Hey, let’s not be too hard on an occasional poster, we all started somewhere. This is the nicer corner of CGN, remember?
To the OP, welcome to the world of SxS shotguns. All are not created equal, and a vast quantity of them out there are not safe to use with modern loads, either because they were never built for them in the first place, or time has introduced weaknesses that might result in serious injury to one’s self or others. Shooting old SxSs is not a beginner’s game, at least not without a lot of reading, understanding, and competent advice. You have to be conversant on types of metals and construction, reading proof marks, being able to spot damage and assess wear, measure chamber sizes etc. Some 100-year old SXSs were built to last 150 years, some were built to last 10. Some makes are sturdier than others, a great many were produced not in factories, but by hand in small workshops. Some were built with no attention to quality, being little more than a farm implement, while others are fine hunting guns built with the best materials of the day. ‘Of the day’ being important here, as when new, they were often made for low-pressure black powder, not the high-pressure loads of today. Add 100+ years of abuse, neglect and rust, and do you really want to risk using one inches from your face? Even the most experienced among us still turn to other experts and gunsmiths. It is almost never as easy as finding new firing pins for an old double and going to the clay range.
I’ve made some assumptions here, apologies if I’m wrong. But to get the most advice from the very knowledgeable folks here, more information is needed, and pictures save a lot of time. This really is the most enjoyable corner of CGN, with much experience to be tapped and shared.