During years I shot a lot of 44-40 BP and nitro loads in a 44-40 Brazlian 1892 and a Ruger Vaquero 44-40 I had absolutely NO loading issues with bullets being shoved back in the case with nitro loads. My 44-40 reloading dies were designed for 0,427" bullets, so held 0,429" bullets securely at the positions I seated them. I did use only Starline or Remington brass, not the reportedly thinner necked Winchester brass.

Other factors that may have been in my favor are; 1) shortened magtube spring to fix a problem with hard to load 8-10th rounds through the loading gate. 2) polished inside of magtube so that feeding was easy and prompt. 3) never used 0,427" bullets in the 0,429" bores of my guns. 4) both my 44-40s liked best the original Ideal 427098 bullets, which do not have a crimp groove, 5) I did routinely use a Lee crimp die that really indents the case mouth into the soft Pb alloy bullets -- primary reason for using this crimp die was the minimalist chambers in the Ruger replacment cylinder.

44-40 has long been my favorate small rifle cartridge. I refuse to call it a "pistol" cartridge!

I did hear some comments/complaints about bullets sliding back into cases unless BP was used. All I recall is that those comments came from BP addicts, so, were suspect.