OK, one last item. I read through all the Monster Muley posts and post #49, I remember this now from buying Savage parts at SSS.
49. "RE: Savage 116 keeps blowing up"
Here is what I found regarding changes made to the Savage 300RUM series bolt heads.Courtesy of Sharp Shooter Supply. . Firing Pins & Bolt Faces
Over the last several years Savage has incorporated some design changes that need to be addressed in order to acquire the correct parts for your Savage rifle project.
For the last several years, Savage has used a smaller diameter firing pin on their magnum caliber rifles. The reason behind this is the bolt head retaining pin can use a small diameter through hole which makes it stronger. The standard caliber firing pin measures .145" in the area it would pass through the cross pin, the magnum pins are .095" in that area. Because the firing pin diameter is smaller, the cross pin hole is smaller. So is the the diameter of the hole through the bolt head.
Starting in 2001, Savage firing pin diameters were reduced on ALL models. Therefore, when ordering bolt heads it is important to know what diameter firing pin you have to work around.
On the WSM and UltraMag calibers, Savage changed to a controlled round feed bolt head in order to provide reliable feeding from the magazine. This bolt head differs from the rest by having the bottom lip cut away from the bolt face so that the cartridge rim can slide into the extractor instead of snapping over the extractor. Instead of a spring loaded ejector in the bolt face, this bolt head uses a standing ejector located at the rear of the receiver that pops up through a slot on the bottom left side of the bolt head to tip the case out. This is the only way to get the larger cases to feed from a magazine. Also... Barrel Shanks
In 2002 Savage offered rifles in the Winchester Short Magnum (WSM) and Remington Ultra Magnum (RUM) calibers. When these were finally in the catalog, there was a change made to the barrel shank diameter. Standard barrel shank diameter on standard calibers are 1.055" x 20tpi. On the new WSM, RUM, and SAUM calibers it is 1.120" x 20tpi. The barrel nut is also bigger in internal size, but is the same outer diameter and our barrel nut wrench will still fit. Savage also used this size of shank on the first version of the Model 10ML muzzleloader.
However, there were a few WSM and RUM rifles made on the standard barrel shank in the first production run. The best way to tell is to measure the barrel shank right against the nut. The larger barrel shank will have a step down approximately 1/8" ahead of the barrel nut. If your rifle has a serial number with a "G" prefix, it is most probable it will have the larger shank.