Slight Problem With Swiss Reloads This Past Weekend

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PCCUSNRET

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I loaded up 20 rounds for one of my Swiss K-31's this past weekend using Privi Partizan brass, IMR 4895 powder and WLR primers. Of the 20, 2 failed to fire until I slammed them home with a bit of force. The 2 that didn't fire had only very light impressions from the firing pin on the primer (until I slammed the bolt closed). The rounds seemed to fit in the chamber with no problems, including the 2 that didn't fire. The only thing I did different with these reloads was I tried partial resizing (using a full length sizing die but only resizing the neck down to the shoulder and not bumping the shoulder back any) instead of the normal full length resizing that I tend to do with Swiss rounds. All of this brass was once fired in the same gun I was shooting the reloads. Any ideas as to what may have caused these two rounds not to fire?
 
Thanks! I am pretty sure the bolt was closed all the way. If it wasn't, would the trigger have released the firing pin? I tried pulling back on the firing pin ring and cocking the gun manually several times on both of these rounds thinking I may not had seated the primers deep enough but until I unloaded the round and reloaded it with some force the rounds would not fire. You could just barely see where the firing pin had touched the primer (hardly a dent). I'm guessing that these rounds needed the shoulder bumped back a little after the first firing and I didn't do this. On the brass fired this weekend, from the bottom of the case to where the bottom of the neck meets the shoulder, measures 1.873". On the brass that I resized after being fired once in this gun, measures 1.866. It appears that I must have bumped the shoulder back just a hair. The brass from the rounds that I fired this weekend will "not" fit back in the chamber without some force. Funny, they ejected very easily after being fired. The only reason this concerns me is that it was only 2 of 20 that failed. Had they all failed it would have been a lot easier to figure out what caused the problem. Thanks again!
 
I’ve had failure to fire problems with my 7.5 X 55 reloads as well. The problem was with my sizing practices.

You need to full length resize the cases. When resizing make sure that the bottom of the resizing die contacts that shell holder. You should see no light between them. This should eliminate your problem.
 
High primers. I have had the same problems with PPU brass, particularly with CCI large rifle primers. Get a primer pocket reamer or swaging tool, and it should help you seat those primers properly.
 
FWIW, while pocket reaming 40 pieces of Prvi 7.5 brass last night I was again reminded that Prvi seems to have slightly deeper pockets than other LP brass, at least in that caliber. I don't have any other Prvi calibers to verify but the Sinclair LP pocket reamer would not seat in to it's shoulder in any of the 40 7.5 cases.

On my Graf's headstamp, it does bottom out.

/Bryan
 
Thanks. Good information from all but I just don't see how high primers would have not had at least an indentation on them after 4 strikes with the firing pin. That is what I suspected at first but I just can't see how this would be possible without any marks on the primers until the rounds actually fired. I am going to try full length resizing the same brass and see if I have the same problems this weekend. I am also going to measure the depth of the primer pockets to see if it is possible that the primers are not being seated to the bottom of the pockets with the RCBS hand priming tool. Thanks again.
 
Just wanted to let you know the results from my last trip to the range with this Swiss rifle. This time I full length resized the brass to where the die was set to 1/4 turn more after the die touched the shellholder. I had zero rounds fail to fire out of the 40 that I fired. I still haven't found a decent load for this rifle using IMR4895 and 168gr Nosler BT's. I have just tried just about every recommended powder weight I could find for this round and the best I have come up with so far was 4" groups at 100 yds. I'll give Varget and IMR4350 a try next and hopefully will find some combination that will work in this gun. It shoots GP-11 in one or two inch groups at 100yds on a regular basis so I believe the problem is my reloads and not the gun.
 
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