I've been considering building either a .338 Lapua AI or a 375 Cheytac and diving into ELR...just seems like too much fun. How often are you guys who are shooting something like this having to adjust your COAL to chase the lands to keep these cartridges in tune? Are you constantly having to adjust your load or is it something you're doing every 200 rounds or so? What kind of barrel life are you getting? Appreciate your insight.
Chasing the lands & barrel life on big .338s/.375s
- Thread starter Chase723
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Jeff Heeg osoh
Well-Known Member
Here's a little info that may be of use.
It does not matter if its a 260, 338lm or a 375, it is a good game plan to check and record the measurement of a given round to the lands on a new barrel or rifle. Then while doing load development record the measurements of your accuracy load. Use a comparator with the right bushing to match your bullet so you can measure the seated bullet in a case off of the ogive and not the tip or meplat.
For example my 260 with the 139 grain Scenars has a sweet spot at 25 thou of jump to the lands. Yet my 338LM prefers 50 thou and the 416 using solids shoots very well with 33 thou of jump.
So then every round and barrel will react different in terms of throat erosion, some will push 1000 rounds down the barrel with very little erosion and some might walk 10 thou per 100 rounds. This also is affected by how hard you have to push them, some events force the shooter to shoot a lot of rounds in a short time restraint and some are more forgiving. The faster we have to shoot the high powder capacity rounds the faster things heat up like a torch and steel starts to flow let alone the abrasive action of powder that is sand blasting the lead of the lands at the same time.
The 338LM improved and the 375 Cheytac will heat things up, but if you pay attention to your pace and even some of the events that push you a little you should be ok. One of our rifles was a 375 Snipetac in which is a 375 Cheytac improved we ran it hard at times and she got hot but we still only had a total of 30 thou throat erosion with 900 rounds down the barrel shooting solids with RL33.
So if you check it periodically and you recorded your original barrel and then where the sweet spot was as far as being a jump to the lands or jam then you
always be able to check your barrel and re-adjust your bullet seater to move the bullet out a hair to get it back in the sweet spot and your best accuracy node.
Hope some of this helps
Iamosoh
JH
It does not matter if its a 260, 338lm or a 375, it is a good game plan to check and record the measurement of a given round to the lands on a new barrel or rifle. Then while doing load development record the measurements of your accuracy load. Use a comparator with the right bushing to match your bullet so you can measure the seated bullet in a case off of the ogive and not the tip or meplat.
For example my 260 with the 139 grain Scenars has a sweet spot at 25 thou of jump to the lands. Yet my 338LM prefers 50 thou and the 416 using solids shoots very well with 33 thou of jump.
So then every round and barrel will react different in terms of throat erosion, some will push 1000 rounds down the barrel with very little erosion and some might walk 10 thou per 100 rounds. This also is affected by how hard you have to push them, some events force the shooter to shoot a lot of rounds in a short time restraint and some are more forgiving. The faster we have to shoot the high powder capacity rounds the faster things heat up like a torch and steel starts to flow let alone the abrasive action of powder that is sand blasting the lead of the lands at the same time.
The 338LM improved and the 375 Cheytac will heat things up, but if you pay attention to your pace and even some of the events that push you a little you should be ok. One of our rifles was a 375 Snipetac in which is a 375 Cheytac improved we ran it hard at times and she got hot but we still only had a total of 30 thou throat erosion with 900 rounds down the barrel shooting solids with RL33.
So if you check it periodically and you recorded your original barrel and then where the sweet spot was as far as being a jump to the lands or jam then you
always be able to check your barrel and re-adjust your bullet seater to move the bullet out a hair to get it back in the sweet spot and your best accuracy node.
Hope some of this helps
Iamosoh
JH
