OAL problem in my Dasher?

[40X Guy]

I have around 180 rounds thru my Dasher and have found the load as per my other thread, but was getting ready to seat bullets this afternoon in my prepped brass and figured i'd recheck my OAL with the same Hornady tool and modified case that I had used before as i was going to seat a batch of the Hybrid 105's that were just a tad longer bearing surface. Problem being my measurements are a full .009 longer than what I measured 100 rounds ago. Would the throat be smoothed out after so many rounds? What I thought was .010 off the lands may have been almost .020? Basically i don't know where to seat them, rifle shot well last time out. Should i seat them at .010 off again according to my measurements today? Just trying to figure out why measurements are that much longer. My modified case I FL sized without a bushing and bumped shoulder according to my fired brass and case goes in chamber very smoothly by hand. I just find it odd and am looking to expand on my knowledge from fellow members.

Frank

 

[DJ111]

Frank,
Did you change lot # on the Hybrids that you have the longer bearing surface now? That can change your measurement slightly. Also the Hornady tool is very easy to come up with differant readings depending on how hard you push the bullet in the lands, if you are holding the case in the chamber tight...ext

If your bearing surface changed just set up your seater to get you back to your .010 off and go try it.

My testing with the hybrids I did not see much difference between .020-.010 off.

Good Luck,
Dallas

 

[40X Guy]

Dallas, same lot number of the hybrids, just .001 difference in bearing surface. I checked 8 times today measuring and all were within .001. I feel I have the OAL tool down pretty well and I also agree that the Hybrids will not see much difference from .010 to .020 off the lands. At this point i am thinking I will set Wilson seater to .010 off based on todays measurements and shoot a few, I can always press them in deeper.

Frank

 

[DJ111]

Frank,
That's what I would do also. Your throat is probably starting to move some also, its bound to happen!

Dallas

 

[40X Guy]

Dallas, I just started all over again and you were right, I was putting too much pressure on the OAL tool as i got in a hurry to check measurements. Haste makes waste! I ended up just turning mike top .001 down to compensate for the fatter bearing surface and all is good in Dasher land.

Frank

 

[johara1]

Frank, I don't see a reason to worry, your seating stem works off the ogive and bearing surface length does affect seating depth....jim