VALUE FOR MONEY
JSB Exact Premium Diabolo 8.44 Grain pellets are manufactured in the Czech Republic by JSB from soft lead. The shape is a domed diabolo. The MSRP is $14.99 for a pack of 200 pellets.
JSB pellets have a great reputation in the market for quality and consistency. That leads to a high chance of accuracy with many types of air rifle.
At an MSRP of $0.075 per pellet, JSB Exact Premium Diabolo 8.44 Grain pellets are expensive, about twice the average MSRP price per pellet of $0.033 for .177 caliber lead pellets. However, this is still very cheap compared to the cost of alloy pellets. And these pellets are hand-selected for consistency. with an awesome reputation among precision shooters.
BUY FROM PYRAMYD AIR
JSB Exact Premium Diabolo, .177 Cal, 8.44 Grains, Domed, 200ct![]()
BUY FROM AIRGUN DEPOT
JSB Exact Premium Diabolo 8.44 Gr 200 Ct
COMPARISON TO MAKERS CLAIMS
The manufacturer claims that JSB Exact Premium Diabolo 8.44 Grain pellets have a weight of 8.44 grains – 0.547 grams, plus or minus 0.001 gram. This is an incredibly tight tolerance range that it nearly – but not quite – matched by the pellets tested by HAM.
In fact, the JSB Exact Premium Diabolo 8.44 Grain pellets tested by HAM showed an average weight of 0.545 grams per pellet. That’s 8.42 Grains.
The head diameter specified on JSB’s website for these pellets is 4.52 mm. The average head diameter of the pellets tested by HAM using a Pelletgage “go, no go” gauge was 4.51 mm. Again very, very close, but not exactly matching the claims.
The manufacturer also claims that 200 pellets are in each pack. And yes, there were exactly 200 pellets in the package tested by HAM.
CONSISTENCY
Of the 200 pellets in the pack of JSB Exact Premium Diabolo 8.44 Grain pellets tested by HAM, there were zero damaged or malformed pellets. This is undoubtedly due to the hand selection and individual packaging into styrofoam trays in a robust clamshell box.
76% of the JSB Exact Premium Diabolo 8.44 Grain pellets tested by HAM had a head diameter of 4.51 mm. 18% of the pellets had a diameter just 0.01 mm smaller, while 6% of the pellets tested showed a head diameter 0.001 mm larger. This is a very consistent distribution of head diameters!
The average weight of the pellets tested by HAM was 8.42 grains. However, interestingly, none of these individual pellets actually had that specific weight!
The JSB Exact Premium Diabolo 8.44 Grain pellets tested by HAM showed a tight distribution of weight. 16% weighed 8.40 grains, 40% weighed 8.41 grains, 0% weighed 8.42 grains, 30% weighed 8.43 grains, while 12% weighed 8.44 grains. There was one outlier (= 2%) where the pellet weighed 8.46 grains.
Pellet length was also very consistent for the JSB Exact Premium Diabolo 8.44 Grain pellets tested by HAM. The most common length was 5.29 mm: 62% of the pellets measured by HAM were of that length. 22% of the pellets were 5.28 mm long and 14% 5.30mm long. Again, there was just one pellet that measured 5.31mm in length, that’s 2% of the 50 pellets measured.
To put things into perspective, 98% of the JSB Exact Premium Diabolo 8.44 Grain pellets tested by HAM were effectively the same length. That’s 5.29 mm. The variation was less than one third of the diameter of an average human hair (0.06 – 0.08 mm)!
DOWNRANGE PERFORMANCE
Downrage performance of JSB Exact Premium Diabolo 8.44 Grain pellets has been charted using the popular ChairGun ballistics program.
This shows that – for the ” nominally 1,000 FPS” standard air rifle used for HAM testing, if sighted-in at 29 yards, the point of impact would be within plus or minus half an inch on the target at all ranges between 12.0 and 42.7 yards.
The Ballistic Coefficient used for these calculations was found in the ChairGun database. It’s 0.0210.
If you prefer to see numbers rather than charts, here’s the data from ChairGun from which this graph was created.
Range POI Drift Time Vel. Vel. Energy Energy Drop
(Yard) (In) (In) (sec) (Ft/s) (%) (FtLbf) (%) (In)
10 -0.56 -0.20 0.034 846.1 93.7 13.38 87.78 -0.2
15 -0.14 -0.44 0.052 820.6 90.9 12.59 82.57 -0.5
20 0.15 -0.78 0.071 796.8 88.2 11.87 77.85 -0.9
25 0.30 -1.22 0.090 774.4 85.7 11.21 73.52 -1.5
30 0.31 -1.76 0.110 752.8 83.4 10.59 69.49 -2.2
35 0.16 -2.39 0.130 732.2 81.1 10.02 65.73 -3.0
40 -0.14 -3.12 0.151 712.3 78.9 9.48 62.21 -4.1
45 -0.62 -3.96 0.172 693.2 76.8 8.98 58.92 -5.2
50 -1.28 -4.89 0.194 674.8 74.7 8.51 55.83 -6.6
55 -2.13 -5.94 0.216 657.0 72.7 8.07 52.92 -8.2
60 -3.19 -7.09 0.240 639.6 70.8 7.65 50.16 -9.9
HUNTING USE
The Muzzle Energy of the JSB Exact Premium Diabolo 8.44 Grain pellets tested by HAM averaged 15.25 Ft/Lbs. As Muzzle Energy had dropped to just 70% at 30 yards, this should be considered a maximum hunting range for small game in most medium-powered air rifles. Shot placement is likely to be outstanding, if you do your part!
Remember that the JSB Exact Premium Diabolo 8.44 Grain pellet is really a target shooting pellet and not a dedicated hunting round.
HAM tests the penetration of pellets using a standardized bar of soap. A sample JSB Exact Premium Diabolo 8.44 Grain pellet penetrated 47mm into this soap with a straight wound channel, as you can see below. The entry wound had a diameter of 6.0mm. The pellet did not fragment or significantly change shape in the soap block.
BUYING AND OWNING
JSB Exact Premium Diabolo 8.44 Grain pellets are easily available online from the usual sources including Pyramyd Air and Airgun Depot. As you can see, the packaging is exemplary!
As part of this HAM test review, we weigh the total pellet package “as received” and then after washing the pellets. This enables us to discover the amount of lead dust – or dirt – on the pellets.
In the case of the JSB Exact Premium Diabolo 8.44 Grain pellets tested by HAM, the dirtiness of the pellets is just 0.093 grains per 100 pellets. This is extremely low for lead pellets and not much more than that for many types of alloy pellets. This means that these pellets are very clean to handle, even though all appropriate precautions associated with any lead product still must be taken in use.
TEST DATA
For background details on HAM’s Pellet Test Review methodology, check out this link.
Chairgun is a product of Hawke Sports Optics LLC and is used with permission. Check out http://www.hawkeoptics.com
BUY FROM PYRAMYD AIR
JSB Exact Premium Diabolo, .177 Cal, 8.44 Grains, Domed, 200ct![]()
BUY FROM AIRGUN DEPOT
JSB Exact Premium Diabolo 8.44 Gr 200 Ct
This entire article including scoring, data etc is Copyright Hard Air Magazine and may NOT in part or in whole be reproduced in any electronic or printed medium without prior permission from the publisher.
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