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270 vs 7mm Bullets

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Mummichog

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0.277 and 0.284 inch. 

 

The difference in diameter is only 0.007".  7/1000..............seven one thousandths of an inch. 

 

 Been pouring over a lot of ballistics and load data lately and this jumped out at me.  I always knew that they were .277 and .284 but never did the math.

 

I dunno.....just kind of jumped out at me recently.

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On 5/8/2023 at 10:38 AM, giggyfish said:

I am a firm disciple of the O’Conner clan. My .270 Winchesters have never let me down from whitetails to moose. My favorite is my home made 150 gr. Partitions but killed many a deer with Remington core-locts as well. 

 

I have hunting buddies with 270 Wins and have shot a deer with one myself.  They do the job and do it well.  I just picked up the Weatherby version of the 270.  Same bullet, more speed.  I ordered a box of Barnes TTSX 130 grains for hunting.  Interested to try some different bullets and loads and can't wait to get the chrony on it.  

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On 5/8/2023 at 8:38 AM, giggyfish said:

I am a firm disciple of the O’Conner clan. My .270 Winchesters have never let me down from whitetails to moose. My favorite is my home made 150 gr. Partitions but killed many a deer with Remington core-locts as well. 

I've killed a whole pile of moose and a few elk with 150 grain Corelocts out of a .270 Win. I've had them break both shoulderblades on a couple ocasions. Once I had one go through the lower shoulderblade, something like 2" of bone, and still get enough penetration to take out the lungs. For any shot that you've got any buisness taking with a .270 , a 150 grain Coreloct will get the job done.

If the good lord didnt want me to ride a four wheeler with no shirt on, then how come my nipples grow back after every wipeout?

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On 5/8/2023 at 10:13 PM, Bushleague said:

I've killed a whole pile of moose and a few elk with 150 grain Corelocts out of a .270 Win. I've had them break both shoulderblades on a couple ocasions. Once I had one go through the lower shoulderblade, something like 2" of bone, and still get enough penetration to take out the lungs. For any shot that you've got any buisness taking with a .270 , a 150 grain Coreloct will get the job done.

 

Are those hand loads or the green and yellow box?  I haven't hunted with the Core-Lokt in a few years.  Since I started hand loading.  They used to shoot great out of my 30-06.  Some time in the mid-1990s, I got into this premium bullet craze.  I think my dad got me started on it with the Nosler Partition.  I wasn't a huge fan of them so I researched all the other ones.  Winchester Failsafe, Swift A-frame, Trophy Bonded Bear Claw and then Barnes X.  I really liked the Bear Claws, but they were super expensive.  By the late 1990s, I had settled on the X bullet and didn't look back.  I did have many good experiences with the Core-Lokt, though.  The deadliest mushroom in the forest, is what they say.    

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On 5/9/2023 at 5:14 AM, Mummichog said:

 

Are those hand loads or the green and yellow box?  I haven't hunted with the Core-Lokt in a few years.  Since I started hand loading.  They used to shoot great out of my 30-06.  Some time in the mid-1990s, I got into this premium bullet craze.  I think my dad got me started on it with the Nosler Partition.  I wasn't a huge fan of them so I researched all the other ones.  Winchester Failsafe, Swift A-frame, Trophy Bonded Bear Claw and then Barnes X.  I really liked the Bear Claws, but they were super expensive.  By the late 1990s, I had settled on the X bullet and didn't look back.  I did have many good experiences with the Core-Lokt, though.  The deadliest mushroom in the forest, is what they say.    

 Just the regular green box. I've used a few different bonded bullets, and they worked too, but I've experienced erratic terminal performance too with them. The Corelocts basically always do what they do, and any recovered bullets (all out of moose, the will run a deer through from end to end) all look the same.

 

  I've used 180 grains out of the 30-06 quite a bit too, and was puzzled for a bit that the 150 grain .270 bullets actually seemed to get better penetration. At first I was somewhat inclined to think it was a SD thing, the .270 bullet does have a better SD but not by enough that I would think it'd matter. Then Remington started printing cross section pictures of their bullets on the box, and I realized that its because in the .270 they only load round nose 150 grain bullets. Being designed for bush hunting/ close range shots/ faster impact velocitys, the round nose has a thicker jacket than the spire point Corelocts I was using in my 06. 

If the good lord didnt want me to ride a four wheeler with no shirt on, then how come my nipples grow back after every wipeout?

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On 5/9/2023 at 12:12 PM, Bushleague said:

 Just the regular green box. I've used a few different bonded bullets, and they worked too, but I've experienced erratic terminal performance too with them. The Corelocts basically always do what they do, and any recovered bullets (all out of moose, the will run a deer through from end to end) all look the same.

 

  I've used 180 grains out of the 30-06 quite a bit too, and was puzzled for a bit that the 150 grain .270 bullets actually seemed to get better penetration. At first I was somewhat inclined to think it was a SD thing, the .270 bullet does have a better SD but not by enough that I would think it'd matter. Then Remington started printing cross section pictures of their bullets on the box, and I realized that its because in the .270 they only load round nose 150 grain bullets. Being designed for bush hunting/ close range shots/ faster impact velocitys, the round nose has a thicker jacket than the spire point Corelocts I was using in my 06. 

 

Couple of things....the 270 factory ammo for 150 grains runs about 2850 fps.  At any distance, they may not be going fast enough to open the tougher bullets consistently.  That's just a guess as I don't know how far your shots were.  The premiums like speed. 

 

The 270 vs 30-06 in penetration:  SD is one factor, thicker jacket is another factor....velocity could be another.  Factory 270 Win is 2850 fps for 150 grains.  30-06 factory is 2700 for 180s.  So, you have 150 fps more momentum to start with.  

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On 5/9/2023 at 10:19 AM, Mummichog said:

 

Couple of things....the 270 factory ammo for 150 grains runs about 2850 fps.  At any distance, they may not be going fast enough to open the tougher bullets consistently.  That's just a guess as I don't know how far your shots were.  The premiums like speed. 

 

The 270 vs 30-06 in penetration:  SD is one factor, thicker jacket is another factor....velocity could be another.  Factory 270 Win is 2850 fps for 150 grains.  30-06 factory is 2700 for 180s.  So, you have 150 fps more momentum to start with.  

  

  The bonded bullet surprizes all came on close range shots, a couple going to shrapnell on frontal deer shots at 20-40 yards, a few extremely ugly mushrooms after hitting little more than a moose rib at 100 yards or more, which IMO is no excuse. Another thing I found is that with some bullets, the terminal performance difference between different weights or calibers can be unpredictable.

 

  I agree that the velocity can make a difference, but I kill most of my animals within bow range... with a bullet like a Coreloct and high impact velocitys, usually the slower bullet will perform better. In my experience, from 100 yards out to 300 ( I dont shoot any farther than that) the velocity difference of those rounds is negligable in terminal performance, indeed with a RN vs a SP there very likely isnt a velocity difference through much of that range.

Edited by Bushleague

If the good lord didnt want me to ride a four wheeler with no shirt on, then how come my nipples grow back after every wipeout?

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On 5/9/2023 at 12:46 PM, Bushleague said:

from 100 yards out to 300 ( I dont shoot any farther than that) the velocity difference of those rounds is negligable in terminal performance, indeed with a RN vs a SP there very likely isnt a velocity difference through much of that range.

 

I was looking at a couple of factory ammo boxes that have the muzzle, 100, 200, 300, etc... velocities on the box.  The 6.5 Creedmoor loses 600 fps at 300 yards and the 270 WBY loses 700 fps at 300 yards.   

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On 5/9/2023 at 11:33 AM, Mummichog said:

 

I was looking at a couple of factory ammo boxes that have the muzzle, 100, 200, 300, etc... velocities on the box.  The 6.5 Creedmoor loses 600 fps at 300 yards and the 270 WBY loses 700 fps at 300 yards.   

 Point taken, I just think that at those ranges its not going to have much effect on how a Coreloct out of a standard round is going to perform... at these distances they are sitting nicely in the velocity range that they were designed to operate at.

 

 But I could be totaly wrong on that, I just dig bullets out of dead animals and dont get too technical about it. Either way, if you want to kill a big animal with a standard round and cheap bullet, the .270 150 grain Coreloct is damn good choice. At normal hunting ranges the capabilities of the round are no greater than the capabilities of the bullet.

If the good lord didnt want me to ride a four wheeler with no shirt on, then how come my nipples grow back after every wipeout?

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On 5/9/2023 at 1:59 PM, Bushleague said:

at these distances they are sitting nicely in the velocity range that they were designed to operate at.

 

 

Yes, I think the Core-Lokt has a broad velocity range.  It will open up at slower speeds and does a decent job at higher speeds.  A lot of wiggle room.  Some of the other bullets need one extreme or the other.  A Swift A-Frame might be too tough to open at low velocities.  A Nosler Ballistic Tip might explode at high impact velocities.  Core-Lokt handles what most hunters will encounter.

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