Senior Member
If the rounds will not feed from the magazine, they are worthless unless you load one round at a time.

Find the maximum length that will fit in the mag and work with that. Start at 2.81 and work down until the rounds feed in and out of the mag without binding.


Senior Member
Went down to 2.77 fed well and got dime size groups, 👍

Every rifle is different. Shooting yours is the only way to find out.

Sounds like a winner. Confidence in that bullet hitting where you want is more important than speed.

Congratulations on the 10 cent groups!


Senior Member
You load manual should have a diagram showing the SAAMI dimensions for that caliber. The COAL shown in that diagram is the max OAL that the mag was designed to work with.

The COAL that Sierra gave cannot be longer than the SAAMI number. If it is, then it's a mis-print and you should call Sierra for the corrected information. They might even send you a new manual.