VALUE FOR MONEY
JSB Exact Jumbo Heavy 18.13 Grain pellets are a high quality pellet from the famous Czech manufacturer. As we can see from the chart below, they’re not much more expensive than the Median (average) price for .22 caliber lead pellets at just 4.40 cents each in a 250 count tin. This makes them excellent value for money.
In fact, if they are purchased in a 500 count tin, the price per pellet falls to just 3.70 Cents each, actually below the Median price per pellet. Predator International, the US distributor of JSB products, says these are their best-selling .22 caliber pellets. It’s easy to see why!
BUY FROM PYRAMYD AIR
JSB Match Diabolo Exact Jumbo Heavy .22 Cal, 18.13 Grains, Domed, 250ct![]()
BUY FROM AIRGUN DEPOT
JSB Jumbo Heavy 18.13 Grain 250 Count
TEST DATA SUMMARY
| Price per Pellet | 4.40 cents |
| Most Common Weight | 18.15 Grains |
| Pellets at That Common Weight | 18% |
| Variation in Pellet Weight (Smallest to Largest) | 2.23% |
| Most Common Head Diameter | 5.52 mm |
| Pellet at That Common Head Diameter | 54% |
| Variation in Head Diameter (Smallest to Largest) | 0.36% |
| Most Common Length | 7.77 mm |
| Pellets at That Common Length | 38% |
| Variation in Length (Smallest to Largest) | 1.81% |
COMPARISON TO MAKERS CLAIMS
The manufacturer claims that JSB Exact Jumbo Heavy pellets have a weight of 18.13 Grains. The sample of these pellets tested by HAM gave an average of 18.15 Grams – just 1.1% less than the specification.
HAM found that there were 249 pellets in the tin we tested. One short of the claim. In our experience, this is very unusual and we wouldn’t get too excited about it.
Head diameter is given as a nominal 5.5 mm. In fact, the average – and most common – head diameter of the JSB Exact Jumbo Heavy 18.13 Grain pellets tested by HAM was actually 5.52 mm.
JSB does not publish Ballistic Coefficients for its pellets. However, HAM testing established a BC of 0.035 for these pellets.
CONSISTENCY
No damaged pellets were found in the tin of JSB Exact Jumbo Heavy 18.13 Grain pellets.
As we can see below, head diameter was well controlled, with 54% measuring 5.52 mm in the sample of 50 pellets tested by HAM. This is good consistency from the price being asked.
As usual, weight was somewhat more variable. The most common weight per pellet was 18.15 Grains, with 18% of the pellets tested having that weight.
The variation between the lightest and heaviest JSB Exact Jumbo Heavy pellets tested was 2.23%. This is rather better than average, based on HAM’s highly standardized, precise test protocol.
As always, all weights are measured using on Hard Air Magazine’s incredibly-precise, laboratory-grade milligram balance. This is so sensitive that it even registers a person’s breath! That’s where HAM tester Doug Wall’s many years of research laboratory experience is vital for achieving such accurate measurements…
Normally in HAM testing, we find that pellet lengths are the least consistent. However, the JSB Exact Jumbo Heavy 18.13 Grain pellets showed good length consistency. As many as 38% of the tested pellets had a length of 7.77 mm. This is a very high figure!
The difference between the shortest and longest pellets tested by HAM was 1.81%. Again, this was a good result.
DIRTINESS
The JSB Exact Jumbo Heavy 18.13 Grain pellets tested by HAM had a total of 0.160 Grains of dirt per 100 pellets. Again, this is a good (low) figure.
Some residual dirt and dust is an inevitable part of manufacturing any lead pellets and a certain amount of it inevitably finds its way into the tin. The photograph below shows the amount of this “junk” which resulted from carefully washing these pellets.
DOWNRANGE PERFORMANCE
As usual, the HAM Team has used the Chairgun ballistic software application to derive the downrange performance of JSB Exact Jumbo Heavy 18.13 Grain pellets.
As we can see, the relatively low power of our “1,000 FPS standard” Beeman 1074 air rifle, gave a rather curved trajectory. However, this would be much improved with a more powerful gun.
Sighting-in at 30 Yards gives effectively “flat” shooting from 9 to 33 Yards.
HUNTING USE
The high Ballistic Coefficient of 0.035 means that JSB Exact Jumbo Heavy 18.13 Grain pellets slow down gradually with distance. This means that they retain a considerable amount of energy downrange. In fact as much as 70% of the Muzzle Energy is still retained by the pellet as far out as 55 yards downrange.
Combined with the relatively-high his means that these are a great choice for airgun hunting in .22 caliber.
Penetration into our standard ballistic soap block was a long 46mm using the Beeman 1074 air rifle. The diameter of the entry hole was 7.0 mm.
The photograph below shows the fired pellet after extraction from the soap – right. As we can see compared to an unfired pellet, the head diameter increased from 5.52 mm to 5.58 mm. At the same time, the length shortened from 7.78 mm before firing to 7.49 mm.
BUYING AND OWNING
JSB Exact Jumbo Heavy 18.13 Grain pellets are readily available online, although you’re less likely to find them in a big box sporting goods store.
The pellets are well-protected in transit by a foam disk in the top of the tin. However – as always – we struggle with JSB’s standard push-top tins. A screw top would be much appreciated by most shooters, we believe.
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 Match Diabolo Exact Jumbo Heavy .22 Cal, 18.13 Grains, Domed, 250ct![]()
BUY FROM AIRGUN DEPOT
JSB Jumbo Heavy 18.13 Grain 250 Count
Understanding HAM Pellet Awards
HAM Pellet Awards come from the most rigorous, professional and comprehensive pellet testing by any independent publication. They are the result of much precise measurement and analysis using high precision measuring devices and highly-experienced testers.
Note that accuracy is a product of the complete “system” of airgun, scope, atmospheric conditions and shooter ability – not the pellet alone.
This means that no pellet test review can predict the accuracy of a particular pellet with YOUR individual air rifle. That’s why we do not measure accuracy in these pellet tests.
What HAM Pellet Awards do recognize is manufacturing consistency. Inconsistent pellets definitely will be inaccurate, consistent pellets are much more likely to be accurate.
HAM Awards also recognize value. There’s considerable variation in the price of airgun pellets. This means that an 8 cent pellet needs to score higher than a 2 cent pellet to achieve an award.
For full details of the HAM Pellet Award scoring methodology, please check out our Pellet Testing page.
For a full listing of HAM-tested Ballistic Coefficients, please see our Ballistic Coefficients page.
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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