gloob
05-19-2015, 06:40 PM
After finding that cheap 22 Daisy wadcutters shoot really, really well in my rifle, I decided to do some measuring on my pellets.
in 22 cal, I only have 3 pellets.
THE LINEUP
1. CP 14.3 gr domes
2. JSB 18.1 gr Exacts
3. Daisy 22 wadcutter (I weighed at 13.6 gr)
ACCURACY
In order of accuracy, I think CP and the Daisy shoot about equally well in my rifle. The JSB's are not quite as accurate, last I checked, but they aren't bad.
PELLET HEAD DIAMETER and CONCENTRICITY
As far as I can tell, one of the most important things for pellet accuracy is a good fit of the head of the pellet to the bore. So I measured multiple points on the heads of many samples, and this is what I noted.
CP's are measuring the most consistent in diameter, and they are about tied for concentricity. Almost all pellets are measuring 0.216" minimum measurement and 0.216 1/2" maximum measurement when taking multiple measurements around the circumference. Samples were taken from 3 different tins from 3 different purchases in time over about 3-4 years.
The Daisy 22 Wadcutters are the least round, with all pellets showing at least a 1 mil spread between the smallest and widest point on the head. About half the pellets measure 0.214 1/2" on the narrowest point and 0.216" on the widest point. The other half measure 0.215" on the narrowest point and 0.216" on the widest. There are a few pellets that measure up to 0.216 1/2" on the widest point. Pellets were sampled from 10 different tins spanning two orders, but which were close in time. (Once I found out how good these cheap pellets shoot in my rifle, I stocked up!)
The JSB exact were about as concentric as the CP's. Most of the pellets were within a half mil of round, with a few rare ones with a 1 mil flat spot. But the heads had the most variation in head size, and all were much smaller than expected. Most measured 0.214" around (more or less perfectly round with maybe a flat spot at 0.213 1/2"), while there were also a good number measuring as much as 0.215" all the way around. So the JSB probably had the largest variation in diameter with nominally a full mil difference in diameter between some of the pellets (within the precision of my calipers).
Full disclosure: I bought two tins of the JSB in the same order and at some point I mixed them together. So maybe these pellets were from two different lots - a 0.214" lot and a 0.215" lot. But in either case, these particular pellets are plain small. In metric, this is 5.44mm and 5.46mm, respectively. Ted of Ted's Holdover Youtube channel did some measuring on his JSB 18.1 gr pellets, and he had batches at 5.50mm on up to some at 5.53mm. And apparently, in some places in Europe, JSB labels the exact head diameter to a 100th of a millimeter with a sticker on the bottom of each tin. My JSB pellets did not come with that information.
Subjectively, the JSB drops into my rifle's chamber under gravity. The Daisy pellets are a push fit with almost no resistance. The CP's have to be stuffed in.
SKIRT SIZE
I will also note that the CP's have a much bigger variation in skirt diameter than the JSB's. I have segregated my CP's by skirt size, and it doesn't seem to make any significant difference. It seems like the skirt just as to be bigger than the bore by at least a couple, and even the smaller skirted CP's shot fine. I didn't measure the Daisy skirts, because at this point I don't feel like skirt consistency in diameter is very important.
THOUGHTS ON CONCENTRICITY
It seems to be that the lack of concentricity of the Daisy pellets is not making a huge impact on accuracy, probably because the overall size of the pellets is pretty consistent and is the right size for my particular bore, as are the CP's. I wonder if pellet heads shouldn't be oval on purpose. That might make them work better in a variety of bore sizes. If the pellet head were a little too big for the bore, only the ends of the head would have to engrave into the lands, causing less resistance and potential for bending the pellet at the waist. And in a larger bore, the widest portion of the pellet would ride the bore tightly, even if the narrower dimension was slightly small. On another note, I feel like the CP's are still accurate, even though the heads are so tight in my rifle, because the waist is so thick and stocky and the skirts are so beefy. I think the CP's are less likely to tilt the head in the bore and bend the waist if the fit is too tight, compared to a narrow-waisted, delicate skirt design, such as is how I would describe the JSB Exact Jumbo Heavy 18.1, in comparison (if one were to get a tin with too large a head for their rifle, anyway, which is the opposite problem I seem to have with mine.)
CONSISTENT GARBAGE
One day I will sit down and sort my JSB pellets by head diameter and see if the larger ones will shoot better in my gun than the smalls. I have to say, I feel really lucky that my rifle likes Daisys. They are about 1/4 the cost of JSB's and barely more than half the price of CP's. I bought 10 tins, and I measured some samples out of each tin, and they are all essentially the same garbage concentricity but at least consistent in the size of said garbage.
in 22 cal, I only have 3 pellets.
THE LINEUP
1. CP 14.3 gr domes
2. JSB 18.1 gr Exacts
3. Daisy 22 wadcutter (I weighed at 13.6 gr)
ACCURACY
In order of accuracy, I think CP and the Daisy shoot about equally well in my rifle. The JSB's are not quite as accurate, last I checked, but they aren't bad.
PELLET HEAD DIAMETER and CONCENTRICITY
As far as I can tell, one of the most important things for pellet accuracy is a good fit of the head of the pellet to the bore. So I measured multiple points on the heads of many samples, and this is what I noted.
CP's are measuring the most consistent in diameter, and they are about tied for concentricity. Almost all pellets are measuring 0.216" minimum measurement and 0.216 1/2" maximum measurement when taking multiple measurements around the circumference. Samples were taken from 3 different tins from 3 different purchases in time over about 3-4 years.
The Daisy 22 Wadcutters are the least round, with all pellets showing at least a 1 mil spread between the smallest and widest point on the head. About half the pellets measure 0.214 1/2" on the narrowest point and 0.216" on the widest point. The other half measure 0.215" on the narrowest point and 0.216" on the widest. There are a few pellets that measure up to 0.216 1/2" on the widest point. Pellets were sampled from 10 different tins spanning two orders, but which were close in time. (Once I found out how good these cheap pellets shoot in my rifle, I stocked up!)
The JSB exact were about as concentric as the CP's. Most of the pellets were within a half mil of round, with a few rare ones with a 1 mil flat spot. But the heads had the most variation in head size, and all were much smaller than expected. Most measured 0.214" around (more or less perfectly round with maybe a flat spot at 0.213 1/2"), while there were also a good number measuring as much as 0.215" all the way around. So the JSB probably had the largest variation in diameter with nominally a full mil difference in diameter between some of the pellets (within the precision of my calipers).
Full disclosure: I bought two tins of the JSB in the same order and at some point I mixed them together. So maybe these pellets were from two different lots - a 0.214" lot and a 0.215" lot. But in either case, these particular pellets are plain small. In metric, this is 5.44mm and 5.46mm, respectively. Ted of Ted's Holdover Youtube channel did some measuring on his JSB 18.1 gr pellets, and he had batches at 5.50mm on up to some at 5.53mm. And apparently, in some places in Europe, JSB labels the exact head diameter to a 100th of a millimeter with a sticker on the bottom of each tin. My JSB pellets did not come with that information.
Subjectively, the JSB drops into my rifle's chamber under gravity. The Daisy pellets are a push fit with almost no resistance. The CP's have to be stuffed in.
SKIRT SIZE
I will also note that the CP's have a much bigger variation in skirt diameter than the JSB's. I have segregated my CP's by skirt size, and it doesn't seem to make any significant difference. It seems like the skirt just as to be bigger than the bore by at least a couple, and even the smaller skirted CP's shot fine. I didn't measure the Daisy skirts, because at this point I don't feel like skirt consistency in diameter is very important.
THOUGHTS ON CONCENTRICITY
It seems to be that the lack of concentricity of the Daisy pellets is not making a huge impact on accuracy, probably because the overall size of the pellets is pretty consistent and is the right size for my particular bore, as are the CP's. I wonder if pellet heads shouldn't be oval on purpose. That might make them work better in a variety of bore sizes. If the pellet head were a little too big for the bore, only the ends of the head would have to engrave into the lands, causing less resistance and potential for bending the pellet at the waist. And in a larger bore, the widest portion of the pellet would ride the bore tightly, even if the narrower dimension was slightly small. On another note, I feel like the CP's are still accurate, even though the heads are so tight in my rifle, because the waist is so thick and stocky and the skirts are so beefy. I think the CP's are less likely to tilt the head in the bore and bend the waist if the fit is too tight, compared to a narrow-waisted, delicate skirt design, such as is how I would describe the JSB Exact Jumbo Heavy 18.1, in comparison (if one were to get a tin with too large a head for their rifle, anyway, which is the opposite problem I seem to have with mine.)
CONSISTENT GARBAGE
One day I will sit down and sort my JSB pellets by head diameter and see if the larger ones will shoot better in my gun than the smalls. I have to say, I feel really lucky that my rifle likes Daisys. They are about 1/4 the cost of JSB's and barely more than half the price of CP's. I bought 10 tins, and I measured some samples out of each tin, and they are all essentially the same garbage concentricity but at least consistent in the size of said garbage.