PART I - Weight variation out of the tin.
By Asa
Huddled over a set of scales the night before a competition, examining and weighing your tried and tested pellets - essential for achieving you best score or just sad...?
I wanted to have a go at proving whether sorting pellets by weight is actually going to be helpful or just a way of passing the time when we can't be out shooting.
So, first of all I have set out to weigh at least a hundred of as many makes of pellet as I can in order to establish the spread of weights and extremes of weight that you are likely to have in your tin.
Rather than record the weight of every single pellet to 100th of a grain, to save time I sorted the pellets into 10th of a grain groups and plotted the results on the graphs below. As you will see each coloured bar represents the number of pellets that fell into any given 1/10th grain bracket ie: in the JSB Exact .177 graph: 32 pellets weighed between 8.30 and 8.39 grains (orange bar). The figure on top of each bar represents the number of pellets in each bracket as a percentage of all the pellets weighed, so in this case 32 pellets was 29.91% of all the JSB Exacts that I weighed.
These are the pellets tested in .177 from samples of at least 100 pellets:
JSB Exact
Air arms Field
H&N F&TT
H&N F&TT Green
Pax Defiant
Daystate Rangemaster
Webley Mosquito Express
Daystate FT
Bisley Magnum
Pax Thunderbolt
RWS Superfield
Crosman Premier 7.9gr
Crosman Premier 10.5gr
Crosman Premier 7.9gr
Crosman Premier 10.5gr
The JSB Exact with a published weight of 8.44gr showed a heaviest pellet at 8.63gr and lightest at 8.24gr which is a difference of 0.29gr which represents a 3.5% variation in the pellet weights.
The Air Arms Field with a published weight of 8.44gr showed a heaviest pellet at 8.63gr and lightest at 8.27gr which is a difference of 0.36gr which represents a 4% variation in the pellet weights.
The H&N F&TT – published weight 8.5gr - showed a heaviest pellet at 8.65gr and lightest at 8.48gr which is a difference of 0.17gr which represents a 2% variation in the pellet weights.
The H&N F&TT Green – published weight 5.56gr, showed a heaviest pellet at 5.65gr and lightest at 5.55gr which is a difference of 0.1gr which represents a 1.8% variation in the pellet weights.
The Defiant showed a heaviest pellet at 7.62gr and lightest at 7.39gr which is a difference of 0.23gr which represents a 3% variation in the pellet weights.
The Daystate Rangemaster showed a heaviest pellet at 8.52gr and lightest at 8.43gr which is a difference of 0.09gr which represents a 1% variation in the pellet weights.
The Webley Mosquito Express with a published weight of 7.9gr showed a heaviest pellet at 7.99gr and lightest at 7.70gr which is a difference of 0.29gr which represents a 3.7% variation in the pellet weights.
The Daystate FT showed a heaviest pellet at 8.63gr and lightest at 8.24gr which is a difference of 0.39gr which represents a 4.6% variation in the pellet weights.
The Bisley Magnum showed a heaviest pellet at 10.25gr and lightest at 10.02gr which is a difference of 0.23gr which represents a 2.3% variation in the pellet weights.
This zinc super lightweight pellet from Pax, the Thunderbolt, published weight of 5gr, showed a heaviest pellet at 5.02gr and lightest at 4.95gr which is a difference of 0.05gr which represents a 1.4% variation in the pellet weights.
The RWS Superfield with a published weight of 8.4gr showed a heaviest pellet at 8.64gr and lightest at 8.32gr which is a difference of 0.32gr which represents a 3.8% variation in the pellet weights.
The Crosman Premier 7.9gr showed a heaviest pellet at 8.07gr and lightest at 7.76gr which is a difference of 0.31gr which represents a 3.9% variation in the pellet weights.
The Crosman Premier 10.5gr showed a heaviest pellet at 10.70gr and lightest at 10.19gr which is a difference of 0.51gr which represents a 4.8% variation in the pellet weights.
What does the % variation figure tell us:
The % variation figures give us a measure of the range of weights that you could expect to find in any given tin of pellets as a percentage of the weight of the pellet in question. It is a measure of the consistency of manufacture but not necessarily a measure of how “good” a pellet is overall. It is only part of the picture.
However, % variation is potentially very useful because it tells us if there is a possibility that one or two much lighter or heavier pellets are lurking somewhere in your tin. So if they do prove to be significantly different enough in weight to effect the accuracy, then that is important and would justify getting out the scales!
The question now is: does it make any difference to accuracy?
Next is some testing to see how much, if at all, these levels of weight variation effect the consistency of a pellet.
I attempt to answer this by carrying out accuracy tests at different ranges using any given pellet in their 1/10th grain groups. If there are going to be differences due to weight they will probably only start to be significant at the extremes of range, so for sub 12ftib rifles I test at 45yds and 55yds.