6mm erosion

[edw]

for what it's worth I measured my cbto and found it to be .017 longer than new after 760 rounds. 6mm Norma Dasher cases. 105 Hybrids 31.1 grs of H4895. CCI450

 

[swadiver]

I just measured big erosion in my Krieger 6BR after 1200 rounds or so. never shoot hotter than 30.3 of Varget with 105/107/108 class of bullets. looking at .025" in growth

 

[243BR]

If my math is correct that's 0.001 / 45 rounds. From my experience that's well within the "normal" range for a 6br. I've seen hotter rounds (like the 22-250) loose 0.001 at the rate of 1 / 10 - 15 rounds. Powder burns at 6000 degrees and steel melts at 3000 degrees (roughly). Throat erosion starts with round one.

 

[LarryDScott]

If I have been informed properly: the bigger the stick/grain, the hotter the burn,
which dictates more throat erosion.
When I was shooting a 220 Swift Pdoggin, I had most of my cases loaded w/H380. The others were w/RL15, w/nearly identical MV. There was a tremendous difference in barrel heat for the same number and frequency of rounds fired, w/380 being the coolest by a large margin. LDS

 

[dmoran]

I just measured big erosion in my Krieger 6BR after 1200 rounds or so. never shoot hotter than 30.3 of Varget with 105/107/108 class of bullets. looking at .025" in growth

When your throat gets out to 0.040" of erosion, consider re-chambering, and you will be staying ahead of it.
0.025" in 1200-rnds isn't bad, especially when a large percentage of that erosion more then likely occurred in the first couple hundred rounds of the new barrel. New rifling wears faster then after it settles in - IME
Donovan

 

[tmwinds]

for what it's worth I measured my cbto and found it to be .017 longer than new after 760 rounds. 6mm Norma Dasher cases. 105 Hybrids 31.1 grs of H4895. CCI450

I assume that you are using the same bullet and brass as the original measurement to determine the throat wear. Bullets ogives vary from lot to lot and can give a false indication of wear.

 

[expiper]

in my time fiddlin with various 6mm's,,,I have found the ppc's and BR's to erode ~.002-.003" per hundred rounds and a .243 win to erode ~-006-010" per hundred,,,,I have never used a bbl from start to finish with ball powder or "cool" powders,,,( usually tinker all the time and use ever powder known to man,,hahaha),,,but I have bbl that have wore out bbls. using N-133 or Rx 15 or4895 or 4350 almost exclusively,,,Roger

 

[swadiver]

I just measured big erosion in my Krieger 6BR after 1200 rounds or so. never shoot hotter than 30.3 of Varget with 105/107/108 class of bullets. looking at .025" in growth

well, took the rifle out today after I "chased the lands" with new sweating depths and it shot excellent. hope i can get up to 3500 rds out of this barrel.

 

[AckleymanII]

If I have been informed properly: the bigger the stick/grain, the hotter the burn,
which dictates more throat erosion.
When I was shooting a 220 Swift Pdoggin, I had most of my cases loaded w/H380. The others were w/RL15, w/nearly identical MV. There was a tremendous difference in barrel heat for the same number and frequency of rounds fired, w/380 being the coolest by a large margin. LDS

Same with win 760, 414, 748, and H335, AA2230. I get 8000-10,000 rounds out of 6 ppc and 6 BR's shot with H335 or a variant there of, still shooting in the 2's when I take the bbl off when copper fouling gets aggravating.

 

[edw]

I assume that you are using the same bullet and brass as the original measurement to determine the throat wear. Bullets ogives vary from lot to lot and can give a false indication of wear.

The first thing I do with a new barrel is make a dummy round that mimics my throat. Then I put it in my die box to use at any time later. I pull the bullet out and check the new wear and write it down.

 

[243BR]

well, took the rifle out today after I "chased the lands" with new sweating depths and it shot excellent. hope i can get up to 3500 rds out of this barrel.

Good deal on the excellent shooting. 3500 rounds is possible. IMHO it will shoot better longer if you set it back sooner rather than later. If you can take a look at the rifling directly in front of the chamber. if you see heat checking it may be time to consider a set back.