A PH friend had a .470 sidelock blow as he was firing at a buffalo. I don't recall the maker, but it was a very good between-the-wars gun by a second tier British maker. A six inch shard of steel blew out ahead of the chamber, barely missing my friend and his client. He had it rebarrelled, and that gunmaker blamed the failure on modern solids. I have a 1918 Evans .470 that had seen a lot of use across Africa, and since that incident only use cast and soft nose bullets in it.