Complex sentence: After White's patent finally expired in Avril 1869, a 3rd an extension was refused, other gun-makers were finally allowed to produce their own weapons using his rear-loading method, without having to pay a royalty on each gun sold.
Split into simpler sentences: After White's patent finally expired in Avril 1869, a 3rd extension was refused. Other gun-makers were finally allowed to produce their own weapons using his rear-loading method, without having to pay a royalty on each gun sold.