04-17-2020, 12:19 PM
Lemonaid Wrote:grayfox, thanks for the thoughtful, informative replies. I'm still trying to grasp what happens. Explain what you think will happen in my real world example of loading a Barnes 120 match burner with 29.3 grains of RL 15 seated to 2.290 vs. seated to 2.200 as is in the barns load data.
Will seating deeper to 2.200 increase or decrease chamber pressure and/or muzzle velocity?
To add to confusion, take a look at the test #5 data from the bullet jump test at precision rifle blog https://precisionrifleblog.com/2020/03/2...velopment/
Would you say the trend in velocity is going down as the bullet jump increases?
Thanks for the help, I need it!
LA:
You are being paralyzed by technical minutia that has marginal meaning for most chambers and barrels. If you buy a barrel with a minimum spec bore diameter like some Palma barrels, then you need to pay attention to such minutia but those rifles have gigantic actions that can take the excessive pressures of overloads plus minimal diameter bores. Unless your Grendel barrel is really a 6 AR barrel with a Grendel chamber, you won't have a problem providing you follow the data offered in an up to date loading manual. Jam the bullet and you will spike pressures no matter your load. Overload with a Grendel and you invite shearing bolt lugs and or weakening of the receiver.
Look at all the load data on the Grendel and make a rational decision on your powder charge. Seat the bullet off the lands with a safe charge of powder and you will be fine. Although I do not overload the Grendel, it doesn't mean I won't go to a max charge as long as it is in a loading manual from a respected powder or ammunition company. I have a hard time believing anyone could jam enough RL-15 into a Grendel case for it to be dangerous no matter the bullet being used. Been there and RL-15 only gave me slow speeds compared to powders with more bulk density.
LR55