BP grease wonder wads
I too first started in the 70's. Found for general plinking and hunting it was a pain to keep cutting patches.
Went to a premade patch. Used crisco and commercial lube to saturate the patch for the rifle.
Then went to a conical bullet. I used the pan dip method to seal the gas check grooves, still do.
I have 2 navy arms new model army 44's bought both in the 1970's
I started with .451 round balls moved to .454 better fit. Always used the wonder wads and no grease. As that is what a friend recommended.
Never in all these years have I had a cross fire.
Upon some research I came to a conclusion concerning the cross fires.
Many of the originals (mostly the copy cats) weren't consistent in their tolerances.
Both in the guns themselves and the bullets.
So if you got a gun that was slightly oversized in a chamber and or a ball slightly smaller, possible to crossfire at the chamber mouth. Thus the practice of the lube.
Plus the lube helped clean residue.
Another thing was in loading. Pour powder one cylinder, then add the ball.
Then while pouring powder in next cylinder, if not careful, could get a little powder spill over in the previously loaded cylinder. Which if combined with the oversized chamber or undersized ball, could allow the cross fire.
As most myths go, it would only take a few times for it to become legend. And then be perpetuated throughout time.
But this is just my opinion.
I now shoot almost exclusively conical bullets in both 44's
I also now use paper cartridges. No wads. The bullets have again been pan dipped to seal the gas check grease grooves. I use my own mixture of beeswax and hog lard.
Happy shooting one and all.