09-28-2019, 04:55 PM
A real Grendel bolt is designed to be compatible with standard Mil-Std firing pins, not that there are many of those outside of a few companies.
Remember that there is no set of specs that describes the misnomer, "Type II". Nobody in the industry can tell you what "Type II" means for this reason.
An AR15 Grendel bolt has a deeper bolt face depth to allow for a stronger extractor lip, a different extractor pin location, and a different extractor shelf depth to compensate for extractor snap-over inside the constraints of the AR15 barrel extension Inner Diameter (ID). A Grendel bolt also is longer at 2.810" to bring more tail into the overall length so that Mil-Std length firing pins will not have excessive firing pin protrusion.
Some companies recognized the need for a deeper bolt face depth and spec'd their bolts out that way, but failed to accommodate the standard firing pin parts supply by using a 2.800" bolt length.
The best thing to have is a Grendel bolt with 2.810" OAL, .136" face depth, a certain grade of 9310 alloy heat treated correctly and batch-tested with destructive testing and MPI (not HPT non-destructive).
I like the AA firing pins that have a triangular cross section. That's an interesting improvement to the AR15 firing pin design, not that there have been many problems with FPs once they dropped the heavy head pins from the early AR15 Model 601, which was prone to slam-firing from pin inertia.
Remember that there is no set of specs that describes the misnomer, "Type II". Nobody in the industry can tell you what "Type II" means for this reason.
An AR15 Grendel bolt has a deeper bolt face depth to allow for a stronger extractor lip, a different extractor pin location, and a different extractor shelf depth to compensate for extractor snap-over inside the constraints of the AR15 barrel extension Inner Diameter (ID). A Grendel bolt also is longer at 2.810" to bring more tail into the overall length so that Mil-Std length firing pins will not have excessive firing pin protrusion.
Some companies recognized the need for a deeper bolt face depth and spec'd their bolts out that way, but failed to accommodate the standard firing pin parts supply by using a 2.800" bolt length.
The best thing to have is a Grendel bolt with 2.810" OAL, .136" face depth, a certain grade of 9310 alloy heat treated correctly and batch-tested with destructive testing and MPI (not HPT non-destructive).
I like the AA firing pins that have a triangular cross section. That's an interesting improvement to the AR15 firing pin design, not that there have been many problems with FPs once they dropped the heavy head pins from the early AR15 Model 601, which was prone to slam-firing from pin inertia.
NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
www.AR15buildbox.com