• The Callaway Big Bertha B-21 irons and B-21 hybrids target the highest-handicap golfers who are more dependent on advances in technology to find improved performance.
  • The key technologies in the Big Bertha B-21 iron and hybrids sare: SS21 club faces created using AI (Artificial Intelligence), VTEC (Visible Tungsten Energy Core) and vibration dampening urethane microspheres.
  • For the first time since the X-14 irons (2000), the company is using RCH graphite shafts as a stock option in both the Callaway Big Bertha B-21 irons and B-21 hybrids.
  • Historically, “Big Bertha” denotes a “best of available technologies” product in Callaway’s line-up.

The Callaway Big Bertha B-21 irons and hybrids serve as the brand’s latest entry into the super-game improvement category of equipment.

It’s a no-bones-about-it release that reminds us there’s always a cost-benefit analysis in product design. In this case, the upside is Callaway packs in a lot of its flagship technology in a single offering. The downside? Well, if you’re looking for SGI performance in something that looks more playerish, this isn’t it.

I have to give credit to Callaway for it straightforward and unapologetic approach with Big Bertha B-21. This is a super-game improvement offering with all of the requisite SGI features. This means thicker toplines, mega-wide soles, larger clubheads and big offset.

The Callaway Big Bertha B-21 isn’t billed as anything other than what it appears to be: Equipment that targets golfers who are most likely to find better performance through technological advancements.

Callaway Big Bertha B-21 Irons

The number-letter combination of product names is commonplace in the golf industry. Yet, for some reason, B-21 seems a little Star Wars-ish. I guess after names like Rogue, Epic and Mavrik, Big Bertha B-21 seems mundane. Then again, where do you reasonably go from Mavrik? Big Bertha Complete Rebellion?

Regardless, if the Big Bertha B-21 irons had a theme song, it would be Lil John’s, “Shake what your momma gave ya.”

It’s the “dad bod” of golf equipment. It’s purposely chunky and owns every bit of it. That’s an approach I’ll always support.

In terms of performance, golfers will want to compare Big Bertha B-21 to Mavrik Max. This makes sense as Mavrik Max sits at the very end of the game improvement category. That said, Big Bertha B-21 is more forgiving, higher launching and a bit faster overall than Mavrik Max.

Big Bertha B-21 Features

The AI-designed Flash Face Cup works to give golfers more consistent performance out of each individual iron.

Quick recap: Callaway’s engineers use supercomputers to help construct various designs and internal structures. One of the stated benefits, according to Callaway, is that leveraging artificial intelligence allows it to take less conventional design approaches. Callaway certainly isn’t the only manufacturer that relies on computers to do some of the heavy lifting regarding design iterations. In fact, every manufacturer does this to some degree.

That said, starting with the 2019 Epic Flash line, Callaway has consistently promoted AI as a point of differentiation that it believes provides an advantage over competitors.

Part of what AI allows for is face-specific designs that can vary by loft. In the case of Big Bertha B-21, Callaway prioritized consistent launch conditions in shorter irons while working to create higher launch/spin in longer irons.

Callaway repositioned 40-plus grams of tungsten in the toe area to help pull the center of gravity towards the geometric center of the face. A Visible Tungsten Energy Core (VTEC) is positioned in the low/rear cavity of the iron and helps support higher launch throughout the set.

Urethane microspheres sit inside the cavity, behind the face. The chief purpose of this fancy goo is to dampen unwanted vibration that often occurs as a result of high-speed, razor-thin faces. Because the elastic polymer isn’t entirely solid (microspheres are essentially a bunch of really small air bubbles), it doesn’t resist face deflection. Simply, this means the face can move as much as it needs to in order to maximize ball speeds, with the added benefit of a better feel at impact.


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Callaway Big Bertha B-21 Hybrid

Compared to irons, hybrids have more volume. This gives engineers a larger sandbox in which to play. And within the hybrid continuum, the Big Bertha B-21 is much closer to a small fairway wood than it is to a long-iron replacement. As such, the tech story tends to mirror that of recent Callaway fairway woods.

The Callaway Big Bertha B-21 hybrid features AI face construction, Jailbreak technology, MIM’d tungsten weighting and a T2C carbon crown.

As with the irons, the SS21 AI face prioritizes face thickness with an emphasis on maximizing ball speed.

The other point of emphasis with the Big Bertha B-21 hybrid is harvesting as much weight as possible and repositioning it low/rear in the head. The primary benefit of a low/rear CG location is increased launch for players who don’t generate sufficient swing speed to produce ideal launch conditions.

In club design, weight serves as its own form of currency. Redistributing weight in a clubhead changes the mass properties which in turn alters performance. The lighter a clubhead, the harder it can be to find the additional weight to move around. It’s quite a bit easier to accomplish this in fairway woods and hybrids which are significantly heavier than sub-200 gram, 460-cc drivers. Nevertheless, Callaway generated roughly 70 grams of discretionary weight that is used to create MIM’d tungsten weights to help pull the CG as low/rear as possible.

So, where did the weight come from?

The T2C carbon crown is five to six grams lighter than previous versions. Rather than using an adjustable hosel, Callaway increased the number of discrete lofts. The reasoning for this is two-fold. First, adjustable hosels are heavy and Callaway felt it would be better to use this weight in other areas. Also, Callaway could either increase the offset or include an adjustable hosel but not both. So, it felt the target golfer would benefit more from increased offset as opposed to adjustability.

Specs and Shafts

From a specifications standpoint, the Big Bertha B-21 irons are essentially an oversized version of the Callaway’s flagship game-improvement iron line, Mavrik. The majority of the differences are clearly visible – more offset, thicker topline, longer heel-toe length and a bigger overall footprint.

Then there’s loft.

Static loft is a just a number on a spreadsheet. Moreover, in terms of design criteria, it’s perhaps one of the least important. Ultimately, golfers are better off focusing on the type of shots (launch, spin, descent angle, carry distance, total distance) that specific club generates.

All that aside, the Big Bertha B-21 has a 43-degree pitching wedge, which isn’t as strongly lofted as other irons in the same category. In fact, the Callaway Mavrik pitching wedge is two degrees stronger. I’m not suggesting loft doesn’t matter. That said, it doesn’t matter nearly as much as some would like to think. In general, golfers would be better served by paying attention to basic shot characteristics (launch angle, spin rate, descent angle, carry/total distance) as opposed to any single measurement.


The stock steel shaft in the Big Bertha B-21 irons is the KBS CT80. However, it’s the made-for graphite option that is resurrecting an old and probably nearly entirely forgotten name.

Twenty years. That’s how long it’s been since Callaway last used proprietary RCH graphite shafts in any piece of equipment. In fact, the RCH 99 graphite shafts last appeared in the Steelhead X-14 irons, circa 2000.

In the 1990s, before aftermarket shafts were officially a thing in the industry, RCH shafts appeared throughout Callaway’s equipment line. At that time, mainline shaft manufacturers (Aldila, Mitsubishi, Graphite Design) produced the shafts as private-label offerings directly for the club companies.

Now, it’s back. And theoretically better.

Two decades later, the proprietary shaft market is a mixed-bag, at best. We have a lot of terms that get floated around without any real universal definitions. Made for, real deal, proprietary, co-designed and aftermarket. Sometimes the differences between certain shafts is significant and other times it’s nothing more than a paint job and some marketing gobbledygook.

Anyway, with the RCH shafts in the Big Bertha B-21 irons and hybrids, this is where we stand.

The stock RCH is offered in three weights (55/65/75) in the B-21 irons and in the 65

Why Now?

Callaway says it decided to go a different direction on this release “because we wanted a family of shafts that would work perfectly with the Big Bertha head. We have a lot of shaft knowledge within Callaway and we have worked with shaft companies for years on their designs.”

The first part of the statement is what a majority of companies use as validation of the need for so-called proprietary shafts. The made-for shafts are often painted to look like the more expensive aftermarket version and quite often golfers are none the wiser.

But it’s really the last sentence that piqued my curiosity. Callaway may very well have a boatload of internal staff sailing atop oceans of shaft knowledge. Fair enough. But I’m not sold on the idea that major shaft companies are consulting with Callaway on shaft designs. At least not any more than a shaft company would with any other major equipment brand. Typically, the most important feature of any proprietary, made-for or line-specific shaft is cost, not performance.

Callaway cites a non-disclosure agreement as the reason it won’t state which company is making the RCH shafts, other than it’s “one of the most well-known and respected shaft companies in the market.”

Absent this information, it’s fair to think most golfers will likely associate the RCH shaft with Callaway instead of Fujikura, Aldila or Mitsubishi – which is probably exactly the point.

A Parting Thought

In 1991, Callaway unveiled a 190-cc driver that paid homage to the German Big Bertha howitzer. Since that time, Callaway has used the Big Bertha moniker to introduce key technologies it believes are innovative and impactful. Callaway is quick to cite tungsten weighting and Face Cup iron technology as examples.

So, what do you think?  Does Big Bertha B-21 redefine what golfers should expect from super-game improvement equipment?

Callaway Big Bertha B-21 Pricing, and Availability

The Callaway Big Bertha B-21 irons are offered 4-PW, AW (gap wedge), SW, LW.

The stock steel shaft is the KBS CT80. The stock graphite shaft is a Callaway RCH (55/65/75)

The retail price for a seven-piece set is $899.99 (steel) or $999.99 (graphite).

The Callaway Big Bertha B-21 hybrid is available in 3-, 4-, 5-, 6-, 7- and 8- iron lofts. It is not adjustable.

The stock shaft is a Callaway RCH (65).

The retail price is $249.99.

Retail availability begins Sept. 10.

For more information, visit CallawayGolf.com