filled my tag! 220 grain rn surprise!

[JD0x0]

All that aside I would bet Tom is right the twist rate was too slow to stabilize that long RN 220 bullet and it began to tumble on impact.

If the rifle is 1:10 it's got more than enough twist. RN bullets are shorter than spitzers and dont require such a fast twist because they're short for their weight. If the bullet isn't stabilized enough, it's going to be tumbling through the air, not through flesh. AFAIK soft point bullets dont typically tumble in flesh, they're meant to open up and travel straight through. If the bullet tumbles, I'd assume it'd gain penetration, if it's not shedding weight since the large frontal area of an expanded soft point typically causes more drag than a yawed bullet.

According to the OP the bullet only lost about 40 grains of mass, which actually isn't too bad for a lead core bullet at .300 Win mag velocities.

The length of the 220 grain RN is 1.283''
The length of a 190 grain Nosler ABLR is 1.460
The length of a 150 grain Nosler AB spitzer is 1.230''

The 220 grain bullet is barely longer than a 150 grain spitzer, and due to its significantly higher mass and more forward center of gravity, it may actually have more stability than a 150 grain spitzer bullet, in the same barrel.

 

[Tom Matiska]

I agree JD the bullet is very stable in air, but all bets are off after impact, and as with air, the longer bullets are more likely to tumble. Very possible it tumbled.

 

[Roadkill2228]

Thanks for your insight and ideas guys...I think I'm going to conclude that the bullet did indeed tumble...that would explain why it broke into 2 at the cannelure...that must be the weak spot from the side...about this idea that the bullet fell apart/didn't penetrate because it met insufficient resistance...I must respectfully say I don't think this happened and I don't think it ever happens with deer size game and larger. Now I do understand what is said about how when shooting at bowling pins or in my experience even tin cans with a pellet gun, the target is pushed back further when it contains the bullet...but this is not a bowling pin or a tin can, this is a 250 (ish) lb critter (live weight)...mythbusters did an episode about the ideas of bullet "stopping power" or "knockdown power"...these are indeed myths...for the deer to be "pushed" enough to absorb any of the bullets energy in that manner, the bullet would have had to have a huge frontal area and the deer would have had to fly aff it's feet (this did not happen) at a terrific speed. Also, as was alluded to, the fact that the bullet broke in half means it met gobs of resistance.

 

[Snyper]

.for the deer to be "pushed" enough to absorb any of the bullets energy in that manner, the bullet would have had to have a huge frontal area and the deer would have had to fly aff it's feet (this did not happen) at a terrific speed.

Bullets lose speed VERY quickly once they enter the animal.

That energy went somewhere, and if it were converted to forward motion, you'd never notice in the short time it takes,

The deer was already moving away from you, so you wouldn't have seen any change in motion, since it would only be a few feet for a 250 lb animal that was already running

 

[Roadkill2228]

Indeed there was no noticeable motion on the 250 lb animal...that was MY point (and panfishers)...and indeed the bullet loses speed very quickly upon impact...this indicates a tremendous amount of resistance is encountered...again, that's my point. What we are trying to refute here is the plainly backwards notion that "bullets can't penetrate if there isn't enough resistance"...are you honestly suggesting that a bullet that won't go through a deer will go through a larger animal like a moose or elk because it is met with greater resistance? Because that's the logical progression of thought from here if the low resistance=low penetration theory has any merit (and most of our hunting experiences/common sense informs us it does not)