There are alot ways to reinforce a rammer so that it maintains strength in the field.
One way is to soak the rod in molten pine pitch / rosen with turpentine, these turns this enriches the wood with essentially a sap that hardens, Native Americans used to do something like this with their arrows.
You can also make special rod for the field.
Reinforcing a rod is key. Theres many ways to do it.
You can hollow out 10” sections of dowel rod on a drill press or lathe and use the wooden sections as a cover for a 3/32 brass or steel rod, epoxying each section down and then cross pin a 1/16 pin through the steel or brass rod, i know some fellas use a music wire or spring steel ribbon.
However with all of this said, i have to be honest, I’ve made one reinforced rod, and it works rather well, but for all of my other guns, I’ve never had any issues in the field with them breaking ever or losing the tips.
Personally i think the idea of losing a rammer in the field is overkill, if you’re losing shots that you need to pull with a screw tip, then there’s something else wrong with the gun you’re not identifying, it could be the bore is too oxidized or the patch is too thick or your charge was not correct.
if your wooden rammers are breaking its not because they’re either made from bad wood, or the user is being careless with them.
For smaller caliber guns, 32-45 you rammers will be pretty delicate, the way I’ve dealt with this issue is to make a very long sleeved rammer tip, 2-3” long for the shaft to go onto the rod.
I think if you imagine how they dealt with these issues in the field in the 18th century, you’d come to one logical conclusion, most of the time they were ahead of the actual issue or they simply…. Went home to fix the problem, maybe made a temporary rod in the field too.