I had a long email discussion with a customer who wanted my recommendation on the checks that can be done to assure the best pellets. This was my response:
Generally, I consider pellet head diameter to be more critical that the weight variances normally seen. So from the viewpoint of “quality assurance” for pellet users, I think that the equipment necessary is a Pelletgage, an electronic weight scale capable of 1 mg resolution (with a means of calibration), a loupe or similar magnifier, and a piece of framed glass.
Sample 50 pcs from a tin, check to see that:
1) the variance of the head size is less than +/- 0.01 mm from mean size (which can differ from nominal)
2) the weight variance is less than +/- 0.08 grain (+/- 5 mg).
Inspect the sample pellets carefully with eye loupe or other magnifier at 4X or better. While slight bending of the skirts is not significant, look for any excess parting material on the edges of the skirt. Any material that affects the rotational stability of the pellet is a problem. If you have more than one, this tin needs sorting.
Any visible dents or flat spots on the pellet head is a problem. As above, more than one would indicate a need for sorting.
Rolling the pellets on the glass can reveal a wobble indicating the heads are not concentric and round, and also whether the skirts are true. Again, it is more critical that the head is perfect.
Examine the recess in the back of the pellet. In swaging, the wire slug is pushed into a die with a cylindrical rod. Look to see that the diameter of this recess is the same, and that it is concentric with the pellet skirt. It is all too common to see big differences here, even within a tin.
And consider that the pellets you believe to have a nominal head diameter of 4.50 mm (for instance) may in fact be 4.52 in a new tin. This is a result of the process variation in swaging, and also a limitation from the inspection methods in use by manufacturers. This shift in size between production lots could be a factor for some rifles.
I believe the first consideration should always be consistency, but it is also important to know which size and weight produce the best patterns for a given rifle at a given distance.
Taking the time to measure and find this “optimal” pellet for a particular gun is productive, and then checking pellets whenever getting new ammunition assures that you will continue to see good patterns.
My favorite brand of pellets is JSB/Air Arms. International competitors overwhelmingly use these pellets. Although I believe this is with good reason, there is still enough inconsistency to warrant the inspections I recommend unless you are simply plinking.
Generally, I consider pellet head diameter to be more critical that the weight variances normally seen. So from the viewpoint of “quality assurance” for pellet users, I think that the equipment necessary is a Pelletgage, an electronic weight scale capable of 1 mg resolution (with a means of calibration), a loupe or similar magnifier, and a piece of framed glass.
Sample 50 pcs from a tin, check to see that:
1) the variance of the head size is less than +/- 0.01 mm from mean size (which can differ from nominal)
2) the weight variance is less than +/- 0.08 grain (+/- 5 mg).
Inspect the sample pellets carefully with eye loupe or other magnifier at 4X or better. While slight bending of the skirts is not significant, look for any excess parting material on the edges of the skirt. Any material that affects the rotational stability of the pellet is a problem. If you have more than one, this tin needs sorting.
Any visible dents or flat spots on the pellet head is a problem. As above, more than one would indicate a need for sorting.
Rolling the pellets on the glass can reveal a wobble indicating the heads are not concentric and round, and also whether the skirts are true. Again, it is more critical that the head is perfect.
Examine the recess in the back of the pellet. In swaging, the wire slug is pushed into a die with a cylindrical rod. Look to see that the diameter of this recess is the same, and that it is concentric with the pellet skirt. It is all too common to see big differences here, even within a tin.
And consider that the pellets you believe to have a nominal head diameter of 4.50 mm (for instance) may in fact be 4.52 in a new tin. This is a result of the process variation in swaging, and also a limitation from the inspection methods in use by manufacturers. This shift in size between production lots could be a factor for some rifles.
I believe the first consideration should always be consistency, but it is also important to know which size and weight produce the best patterns for a given rifle at a given distance.
Taking the time to measure and find this “optimal” pellet for a particular gun is productive, and then checking pellets whenever getting new ammunition assures that you will continue to see good patterns.
My favorite brand of pellets is JSB/Air Arms. International competitors overwhelmingly use these pellets. Although I believe this is with good reason, there is still enough inconsistency to warrant the inspections I recommend unless you are simply plinking.
