Chasing the lands?

[fw707]

I know it varies depending on several factors, but could anybody give me some numbers you've experienced on extending seating depth in relation to increasing round count?
Numbers on the 6.5x47L in particular would be great.

Thanks!

 

[Killswitch Engage]

cant say on the 47 but my last creed barrel had about .002 of erosion at 1500rds. keep in mind when you seat out to stay into the lands you will probably need to chase your load with a .1gr or so to keep it in the pressure node along with seating depth.

 

[fw707]

Thanks Doug.
I think I may need to check my measurement again. My 47 is showing way more than that at 1729 rounds.

 

[MDM]

Jeff, I didn't hardly see any in my x47 in 2000 rounds. Maybe .005 or so. That's with mostly strings of fire at the monthly's so nothing got too hot. You aren't checking the measurement with a different lot of bullets are you? I check my new barrel with a bullet and write down my measurement for that particular bullet and set that bullet aside so I only use that bullet to get my reading. I've seen bullet lots vary by .020-.030 in length so I just use the same bullet and seems to work pretty well. Like Doug said, if you are seeing your load open up and the throat is moving try bumping your charge up just a tad.

 

[fw707]

Dave, the bullet I used yesterday was from a different lot, and I didn't save the original.
But I did write everything down from the original measurement on the new barrel. The bullet I used yesterday was .025 shorter than the original. I allowed for the difference and I'm still getting a bigger number than yours and Doug's.
I think I need to check my process again.