Opinion & Analysis
Callaway R&D Director on the XR irons, 360 Face Cup
Scott Manwaring, Callaway’s director of R&D for irons, hybrids and wedges, has been with the company for nearly two decades, and he’s worked in club design since the mid-2000s. He’s seen a lot in his time at the Carlsbad-based company, which under the direction of CEO Chip Brewer, is putting product front-and-center, according to the R&D specialist.
The company’s latest product to stand front and center: Callaway’s XR and XR Pro irons with Callaway’s Face Cup 360 technology.
Manwaring, who graduated from Brigham Young University with a degree in mechanical engineering, said he was incredibly proud of the new XR and XR Pro irons, which were the focus of our conversation.
Note: Topics in bold with Manwaring’s replies beneath
Callaway’s primary focus, how it influences product
The broad umbrella changed with Chip coming here. He said, “Be proud of the product that you’re creating.” Before, it was a lot more nuanced and complicated.
Chip is driven on the product front. Callaway spends more than $30 million per year in R&D, so that philosophy comes from Chip himself: Be proud of it. Drive every last detail, do it as quickly as possible.
That has to drive its way into every category. With the X Hot fairway wood, we took it all the way to the finish line. The next year, we said, “Let’s get the hybrids.” This was the first year that that mantra really hit irons. I obviously had a lot going on, and we’re trying to change a lot of products, but you can only turn a boat so fast; this is the first year we said, “Let’s really drive it home in irons.”
Developing the XR Irons
On the Apex iron, where your COGs are a lot higher, it’s easier to fix that one. When you get down to the $799 category, you have to think a lot harder about every nickel you spend and why you spend it to give the consumer the best value and also make a product you’re proud of. That just takes a little more time and effort.
Just to give you a perspective of what a pain in the a** this iron was to make: We did eight prototyping iterations with the suppliers alone — You know, get the part back, test it, change it. That is at least five or six more than we would normally do. That doesn’t even count internally. We did about four or five…using our own machines.
Addressing concerns about hot spots
We were aware of the complaint. From our position, a common complaint is just an opportunity to do something completely different and completely out of the box.
You have this opportunity with Chip coming on board and saying, “Do something different…do something that you’re proud of. Do something that’s harder.”
You have this great opportunity to break the problem up and really dig into every detail…and think in different ways to tackle all those items.
An overview of Cup 360 technology
Talking about the 360 cup face: By separating an iron into two pieces, you inherently increase the complexity and the cost. And when you weld two similar materials, it’s kind of counter-intuitive. But we needed to cast the face independently because we needed control of every…point on the back of the face.
We needed to control the thickness at every location to avoid changes in thickness that create hotspots.
You’re seeing a lot of companies take the easier solution and not keep the CG in the optimal spot, because they know they need to control face. And you see them taking the simple solution and not worrying about the thickness.
You’re still using the same FEA tools and all the stuff you’ve used in the past, but when you do things like this…when you’re trying to get the distance, plus maintain consistency, your material properties become way more critical. So all your analysis tools start to struggle. You pick up failure modes that are somewhat unexpected.
I think one aspect that’s kind of lost on everybody here is when we did the face cups on the fairway woods and the hybrids, you had this eggshell principle going on where it was a closed-back system…it was naturally stronger and thicker.

Callaway’s X2 Hot and X2 Hot Hybrids (2014) brought the company’s face cup technology to hybrids, giving them the 455 carpenter steel faces used on the 2013 X Hot fairway woods.
On a cavity back iron, when you open up the back of that iron, you’re now on a way more flexible system. Dealing with your durability requirements and your strength requirements is a lot more complicated. And when you overlay the cost…you’ve got a real problem.
The face cup, it’s just as critical as the body. When you separate the face cup…it allows you to minimize your hotspots, especially when you cast it, because then you don’t have any machining marks, you’re not dealing with forging or some of the inherent problems that come there with draft analysis and some of the complexity there…and the cost.
The COR testing becomes obvious. You put that cup face on there and your COR gains across the face are just incredible. So the face cup is critical, but then you’ve got to move to the body. The second you…pull the mass away from the face…your center of gravity just climbs immediately…and then you’ve washed out all the gains. So, step two is finding a body design that when all that energy is transferred off the face, it doesn’t die.
The XR Pro
On the Pro, we wanted to not offend PGA Tour players with the thicker top line. Getting that just right—where it still has the durability and still has the ball speed and still has the COR numbers we were interested in, and it still has the CG and can carry the load—it was a challenge.
Your thickness on that top line: As you get that face to transfer energy more efficiently to the ball and ultimately also to the body…it becomes a trampoline. And if you wanted the metal rims around the trampoline to be thinner, the person jumping on it is still transferring the same load, and if you start thinning those rims down too much, they just give out.
So, the Pro iron is an incredible club…some better players hit the Pro farther than they do the standard [XR]. When I was looking at the COR data, I originally thought it was just the offset and they were able to swing at it more aggressively. But…we did a damn good job…it’s incredibly efficient for its face area.
A walkthrough of Callaway’s 2015 irons
With Big Bertha, it’s just “how can we help you?” We’re doing everything we can to help you enjoy the round of golf. We’re going to help you get the ball to fly far. You’re going to have a lot of hybrids in your bag.
With the XR, we intentionally designed stuff in there to help the average golfer that we knew the better player would snub their nose at. But with the XR Pro, Chip said: “You’re not allowed to skimp on the technology.”
In creating the XR Pro, we took everything we learned from the XR—because we did that first—and applied those lessons to the XR Pro in a shape that we knew wouldn’t offend, and it ended up doing really, really well.
The XR is for the center-of-the-green player. The player who isn’t going to work the ball, who just wants to check the yardage and hit it. But in order to help that player along, it requires a certain offset, a certain top line thickness, a sole width to help with turf interaction, a little more MOI. The XR is for that weekend guy that’s out there quite a bit.

At Address: Callaway’s XR Pro (left) and Apex irons.
The XR Pro…was really going after someone who really likes his Apex irons but would like a little more control. We kind of kept the offset; we narrowed the top line back down. We brought the sole width back down…and this is a guy we see wanting to be a pin-seeker, wanting to really go after it…he’s going to be disappointed if he didn’t pull the shot off. So the MOI is a little lower, the top line is a little thinner. The Pro is for someone who I think is truly passionate about their game.
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AVL: My U.S. Amateur local qualifying experience
This past Monday, I played in the U.S. Amateur local qualifier at Rock Creek Country Club in Portland, Oregon. A full tee sheet from 7:30 a.m. to 1:55 p.m., the top 11 scores would make it to the U.S. Amateur final qualifying.
I teed off at 10:48 a.m.. With the 7:30 am tee time, you can get a feel for the leaders’ pace, and they were off and running on the challenging setup at Rock Creek.
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Getting to the highlight of the round on the par five 17th, a drive up the left side and 212 yards left to the front hole location. I took out a 5-iron with plans of middle of the green. The ball ended up 8 feet left of the hole, pin high. A slight downhill putt dropped in for an eagle 3 on the 17th. With the cut line looking to be anywhere from -2 to even par. This was the boost I had been waiting for all day.
With making par from the trees on 18, it was time to wait for a potential playoff with a posted score of one under par 71.
Three hours later, it was playoff time. 8 players for 6 spots. I made par on the playoff hole, which was good enough to advance to the U.S. Amateur final qualifying in July. USGA qualifiers sure deliver on all of the emotions in golf!
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t golf
Mar 3, 2015 at 8:30 am
How much different are these than something like the speedblades? Those have little off set for a GI and pound the ball. Straight too.
Vito
Mar 1, 2015 at 1:19 pm
Just ordered my XR Pro and Apex MB combo set. Now if the snow will just allow me to use them…
Jeff
Feb 24, 2015 at 5:24 pm
Oh great, now I have to throw out my Apex Pros. The marketing on these new iron sets leaves the guys who bought last year’s sales pitch hung out to dry. Basically, last year’s 1200 dollar set is obsolete, because, you know, face cups and stuff. High CT, face cups, progressive this, channel slot that. I hope the garbage man takes my Apex Pros without charging me extra.
killerbgolfer
Feb 24, 2015 at 10:16 pm
I hope not, i just got the Apex forged! I don’t see these really threatening the forged offerings. Until there’s new forged offerings…
Ol deadeye
Feb 25, 2015 at 11:29 am
Well, keeping in mind that the USGA limits the COR of all club faces, I took my 20 yr old daughter(12 handicap) to a big box store. We compared her shots with her Ping G20 seven iron (steel R shaft) and both Taylormade RSi 1 and Callaway XR seven irons. Distance increase? About one or two yards with either club. With both steel or graphite shaft. She preferred the steel shafts. These were 85 grams and Ping steel is about 100. She preferred the impact feel and swing weight of the Taylormade. Enough there to replace her clubs? Not in our opinions.
Ol deadeye
Feb 23, 2015 at 2:04 pm
It would seem that the players most interested in distance with irons would be the better women players. Not granny who retired and took up golf at 65. Younger women who hit an eight iron 110 yards. If the shaft is about the same length but flies the ball ten yards further that would be a game changer.
Roosterredneck
Feb 23, 2015 at 1:12 pm
The 360 club design is not new. Macgregor did this years ago.Yes the thick top line and off set is excessive for me .. Buy a Macgregor model it should be much cheaper.
Teaj
Feb 20, 2015 at 3:37 pm
These things get out there, stronger then your traditional lofts yes but if your looking for a little extra distance with forgiveness and less offset these might fit the bill. They go a little to far for me as I don’t really need to hit my clubs farther but the forgiveness with less offset is something to think about for players not playing as much as they used to but still don’t need offset. Go try it before you knock it, for the right person these would be a great club.
Person
Feb 20, 2015 at 11:52 am
What throws me off about those irons is how round the topline looks from address. Also yes they look just a little too thick for my tastes.
Vincent
Feb 20, 2015 at 10:45 am
Callaway could forget the “Big Bertha” trademark. This is a cannon built and used by the German army against Belgian and French soldiers and fortresses during the First World War. What could we think about a golf club named Kalashnikov?
graymulligan
Feb 22, 2015 at 7:26 pm
If you asked most folks at this point, especially golfers, they would equate the Big Bertha name to the clubs, and not the cannon. It might be a couple decades too late to have this conversation.
gwillis7
Feb 20, 2015 at 10:36 am
Very interesting article. Haven’t had a ton of Callaway gear in the past, but did have the x-hot driver and that thing was a beast. Last couple years they def have made huge strides in woods
Dave S
Feb 20, 2015 at 9:15 am
This probably isn’t the forum to post this, but looking at the top-line pics of these irons, it really struck me. I’ve always struggled with the large off-set that typically exists in a true GI iron. My natural shot shape with irons is right to left, with my miss usually being a hook. I’m not a great player by any stretch (14 hcp) and I’ve been playing the Adams CMBs for three seasons now. I’ve always been a naturally good athlete, but I really don’t play enough to get great at golf (every other weekend in the spring and summer), so I think GI irons could help. BUT, they all have that huge off-set, which with my natural in-to-out swing path, would likely exacerbate my hook. I guess these OEMs have to make a product that fits the majority of mid-high handicappers and their miss is usually left to right… I’m kind of in a weird spot.
Jeff
Feb 24, 2015 at 5:19 pm
Dave, players cavity backs. Less offset, more forgiveness.
CHRIS
Feb 20, 2015 at 8:40 am
Looks like tennis rackets to me, both of them. I just cannot bear to look down and see a topline like that.
Rich
Feb 20, 2015 at 9:11 am
Keep playing your blades mate. I’ll take your money with a set of XR pros thanks.
Mike
Feb 20, 2015 at 9:24 am
Rich you know if you don’t use blades you’re a loser! 🙂 Which I guess I am since I just took delivery of my XR Pros.
Rich
Feb 20, 2015 at 5:14 pm
Yep, I know what you mean Mike. Happy to be a loser. Can’t wait to try the XR pro’s, they look pretty good to me. Happy for all the help I can get these days.
Philip
Feb 20, 2015 at 2:29 pm
Maybe, maybe not – if the guy doesn’t like the look than so what? By the way, I don’t like them too, but whether one plays blades or XR Pros is irrelevant to whether they’ll beat someone else in a match. I’ve played both with players using blades and players using clubs like the XP Pros and the deciding factor of their game has NOTHING to do with what type of iron they play, but whether they know their true yardages and whether they know their weaknesses and play accordingly.
Rich
Feb 20, 2015 at 5:08 pm
Easy there tiger. Just poking a bit of fun. I love blades and have several sets but don’t play them much anymore because my game is not what it used to be. All power to those that can.
XR is King
Feb 19, 2015 at 10:59 pm
The XR irons are going to blow everybody away!!!!! Awesome!!!!
Cyd
Feb 19, 2015 at 10:30 pm
Hit the Pro model further???? Difference in lofts maybe?
Cyd
Feb 19, 2015 at 10:29 pm
Hit the Pro further???? Difference in lofts?
I have a new set of irons for the masses. Guaranteed to add 15 more yards. Of course the lofts are 2* stronger than the previous model so now your 7 Iron is what used to be a 5 iron, the PW is what used to be an 8 iron, so on and so forth.
But by golly I can hit a 8 Iron 190 or more and Hogan or Nicklaus could never do that.
Tom
Feb 20, 2015 at 4:17 pm
Pro is +1* on lofts (weaker) and shorter in length in the long irons (3-6) than the plain XR also lie angles are different between the models.
And yes lofts are stronger than in the 60’s or 70’s but when I can get a 7i launching at over 20* why should I care? As to added length, hey 4 wedges is fine in the bag. (Really only 2 or 3 using old lofts.) So long as my misses are closer in results to solid hits.
BTW: Jack could do that. He choose not to most of the time. I remember him being in trouble at Firestone once and hitting a VERY long 8i. But then that was with far worse equipment esp. balls than today!
Steve
Feb 19, 2015 at 7:33 pm
Xhot line with different colors
LMB
Feb 19, 2015 at 10:24 pm
I’d say that was true for X2 Hot irons but these have legit tech updates.
Tom
Feb 19, 2015 at 7:11 pm
Both the XR and XR Pro swing very nice. (With proper fit.) I get my XR Pro irons next week, my pro e-mailed me they got in and would be available at my lesson on Tue. I’ve been hitting the demo iron and LOVE how it feels/swings, the feed back, and how consistent yardage is between center and off center hits. Callaway was not on my radar when I went to get new irons but these just blew me away! 🙂
LMB
Feb 19, 2015 at 6:36 pm
Sounds like they made the XR first, and then figured out how to make a better version of it when they did the XR Pro…