I have the first foam core Classic Hunter that Gregg made. I just sent it back to him so he could take it to Kalamazoo for others to check out to see what they think. I have several other Shrews, all of them with actionboo cores. The foam is not merely a gimmick. It functions very well and seems to me to be somewhat smoother and faster, probably for the reasons Gregg mentioned above. I also have a number of Morrison bows, some with actionboo cores, some with foam cores and some with foam cores and carbon backing. I can say that I prefer the foam/carbon limbs. The foam core limbs seem smoother to me, and with the carbon backing they are appreciably faster than without the carbon. For the most part, carbon backing only works well with the longbow limbs or with very heavy recurve limbs, but the foam cores are great on both. I have a Classic Hunter ordered with foam/carbon limbs and a Lil Favorite ordered with foam core limbs but not with carbon backing. That will give me every combination of limb materials and designs in the Shrew line except carbon backing with actionboo cores. I probably won't ever order that combination when the foam cores are available.
Ask Bob Morrison about foam cores and carbon backing. He can have any material he wants in his limbs and he says he will never shoot anything but foam cores unless some better material comes along in the future -- and he uses carbon backing on his foam core longbow limbs (but not on the recurve limbs). I have hunted with Bob, and he practices what he preaches. When he shows up at hunting camp he now brings a Mini-14 ILF riser with foam/carbon longbow limbs, and a second Mini-14 ILF riser with foam core (and no carbon backing) recurve limbs. I didn't get to go on the Solana Ranch hunt, but I bet he used the same two bows there.
So, are Ron and Gregg just building the foam core and/or carbon backed limbs on the Shrews as a marketing ploy to supply customers with new materials that are just gimmicks? Heck no. The new materials are tried and proven. They really work and work well. Do you need them? No. The Shrews are all wonderful bows no matter when they were made or what materials Gregg built them with. But if you want a bow that feels a little nicer and performs a little better and you are not adverse to using more synthetics in a trad bow, then you ought to strongly consider the foam cores and/or carbon backing -- assuming also you don't mind paying some extra money for them. Even better, get the Bow Bolt option if you like to travel with your bow. One of my Shrews has a Bow Bolt and now I have ordered the next 2 with the Bow Bolt. It works very well, but it also costs an additional $200.
Just for comparison purposes, my foam core Classic Hunter without carbon backing shoots almost as fast as my Lil Favorite with actionboo core and no carbon backing, both of them being identical draw weights (54#@28"). That's really good, because the Lil Favorite with its recurve limbs is usually significantly faster than a comparable actionboo Classic Hunter. If you get a chance to go to Kalamazoo, shoot my foam core Classic Hunter against an actionboo core Classic Hunter and see what you think. By the way, I have a 29 1/2" draw length, and I believe that the benefits of the foam cores become more obvious as your draw lengthens, which makes sense to me.
Allan