Quote Originally Posted by yobuck View Post
Interesting post.
I agree on the Rem action as for the larger cases, and it puzzles me as to why the cartridge designer of the 300/338 Norma chose to use a 700 action?
Explain large? As in custom? Or as in bolt diameter?
No clue as to your question on why a cartridge designer of the 300/338 Norma and or Lapua cases would’ve used a 700 type action. If memory serves me right the first commercial type rifle chambered in 338 Lapua was the AI L115a3. I don’t recall the receiver/barrel thread specs off hand but I do know even the older AI rifles had bolt with larger body diameters than a Rem700 or a Savage 110 or Win.70. The AI bolt and again going off of memory has like a .775” or .800” bolt diameter. I’ll have to measure one to be sure but that is bigger then the .700” diameter of the Rem. Or Sav. Bolt body.

You have actions now a days with a larger receiver tenon thread like the Stillers Tac30, Surgeon XL etc...that use a 1.125” diameter thread. So usually the breech diameter of the barrel starts out at 1.3” to 1.350” and can usually go up a little more. The BAT Model M action has a 1.125” thread as well. My take on having a larger receiver/barrel thread gives you more meat (wall thickness) from the id to do of the bore to the barrel. Some actions with the larger tenon threads also ending up having a larger diameter to the bolt as well.

To me having this extra meat from the bore to od of the barrel and a bigger bolt diameter/bigger lugs gives you more surface area for strength. Also with the pressures that some of these rounds are running at with the larger case diameter....the larger barrel diameter to me gives/stretches less per say. So case/chamber expansion is less or per say equal to a standard caliber/action set up. This helps keep case expansion in check and to me helps reliability and you will see it at times when you reload/resize the cases.

Apply the same logic to reloading/sizing dies. When you start getting into the 338 Lapua and bigger cases the standard 7/8-14 threaded sizing dies are known to crack. Also the more problems with guys getting the cases stuck in the sizing die. It’s usually not if they will it’s when they will. It’s all stress and something has to give.