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If that was Hornady factory ammo, give Hornady a call before shooting any more of it. Just because it's factory ammo doesn't mean there isn't a problem with the load.
The flattened primers can be caused when there is excessive headspace from a chamber that is too large but still within tolerance or a cartridge case that is under length to the headspace datum line, or both together stacking to cause a headspace problem. Upon firing the cartridge stays put until pressures rise, while the primer backs out, when the case finally backs up against the bolt or breach block,it rivets the primer cup flat.
Your mention of snow may be a clue to another problem. Cold temperatures may have effected the priming mix and/or powder charge resulting in erratic ignition. If the primer squibs, not fully igniting the cold powder charge, the powder partially begins to burn forcing the rest of the charge into the case shoulder and neck, essentially forming a plug. When pressure and heat finally ignites the powder fully, pressure rises dramatically with sometimes disastrous results. This occurs within a few thousandths of a second, and may not be noticed. if there was a noticeable hangfire or double report similar to a very quick flintlock 'poof' 'bang', this is the cause. A flattened primer may also result.
Cold weather can also cause ignition problems if solidified oil or grease in the action retards the firing pin strike. Cold weather rifles are best cleaned of all lubrication and treated with a dry type lube.
Pin holes on primer cup edges are due to weak or understrength primers. I used to shoot competition with 7mm TCU in a Contender, using Remington 6-1/2 primers for their gilt edge accuracy. Nearly everyone would pin hole. The 7-1/2 BR primer would handle the pressure, but the 6-1/2 won matches. Gas erosion from the pin holes ate away at the firing pin bushing, but I accepted that damage and replaced the bushing regularly. On an expensive bolt, that damage would be expensive.
Also, LynnJr is correct. All my bolt actions, except the Savages, are reworked by Greg Tannel including the firing pin bushing installation.
Good luck.
The flattened primers can be caused when there is excessive headspace from a chamber that is too large but still within tolerance or a cartridge case that is under length to the headspace datum line, or both together stacking to cause a headspace problem. Upon firing the cartridge stays put until pressures rise, while the primer backs out, when the case finally backs up against the bolt or breach block,it rivets the primer cup flat.
Your mention of snow may be a clue to another problem. Cold temperatures may have effected the priming mix and/or powder charge resulting in erratic ignition. If the primer squibs, not fully igniting the cold powder charge, the powder partially begins to burn forcing the rest of the charge into the case shoulder and neck, essentially forming a plug. When pressure and heat finally ignites the powder fully, pressure rises dramatically with sometimes disastrous results. This occurs within a few thousandths of a second, and may not be noticed. if there was a noticeable hangfire or double report similar to a very quick flintlock 'poof' 'bang', this is the cause. A flattened primer may also result.
Cold weather can also cause ignition problems if solidified oil or grease in the action retards the firing pin strike. Cold weather rifles are best cleaned of all lubrication and treated with a dry type lube.
Pin holes on primer cup edges are due to weak or understrength primers. I used to shoot competition with 7mm TCU in a Contender, using Remington 6-1/2 primers for their gilt edge accuracy. Nearly everyone would pin hole. The 7-1/2 BR primer would handle the pressure, but the 6-1/2 won matches. Gas erosion from the pin holes ate away at the firing pin bushing, but I accepted that damage and replaced the bushing regularly. On an expensive bolt, that damage would be expensive.
Also, LynnJr is correct. All my bolt actions, except the Savages, are reworked by Greg Tannel including the firing pin bushing installation.
Good luck.
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