Ollin Magnetic Digiscoping System

Slower than posted velocity

Bigjav

Active member
Joined
Aug 3, 2016
Messages
479
Location
Central California
I loaded some 308 the other day with Barnes 168 TTSX at max charge of 47.9gr BLC2 powder with federal gold medal primers and went to the range today and got chronograph readings an average of 100fps slower than the published velocity out of a 26" barrel. Could it be a bad chronograph or could 3gr of bullet make that much difference?
 
I loaded some 308 the other day with Barnes 168 TTSX at max charge of 47.9gr BLC2 powder with federal gold medal primers and went to the range today and got chronograph readings an average of 100fps slower than the published velocity out of a 26" barrel. Could it be a bad chronograph or could 3gr of bullet make that much difference?

Do you have a 26" barrel? I would expect a 22" barrel to be at least 100 slower than a 26. I also think that each barrel is an individual and each chronograph is an individual. With all those factors, it would be a surprise to me to ever match published velocities exactly.
 
Do you have a 26" barrel? I would expect a 22" barrel to be at least 100 slower than a 26. I also think that each barrel is an individual and each chronograph is an individual. With all those factors, it would be a surprise to me to ever match published velocities exactly.

Not to mention the fact that temperature will affect velocity...
 
Getting within a hundred feet of published load is very typical.
How new is your barrel?
It's common to need a hundred rounds down the bore to get the most out of one. Barrels will tend to speed up as they age some and wear smoother internally.
 
Back
Top