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Why do Magnum shells kick harder?

Discussion in 'Tactical Shotguns' started by powder86, Feb 15, 2011.

  1. powder86

    powder86 SHOOT SAFE!

    Is it true that magnum shells kick harder? (i've only ever fired 2.75 shells.) and if they do kick harder, i guess i don't know why... because i thought magnum shotgun shells had more shot, but not a stronger powder charge. am i understanding that correctly?

    so obviously this is a basic question... but it's one i've been wondering.
  2. rjrivero


    Apr 23, 2009

    Heavier shot load, higher velocities, more recoil. Newton's third law still applies.
    Last edited: Feb 15, 2011

  3. BBJones


    Mar 2, 2010
    Why do heavyweights hit harder than bantams?
  4. byf43

    byf43 NRA Life Member

    Apr 13, 2006
    Southern Maryland

    "Magnum" shotshells usually have a slower burning (rate) powder and more of it, heavier payload (usually) and can also be a longer shell (3" and/or 3-1/2" shotshell) versus the 2-3/4" shell.

    This causes in increase in pressures, velocity and recoil impulse.

    I'm not certain about now (haven't bought many shotshells, lately) but, there used to be 2-3/4" "magnum" 12 shotshells available.
    Last edited: Feb 16, 2011
  5. powder86

    powder86 SHOOT SAFE!

    to make a heavier load travel at higher velocities, it requires a stronger powder charge... so magnum loads do have a stronger powder charge... yes?
  6. Z71bill


    Feb 19, 2007
    Most magnum loads travel at slower velocities than "standard" loads.

    Some magnum loads use the same amount of gun powder as a standard load - others use more. In GENERAL magnum refers to the amount of shot not the powder.

    Remington uses more powder.

    3" magnum 00 buck 15 shot at 1,225 FPS using 4 dr eq of powder

    2 3/4 inch 00 buck 9 shot 1,325 FPS using 3 3/4 dr eq of powder

    IIRC Winchester & Federal use the same amount of powder - I could not find the info - so I may be wrong.

    The 3" mags from these companies only hit 1,210 FPS - but their standard loads hit 1,325.

    I recall several threads on GT where people were debating felt recoil -

    Many said the heavier bullet has more kick - but others claim the math proves that all other things being equal a lighter bullet will generate more recoil.

    Something about a formula where velocity is squared. :dunno:

    I can't tell much difference between a 115 or 124 in a 9MM a 165 or 180 in a 40 S&W

    I don't shoot many 3" magnum shells because I don't see a need for it.

    Last edited: Feb 16, 2011
  7. jtull7

    jtull7 Pistolero CLM

    Jan 27, 2006
    Santa Fe, New Mexico
    'Cause they are bigger, Bubba.
  8. powder86

    powder86 SHOOT SAFE!

    but isn't the kick derived from the powder charge? having a longer shell filled with more mass to be propelled has nothing to do with the propellant, which causes the felt recoil... right?

    this is what i don't get. if magnum for a shotgun means more shot and not also more powder, then longer shells shouldn't kick harder. but some are saying that some magnum loads do use more powder...(which explains the harder kick) but that's not a hard and fast rule. so really magnum means whatever that individual manufacturer uses it for. always more shot... sometimes longer shells, sometimes more powder as well.

    so magnum doesn't have just one meaning for shotguns thus far. right?
  9. Z71bill


    Feb 19, 2007
    What I posted could be misleading -

    I think of 3" shells as magnum - which is NOT always true -

    Many companies make 2 3/4 inch shells labeled as magnum - they do have more gun powder.

    My bad -

    I guess the best thing to do is just try and compare the individual loads you are interested in. :dunno:
  10. rjrivero


    Apr 23, 2009
    Magnum doesn't mean squat. (It's not a standardized term. In fact, it was stolen from the French Champagne and adopted by the firearms industry because it SOUNDED BIG AND BAD.)

    RECOIL is a multi faceted force that is VERY difficult to quantify. There is the muzzle blast, rearward push, and upward motion of the barrel that are all contributors to FELT RECOIL. As well as the mass of the gun, mass of the bullet/projectile.

    I don't have a degree in physics, nor have I ever wanted one, but if you have a larger mass (shot charge) and keep the same amount of powder in a shell for any given gun, you are probably right in assuming the heavier shot charge will be moving at a slower velocity. You would assume that these factors would be proportional, and therefore the felt recoil should be the same weather you are pushing a heavy shot load, or a lighter shot load.

    Sounds logical, but that isn't how smokeless powder works. Because of the inertia of the heavier load, the burning powder will have a different volume at any point in time after ignition. This will change the pressure curve of the chamber. It may make it peak higher, and the higher pressures can last longer than with a lighter load. This change in peak pressure can and usually will effect the "felt recoil."
    Last edited: Feb 16, 2011
  11. powder86

    powder86 SHOOT SAFE!

    are you saying that the powder will literally be packed tighter in a 'magnum' shell? because that would make sense to me. or are you literally saying the heavier load's resistance to motion would cause the increase in pressure under which the powder is firing. which wouldn't make sense to me.

    and thank you for the cogent response.
  12. I think it is momentum, not inertia. But I don't have a degree in physics either.

    Ignore the words like magnum and look at the shot weight and velocity.

    Heavier load at same or faster velocity will recoil more.

    Lighter load at faster velocity may or may not recoil more.