I apologize in advance for the lengthy post but I’m trying to include as much info as possible.
I’m pretty new to reloading and only load for 1 round, 6 Creedmoor. I recently switched powders from N555 to H4350. I loaded some middle of the road charges from Hornady’s manual and had some minor pressure issues, slightly flattened primers and a bit of cratering. The load was faster than I’m trying to run so I pulled the remaining rounds apart to start over. I loaded a new batch starting at 36.0 grains increasing in .2 grain increments to 37.8 which is at or just slightly above the minimum recommended starting load from three manuals, Hornady, Nosler, and Lyman and well below max. I shot the first five rounds and had an extreme spread of over 100 fps. Some of the rounds chronographed where I was expecting them to at 2940 fps but a couple were much higher. I shot a couple of the other charges with similar erratic results then had a blown primer with a 36.4 grains. It was very obviously way over pressured and the case was stuck in the bolt face. Thinking it was an anomaly I shot a few more rounds than had another blown primer/stuck case. Obviously, I stopped at this point. I thought perhaps I’d loaded the bullets too long and was touching the lands so I duplicated the CBTO measurement of some factory Berger ammo which uses the same case and bullet I’m loading. I fired one round at 36.0 and had a blown primer. I’m at a loss for what is causing this and it’s quite disconcerting as a new reloader. I’ve pulled several of the remaining rounds apart to measure the powder charge and all were where they should be. All rounds were loaded using an Autotrickler with FX120-i. The brass is Lapua on its 5th firing and is sized in a Redding full length bushing die. I’ve never trimmed them, but I measured and all case length is between 1.905 and 1.915 which is within SAAMI tolerances. I’d planned on starting over with new brass as that’s the only variable left I can think of but I need to make sure I’m not missing something else. The rifle is an MPA PMR Pro, the bolt closes on a go gauge and doesn’t close on a no-go headspace gauge and it shoots factory ammo just fine. I’m shooting Berger 109 Hybrid Target bullets and using CCI 450 primers. I’m at a loss as I’ve followed the manuals religiously and never had my safety concerns until now. Thanks for reading and I appreciate any advice.
I’m pretty new to reloading and only load for 1 round, 6 Creedmoor. I recently switched powders from N555 to H4350. I loaded some middle of the road charges from Hornady’s manual and had some minor pressure issues, slightly flattened primers and a bit of cratering. The load was faster than I’m trying to run so I pulled the remaining rounds apart to start over. I loaded a new batch starting at 36.0 grains increasing in .2 grain increments to 37.8 which is at or just slightly above the minimum recommended starting load from three manuals, Hornady, Nosler, and Lyman and well below max. I shot the first five rounds and had an extreme spread of over 100 fps. Some of the rounds chronographed where I was expecting them to at 2940 fps but a couple were much higher. I shot a couple of the other charges with similar erratic results then had a blown primer with a 36.4 grains. It was very obviously way over pressured and the case was stuck in the bolt face. Thinking it was an anomaly I shot a few more rounds than had another blown primer/stuck case. Obviously, I stopped at this point. I thought perhaps I’d loaded the bullets too long and was touching the lands so I duplicated the CBTO measurement of some factory Berger ammo which uses the same case and bullet I’m loading. I fired one round at 36.0 and had a blown primer. I’m at a loss for what is causing this and it’s quite disconcerting as a new reloader. I’ve pulled several of the remaining rounds apart to measure the powder charge and all were where they should be. All rounds were loaded using an Autotrickler with FX120-i. The brass is Lapua on its 5th firing and is sized in a Redding full length bushing die. I’ve never trimmed them, but I measured and all case length is between 1.905 and 1.915 which is within SAAMI tolerances. I’d planned on starting over with new brass as that’s the only variable left I can think of but I need to make sure I’m not missing something else. The rifle is an MPA PMR Pro, the bolt closes on a go gauge and doesn’t close on a no-go headspace gauge and it shoots factory ammo just fine. I’m shooting Berger 109 Hybrid Target bullets and using CCI 450 primers. I’m at a loss as I’ve followed the manuals religiously and never had my safety concerns until now. Thanks for reading and I appreciate any advice.
