for a given bullet. You don't need to pull firing pins or ejectors. I do similar for any bullets I load - but I make tooling by taking a case ready for loading but unprimed and split the neck with a hacksaw, remove burrs inside and out. Put a bullet in the case and chamber. Then measure the COAL. That is the maximum length that round can be with that bullet without jamming. I set neck tension of the tooling so I can barely pull the bullet with bare hands (using rubberized gloves). If it gets too loose at some point you can always tighten it back up by running it through your resizing die again. This tooling is also useful to setup your press when ready to load live ammo.