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By Bat Digest | Last Updated November 17, 2022
Despite a lackluster performance at the box office for BBCOR bats, Mizuno continues to pump out good content–especially in the Mizuno Hot Metal series. We’ve hit the 2021 B21 Hot Metal from Mizuno with three different hitters so far. Each is impressed. In particular, to the exit speeds, they can generate when compared to other name brand bats. We spent time with the 33 and 32-inch in BBCOR and write our review of those bats below. In time, USSSA and USA bats might be coming out too, and we’ll add that to our analysis when we get it.
Our hitters loved the exit speeds. The feel on the bat was good, but nothing to write home about. If you hit one off the end cap, you for sure felt it. But, that’s the type of feedback some players prefer. In terms of straight exit speeds and overall performance in BBCOR, the B21 performed like highly recommended Rock Star.
It swings on the heavier side. Of all the 33-inch bats we measured in swing weight for 2020, the 9500 score on the B21 puts it in the top 5 of heavy swing weights. (We realize this is a 2021 bat, but at the time of release, it was one of the only 2021s around. So, our reference point, for now, is in the 2020 swing weight realm).
In as much as it is a heavier swinging bat, and the fit is just about everything in BBCOR bats, do know you are getting one that’s a bit more difficult to swing than you might hope. See our full list of BBCOR bat swing weights here.
There are plenty of single-piece aluminum bats with a big swing on the market today. Off the beaten path, you can find a bat like the Widowmaker from Anderson. In more traditional routes, look for something like the Omaha or 5150 from Rawlings. As well, our hitters like the Bonesaber from Warstic. Each of those bats listed does a great job on top-end exit speeds for those who can wield them well.
Also, the B21 is a lot like a CAT 8. Both have variable wall thickness and use a single piece of aluminum for the entire bat. Of course, the CAT 8 has some sting dampening technology in the handle, but in terms of barrel and performance, we think they are very similar.
Compared to the 2020 Mizuno Hot Metal, there have not been a lot of changes. It is still a single piece aluminum bat with a big barrel and end load. Expect similar feel too. In either case, expect big hits if you can handle it.
The Mizuno B21 Hot Metal is a single-piece aluminum bat made from a single wall of aluminum. The bat wall adjusts it’s thickness as it moves from the center of the bat to its outsides. This helps increase bat performance outside of the dead center of the bat. Several companies, including the CAT 8 from Marucci and Velo from Rawlings, use a similar tactic.
B20-HOT METAL BBCOR Baseball Bat combines Mizuno’s powerful HotMetal™ single-wall aluminum alloy with innovative CorTech™ technology, which adjusts wall thickness across the barrel to create a high-performance bat with an aggressive sweet spot. Engineered details like an Optimized End Cap create a booming sound, while also increasing the size of the sweet spot to give you the hottest one-piece bat in the game. (source)
The overall rating uses seven different weighted metrics to determine our overall score. Half of total rating comes from the player and our exit speed tests (Player Rating: 25%, Performance: 25%).The other categories are Relevance (20%), Demand (10%), Durability (10%), Resell Score (5%), and Tech Specs (5%).
*: When a bat is denoted by a star (*) it is a preliminary rating. Expect it to be updated as we learn more about the bat and gather more data.
(PlaRa) Player Rating: We measure player rating from user reviews. Those users include our own hitters that we test at the lab as well as reviews we find online.
(ExVe) Performance: Performance measures the exit speeds and distances we capture in our hitting lab with HitTrax using these bats.
(Relv) Relevance: We measure the number of sizes and the MOI of the bat. Bats with a wider range of options get a better score.
(Dmnd) Demand: Demand is measured by consumer sentiment and the buzz around the bat.
(Drb) Durability: A bat’s durability is measured by user reviews as well as feedback from manufacturers.
(ReSl) Resell Score: Based on the price the bats go for used. Higher prices mean greater user demand which means, generally, a better bat. A resell value closer to its original price means a higher score.
(Tech) Tech Specs: We rate the bat on its technological advancements from previous years and compared to the industry at large. This is our chance to reward companies who are trying to innovate.
MOI or Mass Moment of Inertia is a measurement of bat swing weight. This quantifies how difficult it is to swing a bat. The industry often refers to this as things like End Load or Balanced but those words have been overused to the point of meaninglessness. We measure the actual swing weights of each bat we test using the industry-standard pendulum period, balance point, and scale weight. You can read more about that here.
The price is the original MSRP price of the bat.
The types of bats are single-piece alloy (SPA), two-piece composite (TPC), single-piece composite (SPC), hybrid (Hyb.), and wood (Wood). Hybrid bats are made of composite handles and alloy barrles.
The estimated date the bat began distribution.