Had two strange occurrences while shooting some reloads at a range last week.

I fired 10 reloads each of a 7.62x54R load using Varget, IMR 4895 and BL-C(2) and ten reloads of a .303 Britishicon using BL-C(2).

The last fired case for the 7.62x54R using 41.0 gr. BL-C(2) (starting load as listed in the LEE "Modern Load" manual). and a 150 gr (.312) Hornady SP exhibited an elongated dimple in the brass starting at the shoulder and running aprox. 3/8" length, 1/8" deep and 1/8" wide. The brass used was twice fired PRIVI PARTIZAN brass. The brass was neck sized only. The firearm used was a Mosin-Nagant M91/30 rifle. I had fired this rifle many times using mil surplus and reloads. I have never seen a dimple appear in any brass using mil or the reloads using IMR 4895 or VARGET.

I then fired 10 reloads of .303 using 42.0 gr. BL-C(2), 150 gr PRIVI PARTIZAN FMJ, The ninth fired case exhibited a similar elongated dimple but slightly deeper. The brass used was unfired Remington (thin brass) brass that had been neck sized only. After the 10 reloads, I fired 20 rds of PRIVI PARTIZAN , .303, 150 gr. SP BT. There were no dimples in the brass after fired. The firearm used was a No. 4, Mk 1* (Savage) Enfield.

I have always used IMR 4895, IMR 4064, AA 2460 and Varget powders in the older mil rifles. This was the first time I have ever used BL-C(2) powder. I only purchased this powder because I have not been able to find IMR 4895 or H4895 powders.

I have never seen the elongated dimple appear in any rifle or pistol reloads, ever. I am wondering if anybody has had this experience before, why it would happen. I am wondering if the BL-C(2) powder has something to do with it. I was going to do some .223 and .308 loads with the powder but am holding off to see if anybody might know if the powder is the cause or what else might be the cause. Hopefully someone has some info.
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