7mm-300win thoughts

[cummin_un_glued]

Now use my data from my proven 300 win mag with a 215 Berger. Bc of .696 G1 and MV of 3035. It will be a good comparison to your 7-300 since your field data for the 7-300 and mine are the same.

Jeff

Oh I know Jeff, my point was just that mass wasn't the only thing to consider and that not in every situation that bigger is better and that the 7mm can hang in there further then some give it credit for. Now i'm no fool I know that the 30 and 338 class rifles own the 1500-2500 yard realm. But I wouldn't be afraid to take an animal out to 1500 with mine given that the conditions were where I felt confident that I could place the bullet where I intended.

Jeffs rifle for the same conditions

1000lb ft @ 1815 yards and 1.7 moa per 5 mph @ 1000 yards.

 

[yobuck]

Well we have to consider there would be east/ west differences due to altitude.
Where i hunt in N C PA we would choose 1500/2000' as our base elevation.
Even considering that however the difference wouldnt be enough to settle our dissagreement. I doubt you would find many (experienced) hunters here agreeing
with your opinion on the 7mm or Jeffs opinion on the 300 win mag. Neither, would
receive many if any votes for a 1500 yd gun. Think of what im saying this way, how
many guys would downgrade their own gun? Ive stated how many deer ive (watched)
die to 7mms. Ive also watched lots die with 30s and some with 338s. Ive given my
honest opinion based on observation. What i see coming back is opinion based on other opinion. Nothing personal here, and dont take it that way. In fact id
appreciate a visit to our camp where we can shoot out to a mile from our yard.
Im anxious to learn and would appriciate seeing how this should be done.

 

[dragman]

Your right yobuck,
We all have opinions and some of us look at the big picture some don't but its all about application for me. I just shot my saum with the 168's and my new load 70 degrees 18.5 moa too 1000 yards. And it shot well. If I wanted to trump it I would jump to the 300 RUM and some 230's just me for what its worth.

 

[MudRunner2005]

Oh I know Jeff, my point was just that mass wasn't the only thing to consider and that not in every situation that bigger is better and that the 7mm can hang in there further then some give it credit for. Now i'm no fool I know that the 30 and 338 class rifles own the 1500-2500 yard realm. But I wouldn't be afraid to take an animal out to 1500 with mine given that the conditions were where I felt confident that I could place the bullet where I intended.

Jeffs rifle for the same conditions

1000lb ft @ 1815 yards and 1.7 moa per 5 mph @ 1000 yards.

7mm's can hang in there alot farther than 95% of the people on here will give them credit for. Simply because they want to continue the hug'er is always better elusion.

Because, if the 7mm surfs learn that king .338 is no more special than an ordinary man, like they thought he was, then they could easily overtake the kingdom.

 

[.284]

I see a lot of reference to ft lbs of energy as a measure of max distance for hunting.
Why?
Yes you need to use a suitable bullet weight for the type of game but I think remaining velocity is much more important. Berger says their hunting vld's will expand down to 1800 fps. I use 2000 to be safe.

I did read bros thread on the 215 hybrids although I don't remember what velocity those were expanding down to

 

[dragman]

I see a lot of reference to ft lbs of energy as a measure of max distance for hunting.
Why?
Yes you need to use a suitable bullet weight for the type of game but I think remaining velocity is much more important. Berger says their hunting vld's will expand down to 1800 fps. I use 2000 to be safe.

I did read bros thread on the 215 hybrids although I don't remember what velocity those were expanding down to

Hunting VLD's are good down to at least 1800 fps and depending on game I think they are good clean too 1500FPS.

 

[cummin_un_glued]

I see a lot of reference to ft lbs of energy as a measure of max distance for hunting.
Why?
Yes you need to use a suitable bullet weight for the type of game but I think remaining velocity is much more important. Berger says their hunting vld's will expand down to 1800 fps. I use 2000 to be safe.

I did read bros thread on the 215 hybrids although I don't remember what velocity those were expanding down to

I look at retained energy because when comparing different calibers and different bullets it is a more equal measure. When your talking opening velocities for bullets there are a lot more variables. I like to know that if my bullet hits a bone that its going to go on through it.

For example this was my 7x300 at 1340 yards. Impact velocity was 1844fps and energy was 1359ft-lbs. The target was 1/4" mild steel now I know its not AR500 target steel but game isn't armor plated either.



As you can see on the 5 fresh holes they were clean pass through.

 

[.284]

Looks like plenty of penetration and your velocity is still good too. I'm sure they would go through bone no problem I just like to know that the bullets will still open up should they not hit bone and that is my reason for using remaining velocity for max hunting distance. I'm at sea level so I hit 2000 fps at about 1000yards, you must be a bit higher.

 

[fmajor]

I look at retained energy because when comparing different calibers and different bullets it is a more equal measure. When your talking opening velocities for bullets there are a lot more variables. I like to know that if my bullet hits a bone that its going to go on through it.

For example this was my 7x300 at 1340 yards. Impact velocity was 1844fps and energy was 1359ft-lbs. The target was 1/4" mild steel now I know its not AR500 target steel but game isn't armor plated either.



As you can see on the 5 fresh holes they were clean pass through.

That's some *serious* smackdown!!!!

I'm all for 7mm's and the 7mm/300 Win (it will be my next build) in particular and a strong proponent for long range hunting, but to me the thing that's tough to get to is retained inertia.

What I'm thinking of is not simply retained energy; Rather, a projectiles ability to continue penetrating through heavy, energy sapping material. For example, like a poorly hit/angling away elk with a full stomach of ground up, moist grass/hay at (for the sake of illustration) 1,400-1,500yds.

A 220 Swift may be able to break a bone, but certainly wouldn't penetrate all the way through whereas a 20mm Vulcan round would be able to not just break the bone, but would have enough retained inertia to continue on through the elk in the conditions set above.

So really, the question is how much energy/BC/velocity/etc is needed to ensure a projectile could slam through the entire length of a large elk to unquestionably destroy vital organs and create a significant wound channel? Sure, a 20mm Vulcan round would undoubtedly accomplish that, but otherwise how much is actually needed?

Retained energy at the point of strike/impact is one thing and has a "simpler" mathematic path derived from initial velocity, projectile weight, projectile twist rate, BC (which is comprised of diameter/weight/drag coefficient, etc) and probably a few other variables I've forgotten. But I don't think that's all there is to the "penetration puzzle".

However, calculating how much inertia a given projectile will loose (in a given medium) is (for my simple mind) more elusive to calculate. I've read on this topic for a few decades so it's not a flippant question/topic, but since I'm not a mathematician/ballistician I simply don't have the necessary tools to begin to arrive at a solution.

Sorry if this is a de-rail.... I'm hoping to learn as well as pose questions which may require a fresh look/approach...

 

[cummin_un_glued]

Looks like plenty of penetration and your velocity is still good too. I'm sure they would go through bone no problem I just like to know that the bullets will still open up should they not hit bone and that is my reason for using remaining velocity for max hunting distance. I'm at sea level so I hit 2000 fps at about 1000yards, you must be a bit higher.

I agree about the velocity pertaining to a particular rifle/bullet but for me that's after the cartridge and projectile has been chosen. That's why in a discussion about different cartridges I choose to look at retained energy. Since even two bullets the same caliber and weight will have different opening velocitys .