I measured about 0.434" on both beech and syn stocks, which is close to what Matt measured. When I look at the TW and Beech stocks, the Beech is definitely "thicker" in that area. But, what I don't see is a difference between the bottom tip of the trigger blade to trigger guard. ie the gap looks the same with the same action installed in both. I think that means that the trigger assy is not hitting on the stock, the air tube itself is what is controlling the overall height. You could prove/dis-prove with a little dab of putty.This replacement TW stock had the same issue as my first with not having the air tube free floated at the front of the foregrip. Testing with just an air tube and end cap, it looks like it is caused by the top inletting for the tube, near the endcap. It is slightly higher. If I move tube/end cap forward 1", I get a gap at the front foregrip. I do plan to fix that before doing strip and re-finish.
Steady rain here today, so did some work on the stock. Turned out to be two issues causing the pinching at the foregrip/air tube. The second of which might apply to your issue.I sanded out the ridge in the back of the stock, until the tube/cap set correctly, which did allow the gap. But, when I re-installed the action, it was pinched again. OK, wat's going on? I put two small dabs of modeling clay on the ledge where the rear tab of the trigger assy will go. After tightening down the stock lug, there was no contact with the clay. OK, mystery deepens.Then, what I found was the bottom of the trigger assy was hitting on the trigger guard. I suspect the inletting for the trigger guard is too deep. In the photos below, you will see one that looks like it is flush with the stock That picture was taken with the wood screw removed and trigger guard sitting in place on the trigger assy. Another one shows the trigger guard tight to the stock with screw, and you can see a ledge above it. I then put some washers between trigger guard and stock to create a gap from the trigger assy. Two small ones on trigger guard screw, and one larger one at the stock lug location. Tightened down the stock lug, and all seems fine. I have the gap and did the paper test, no pinching. Now, what I think is happening, is when the trigger guard is tightened to stock, prior to action install, and then stock lug is tightened it is pushing against the trigger guard, which is also putting tension on that trigger guard screw, which is in the direction of pulling it out.
Since you have crosman's attention, here is the link to the 1st stock I received: https://www.gatewaytoairguns.org/GTA/index.php?topic=188911.120 Reply #161 is where I received the replacement one.
Mine is all torn down now, to start the striping process.
I measured using the plunge feature on a caliper. Measurements ar subject to keeping it straight, so some error there. The back of the trigger guard where the screw is, can't be measured accurately, due to the curvature of stock. I picked places at the corners of the openings. See diagram below: