And read, understand and follow the instructions for your specific rifle.

If you are buying a used rifle, obtian the operation & loading instructions for that model. Also a great idea to have used rifle inspected by a gunsmith or the factory if you are not sure on the condition. There still is nothing for sure.

Many of the rifles being produced TODAY & recently are rated for higher charge usage up to 150gr loose BP. One thing for sure is a fair amount of the older rifles were not rated for 150gr powder.

Unfortunately, with more and more folks shooting ML's every year there will be boneheads that either cannot or will not read or ignor what they have read which will result with more accidents.

With BPI/CVA & Winchester, they did have a run of rifles that were recalled under a "Do not attempt to fire" warning.

Also the lack of cleaning and maintenance can cause dangerous situations.
Residue left down the bore can cause a rise in pressure because the bore becomes smaller as it cakes up. Rough spots (pitting) are created that affect accuracy. Loading becomes difficult forcing you to exert more pressure on the loading rod and increases the possibility of the projectile not seating all the way down. If you are not seating the projectile on the powder and leaving a space, you are creating your own pipe bomb.