Very good video but look, it's pretty easy really.  It all has to do with burn time and pressure.  Pistol powders are very fast because they have little time to burn to push that projectile down a 4" barrel.  Rifle powders burn much slower because they have a longer time to burn down that 24" barrel to build up more speed.  There is of course more to it than that but those 2 constants are pretty much the story.  Powder burn speed vs time at a determined pressure.  The reason there are so many powders is because your job as a handloader is to find the combination of case, primer, barrel length, bullet and bore diameter that will work best and be the most accurate and there can be millions of combinations. We're talking powder here and I've literally used so many I've lost count so I'll drop my favorites on the new guy's out there to help them along if they want the info.  Trap & Skeet - Red Dot.  Loads anything including Pistol rounds, it's great for pistols and is one of the best for target work.  Pistol - Bullseye and Unique.  Both will load anything from target to hunting and do it well.  CFE Pistol is an almost universal powder and will give you top velocity's, after that Autocomp & Silhouette will handle anything else.  Honorable mention goes to HP 38/Win 231.  Rifles - This is where we can get really into the weeds.  My 7mm PRC loves that can you have, StaBall HD. Add RL26, H1000, Retumbo and LRT.  That's magnums.  For the average guy or myself and my Tikka 270, 748 and CFE 223 are almost universal powders along with StaBall 6.5 which IMHO will load anything and do it well.  My most accurate load in 6.5 Creedmoor uses either 748 or SB6.5 and a 120gr PPU OTM.  .300" 5 shot groups are normal and most times it's very boring to shoot because out of my 26" Savage 12FV it will put 5 rounds into the same hole, literally.  All you have at 100 yards is a single dot on the target.  RL15, IMR 4350, 4064 & 4895 are held as the Gold Standard and Varget just seems to rule the roost for accuracy and a pleasantly shooting round.  This isn't even scratching the surface but are my suggestions on where to start.  Good Luck & Good Shooting.  What think you ?

168 Gr Barnes LRX. With 68.5 Gr of Staball HD. 2962 FPS 24” barrel. SD of 3. 1/2” groups at 100 yards.  My load for Elk this year.

Starting initial trial tomorrow with the Bergara 7PRC, 26" barrel, new ADG, Fed215m, 180 ELDM, H1000 seated 10 thou off lands. 67, 68, 69 grains. The 175 ELDX was 3053 with 69.0 H1000

I may well be wrong but with ball powders, and the range of powders load in the 7mm PRC, I would always go with magnum primers. Maybe even with extruded powders but, never played with that beast of calibre...

Can go wrong with sum varget and 150gr-165gr .308 loads.  Or ramshot TAC and 130gr .308

I picked up some NAS3 cases an 53gr vmax bullets with a heath dose of ramshot TAC an from my 16" howa mini action i am getting 3600fps.... an i dont see any pressure signs or hard bolt lift... i did try a few other powders but nothing got me the velocities of tac  "so far" i need to try benchmark or h4895  see what happens with more temp stable powder... TAC also gives me very impressive results in my 6max..  🚀

So, newbie.  
Everyone says don't trust online recipes.

Not all caliber/powder  combos have a recipe published.

Risk is very high.

Everyone warns too big or too small a charge is very dangerous.

Published recipes vary between sources.

Can't trust powder names; H4295 and IMR4295 not the same and Old Alliant Unique not the same as new Alliant Unique. BLC VS BLC(2)

Burn rate chart is interesting but not definitive.

No good interchange data available.

Powder availability.  Can't find the recipe ingredient and no recipe for what IS out there.

Missing data/gaps.  Recipe for 140 gr bullet,  150gr,  gap at 160gr, completely different powders in 170gr. Recipe at 180gr, no 190. Etc.

Oh, and don't die or get the nickname Lefty