C.O.L. Issue with .300 BO...

[RLinNH]

I am loading a bunch of plinking rounds for a couple of my .300 Blackout weapons. They are both SBR's, hence 100yds and in. Accuracy isn't the end all here. My issue is that the Hornady Manual calls for an O.A.L. of 2.090. I am loading 150gr FMJ-BT bullets. At that length, the crip isn't catching the cannelure on the bullet. Even at 2.070-2.075, the bullet is seated just far enough for the crimp to just barely catch the cannelure. Think that 20 thousandths shorter will be an issue?

 

[RLinNH]

I am loading a bunch of plinking rounds for a couple of my .300 Blackout weapons. They are both SBR's, hence 100yds and in. Accuracy isn't the end all here. My issue is that the Hornady Manual calls for an O.A.L. of 2.090. I am loading 150gr FMJ-BT bullets. At that length, the crip isn't catching the cannelure on the bullet. Even at 2.070-2.075, the bullet is seated just far enough for the crimp to just barely catch the cannelure. Think that 20 thousandths shorter will be an issue?

 

[RLinNH]

Even at that short length (that cartridge is at 2.072) I feel that I am crimping on the jacket, not the cannelure...

 

[Middle Man]

Not necessary to have the case mouth meet the cannelure. Your OAL and how that effects pressure is much more important. Don’t load them shorter, ignore the cannelure. Many of the bullets we load don’t have cannelure....

 

[RLinNH]

Not necessary to have the case mouth meet the cannelure. Your OAL and how that effects pressure is much more important. Don’t load them shorter, ignore the cannelure. Many of the bullets we load don’t have cannelure....

Now I’m thinking that any cartridge under 2.080 may need to be pulled...

 

[RLinNH]

I’m pulling the cartridges under 2.080. Lesson learned. Only 20ish to pull

 

[Middle Man]

I’m pulling the cartridges under 2.080. Lesson learned. Only 20ish to pull

Yep. Whack ‘em with the kinetic puller and reseat....

Watch out with those 150gn bullets (same with heavy subsonics) and the internal rib in standard AR magazines. Load up four or five in your magazines and look closely at the rounds stacking. The rib normally keeps the 22 caliber bullets tracking up the column in good order. However, it can interfere with heavier, longer projectiles stacking and feeding in the Blackout.