Home Forums Hunting & Shooting Ask The Gunwriters Any issues stabilizing 160 gr partiion / .270 Win?

Writers,

I know you get to test many different powders, bullets and bullet weights in all kinds of calibers, etc. My question is, have any of you noticed any instabilities with the 160 gr Nosler partition in the 270 Win, at say 300 yds or further? I have been shooting the 150's with no issues (of course) but that 160 is a bit longer, and I wonder if a faster twist may be required for that one.

Thank you.

gundog

You should be just fine. Most 270's are a 1 in 10 twist, my first 270 Win was a Rem 700 CDL with that twist an the 160 gr Partition was the most accurate load in that gun. My current 270 with a 1 in 9 shoots that bullet quite well. I asked the question a few years ago on here and most people who use that bullet say it shoots real well for them, my experience mirrors that. First gun liked Magnum and the second IMR 7977 best, haven't had a chance to try RL 26 but lots of guys are getting great results with 150's and heavier bullets.

I have a Husqvarna with a one in 11 twist.. and it stabilizes the 160 SMP partition just fine..

I run a full charge of H 1000 and it is running in the 2900 fps range....

gundog,

The 160 Partition is listed as a "semi-spitzer," with a blunter nose than the 150 spitzer. While it's slightly longer than the 150 (according to Nosler 5/100ths of an inch) it's designed to stabilize in the standard 1-10 .270 twist--which will stabilize even longer bullets under most environmental conditions. One example is the Berger 170-grain Extreme Elite Hunter .270 bullet, almost 2/10ths of an inch longer than the 160 Partition. Berger lists the ideal rifling twist as 1-8, but it stabilizes in the 1-10 twist of my own .270 Winchester at 4000 feet above sea level here in southwestern Montana.

You also have a common misconception: Big game bullets do not start to lose stability at 300 yards. There are two opposing forces in stabilization, the spin of the bullet, which provides stability, and air pressure on the nose of the bullet, which destabilizes the bullet.

As the bullet travels through the air, its forward velocity drops far faster than its spin rate, and velocity is what creates air pressure on the nose of the bullet. Consequently, if the rifling twist is enough to stabilize the bullet at the muzzle, the bullet becomes more stable as it travels downrange, because there's far less pressure on its nose.

An exception to this may occur (though not always) when velocity drops near the speed of sound. Depending on air density, this "transonic zone" starts at about 1300 fps, far slower than most big game bullets will expand. It wouldn't affect a 160-grain Nosler Partition started at 2800 fps at any range under 800 yards.

JB: thanks again for the knowledge and the voice of clarity ...we can always bank on your info.

I got my 1st 270 when I was 12.
I have been loading 270 ammo since I was 13.
I have been using 160 gr Nosler Partitions for various 270s since I was about 17.
I have not shot them in any 270 of mine, (11 of them in 49 years) or any other one that I loaded ammo for that belongs to friends (probably about 15) that didn't shoot them just fine.

And they do a VERY good job on game.
Have no fears Gundog. They'll be fine.

Good bullet. Two of the three deer family members hit with 160s were DRT. Number 3 went 20 yards, according to my son's recent description of the kill.

I use 56gr of W780, right in the middle of the last data Hodgdon published for 780.

https://www.24hourcampfire.com/ubbthreads/gallery/80/medium/48704.jpg

Thank you everyone for your replies. John, thanks for the explanation. Yes I was thinking along those lines.

I have been thinking about trying the 160 partition, but until now was a little concerned about stability. Now, I will start working up some loads with RL 26. Deer and Elk beware.

Thanks again.

Mark

Have shot 160gr NPt's through four different factory 270's with no problem, one of the rifles definitely preferred 160's over 150 NPt's. Limited observation but the 270 cal 160gr, 7mm 175gr, and 30 cal 200gr on elk were very similar in their performance on elk--they're all hammers.

Casey

Here is the thread where I asked about them a few years back, I have taken 3 bears now with that bullet and have been pleased.

https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/topics/6376805/1

Casey, the 220 gr Partition is a real hammer too on the bears we have shot with them.

I was 14 when I killed my first bull elk. At last shooting light (maybe a touch later, I was a high schooler) I caught a glimpse of some critters standing in the middle of the long meadow my mom and I were driving through. My rifle was a 270 which I helped my dad build on a commercial Mauser action (I did most of the stock whittling). The load was an unknown to me amount of old T870 powder topped with a 160 Partition. At 75 yds the 1st shot hit him through the chest behind the left front leg, he jumped in the air and began to run in an arc back toward the timber. After the first 20 yards he did not look as if he was gonna slow down like a mulie normally would and I began to perceive I might loose him. So being the young whipper I was I proceeded to unload the rest of the magazine into him, the 2nd shot entered the ribs and plowed through to the front of his right shoulder, the 3rd shot clipped his right rear knee and pushed through the stomach and diaphragm and lodged below where the 2nd shot entered, the 4th and 5th shots all enter his chest on the right side and drove through to the meat of the left shoulder and were found under the hide. 5 shots in about 8 seconds, and he disappeared at the edge of the timber. I finally got a flashlight to work and we found him. The next morning I recovered 4 of the 5 bullets just under the hide and the only bones broken were ribs. The shots were all taken from 75 to 120 yds. Bullets were traveling about 2700 fps as that was about as much as you could get from that powder. All bullets performed as they were intended, nice mushrooms and they retained 35-50% of their weight, if only I had hit solid bone with one of them.

"What he said".

Thanks, John

A great moose round!

35-50% Weight retention? Were those the old screw machine type 160s with the relief groove? The current ones I believe the partition was moved forward and would retain more weight.

If they were not so though to find, I would it for all my elk and moose hunting. A 1/ 10 twist works well, it might be the perfect bull elk bull for my .270's .
It is a fairly streamlined bullet and I am pushing it at 2900 +.
One day I would like a fast twist barrel on a .270, to accept some of the vld stuff available but in the mean time the 160's anchor them in tough conditions.
Shoot a little flatter and hit with the same authority as a 30 /06@ 180 NP's. This I consider the bellwether bull elk round. Remember I said ( wild)Mature Bull Elk

I sure liked that 160 and R26 in my last 22" .270! It was under an inch at 100. I now have a 24" to try them in!

Don't mean to high jack your thread but ... I couldn't get them to group well in my Model 70 w/24" tube unfortunately.
So I have a bag of 50 160 gr. Partition seconds that I won't be using.
If anyone wants to try them out you can for $20 + actual shipping. Shoot me a PM.

That's a good deal. If I hadn't already gathered up several boxes of them, I'd jump on it myself.