Well since you haven't contributed anything to this thread yet, I'll ask you directly since nobody else will answer me.
Can you safely run a rebated rimmed Lapua above standard pressures safely and not worry about bolt lug set back?
Will a standard Lapua shooting a 300gr bullet have the same effect on the bolt lugs as a Lapua shooting a 55gr bullet at equal PSI?
If you take a .223 and add a Lapua bolt face and shoot a 55gr bullet with 25grs of powder will it have the same force applied to the bolt lugs as a standard Lapua shooting a 300gr bullet?
How does recoil transfer AROUND the bolt lugs?
I have read the replies, and it seems all these have been answered, at least from my interpretation. Of course, all of this is applying to a standard rem 700 action.
"Can you safely run a rebated rimmed Lapua above standard pressures safely and not worry about bolt lug set back?"
- Assuming your running within safe pressures for the cartridge components being used, then no, because as stated, it is the case inside diameter that is the "Piston" that applies the force. The "bolt face" term is being used for simplicity sake, as 99% of the rounds that apply to what we are speaking of are not rebated or rimmed enough to matter, and generally have the same or very similar diameter in relation to the case diameter, so we just use the term "bolt face".
"Will a standard Lapua shooting a 300gr bullet have the same effect on the bolt lugs as a Lapua shooting a 55gr bullet at equal PSI?"
-Yes, because the bullet does not have a significant affect on bolt lug pressure. What affects bolt lug pressure is the inside diameter of the case, in conjunction with the pressure that is being ran. What is in front of the pressure is insignificant.
"If you take a .223 and add a Lapua bolt face and shoot a 55gr bullet with 25grs of powder will it have the same force applied to the bolt lugs as a standard Lapua shooting a 300gr bullet?"
- Assuming both are running the same pressure, no, because again, if the inside case body is only a .223 diameter, that is the driving force, or "piston" that is creating the lug pressure. However, if you shortened a Lapua case to the point it would only have the capacity of a standard .223, but same inside diameter of the 338 lapua, then necked it down and ran it at 60,000 psi with a 55 grain bullet, and ran a .338 Lapua at 60,000 psi with a 300 grain bullet, the pressure on the lugs would be essentially the same barring the small variables, such as brass grip on the chamber, chamber grip, and so on.
"How does recoil transfer AROUND the bolt lugs?"
- The recoil is not directly transferred to the lugs because it is transferred from the bullet, to the rifle bore, to the recoil lug, to the stock, to your shoulder, NOT to the case, then bolt face, then bolt lugs, and so on. Another contributing factor to why a 338 LM has the same pressure to the lugs shooting a 300 grain bullet running 60,000 psi as it would if it was shortened to a case capacity of a .223, necked down and shot a 55 grain bullet with 60,000 psi, but yet the recoil would be substantially different, is the amount of muzzle blast and the bore diameter. A larger bore will have more blast come out, and also since more powder was burned, is again likely to have a larger volume of blast, contributing to recoil. That is why recoil is reduced significantly by using a suppressor, the muzzle blast is greatly reduced, thus reducing recoil, so the recoil you feel with a suppressed rifle is almost completely contributed from the bullet transferring it's energy to the barrel as it travels down the bore.
You don't hear of very many issues with lug set back in the many, many .338 Edges or .338 rums on standard 700 actions around, but you hear it relatively frequently with .585 bolt face cartridges of the same performance on the same actions, which there are less of. Also, the reason the 338 Lapua is coming up and not so much the XX-378 wby cartridges, is for simplicity sake, there are far more 338 Lapuas built on rem 700's than there are 30-378 wby's and so on. So I believe just for the sake of conversation, that is the example being used.
Again, this is just my interpretation of the information presented thus far in this thread.
