2 x 270 Win bullet performance tests

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Guest
Great info, and interesting history on the Nosler bullets. From your sectioning, it appears the front core of the Parition is relatively soft, as it bled across the crossmember section of the bullet and makes it appear there is a small diameter channel connecting the front and rear cores (an "I" core, for lack of a better term). Soft is good in the front section. I suspect hardness makes almost no difference in the rear section as the gilding metal jacket will maintain the shape just fine.

Interesting results and a testament to using these bullets within the design envelope. I've long been a proponent of using stout bullets in magnum cartridges and Ballistic Tips or other traditional cup/core bullets in cartridges where impact velocities will be in the mid to high 2000s. At this point, I'm down to using just two bullets for hunting, primarily. I use the BT in standard rounds (30-06, 270Win, etc.) and I use the Nosler E-Tip in cartridges with more velocity, like my 270Wby and 300Wby. I'd be interested to see what sort of penetration an E-Tip would have in your two tests, as I've witnessed some pretty dramatic penetration from them and varying velocities. I shot a wounded buck (~150lbs) from close range with a 130gr E-Tip from my 270Wby three deer seasons ago. Entrance was at the base of the neck, facing frontally. That bullet rode down the entire length of the spine, along the right side, destroying the entire right hand half of the spinal column, but damaging none of the backstrap meat. Exit was at the top of the rump about 2" to the right of the tail joint. That was a full 4' plus of penetration through the absolutely toughest part of the animal, with an impact velocity of 3350+. This past season I shot a good sized doe (~130lbs) at roughly 200yds with a 180gr E-Tip from my 300Wby (MV=3200fps). Shot was quartering steeply, and entered the front shoulder/ribcage, busting a lot of bone, ran through the lungs and liver, then into the rear hip, busting a lot more bone, and came to rest under the hide, right at the back of the doe's hind quarter. She dropped in her tracks. Again, more than 4' of penetration, but this time, impact velocity was ~2800fps (roughly 500fps lower than the buck two seasons earlier). The recovered bullet looked like this, after I cleaned all the fat and muscle and bone chips out of it:

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Retained weight was 99%. When dealing with magnum velocities, I will be sticking with the E-Tips henceforth. I bet they make the Partitions look cheap over in your part of the world, though...
 

Oldtrader3

Ammo Smith
Nov 6, 2009
8,406
2
The Partition bullet process (presently) is impact extrusion of a gliding metal slug. There is a small hole in the middle of the extrusion wall (Partition) where material does not flow probably around a pin. I would bet that this hole detail is also used for orienting and processing blanks before the lead goes in. The rear cup in filled with hardened, high impact strength lead. They front cup is filled with softer, low antimony, lead for better expansion of the front mushroom, down to the tangent point of the ogive, where the Partition is located. These bullets always give full penetration and 60% weight retention by design.

The old yellow box Partitions were made by means of a Swiss Automatic (screw machine) from a gliding metal wrought slug cut on the screw machine, then the cups were bored out and parted off from a bar, first front then rear on a second machine.
 

gerry

Ammo Smith
Mar 1, 2007
6,117
10
Bob, those 160 gr 270 Partitions are a bullet I always wanted so even though I don't have a 270 rifle (yet :) ) there is a box of those on the loading bench. With it's s.d. of .298 it would be pretty much a junior version of the well respected 30 cal 200 gr Partition. I bet an animal would never know the difference between the two but push a 200 gr bullet to 2800-2900 fps and the shooter would!
 
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