Book value verses gage value ??

[45C]

Hello
So , I’m just taking some measurements with my Hornad OAL gage and comparing to Nosler recommended OAL.

If I didn’t have the gage and was just using book value I’d be jamming the bullet into the lands by 25 thous.
Cases are FL sized.
I can’t close the bolt on either when measuring from Hornady and Nosler OAL data

What am I missing here?

This is the same scenario with 140 g accubonds and Hornady ELD X and two diff rifles.

 

[Potashminer]

I found similar using procedure from Woodleigh reloading manual to find my lands - Nosler data for 30-06 would have jammed the bullets into the rifling - not "end of the world", if you started with that and did pressure series testing - but likely to drive one to be "batty" if you believe anyone's COAL length number in your rifle.

https://www.canadiangunnutz.com/forum/threads/a-cautionary-tale.2230590/ - i tried a Nosler 180 grain bullet - Post #5

 

[45C]

Would they need the shoulder bumped ? Even though I’m FL sizing?

 

[maynard]

To find out if the seating depth is your problem colour the bullet with a sharpie marker and try to close the bolt. Seat your bullet deeper until the bolt closes then go an other .020” deeper. COAL is just a guide

 

[Potashminer]

OP - I have been reloading since mid-1970's and still do not own one of those gauges - there has been several articles written over the years how to find the lands - several ways to do it - you use the shell holder and reloading die set that you have, and your rifle chamber. So, size a case as you normally do - then try to chamber it - if the bolt closes, then you know the brass is good - you do not need a "bump" or whatever to make it fit better. If the empty brass case does not allow the bolt to close, use maynard's suggestion above and mark up that case with Jiffy Marker - find where contact is being made, that Jiffy Marker will show you. I formed some belted 7x61 S&H from 7mm Rem Mag, that turned out to have hard contact right in front of the belt - where the sizing die has not much sizing effect.

Once you are able to size the brass cases to chamber in your rifle and allow the bolt to close, then do similar by seating a bullet - no powder or primer at this point - initially, seat to a quite long COAL - chances good that your bolt will not close. Turn in the bullet seater - try to chamber - repeat until it does - if you want you can get fussy and back up half way between where it did chamber to where it last did not chamber - gets you closer to where full contact is - then as maynard suggests, back off from that another 0.020" - the Woodleigh manual suggests .020" to .040" from hard contact to do pressure series with their bullets - then you can alter that a bit at a time - deeper or shallower - to find "best" results for your rifle. You get to define what "best" is. For many decades, I seated to .030" from hard stop and just used the rounds like that.