Rossi Rifleman

I said cast RNFP kills as good or better than JHP. An RNFP feeds in a lever gun too. Might as well say this again too...The simple solution is build the proper ammo for the gun, not adapt the gun to shoot handgun ammo...unless you'd like to spend the extra time and money.

I would load the same bullet I use in revolvers- Lyman 429667.

that's my main one too.
I do like the 45 version better [452664] for close in hunting, the 357 see's the 358665 as it's main bullet too.
they are all basically the same design, but the 667 has a slightly smaller meplat percentage than the other two.

Could you show us some pictures of the damaged cartridges? That would help.

A little bit more experimentation might yield some good results. In your next trip to see the rifle, bring some fresh dummy cartridges with you. This time, load the cartridges into the magazine slowly and carefully. Same for cycling the action. You should be able to feel when something starts to bind and force is necessary, and that's where the damage is likely happening.

Deforming a bullet takes a fair amount of force, so my guess is that its happening as the lever is being closed and the cartridge is initially being fed into the chamber at an angle before it straightens out and slides the rest of the way in. The cartridge guides might be holding the cartridge at an angle that's too steep, or the bullet shape is simply too wide to keep from jamming into the side of the chamber before the cartridge can straighten out.

If running the lever slowly doesn't result in any damage, then run the cartridges through again but while running the lever quickly. It might be that the bullet end of the cartridge is raising up too far due to inertia from the cartridge lifter being raised quickly. That might cause the bullet to get slammed into the breech face as the bolt closes.

Those are some educated guesses. Hopefully they will help you figure out what's happening.