Pierced Primers on 2nd Firing - New Build

[lazyMlazyK]

I may have found another piece of the puzzle. I got out the loupe that I use to inspect bevels on my straight razors, and took a closer look at the firing pin. Found a small tit on the end of the pin. Sanded it smooth with some 1000 grit wet/dry sandpaper. I've got a pin protrusion tool coming in the mail now, going to set the pin protrusion just right and try another few shots once it warms back up. We're currently in a freak spring blizzard with no travel advised.

 

[Catfur]

We're currently in a freak spring blizzard with no travel advised.

Hogging all the moisture...

 

[Dusty Stevens]

Before i jump on the bandwagon here i gotta ask my questions. How many times did you clean while shooting that 100rds? Before you went back the second time how did you clean your barrel? Did you feel a tight spot in the first few inches? Brings me to my next question- did you put any type of oil down your barrel and possibly got some in your chamber or did you clean the cases with a solvent after lubing and loading them?

 

[M-61]

I'm very aware that H4350 and IMR4350 are not the same, and load data is not interchangeable. I only use H4350 data.

I wanted to bump the shoulders back to ensure they would chamber in case there was any dirt or debris that found it's way into the chamber throughout the day at the match.

I'm looking into options now to have the bolt head bushed and firing pin inspected.

I have never heard of bumping in anticipation of dirt or debris.

 

[lazyMlazyK]

Before i jump on the bandwagon here i gotta ask my questions. How many times did you clean while shooting that 100rds? Before you went back the second time how did you clean your barrel? Did you feel a tight spot in the first few inches? Brings me to my next question- did you put any type of oil down your barrel and possibly got some in your chamber or did you clean the cases with a solvent after lubing and loading them?

I cleaned between rounds for the first 20 rounds, then shot 34 more for load workup (and a couple just for fun ) Then shot to a round count of 134 without cleaning, then shot the rounds shown with the pierced primers. I don't clean my rifles religiously, only when I notice a difference in accuracy or notice copper fouling near the crown. I don't yet own a borescope, and that's probably a good. My OCD wouldn't let me sleep at night if I had one! I don't remember feeling a tight spot in the first few inches, but that doesn't mean there wasn't one. I don't think it's possible there was oil in the chamber when these rounds in the picture in this thread were shot. If anything, there was a bunch of dirt. Wind was blowing from behind us on the firing line, and it was required to remove the bolt after firing your rounds, and leave it out until you were up to shoot again. I covered up the action the best I could with a sweatshirt, but I'm sure it wasn't a perfect solution. I as also shooting prone.

Cases were not cleaned with any solvent, and all lube was rubbed off well with a rag before loading.

@Dusty Stevens - are you inferring that a dirty bore could be increasing pressures?