sable tireur
Well-Known Member
- Joined
- Oct 8, 2010
- Messages
- 3,390
I'm guessing that this is the model you bought or borrowed since you don't specify.
A couple of thoughts to consider:
Skyscreens are subject to the vagaries of the environment in which they are used. The angle of the sun, cloud cover, time of day, etc. will have an effect of getting consistent readings.
The electronics in the chronograph is a simple timer or clock (counter) if you will. The shadow of the bullet starts the timer when it enters the first screen then stops when it enters the second screen. The quality of the data presented is governed by the quality of this timer and all the differences in the environment where/when you're shooting.
Virtually all of the electronics are manufactured in China with no regard to consistency or quality. These are made to a cheap price point only.
Every barrel manufactured today will be different from the very barrel before it and after it. Yes, they'll be close (very close sometimes) but each will be different even though they come from the same manufacturer and are made on the same equipment. Wear alone on the tooling can have an effect of the barrels. On CNC machines an offset in the program can be applied to compensate for tiny amounts of wear.
Break-in of a barrel or barrels will often show an increase in velocity as you complete the process. Without a definitive break-in process, there is no guarantee of consistent velocities.
Cleaning procedures are an obvious variable to gaining consistent readings for velocities.
Wear and tear on the throat and the quality of the barrel steel is another variable.
The only time I shoot factory ammunition is when I test fire a new build. I do chronograph the velocity along with other data for my files and for the customer. There have been a couple of exceptions where factory ammunition performs so well that even with reloading, I can't match it but few and far between.
Enjoy the process!
