VALUE FOR MONEY
JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets have a great reputation for accuracy and consistency among serious airgun shooters. You’ll see them being used by many serious Field Target competitors, for example.
Surprisingly, they’re also not expensive! Just 2.8 cents each compared to the mean price for .177 cal lead airgun pellets of 2.7 cents each. And – of course – cheaper than that if you buy four tins from Pyramyd Air or Airgun Depot and get one for free.
That makes them outstanding value for money!
JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets are of traditional, conventional diabolo shape. They’re made of soft lead.
BUY FROM PYRAMYD AIR
JSB Match Diabolo Exact .177 Cal, 8.4 Grains, Domed, 500ct, 4.52mm![]()
BUY FROM AIRGUN DEPOT
JSB Exact Diabolo 8.44 Grain .177 Cal Pellets, 500 Ct
TEST DATA SUMMARY
| Price per Pellet | 2.80 cents |
| Most Common Weight | 8.40 Grains |
| Pellets at That Common Weight | 20% |
| Variation in Pellet Weight (Smallest to Largest) | 2.52% |
| Most Common Head Diameter | 4.53 mm |
| Pellet at That Common Head Diameter | 80% |
| Variation in Head Diameter (Smallest to Largest) | 0.44% |
| Most Common Length | 6.14 mm |
| Pellets at That Common Length | 38% |
| Variation in Length (Smallest to Largest) | 1.14% |
COMPARISON TO MAKERS CLAIMS
There are few claims made for JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets. The main one is that the pellet weight is 8.44 Grains.
The sample pellets tested by HAM actually had an average weight of 8.41 Grains. That’s just 0.36% lighter than the claim.
The contents of the tin are supposed to be 500 pellets. In the tin of JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets tested by HAM, we received 503 pellets. That’s 0.4% more. As the tins are likely to be filled by weight rather than counting individual pellets, the slightly lighter average weight would almost exactly account for the overage of pellets.
The head diameter of 4.52 mm is indicated on the tin’s base label. However, the pellets tested by HAM had a head diameter of predominantly 4.53 mm when measured using our standard PelletGage. That’s a difference of just under 4 thou.
Here’s JSB’s full claims for this pellet on their website:
” The company’s best seller. It is absolutely the most popular ammunition at present. The weight has been designed so that it agrees with most of the FT air rifles on the market. It is a very functional profile common for the whole Exact series. It owes its stable flying properties especially to the higher weight and the ideal gravity centre placement. The perfect alignment once again guarantees a perfect grouping! “
Of course, accuracy will be a systems combination of pellet and gun – not to mention the scope and shooter. However, widespread experience indicates that JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets are indeed the pellet of choice for many different air rifles. You can see this for yourself in the results of HAM airgun tests in .177 caliber.
It’s very difficult to seriously disagree with JSB’s claims for these pellets.
CONSISTENCY
Consistency of head diameter was well controlled in the JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets tested by HAM. As the chart below shows, 80% of the pellets had a head diameter of 4.53 mm, with 10% each for 4.52 and 4.54 mm. This means that the variation between the smallest and largest head diameters measured by HAM Tester Doug Wall was just 0.44%.
Pellet weight was also well controlled. The average weight of the JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets tested by HAM was 8.41 Grains.
Just 4% actually met the 8.44 Grain weight claim,. However the spread between lightest and heaviest pellets tested was very well controlled at just 2.52%
Length was very consistent also. 49 out of 50 pellets had lengths of between 6.12 and 6.15 mm. This is far tighter consistency than that for most pellets tested by HAM.
The average length was 6.14 mm.
Only one pellet was a “flier” with a length of 6.19mm. This made the variation Between shortest and longest pellets 1.14% – still an excellent figure.
Of the 503 pellets contained in the tin tested by HAM, there was one damaged pellet. This had the skirt flattened, as can be seen from the photograph below. It’s not clear if this was a malformed pellet or the result of damage in transit. At any event, it was easy to identify.
DIRTINESS
A total of 1.018 Grains of lead dust was present in the tin of JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets tested by HAM. This translates to 0.204 Grains of lead dust per 100 pellets. Yet again this was a good performance by these pellets.
DOWNRANGE PERFORMANCE
HAM generated a Ballistic Coefficient for JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets pellets of 0.019.
Fired from our standard Beeman 1074 “1,000 FPS” pellet testing air rifle, this gives effectively flat shooting between 11 and 41 yards, with a zero range of 41 Yards.
As always, this data is produced from the Chairgun ballistics application.
HUNTING USE
Although not specifically intended as a hunting pellet, 70% of the original Muzzle Energy is retained out to 27 Yards and 60% at 40 Yards. This provides the potential to use JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets for hunting at short- to mid-ranges with an air rifle of appropriate power.
Penetration into the ballistic soap block was 56 mm. The entry hole of the wound channel was 7 mm in diameter.
When extracted from the soap, the fired pellet was seen to have expanded in diameter from 4.53 mm to 4.69 mm. That’s an expansion of 3.5%. The pellet shrank in length from 6.13 mm to 5.47 mm, as can be seen from the photograph below.
BUYING AND OWNING
JSB Exact Diabolo 8.44 Grain .177 caliber airgun pellets will not be found in big box sporting goods stores. However, they’re readily available from just about all specialist online airgun stores.
There’s a disk of foam padding inside the tin to help protest the pellets against damage in transit.
The only downside to these pellets is the push top tin. It’s best to transfer them to a spare screw top tin or other pellet container to avoid potential disasters in the field when trying to open JSB’s standard tins.
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 .177 Cal, 8.4 Grains, Domed, 500ct, 4.52mm![]()
BUY FROM AIRGUN DEPOT
JSB Exact Diabolo 8.44 Grain .177 Cal Pellets, 500 Ct
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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