Hello, While cleaning after shooting 1500 rnds over a few days I noticed a ring of erosion around the striker slot in the breech face. I had noticed a slight ring before but I am pretty sure the ring became more pronounced in the last few days. The loads used were made with Remington SPP. Since I switched to this batch of primers I have at times noted soot on the back of the brass which appears to be coming back from around the primer. I do not think I have noticed this with reloads before. I just sorted some brass and found 13 rounds with soot out of approx 250 fired. The majority seemed to be Blazer but also saw Speer, Remington and Federal. Gun is a Gen 2 G17 which has been well used. Loads were made with range pickup brass sorted to remove off brands and damaged brass. Remington 1 1/2 SPP (not newly purchased - on the shelf for years), Unique powder, Montana Gold 115gr HP. I worked up to the load over time and it is well within maximum loads in several references. Loads were done on Dillon equipment, with all rounds case gaged. I suspect that the erosion is being caused by gasses venting backward around the primer cup. Does this make sense? How do I stop this from happening. Is it likely an issue with the primers? I thought I had read some time ago about an issue with some Remington primers, but I'm not sure about this. If it is a brass issue how would I go about solving that? I am looking to replenish primers. If it is a primer issue can someone recommend primers to stay away from? CCI, Wolf and Tula seems to be the most inexpensive and instock now. I have loaded with CCI in the past but am leary of Wolf and Tula just because I have not loaded with them before. Thank you for your input. rube Wanna kill these ads? We can help!