Same load throughout the life of a barrell?

KQguy

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Joined
Dec 7, 2007
Messages
322
Do you guy's ever tweak a load occasionally,after so many rounds?I was just wondering if you anticipated on getting say 2000+ rounds out of a barrel,if you would use the same load for the life of the barrel,or do things change as it wears?I don't load to touch the lands,so would "chasing the lands" be necessary as the throat wears?
 

Varmint Hunter

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Joined
Dec 26, 2001
Messages
3,245
Location
Long Island, New York
Throats definitely recede and could cause a change in accuracy. The throat geometer also changes and accuracy will rarely remain the same. As throats wear in my varmint rifles I often change the cartridge oal or (occasionally) have switched to a longer or different bullet.
 

BHP9

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Joined
Dec 4, 2007
Messages
219
Location
Ontario, Canada
If you've got an accurate load when new that's chrono'd you may need to up the charge by 0.?gr to maintain that velocity.

Dave Tubb does this to maintain accuracy and it appears to extend the usable life of the barrel.
 

johnnyk

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Joined
Dec 24, 2001
Messages
2,198
Location
Potters Hill, NC
I change bullets in all of my rifles all the time. Depends on what I'm hunting or if I just want to try another bullet or powder. I always check the OAL with the Stoney Point gauge and I try to seat every bullet at .010" off the lands. This is probably not the perfect distance for every bullet, especially the Bergers, but it has proven to be a good place to start for me over the years. Most of the time I leave my seating die set to that OAL, until I notice a change in accuracy. First thing I do is check the velocity and if that's the same I check the OAL with the gauge.
Depending on the amount and frequency of shooting done, the throat does erode. "Chasing the lands" is merely adjusting the OAL to find that sweet spot again.
On the first 7mmRM Sendero that I owned I noticied at the end of that barrels life that it started to do some freaky things. I don't have any scientific evidence to base this on only what I experienced. It would occasionally throw a shot. There was no way I could tell which shot would go astray or why it did. At the time I didn't own a chrono so I could measure the speed. I reckoned that the barrel was "loosing pressure" due to wear but like I said I don't have enough knowledge in that area to make a proven statement. The rifle was extremely accurate and easy to clean up until about 12 to 1300 rounds (best recollection). Hope this helps. JohnnyK.
 

MagnumManiac

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Joined
Feb 25, 2008
Messages
2,114
I found after shooting F-Class that it was better to keep an eye on the velocity of your load and adjusting the load to maintain that velocity rather than chasing the throat.
It has worked very successfully for me on 3 LR rifles I have, I shoot quite a bit over here, and I have definitely increased the usable life of my barrels by doing this.
I also found that it takes more than a 100fps drop to affect accuracy all that much, but it did play havoc with my vertical over long distances!
gun)
 

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