"Sorry, but it is the amount of powder that creates recoil not bullet weight"
Nope. It's both.
"If you shoot the same powder load and in one use a 150 gr and the other a 180 gr bullet you will not detect any significant amount of recoil increase, actually you would find a small decrease since you're having to propel a heavier bullet"
Nope.
"To propel heavier bullets, they put larger charges of powder in the case so that 180 gr will shoot at about the same velocity as a lighter bullet."
Nope. Totally incorrect.
Sorry, but "Yep" it is.
Take for example the S&W Model 500 in .500 S&W—the most powerful
commercial handgun cartridge there is…Using the same 440 gr bullet I can make that into a pussy cat or a tiger or something somewhere in-between by just adding or reducing the powder charge.
SPECIFICATIONS
Bullet Diameter: .500 in.
Max Overall Length: 2.250 in.
Case Capacity: 64.8 gr. water
NOMINAL PERFORMANCE
Bullet Weight: 440 gr
Muzzle Velocity: 1625 fps
Muzzle Energy: 2581 ft-lbs
440 gr Cast
Velocity…..Energy
Fps………..ft/lbs
1191…..1386
1278…..1596
1300…..1651
1393…..1896
1483…..2149
1496…..2187
1509…..2225
1609…..2530
1653…..2670
1654…..2674…..All fired from a 10” barrel
Difference is in the amount and/or type of powder used but it’s still a 440 gr bullet exiting the same barrel of the same gun there will be a noticeable difference between the top and bottom load.
You have to get your projectile up to its proper speed to aide in its optimal expansion upon contact…Chart below shows that by keeping the same powder charge, by changing the weight of the bullet reduces velocity and subsequently energy…With the 150 gr Berger you needed different weight of different powders to achieve the same velocity but if you increased the bullet weight and kept the type and volume of powder the same velocity decreased…To get a heavier bullet to travel at a higher speed you have to add more of the same powder or substitute a different powder that will produce a higher velocity i.e. 54 gr of VVN150 produced nearly the same velocity (-22 fps) as 56 gr of H414..
BERGER 150 GRAIN HP
54.0….. VVN 150………..3032
56.0….. H414…………….3010
SIERRA 168 MATCH KING
54.0…..VVN 150……………2951
53.0….. H414………….……2798
SIERRA 180 GRAIN MATCH KING
54.0….. VVN 150…………2759
53.0….. H414……………..2789
BERGER 185 GRAIN BT
57.0…..VVN160………….2739
BERGER 190 GRAIN
57.0…..VVN160…………..2719
BERGER 210 GRAIN BT
57.0…..VVN160…………..2698
Info found at the Ammo Guide, Reloaders Bench and Accurate Reloading as I don’t have my newest powder and bullet manuals here.
Excluding reducing the amount of powder in the case, there are only four things that you can do to a firearm to reduce felt recoil:
Disburse/Disturb—Gas system in semi auto and install devices like Muzzle brakes and Mag-na-port, etc.
Delay—Recoil pads and/or absorbing stocks
Re-direct—Stock shape
Increase weight—Mercury tubes as an example to slow down the pressure.
That’s it, nothing else—anything out there is just a variant or combination of the above.