Getting My New .264 Winchester Magnum Ready For Elk Season

Last year I bought a model 70 Featherweight in .264 Win Mag intending to use it as a general big game rifle. I didn't end up getting the chance - our first daughter was 7 months old last elk season, and I didn't make it out. This year it's going to happen though - elk in the San Juans is ON!



In this thread I'm going to chronicle getting the .264 ready for elk season. Since the .264WM is not a popular elk caliber (although it is a very suitable one), this is going to involve a lot more than just bolting on a scope and buying some factory ammo. Hopefully some people will find this interesting. Among other things I'll walk through how to develop a load when there's zero load data without risking life and limb.

First up we need a rifle. I bought this M70 last year - a Portuguese-made FN M70 Featherweight. I added a Leupold 3-9 lightweight CDS and a set of alloy PRW rings and alloy bases. Strangely, it seems they dropped this scope from their product line. That baffles me - it's pretty much ideal. And yes, it's magnum rated - supposedly OK up to a .375 H&H AI in a 6lb rifle (OUCH!).

The sling is an Andy's Leather Rhodesian sling.



The overall package is light and handy - exactly what I was hoping for. I do have some slight reservations about the stock in terms of positional stability, but I'll see where it's at before doing anything.

Next up we need a load. This is where things get real troublesome. The 6.5mm have a long track record on big deer species, having crossed the million moose milestone (in the 6.5x55) many decades ago. That said, there are not a lot of good elk/moose bullets available in the US. You really want a 156 or 160gr to ensure proper penetration. There are only two available in the US: the Hornady round nose, and a Woodleigh Weldcore protected point. The round nose is out - way too much drag and completely unsuitable for long shots out west. That leaves just the Weldcore, which is going to have to be our bullet.

it's bonded, and has a reputation for good accuracy. The question is, will it stabilize in the 1:9" twist .264 when it was designed for the 1:200mm m96 Mauser?

In order to answer that, we need a stability calculator. Berger has a good one:
http://www.bergerbullets.com/twist-rate-calculator/
Putting in worst-case atmospherics (sea level and hideously cold) we get:

Hmm, not too good. Luckily we have two things in our favor. First, the minimum hunting elevation in the San Juans is 7000ft. That gives us:

Also, the Miller stability formula is designed for boat tail bullets. This is a flat base. That radically increases stability. In reality this bullet would be stable even on Rosevelt elk at sea level. It'll be fine for this application.

So we've got a bullet. Now what we need is a load. Only one problem: there's exactly zero load data for this bullet in the .264WM. So we're going to have to get some data from somewhere. One option is data for similar weight bullets like the Hornady round nose. Another option is Quick Load.

Hodgdon has published data for the Hornady bullet:


That's a start. But there's a big problem. Putting the same config (bullet, OAL etc.) in Quick Load, here's what we get:
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That's not even vaguely similar - for example, QL says the top load for Retumbo should be 70.2gr. Hodgdon says 64.0 - 6.2gr less. If we plug Hodgdon's max load into QL, we get a muzzle velocity of only 2745 ft/s. Hodgdon says it should be 100 ft/s faster. Not close. The reality is that with middle of the road stuff, QL is NEVER very far off. It sometimes disagrees slightly on pressure (mostly due to measuring methodology) or due to minor differences in cases and primers, but in terms of muzzle velocity, I would expect +- 25 ft/s accuracy. This simulation is right in QL's wheel house - a bottleneck cartridge of medium capacity loaded with a very common Hodgdon/ADI powder at a near-100% load ratio. It should nail this.

Something is horribly wrong here, and before I risk blowing my face off, I have to figure out what it is.

So we've got this mystery where the Hodgdon data and QuickLoad disagree on what max charge is by about 10%. That's too much to ignore. And I'm about 99% sure QL is right, both because it's always right and because the .264WM should get performance very similar to the 7mm Remington magnum - exact same case, same max pressure. So with powders of the optimized burn rate, their performance with the same weight bullets will be essentially the same - the .264 will just want a slower powder. Max load for 160 Weldcores in the 7mag is right about 3000 ft/s. I shoot them at 2950 or so where there's an accuracy node. Velocities in the 2900s should be very possible in the .264. So I know QL is right and something is wrong with the Hodgdon data. But what?!?

I might never have figured it out, but I happened to get lucky. I was looking at the LoadData website to see if any other load data sources could shed light on the problem. The loads themselves didn't help, but Wolfe publishing at some point had published the following technical note, which LoadData had a copy of:
https://loaddata.com/articles/PDF/264 Winchester Magnum.pdf
Cliff notes: Winchester chambers for the .264WM were short throated. That changes everything...

Before going farther, I needed to know what the throat of my rifle's chamber looks like. I have a Hornady OAL measuring gauge, and ordered a .264WM modified case. With it I measured the base to lands distance: 2.762". Wowza - that's WAY short. my 7mm mag is 2.759" (basically the same) and it's OAL is supposed to be 3.29", not 3.34" like the .264WM. In orther words, the .264WM's throat is ballpark 50 thousandths short for the SAAMI OAL. The tech note was right.

This is important information, as blindly loading to SAAMI spec could create a bomb. It also explains what's wrong with the Hodgdon data. They're loading to 10 thousands OVER SAAMI length with a round nose bullet. If their chamber looks like mine they're easily 60 thousandths into the lands - probably more. I don't know what the nose length on that Hornady round nose bullet is, but it has to be short. When you jam the lands, you have to drop the powder charge to keep pressure in line, and you net lose velocity. Sure enough, the Hodgdon data is low on charge weight, high pressure, and slow. Now I don't know what barrel they used to test, and I'm sure it's not a factory Winchester because their data says 1:8" twist, and Winchesters are 1:9". But whatever it was, they must have reamed it with a reamer a lot like the Winchester reamer.

QL can be set to model bullets jammed into the lands by increasing the shot start pressure. When I do that, it says the max load for Retumbo would be 65.6gr (vs. 64gr book load) and that with the 64gr load velocity would be 2864 ft/s vs. 2846 ft/s book. Now everything matches and the world is as it should be. With everything matching up, I feel good about using QL to create load data.

Now to re-configure QL for what my real load is going to look like: the Weldcore instead of the Hornady, OAL of about 3.29" (NOT 3.34") and since I'll now be back off the lands, a normal shot start pressure. Plus my barrel's a 24", not a 26". With all these changes here's the powder list I get:



Of the top powders, Retumbo and Norma 217 are in the garage. I'd rather use Retumbo, so that's where I'm going to start. Nominal max velocity is 2930. I'm going to use a Lee Factory Crimp die (these are hunting loads I want to be tough and waterproof), which changes charge weights and pressures a bit but the basic approach will be to use a chrono and load to velocity - whatever charge of Retumbo gives me 2930ft/s is max. Because of the crimp die I expect to get there a couple grains below 68.7gr. I'll start nice and low and watch both velocity and bolt lift. Due to not jamming the lands, my charges are heavier and my velocites higher than what Hornady got without exceeding SAAMI max pressure.

jmr40 said:

Most bullet and powder companies max listed loads are simply where they stopped testing. Another company may push the envelop farther and show a hotter load as max. With less common cartridges there is less incentive for companies to really push the limits of what a cartridge is capable of. QL may well be closer to the true max load. But you're already in uncharted waters. I'd be careful.

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In this case though their data had peizo pressure readings showing max pressure combined with anemic velocities. Something was definitely very wrong.

Robert said:

Barnes doesn't make anything for 6.5/ 264?

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Good question. Barnes is not a bullet company I normally look at. It looks like in the TSX and TTSX lines they've got a 130gr and a 120gr respectively. I know they penetrate deeper than their weight would indicate and leave a narrower wound channel than lead bullets of similar weight. Overall though I'm comfortable with the Weldcore.

.308 Norma said:

I'm envious Bob. The mighty .264 Winchester Magnum has intrigued me since it first appeared as the "Model 70 Westerner" in the Winchester catalogs my mom and dad used to give away in their country store.
I'm really looking forward to following this thread and your quest for the "perfect" load. It might just inspire me to get a .264 Win Mag of my own - not that I need one. But I turned 70 this year, and you only go around once.

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I'm happy to be an enabler Do it!

blue32 said:

I took the Hornady 160 RN out to 500m on steel repeatedly in a 260 and it doesn't exactly give it a light tap. At 300m it was all day every day. I know you're hunting but I wouldn't write that bullet off because of the specs on paper.

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It's an option, but the round nose will drop below 2000 ft/s at about 350y at 7000 ft elevation. The protected point will do it at about 650y. I'd like to be able to shoot out to 500y comfortably. So the round nose is not my first choice by any means. I'd probably use a 140 or one of the euro 156s first.

Gtscotty said:

They also have the 127gr LRX, with a G1 BC of 0.468. I've been playing with them in my Creedmoor, and they shoot very well. I'm also concerned about the monos causing a narrower wound channel. Last year I took my cow with a 140gr Accubond at about 140yds. Full penetration and a nice wound channel, she didn't go far. I'm thinking I'm going to go with the same bullet again this year as opposed to the LRX since the performance was really everything I'm looking for. Have you considered trying the 140gr Accubond or Partition in your .264? Plenty of penetration and easier to source I'd imagine, you also might have better luck with these in the 9 twist.

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I've considered it. There's a pretty big difference in penetration between the 140 AB or partition, which are expected to retain about 70% of weight, and the 160 weldcore, which is designed to retain 90%+. You can expect roughly 50% more penetration from the 160 weldcore. That said, the 140 accubond would be a backup option. Can't see any reason I'd need to go there at this point though.

I had a chance to go to the range at lunch today, and worked up what the max load is for the 160WC + Retumbo off the lands. This consisted of working up in 1.2gr steps, 2 shots per step, to Quick Load's max load of 68.7. Because I'm using a Lee crimp, I didn't expect to get all the way to max - I expected to run the equivalent of a couple of grains hot. That's indeed what happened. Using this data, I then did a least squares fit to figure out what charge weight should give me max velocity. The velocity vs. charge weight and velocity vs. pressure curves are locally linear (ignoring barrel harmonic issues) so this is a legit approach.

As expected, I reached load-to velocity (and thus implicitly pressure) about 2 grains below what QL would have predicted. I didn't shoot the last two charge weights as a result - there was no need.

Bolt lift on all shots was OK, but the last, faster shot at 66.3 grains I felt just a touch of something, which is about right as in M70 actions you start feeling a little something around 60KPSI.



So now we know with the 160gr Weldcore, loaded off the lands 20 thousandsths, with Retumbo, with a crimp, the max load is 66.6gr and that this is a very safe load. It's also 80 ft/s faster than Hodgdon's max despite using a 2" shorter barrel - the reward for not jamming the lands. This load is NOT safe jammed obviously.

We'll be making use of this data shortly to start development for accuracy.

One other aspect of today's loads was a chance to evaluate the dies I was using. Runnout using the RCBS seater was .004" measured with a Hornady gague. That's high - the Hornady gauge reads lower for the same round than some gauges with different geometry. Seating depth accuracy was about +-.003 measured to the ogive. This has never been an easy measuement for me, so I'm not sure it means much. Loaded neck size was .294+.0005, meaning the Nosler brass I"m using has .015 walls give or take. That's about what I expected. Means I probably want a .291 or .292 bushing in whatever sizer I end up using long run.

Overall I'd much rather be using some better dies. I looked at the three usual suspects (Redding, Whidden and Forster) and emailed Forster. They don't do .264WM and aren't taking custom orders. Redding competition sets can be ordered by midway for $400 (!!!) and $350 from Brownells but they take ??? to get here. Whidden is $325 custom made to your brass with a micrometer full length bushing sizer and micrometer seater. The idea of a full length bushing sizer, but made to my chamber dimensions rather than SAAMI min dimensions, appeals to me. That should give me full control of the body, shoulder, and neck without overdoing anything. I'll order a set of the Whidden dies tomorrow. They need 3 fired cases, which I now have. Whidden advertises a 8-12 week lead time, which if true will have them here several weeks before the hunt. They could be blowing smoke of course. I'll do my development with the RCBS dies for now and see what happens.