Glad that you have all enjoyed the article. Will try and answer some of the questions and comments so far.
Anytime you need to do shaping, it is easier to use the 2x4 or any 'soft' lumber. Plywood can be shaped but it is usually denser and leaves ridges along the harder glue lines. There are also void between the layers which are exposed as you shape the wood. This adds more work and can leave unsightly lines in the finished product.
Solid wood is easier to shape and finish. Use plywood where you need more structural strength and it can be used to create 'flat' surfaces. Ideal places for plywood is making forends wider or in the bottom of the buttstock.
The shilen barrel was simply turned down in a lathe so that is had a constant diameter equal to the muzzle. You can see where the barrel was tapered down in the pics.
Yes, you can modify the rail BUT I didn't have a proper shaper and the Alum is quite hard to sand. I did 'grind' the rails in a few areas to fit. The main reason for turning down the barrel was the keep the rail looking thick and durable. If the barrel channel of the rail was thinned down alot, it would not be very durable and may even get flexible - not very strong.
The location of the pistol grip wood was indexed off the actual grip. I wanted the recess at the top of the grip to flow into the trigger guard giving the illusion of a one piece part or at least a combo that was intended to go together.
A bit of cut/shaping to make it all line up then a solid application of epoxy to hold it all in place. There is a long screw that penetrates the grip handle, mounting block and stock (quite solid in this area). The screw adds some additional mechanical support to bending and twisting. Should help prevent cracks from developing in this area too.
What I hoped to see in this article was some description (&pics) of swapping a savage barrel, timing & replacing the bolt handle, adjusting the trigger and even swapping the bolt face. The article mentioned these activities but lacked any description. I don't discount the article for glossing over these details, just wasn't what I expected.
I decided not to get into descriptions of work that would open myself and this site to liability. Although the work is straightforward to swap bolt heads, bolt timing and barrel swapping, any mistakes or carelessness can lead to injury or rifle malfunctions.
There are other sites and blogs with info and a bit of searching can give you the info you would want. Either that or use a gunsmith to ensure your safety.
savageshooters.com and frankford arsenal/midwayusa have info on the work you are interested in. The trigger manfs include instructions for install and set up.
Bolt timing is adjusting the bolt so that bolt lift is made much easier, smoother. Gets rid of the heavy lift and clunky engagements of the hammer.
Look forward to your questions, comments and most importantly, YOUR PROJECTS.
Get some epoxy, a 2X4 and get creative. There are many gorgeous stocks that started life as a plastic throw away.
Enjoy...
Jerry