6.5x284 COL

[kernel gadaffi]

I'm loading up some of the above with Hornady SST140 grainers, CCI LR primers, 47 grains of N160 in Lapua brass, but, I have a problem with the COL, the data I have from the previous owner is the COL should be 3.406", if l do that, the boat tail is just in the case mouth and not deep enough to hold the bullet, looking through the load data, I found some more data that states, "COL-3.164=20/1000 off the lands, 3.144= 40/1000 off the lands both sub 1"@ 100 yards".
Both of these loads are seated deep enough and seem OK, but I'm still baffled by the original COL of 3.406.

Rifle has 24" barrel.

Any suggestions?

 

[Scurvydog]

I say start over, measure your rifles COL and start some load development moving the seating depth back .002-.003 of an inch off the lands until you find the load that works for you. You never know if the recipe given to you has typos or inaccuracies.

 

[kernel gadaffi]

All data was hand written, I called the previous owner and he said the 3.144/3.164 were the best COLs, so I'll make a few up and try them.

 

[Scurvydog]

It never hurts to test things out, it always gives me an excuse to shoot more. I thought you might find this article interesting if you haven't already read it.

http://www.bergerbullets.com/wp-content/uploads/2013/03/COAL.pdf

 

[kernel gadaffi]

I've actually been reading that very item today.