Seems like side lock is the distinction I've seen favored by the moderators.
Bob, is there any chance that those bullets with the bore ride nose are meant for a BPCR rifle?
I used the 45-70 500 grain bullet in my Henry barreled Whitworth for a while
and got good results with it but the Lyman 451112 loaded easier. It is no
longer being made but their 451114 is and at 450 grains it will work. The 112 was
a 485 grain. Both are straight sided with grease grooves.
The Bullet I designed about 20 years ago is for a breech loader. I sold the design to
Dixie gun Works and I think they still offer it. Also available in a 40 caliber.
Bob Roller