Had a few hrs this morning to collect some data on the JSB .22/20.83, aka the “JSB Jumbo Exact Light.” I’m thinking that I’ll just refer to them as “Lights” b/c I can’t think of any other JSB that uses that nomenclature (off the top of my head).
Ballistic Coefficient Test bed is this BRK Ghost.
Reg pressure of 150 b/c it’s set up for .22 Monster Grands and I didn’t feel like lowering the reg pressure for this short test of the Lights. Power wheel on MIN. Barrel is an OEM Ghost barrel. 5 groove polygonal rifling in a 1:30 twist rate. Choked and 23inches long.
First order of business was to gather some speeds at the muzzle. 12 shots over the chrono and those 12 are in column A in the screen grab of the spread sheet I’ll share here in a second. Average was 958-959fps, for about 42.5fpe. I had a larger extreme spread for the muzzle speeds than I’d like to see, likely an artifact of having a reg pressure too high for the hammer strike and this particular pellet. Also hotter than I wanted to test them, but didn’t want to drop the reg pressure so forged ahead at this muzzle speed.
Moved a pellet trap to 29 yards and took 3 shots to see where pellets were hitting, relative to my scope zero for the Grands. That was to prevent shooting my chronograph. Impact point slightly high and slightly left.
Set out the chrono like this……the two “groups” are the 3 poi verification shots, and the 10 shots than went over the chrono right below that. Aim point for the 10 over the chrono was the 8. Didn’t measure, but that 10 shot group is probably about 3/8.”
Then moved the trap to 90 yards. Right next to the steel paddles so I could find poi to help line shots up over the chrono eyes. Took a total of 20 shots, intentionally placing them about 2 inches wide. In the past I’ve had trouble getting shots to line up over the chrono eyes at longer range so took enough shots to make sure that I got a good representation of retained speed at 90 yards. The chrono captured 18/20.
The following spread sheet contains the data from those three chronograph distances.
Column A = all shots at the muzzle
Column B = shots at the muzzle but outliers removed (two lows and one high)
Column D = all shots at 28 yards (just in front of the 29yard trap, 29yards verified with laser rangefinder)
Column F = all shots at 90 yards (90 yards verified with laser rangefinder)
Column G = shots at 90 yards but outliers removed (two lows and one high)
Column H = shots at 90 yards with further outliers removed, essentially the median speed of 90 yard shots
Line 20 = average fps of that column
Line 21 = extreme spread of that column
Line 22 = standard deviation of that column
Line 23 = fpe of the average speed of that column
Line 25 = GA BC of that column (ie BC at 30 yards and BC at 90 yards, differences being how many outliers were excluded) BC calculator used is the “EasyBC” app, and the speed at two distances function.
EBR Card After that I decided I still had time to shoot one EBR card at 100 yards. Top left bull was used for 5 sighters, then shot the next 25 shots as “scored” shots, 5 at each bull and shot in the order of the numbers I wrote on the cardboard backer. Included the backer b/c it’s slightly easier to see the hits than the peach colored paper that ripped. Fresh backer this morning so it has the two 30 yard groups on it, as well as the 20 shots at 90 yards for fps gathering.
3/5 100 yard groups are just a hair bigger than MOA.
The wind picked up a bit towards the end of the 3rd group. Wind was from 8 oclock and quartering out, pushing pellets right and lifting them, as such a wind typically does.
Score was about a 229, depending on plugging.
Impressions and opinions…. I first started getting excited during that 10 shot group at 29 yards. Yes it’s only a short distance, but it’s also a pretty tight group.
Excitement built during the 20 shots at 90 yards. Pellets were going where I wanted them to, as I intentionally scattered them across an area about 2 inches wide to make sure I’d catch enough with the chrono to be useful. There were a couple of those 20 shots that went right into the previous pellet hole that I was aiming for.
I was also pretty dang impressed with how they shot during the card at 100 yards. The wind did lift and push them a bit more than I think it would have in a similar wind if I was using a really good batch of .22/25.4 Monster RDs, but they seem leaps and bounds better than the .22/18.13 at resisting the wind.
42fpe is nothing to sniff at. I was surprised they did so well so fast. I’ve found the 18.1s don’t retain their speed as well. Some guns will shoot an 18.1 really fast, but by 100 yards it doesn’t matter b/c they’ve stripped off a comparable % of their initial speed to where you might as well shoot them at a reasonable 890-920. BUT, the Lights seem to do pretty good at this higher speed.
Ballistic coefficient….couple things here. This is from a slow twist poly barrel at high elevation (5600 feet). When I shoot these from this gun in my area I’ll use a BC of 0.05-0.052. Different barrels and lower elevation are likely not to produce a BC quite that high. A realistic range of 0.046-0.052 is probably very reasonable for the Lights. Which makes them a helluva lot better than a .22/18.13 and perhaps slightly better than a .20/15.89.
I don’t think they’ll turn into a popular option for long range pellet competitions. For anybody still hanging onto .22, they’ll likely use the .22/25.4 Monster RD. And with the new .30 AEA pellets producing BCs up north of 0.07…..I can’t help but wonder if the .22’s days as a viable long range option for pellet competitions is numbered.
The big question is whether or not these .22/20.83 Lights are as good at 890-920 as they were for me at 960 this morning. IF what my prelim data session suggests holds true for them at 890-920 also, this pellet would make a great option for many of those classic .22 PCPs in what has become sort of the midrange power level.
As
@Dairyboy pointed out elsewhere, for what they are, I think JSB hurt sales by pricing them where they did. The serious competitors aren’t likely to buy piles of these to compete with. And the lovers of the .22/18.13 are likely to stick with the more economical option. The flip side of that is that this is an entirely new design, which means new dies, which means these pellets are probably at the pinnacle of their quality. (ie if all of this appeals to you, try a couple tins and if you gun likes em then STOCK up and STOCK UP BIG cuz they’re only going to go downhill in quality, and uphill in price as time goes on). And yeah that’s a bit of a jaded thought, but JSB has done a pretty good job of following that trend so…the truth hurts.
They are much more sippy of the air than this same gun pushing the Grands to the same 960ish speeds. And the report with the Lights was much quieter. That’s a bit of an obvious conclusion I suppose (42 versus almost 60 fpe).
The .22/20.83 grain JSB Monster Light does have a bit more power potential than a .22/18.13, and certainly a better BC. This pellet has my stamp of approval for anybody wanting to eke out more performance from their PCP in the 35-42fpe realm.
With the greater availability of .22 versus .20 pcps, the new .22/20.83 Light is an easier way to get similar performance as I’ve been seeing from the JSB .20/15.89. If I didn't have such a large supply of .20/15.89s, I'd be stocking up on the .22/20.83 Lights.
It’s always good to have options.
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