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JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

Overview
Testers

Doug Wall
Stephen Archer

Caliber

.22

Model Number

N/a

Test Date

Dec 6, 2018

Serial Numbers

N/a

Source of Supply

Supplied by Predator International.

Condition

New

We Like

Head diameter consistency
Price
High Ballistic Coefficient

We Don't Like

Weight variation
Push top tin
Head diameter larger than claim

HAM Rating
Comparison to Makers Claims
50%
Most Common Head Diameter
60%
Variation in Head Diameter
70%
Most Common Weight
35%
Variation in Weight
35%
Most Common Length
60%
Variation in Length
40%
Dirtiness
70%
Hard Air Magazine Test Conclusions

JSB Exact Jumbo Diabolo pellets represent good value at a relatively low price. They would be an effective hunting pellet, particularly for more powerful air rifles.

The weight consistency of the sample pellets tested by HAM was not representative of other JSB pellets we have reviewed. Maybe we got unlucky this time?

51%
HAM Rating
You have rated this
Full Review

VALUE FOR MONEY

JSB Exact Jumbo Diabolo 15.89 Grain .22 caliber pellets are priced exactly (pun intended!) at the median cost of .22 airgun pellets. That’s 4.00 cents each for the 250-count tin. They’re also available in 500-count tins, where the price per pellet falls to 3.8 cents.

This makes them good value for money from such a prestigious pellet-manufacturing name.

Even though the pellets tested by HAM were not the most consistent we’ve found from JSB, they still represent good value for money.

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

BUY FROM PYRAMYD AIR
JSB Match Exact Jumbo Diabolo Pellets, .22 Cal, 15.89 Grains, Domed, 250ct
BUY FROM AIRGUN DEPOT
JSB Exact Jumbo Diabolo 15.89 Grain .22 Cal 250 Ct

 

TEST DATA SUMMARY

Price per Pellet4.00 cents
Most Common Weight16.03 Grains
16.19 Grains
Pellets at That Common Weight8%
8%
Variation in Pellet Weight (Smallest to Largest)3.96%
Most Common Head Diameter5.54 mm
Pellet at That Common Head Diameter70%
Variation in Head Diameter (Smallest to Largest)0.36%
Most Common Length7.44 mm
Pellets at That Common Length28%
Variation in Length (Smallest to Largest)2.75%

 

COMPARISON TO MAKERS CLAIMS

The weight specification for JSB Exact Jumbo Diabolo 15.89 Grain .22 caliber pellets is – duhhh – 15.89 Grains. The average weight of the pellets tested by HAM was 15.93 Grains. That’s pretty close.

However – as we can see in the Consistency section below – none of the pellets tested by HAM actually weighed 15.89 Grains.

JSB Exact Jumbo Diabolo pellets are listed by the factory in multiple different head sizes. The test pellets are 5.52 mm diameter, as we can see from the label on the base of the tin.

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

This did not match-up with the head diameters measured by the HAM Team using our standard Pelletgage “go/no go”gauge.

As we can see below, the most common head diameter of the JSB Exact Jumbo Diabolo pellets tested by HAM was 5.54 mm. There were no pellets with the 5.52 mm head diameter.

Precisely 250 pellets were contained in the tin tested by HAM. None of these was damaged in any way, so that aspect of the specification was met exactly.

 

CONSISTENCY

Head diameter of the JSB Exact Jumbo Diabolo pellets tested by HAM showed better than average consistency. The average head diameter was 5.54 mm and this was also the most common diameter. It was shared by 70% of the pellets in the test sample.

The variation between the smallest and largest head diameters was also well controlled at just 0.36%. This is well above average consistency.

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

Unfortunately, weight consistency was not so good. In fact it was rather below par compared to the usually excellent consistency shown by the JSB factory.

As mentioned, the average weight of the JSB Exact Jumbo Diabolo pellets tested by HAM was 15.93 Grains. But the variation in length of 3.96% between the shortest and longest pellets tested was below average. We also – unusually – do not see a very clear Normal Distribution, or “hump in the middle” to the weight chart (as we do with the head diameter and length charts, for the same pellets).

This spread of weights was a large reason why the JSB Exact Jumbo Diabolo pellets tested by HAM rated “only” a Bronze Award.

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

Length consistency was considerably better among the JSB Exact Jumbo Diabolo pellets tested by HAM – with just the single pellet exception you can see below.

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

The average pellet length was 7.44 mm. This was also the average length of the pellets measured by HAM pellet tester Doug Wall.

 

DIRTINESS

The JSB Exact Jumbo Diabolo pellets tested by HAM secured good marks for cleanliness on manufacture.

Of course, there’s inevitably some dust, shavings and other “junk” present from the manufacturing process in tins of lead pellets. However, this amounted to just 0.352 Grains of dirt per 100 pellets in the tin tested by HAM.

Mainly that “junk” consisted of lead dust and some very small shavings, as can be seen from the photograph below.

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

DOWNRANGE PERFORMANCE

JSB Exact Jumbo Diabolo pellets have a higher than average Ballistic Coefficient of 0.031 – as determined in HAM testing. This gives an effectively “flat” trajectory from 9 to 34 Yards, when fired from the HAM standard test rifle, a Beeman 1074.

Of course this would be even longer for a higher-powered air rifle…

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

 

HUNTING USE

Chairgun shows that JSB Exact Jumbo Diabolo pellets retain as much as 70% of their initial Kinetic Energy out to nearly 48 Yards downrange. Again, a benefit of the relatively high Ballistic Coefficient.

This good energy retention makes these pellets suitable for hunting at medium to long ranges.

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

Penetration into HAM’s “ballistic soap” block was 50 mm. The pellet contracted in length from 7.40 mm to 7.00 mm, while expanding from 5.54 mm diameter to 5.60 mm.

Combined with an entry hole of 8 mm diameter in the soap, this further indicates the suitability of JSB Exact Jumbo Diabolo pellets for hunting.

The pellet on the left was retrieved from the soap block. The change in shape of head and skirt are clear, as are the pronounced rifling marks on the fired pellet.

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

 

BUYING AND OWNING

JSB Exact Jumbo Diabolo pellets are readily available online from all the usual sources. Of course, the “buy four tins, get one free” offers from Pyramyd Air and Airgun Depot make the price per pellet even more attractive…

The standard JSB push-top tin – which the HAM Team will never like – protected the pellets well in transit. This was aided by a disk of foam which padded-out any remaining space in the tin.

We suggest transferring the pellets into a screw-topped tin or dedicated pellet holder for use to avoid disasters in the field as a result of dropped pellets. (Been there, done that!).

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

TEST DATA

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

JSB Exact Jumbo Diabolo 15.89 Grain .22 Caliber Pellet Test Review

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 Exact Jumbo Diabolo Pellets, .22 Cal, 15.89 Grains, Domed, 250ct
BUY FROM AIRGUN DEPOT
JSB Exact Jumbo Diabolo 15.89 Grain .22 Cal 250 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.