Easy bolt lift, primer cratering. 6.5x47L RL17

Goin'Hot

Gunny Sergeant
Full Member
Minuteman
Nov 14, 2008
2,271
56
Central, Ohio
Shot my 6.5x47L for the first time last night to find it's pressure limits. I started at 39.0 gr and went to 42.5gr of Reloader 17 using 139 Scenars.

2010-05-27113959-1.jpg


39.0 was my sighter and I adjusted to the 3/4" dot from there. All shots were fired at the orange dot.

39.0 - 2763 / 39.5 - 2830 / 40.0 - 2867
40.5 - 2906 / 41.0 - 2934 / 41.5 - 2976
42.0 - 3005 / 42.5 - 3043

COAL is 2.764" (0.009" off lands).

The first 3 primers look perfectly normal, as I would expect, and they begin to crater from there. It looks pretty linear with the last 1 starting (just starting) to flatten the primer. NONE of them showed any increase in bolt lift or anything. I'm using wolf SRM primers which i've found to be more pressure resistant. Action is a Lawton 7000 with a standard FP diameter.

My question is (and I know this is the internet) - with no increase in bolt lift effort, can I keep working the load around the 42 - 42.5 area. I'm planning on getting out to 300 yards on Monday to play and it would appear that is the area for a third node. I would certianly be happy if I could get ~3000 fps out of the 139's.
 
Re: Easy bolt lift, primer cratering. 6.5x47L RL17

primer cratering is one short step away from a pierced primer.

I had that happen on my 6.5x47, on my Surgeon action no less. This was with middle-of-the-road loads, using Wolf SRM or CCI 450 primers. The smaller firing pin solved the issue.

I'm no expert, but your COAL suggests a short throat, better suited to 123 or 130 grain bullets.
 
Re: Easy bolt lift, primer cratering. 6.5x47L RL17

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: buffybuster</div><div class="ubbcode-body">I would get the FP hole bushed with a smaller diameter FP.

Running ~140's to ~3000fps, sounds REALLY good to me. </div></div>

^^This.

Send your bolt to Gre-tan or Kampfeld Customs and have the FP hole bushed and this will go away.

http://www.gretanrifles.com/bushfiringpin.asp

http://www.kampfeldcustom.com/