Coming from many backgrounds starting in a cabinet shop I can honestly say that every material moves be it walnut,plastic,steel,aluminum. One of the very worst is aluminum.
Rutland plywood comes with movement pent up inside from the manufacturer.
If you doubt the last statement, take a 12" X 36" piece of 2" thick material from Rutland and saw it lengthwise through the length of the 36 inches making yourself two pieces of 12 X 36" by 1" thick. The moment those two pieces clear the bandsaw they both instantly bow anywhere from 1/8 to 1/4 of an inch and they keep warping until the stress of manufacturing has been elliminated.
The pretty laminates colors of todays gunstock plywood do NOT come in cross laminate like construction grade plywood. All laminates run parallel! That is why many times when a cutter is making a verticle grip stock it will crack right through the grip area. That and the resin has gotten to hot and made the wood hard and brittle. I worked a number of years in a plywood plant directly after working in dad's cabinet shop.
During the past two decades I have found two materials that were inert and did not move before,during and after machining. One is a bit heavy material designed by Boeing for the aircraft industry about 60 years ago. Extremely tough on carbide bandsaws and carbide endmills so we quite using it. The other I told Jim See about and he is currently making rifle stocks with the material. Besides being the most stable material I have run across to date, it is the lightest after carbon fiber and is as strong as anything one might want to make a gun stock out of and still carry it.
One of the properties of this new material to pass the grading process is it must be submersed in water for 48 hours and not come apart nor soak up water. Some other interesting properties was when the first sheet arrived at the cutters. I got a call from the cutter regarding how absolute flat the material was before during and after cutting from the large sheet 4' X8' into stock sized material. How, after cutting into a stock and submersed in water the stuff did not move. Absolute verticle A2,A5 and Tuley style grip stocks the wrist was virtually unbreakable before any finish was applied.
Ever take one of those pretty laminate stocks, hold it over your head and dropped it on a concrete shop floor? I have and I was not happy with the results. The old walnut stocks are a much better material. The new walnut and maple laminates are even a better more stable material of dried correctly.
Neal