264 Magnum load for pronghorn and more - TTSX, LRX, Controlled Chaos

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Jan 3, 2024
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Location
Great Basin, USA
I want to develop a load for a fine 26", 1:9" .264 that has limited barrel life, so I am not afforded limitless experimentation. I'll be using Nosler brass.

I have TTSX in 100 and 120 grain, LRX in 127 grain, and Controlled Chaos in 110 grain and will use one of these for the 264 load.

I hunt mule deer and pronghorn in the Great Basin. I could someday hope to draw mountain goat, black bear, or bighorn tags. I have a better chance of drawing an elk tag. I've seen elk while mule deer hunting, and have built some points up, but haven't applied because I'm not prepared to backpack out an elk.

I've taken a few mule deer with the 115 grain TAC-X in a bolt-action Grendel, and the 127 grain LRX in 6.5 Creedmoor. They worked like I would expect a copper mono to. They penetrated fully. They resulted in expiration in a few seconds with one taking longer but not able to move and no game getting farther than 50 yards after being hit. I aim for heart and lungs and won't change that.

The 264 seems ideal for pronghorn. It would work for all the other game, but the rifle is a bit long and heavy for rough, steep terrain. If I made one load for every possible type of game, it would be with the 127 grain LRX because it's the only bullet of the four I'd use on elk or an unlikely large black bear (most of them here are under 300 pounds). I'd feel confident using any of the other bullets on any of the other game.

The 100 grain is the fastest and flattest shooting, but the heaviest LRX only drops an inch more at 300 yards. The 100 grain strikes with more velocity within hunting ranges typical for me (200 to 300 yards). The lower drag LRX doesn't preserve enough velocity to speed faster than the 100 grain until after 600 yards. The heavier bullets hit with more energy, but I don't see the 100 grain failing to fully penetrate a pronghorn or even a mule deer. The features of the Controlled Chaos could anchor game faster than an expanding mono, but I've not tried them yet.

Barnes recommends a 1:8" twist for the 127 grain LRX and the 264 is 1:9". However, if I use a JBM or Berger stability calculators, they indicate I would have enough stability. Consider that I am hunting from 4000 to 9000 feet. Pronghorn hunting is in September when the air is even thinner because it's hot. Mule deer hunting in October is often at 30 degrees, and can be as cold as 0 deg. F but is likely to be at 8000 to 9000 feet at those temps. In any event, JBG indicates an Sg of at least 1.4 in the worst conditions and Berger's, a little more pessimistic, still indicates a good Sg in the most likely conditions.

I'm skeptical whether the 127 grain LRX will do anything for me vs. the 100 grain TTSX on pronghorn even out to 400 yards. The main reason I'm considering it is that it would make the rifle more versatile for highly unlikely game. So my question is, whether the LRX would cost me anything on the most likely game, pronghorn and mule deer, compared to using the 100 grain TTSX or the 110 grain Controlled Chaos.

If I were to hunt elk, which I have some doubt I ever will, I'm not sure I'd want to do it with this rifle even with the 127. For mule deer, I think I'd rather have a shorter, lighter rifle in the mountains. This rifle is 9 lbs with a Leupold mounted, and it's 46" long. Even so, a Ruger American in 308 with a 20" barrel and a good scope is going to be fewer than 2 pounds less and only 5 inches shorter. This rifle has been in the back of closets and safes for 60 years (it's older than I am) and it's time to do something with it. Also, it is my only hunting rifle. The Grendel and Creedmoor I mentioned earlier are my sons'. I'd kind of like to make it the only one I'll ever need even if it took two loads for it.

So what do you think? Should I load the light 100 grain bullet or the Controlled Chaos and have the best performance on pronghorn? Or should I load the 127 grain LRX and be set for life even if I draw a rare tag?
 
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Here's the ballistics data for the 100, 120 grain TTSX, 110 CC, and 127 LRX:

^^ the data is in there

I don't have any powder in this burn rate range yet. I was thinking of something like H4831SC for the lighter bullet and if I went with the 127, maybe I could try the new Ramshot Grand, or Staball HD. I'm tempted to play to the strength of this rifle and cartridge and go for super velocity, but I'm afraid I would be disappointed if I tried really slow powders like Retumbo or LRT with the 100 grain bullet. Like I wrote, there's limited barrel life and I can't afford to experiment endlessly. H4831, IMR4955 (if I can find it) or IMR 7828SC would be a safer play.
 
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Any of those bullets are more than enough for any antelope. Even the 127 is imho, might be ok for muleys, but is on the too light side for elk or bear. Speed without sectional density (and thus weight) means little to them if a shot is not perfect. I've taken dozens of antelope and a couple elk with a 264, but was using 140gr, antelope all drt, one elk drt and one went maybe 50yds, both boiler room shots like yours. Why not just re-barrel it for 140-156gr and then with proper shot placement it will do all the tasks you list and do them very well! Shot placement is King.
 
western living,

I can't offer any load assistance, but I can say Welcome from North Central Wyoming!

I hope that others can give you some load information and I hope that you can make this your new internet hunting/shooting home! memtb
 
I shot the barrel of a Winchester Westerner in 264 WM with 61g of IMR 4831, Rem brass, Rem 9 1/2 primer with 129g Hornady Flat base which acts like a partition.

I would substitute that load with the 127g Barnes LR, and jump it .050 from the lands.

I have a friend who shoots 140s with H1000 with some incredible speed and accuracy. H1000 is a very cool burning powder and should give you another 30% barrel life.

Best wishes
 
Well, I have my dad's pre64 that's older than I by 4 years. Been shooting it since '76 (11 yo). 2,500+ rounds down the pipe, but don't shoot it much anymore. I have a newer mod70 and a 264wm build w/ 110 action. Not sure how long the 127 is, but I've shot Sierra 140Sbt (not smk) with the 9 twist without any issues. The 140's used imr4831 @ 61.3gr. That's .5gr over Sierra's data max charge. Both mod70's have 9 twist, but the 110 build has a 7.5 twist for the 150smk's. Altitude I shoot at is ~2,300'.
 
Your lighter bullets will work fine for pronghorns,but at the same time they are going to cook your barrel. Have you had your 264 scoped by a gunsmith. Pac-Nor will duplicate your factory pre64 barrel and you would be off to the races with a 1/8 twist. Your 127 Barnes need a faster twist jmho,you could try some ,heck prove it to yourself . A new bbl would bring new Life to that special pre64 you have . Cheers 🥳
 
Your lighter bullets will work fine for pronghorns,but at the same time they are going to cook your barrel.

That's an interesting point. It's hard to predict barrel life precisely, but one rational estimate that I've read is to expect to burn no more than 20 pounds of powder before throat erosion degrades the barrel. If I were to use Barnes load data 20 pounds of IMR7828SSC would yield 2083 cartridges with the 100 grain bullet or 2500 with the 127 grain. The light bullets might burn out the barrel 416 cartridges earlier.

If we expect the amount of powder burned will determine barrel life, but we're not sure if 20 pounds is the rule, expressed as a percent, it could be said that the light bullets will result in 16 percent fewer cartridges in the barrel's life, or that the heavier bullets will result in 20% more barrel life.
 
I think the other questions pertain to ARlife4me who also has a Pre-64 M70 Westerner. I have not scoped this one because I know it has had 19 cartridges down the bore in the last 60 years. It has printed sub-MOA with Nosler factory ammo (140 grain Accubond), albeit only in limited groups -- I just haven't fired it so much that I can say it's always that accurate.
 
I know that Barnes recommends 1:8 twist for the 127, but that is a general recommendation. Bullet stability depends on more factors than bullet length and twist rate. Chiefly, it depends on atmospheric conditions. There are two stability factors, gyroscopic and dynamic stability. We can only concern ourselves with gyroscopic stability as the latter is the domain of the bullet designer. Gyroscopic stability or Sg is considered good at 1.5 and above.

Here are the calculators:

Notice that air temperature (and therefore density) is a major factor in stability. Altitude also affects air density.

The Barnes 127's are 1.402" long. If I shoot them with a 1:9" twist, I should be fine provided it's warm when I'm shooting pronghorn at a lower altitude (4000 feet) in September. If I were to shoot deer, elk, bighorn, or mountain goats in October, it could be colder, but would also likely be at higher altitude (6000 to 9000 feet). The worst-case scenario would be shooting in extreme cold temperatures (which are about -5 deg. F because remember it's only the end of October), but those temps are only likely to occur at the higher altitudes. The last buck taken was at 9300 feet and it was -5 deg. F that morning, but only before sunrise. That shot was at about 9AM and it was quite a bit warmer, maybe in the 20's. It was a 127 grain LRX but out of a 1:8 twist Creedmoor. So, with the 1:9 twist, I would have a worse situation if I were to come down to sea level and shoot on cold days. It probably wouldn't work in Alaska.

It should also be noted that lower Sg affects BC. The Berger calculator shows how Sg's below 1.5 increasingly degrade the BC. Consider that the 127 grain LRX has a G1 BC of .468, whereas the 120 grain TTSX has .412. If I were to take the LRX to sea level in Alaska and shoot it in 1:9 twist barrel when it was 20 deg. F, I would have an Sg of 1.1 and the BC would be degraded by 12% down to .412 -- no better than the 120 grain TTSX. But the 1.322" long TTSX would be degraded down 8% to a G1 of .379. In those conditions, the Berger calculator recommends a 1:7.5" twist for the LRX and a 1:8 twist for the TTSX. In those conditions, the 1.156" 100 grain TTSX would be stable with an Sg of 1.52 in a 1:9" twist barrel.

Swapping in a 1:8 twist barrel allows the use of heavier for caliber and therefore longer and often lower-drag bullets, but over-stabilizing bullets can degrade accuracy. There's no question that with current trends, a 1:8 twist is more practical for a .264" bore. If I had thousands of rounds down my barrel already, I could consider replacing it, but since this barrel has lots of life left in it and has shown to be very accurate, I would rather load to its requirements.
 

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