LADDER TESTING

[Eric H]

Should I or not allow barrel cooling after each shoot?

 

[Koda_]

Yes, if you want the most accurate velocity and group measurements.


Whats a useable tolerance is more subjective. I usually only fire 3 shots then fully cool the barrel. But this depends on other factors like barrel diameter and outside temps.

 

[Recon$$]

I usually wait anywhere from 3-5 min when I want to know what each load can really do.

 

[Texis]

Depends on several factors:
1) weight of the barrel, bull, varmint, sporter, etc
2) the amount of powder being burned.. 6.5CM, 308, 300RUM etc.
in my 708 I use a 3 minute (sand hour glass shape) game/egg timer between each shot to keep things consistent. Although my barrel is a 26" varmint and can typically fire 10+ shots and only get warm.
Whatever the setup, try to keep the barrel a consistent heat within reason.

 

[Eric H]

Thanks. I do have a makeshift barrel cooling device. Hopefully it will be in the 40s since it's a hunting rifle.

 

[Texis]

To clarify, with my barrel and my round I fire 3 shots and then cool for 3 minutes for temps below 65F. For temps 80F+ I cool 3 minutes between each shot.

 

[338 dude]

Should I or not allow barrel cooling after each shoot?

Yes

 

[Mikecr]

If you're developing what I call a hot barrel load, then you would take a few foulers/warmers to stable before moving to a ladder, and shoot the ladder at a rate that does not increase barrel temps further during the test. This could be 3mins for a small cartridge or 10mins for a larger cartridge. A local matter.

I do this to get a hot barrel load for initial precision (grouping). Then I move to cold bore load development for accuracy, with that hot grouping load in center of adjustment.
I've never attempted a cold ladder.