.308 win, using hornady ELD match seating...

[brccd]

Reading the Hornady tables...ELD Match (168 gr) should be seated to make COAL 2.800.
Made a test loading bullet there, and when I measure using a comparator, the OGIVE @ 2.8 exceeds the spec value

If I seat the bullet to make COAL 2.785, then OGIVE is right...

Plan to use Varnaget for powder, with 41gr.

So, the question...does this look like a problem, or something different I should do? What am I missing?

Thanks.

 

[fkimble@charter.net]

Different chambers cut with different reamers can have different throat lengths. Load data seating depth is just a suggestion. Usually for factory chambers and short enough to work thru the magazine. Max length is a hard jam into the rifling. Usually have to be single loaded. Next max is short enough to feed thru the magazine. Not a hard rule for actual OAL.

Frank

 

[Martin52]

Hornady has provided powder load guidance based on their own tests using a COAL of 2.800. Other assumptions typically include a 24 inch barrel length, this is a pressure related consideration, generally for a given load the longer the barrel the less the pressure.

Whether a COAL of 2.800 is right for your rifle depends on a few things including your particular chamber and its freebore.

Scroll down and watch 'Finding Your Lands' by Alex Wheeler a member of this forum. This method should confirm your COAL using your selected projectile, Hornady 168 ELDM. The COAL will change when you change to a different projectile and you'll need to do this again for that different projectile.

Videos | wheeleraccuracy

www.wheeleraccuracy.com

Once you have your COAL touching the lands, take your comparator and measure from the case base to the ogive (BTO), this will be a lesser number. You may then decide to load a few rounds at say 0.020 less than the BTO touch measurement for load testing purposes.

 

[WSnyder]

when I measure using a comparator, the OGIVE @ 2.8 exceeds the spec value

What is this spec value?

As others pointed out a comparator is not going to measure the same (or correctly) for every variation of throat geometry out there if at all. You'd be lucky if your comparator touches the bullet in the same place as the lands touch the bullet, most don't even come close. It is called a comparator for a reason, it compares things not necessarily measures things.

 

[Bill Norris]

Reading the Hornady tables...ELD Match (168 gr) should be seated to make COAL 2.800.
Made a test loading bullet there, and when I measure using a comparator, the OGIVE @ 2.8 exceeds the spec value

If I seat the bullet to make COAL 2.785, then OGIVE is right...

Plan to use Varnaget for powder, with 41gr.

So, the question...does this look like a problem, or something different I should do? What am I missing?

Thanks.

For best results measure base to ogive primarily. The COAL number is mag. length dependent.

 

[brccd]

Thanks for the replies!

I guess I was more concerned that pushing the bullet deeper, and from things I have read and from others, is the pressure would increase. I am starting with the load of 41 gr (Varget) down from max load 44gr and will use 41gr to start. So there will be less pressure from that. I would like to also try H4895 @41 gr, max there is 43.5.

I also was comparing measurments to Federal Factory loads... 168 gr and making things close to that.

Will make 2 batches and compare results! First time trying Varget.