► All
Max OAL barrel testing results are a product of 2 items: how the chamber and freebore have been cut, and the shape of the bullet.
At the maximum permissible OAL, the bullet can foul the barrel in basically 2 ways: on the ogive, and at the shoulder. See the cartoon below...
View attachment 1158574
The XTP, which brings the full bullet diameter out to a sharp shoulder, generally fouls on the shoulder, as per the LH example in the cartoon.
► It's important to remember that the barrel testing results only define the
Max OAL, not
the OAL you want to use. This because SAAMI defines the
Min OAL at 1.240". This leaves you with an
OAL Range, and you are free to choose any OAL within that permissible range. (See the
SAAMI Specs.)
► Lastly, the OAL listed in your load manual is part of
their Testing Report. It is
NOT a recommended or suggested OAL. If that listed number falls within the Max & Min OAL range of
your testing, then you are certainly free to use the listed OAL... but it is
not a recommendation.
Hope this helps.
.