123gr.SMK Ogive

[Old Soldat]

Rifle is 6.5 Grendel 24" barrel. Brass is Alex/Arms trimmed to 1.515". Bullet is 123 gr. SMk with overall length of 1.267", bullet ogive is .603" (using hex comparator nut). Placed bullet in a case that had been slotted, loaded in chamber and closed bolt, repeated this process 10 times. Average COAL is 2.290". OAL (base of brass to point where bullet touches lands) is 1.626"
BUT
same brass and bullet loaded to COAL of 2.260" (magazine max length) gives a OAL of 1.600". Problem is that in a box of 100 bullets the ogive varies as much as .012". If I use 1.600" as a standard, I'll have some rounds that will not fit into the magazine.
RECOMMENDATIONS?

[LR1955]

Rifle is 6.5 Grendel 24" barrel. Brass is Alex/Arms trimmed to 1.515". Bullet is 123 gr. SMk with overall length of 1.267", bullet ogive is .603" (using hex comparator nut). Placed bullet in a case that had been slotted, loaded in chamber and closed bolt, repeated this process 10 times. Average COAL is 2.290". OAL (base of brass to point where bullet touches lands) is 1.626"
BUT
same brass and bullet loaded to COAL of 2.260" (magazine max length) gives a OAL of 1.600". Problem is that in a box of 100 bullets the ogive varies as much as .012". If I use 1.600" as a standard, I'll have some rounds that will not fit into the magazine.
RECOMMENDATIONS?

OS:

Sure. Seat the bullets so they all fit the magazine. And, leave a bit of room between the tips and the inside of the magazine. So, they will seat quite a bit deeper than 1.600.

That said, if your accuracy turns to crap and you can positively attribute it to the bullet seating depth, then use another bullet because you have just proven to yourself that the 123 Sierras are way to sensitive to any slight change for them to be reliable.

One of the things claimed about the compound throat that defines the Grendel chamber is that it is very accepting to many different ogives so you should not have a problem with seating them a bit deeper for reliable magazine feed.

LR1955

[LRRPF52]

Some of the best results I have had are with factory 123gr SMK loads in SAAMI chambers.

Bug hole groups at 100yds from Lilja barreled Grendel. Was wasting time shooting at 100yds really.

Bryan Litz BC on that bullet is .522 G1/.260 G7, quite a bit higher than what Sierra claims and very close to the 123gr Lapua Scenar at .527/.263.