Hi fellas,

I'm very new to reloading and have a general question in regards to seating depth. I understand that a particular rifle has a certain distance to the lands that will make your rifle shoot most accurately however my question is: Is it possible to go over the SAAMI recommended cartridge length. Also will the pressures change when seating depth changes? Thanks for any help with this.

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Originally posted by BigPW:
my question is: Is it possible to go over the SAAMI recommended cartridge length.

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Yes, but you're limited by the rifle's magazine and throat. Each is an individual and needs to be treated accordingly.

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Also will the pressures change when seating depth changes?

Again the answer is yes, but...
as the O.A.L. increases pressures tend to drop as the "combustion chamber" becomes larger, albeit minutely. Once the lands are reached, however, pressures rise. Under normal condition the primer flash not only ignites the powder charge, it can dislodge the projectile before gas pressure does. This cannot happen when bullets are seated to the lands because the "jump" the bullet would normally have has been removed. In fact nothing happens until enough gas pressure is generated to overcome the resistance of the rifling -thus pressures are higher.
My point? Loading to the rifling with other unknown variables(such as those found in new loads)isn't a good idea. Like any other process in the hand loading game, it must be approached one step at a time.

Thank you Buckshot

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Originally posted by buckshot:

....Under normal condition the primer flash not only ignites the powder charge, it can dislodge the projectile before gas pressure does....

I've witnessed 2 different times, some reloaded (not by me) pistol cartridges without powder; the lead bullet was pushed about 1 inch into the rifling by the only primer force; several years ago I reloaded a handful of 300WM rounds in a hurry , for a test; 1 cartridge had no powder, but the primer couldn't move the bullet.