Crony

[Snoepie]

I posted this on the wrong forum, so here it is again:

I have been reloading for some years, but on Friday I complimented my reloading by measuring the muzzle velocity of various loads for three separate calibers.

I shot 5-shot groups and measured different velocities for almost every shot in a 5-shot group. The biggest difference for any of the 5-shot groups between the fastest and the slowest, was 110 ft/sec and the smallest difference was 15 ft/sec. The average difference between the fastest and slowest of 15 groups that I shot, is 48.33 ft/sec.

My questions are:
1. Is this normal or will factory loads measure the same velocity for every shot in a 5-shot group?

2. If it is acceptable that the velocities in a 5 shot group will differ, is there a standard to determine what acceptable tolerances are?

3. What sort of difference in velocity will indicate a serious problem or error?

I shot a .243, a 6.5 x55 and a 30-06 (5 x 5-shot grouping with different loads for each) and for each rifle the groupings were totally acceptable.

I use an electronic scale to measure the loads and rely entirely on this scale for consistent measurements.

Thanks in advance for your advice and ideas.

 

[sunray]

1. Nope. There's always a difference. The trick is to get the average difference as low as possible. 15 ft/sec is great. There's no standard though. In any case, accuracy is far more important than the measured velocity.

 

[stubblejumper]

The trick is to get the average difference as low as possible.

The trick is to get the most consistently accurate load that produces decent velocity.This isn't always the load with the most consistent velocities.

 

[Snoepie]

Thanks to those who responded - it helps to know you are on the right track