School me on .338 win mag reloading

Choupique

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Oct 2, 2022
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I'm looking for some critiquing or advice on any of my rifle reloading habits. So far, I've only shot targets with my reloads and still hunt with factory ammo. I guess I'm looking for some reassurance that I'm making reliable ammo, or some guidance on how to get there before I hunt with the stuff.

I've been reloading rifle rounds for about a year now, mainly .338 win mag. Currently using recycled norma brass on its 3rd firing, 250gr speer grand slam bullets, RL17 powder, CCI mag primers. It's a hunting rifle through and through and reliability and safety are my main priorities, and affordability. I want to be able to shoot my hunting rifle a lot, and since 338win ammo is outrageous now it limits me to reloading. If it weren't for the cost of factory ammo, and Norma discontinuing the load I really liked, I'd just hunt with and shoot that.

I've been using a lee collet neck sizing die, just because I had read that belted mag case life is terrible full length sizing. On the 3rd firing they still chamber butter smooth and extract easily. Powder charge is 2 grains under the speer book Max for this bullet and its fast, I stopped there because it was already faster than book max speed, I think 2,800 fps if I remember right and LOTS of recoil. Using a lee factory crimp die seated to the canalure. RL17 powder, measured on a lee safety balance beam, I believe 67 grains if I remember right (don't have my notebook).

I'm rethinking my approach, mainly worried about having reliability in all weather conditions. I think I want to start full-length sizing, per the die instructions where you cam over against the shell holder. I realize this will shorten case life, but how much? Conversely, if I just bump the shoulder back a couple thousanths, will I have sufficient safety margin for wet cartridges, bad weather, etc? It wasn't clear in the form reloading method thread if he is bumping the shoulder back or actually running the die all the way down. Conventional internet wisdom says bump the shoulder back, but there seems to be more hunting-centered knowledge here than the other places.

Is it going to be really obvious when I should throw the cases out? I read about loose primer pockets, split necks, case head separation... I have no clue what any of that looks/feels like in real life. The cases I started out reloading first (45 colt) are on their 6th loading and still seem fine to me???

Should I be sealing these things in any way? It rains a lot in hunting season in louisiana. My concern with my current ammo is that while I am under book max charge, and everything looks OK to my untrained eye, I don't want to blow myself up from having some water in the chamber or something else that slightly increases pressure. I want safety margin.
 

Caseknife

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Feb 22, 2020
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If your rounds cycle easily with the resizing you are doing, stick with it. Basically all the resizing die does is to allow chambering in the rifle. If you are concerned at all, just run all your rounds through the chamber prior to hunting with them. What are you using for calculating velocity? Interesting that you are over book max velocity, but two grains under max.
 

Leverwalker

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My only thought would be that if you're looking for cold weather tolerance, you might consider Hogdon 4831or 4831-SC. These are designed to be cold- and hot-weather tolerant. I use 4831-SC for my 225-250 gr .338 WM, to really good effect; I abandoned 200 grain bullets but H 4350 works well there, for me. And just a thought, but at 250 grains, have you thought of going with a slower burn rate than R 17? I settled on H4831, but also have had good results in this bullet weight range with Ramshot Hunter and RE 22. I shoot 225 & 250 gr Hornady Interlock SP-RPs, and 250 gr Barnes TSX's.

I set back 0.003. I anneal every 3rd firing for the .338; for my straight wall 45-70, each 10th time (not even sure that's necessary, given prior to annealing, I easily got 20+ 45-70 hot loads without issue); every 4th time with my son's 30-06. I prefer Starline brass everywhere, but they don't make .338 WM. For the .338, I use WW cases, and Rem Mag primers, though I prefer CCI primers for everything, just have a hard time finding them. I can only say all my brass is in good shape, without evidence of loose pockets, splits or imminent separation.
 
OP
Choupique

Choupique

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I have some IMR4831 and made up some loads with it and 250gr accubonds, but I switched to the RL17 because it looked better in the speer load data - it was faster and listed as most accurate. I can't tell the difference in accuracy between the two, but the 17 isn't compressed and the 4831 was, so I guess that seemed like a good thing to me at the time. Maybe the grand slam didn't have listed data for the IMR4831 and that might be why I switched. I dont really remember. I've been sticking to loads I can find book data for. Both loads are noticeably more accurate than the factory loads I'm hunting with. I'll check my notes tomorrow and get the details.

I know with the accubonds, I was loading them all the way out to .050" under magazine length, which is still well off the rifling. With the grand slams I'm loading them to the groove, since that seems like the right place to crimp them?

It seems to me that bumping the shoulder back a few thou and staying within the book loads should be safe in any conditions?
 

Leverwalker

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Be careful - IMR 4831 and Hogdon 4831 are two completely different powders. IMR 4831 is faster than H 4831. I 4831 is fine, but it doesn't have the weather-tolerance that the Hogdon line - the "Extreme" line - is supposed to have. The added performance is merely anecdotal for me. I'd say, go with what you have. If your Re 17 is working for you, great. I just prefer slower powders for heavier bullets. If you have I 4831 and want to try it, I don't think you can go wrong.

Here is what I have for the 4831's. This is from Hornady's data, assuming it's 250 Grain SP-RP:

IMR 4831 maxes out at 69.1 grains and book velocity of 2650 fps.
H 4831 maxes out at 75.3 grains, for the same velocity of 2650.
They do not list RE 17, but for the RE 19, they show max of 73.7 grains and 2700 fps.

I just looked up load data, and came up with:

250Speer GSAlliantRL-1766.02664 fps

For the Hogdon data using IMR 4831, I'm getting:

250Hornady SPIMRIMR-483167.02474
Remarks: start load; COL: 3.340"; 45,300 cup
250Hornady SPIMRIMR-483171.62632
Remarks: max load; compressed; COL: 3.340"; 52,400 cup

On the set back and OAL questions, there are people far more knowledgeable than me. I'm not sure when you're looking to lock in your load (is it for this season?), but if it was me, I would not worry right now about set back and just make sure with your chosen bullet, your round can chamber - and it looks like from Speer for the 250 gr Grand Slam, they suggest 3.300" for an OAL. Whatever you've been doing, if it works and can chamber, I'd stick with it for now and just get your load worked out. I'm with Caseknife on this.

Here's what I see from Speer's data:

speer gs 338 data.jpg
I'm seeing RE 17 max (68.7 gr) is compressed, while I 4831 (69.0 gr) is not compressed. Max velocity for both is about the same, 2665 and 2620 respectively. I can understand the concern on a new cartridge and compression, though I've never had issues. You could always try backing off to 96% or so, and go up carefully to 99%. Hopefully that gives you a good solid load.
 
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Choupique

Choupique

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Definitely not concerned about having this sorted out for this year. I've got plenty factory stuff left and just deer hunting the rest of the year. Right now, the reloads are just for learning how to shoot long range and learning how to reload. Im only using grand slams because they were the cheapest thing i could get that would be an acceptable hunting bullet. I've got a year or two to sort this out at least.

That's the same chart I was working off of (I think), but I'll check the notes tomorrow. I remember getting around 2800fps well short of the book max charge, and that basically made me hit the all-stop for now.

My main concern right now is how I should size my cases. Do I need to FL size them to cam-over for 100% reliability, or is setting the die for a little shoulder setback (say 0.003") going to be fully reliable?

In the same vein, is loading longer than book OAL just because I can, always a good thing to do? Mag length is a good bit longer than book length with both the accubond and grandslam, and length to jamming the lands is much longer than that.
 

Leverwalker

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Again, I'm not a guy to opine on the shoulder bumping process. I only learned it to preserve my bottleneck case life, most especially, like you, for my .338. I merely followed step-by-step having gotten some help, so can't give you a lot there and will definitely deign to others. This was one of the videos I found helpful.

On your OAL, my advice is, to go with the manufacturer's recommendation to start, unless it won't chamber. I think it's important to work on one variable at a time, otherwise you don't know what bettered or worsened things, manipulating multiple variables at the same time. I would seat to Speer's recommended OAL for the GS, get your load worked up, and then, if you want to fine tune it, start to work on your seating depth.

One thing I'd want to ask - are you annealing your cases? I ask, because any time we size, we work harden the cases and as I understand it, absent annealing at least every so often, getting an accurate bump (I mean, one that stays once sized, and doesn't spring back) can be a problem. Take it with a grain of salt per above.
 
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Choupique

Choupique

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I haven't annealed anything. I might try it with some of the old school techniques I've read about, like a candle and bare fingers, just to try it. I've honestly got a fairly healthy pile of oddball brass ill likely never use so if I ruin some it won't really matter. I'm planning to try it after I shoot my most recent batch. I've yet to touch the 338 brass with a FL die yet, so I haven't thought hard about annealing yet either.

I've got my notebook here finally. My last time out. Norma brass, CCI mag primers, 250gr grand slam. Loaded 66.5gr RL17 at 3.315" OAL got me 2785fps. Jam length in this rifle is 3.464" for that bullet and mag length is 3.409"

My accubond / 4831 load was norma brass, cci mag primer, 70gr of IMR4831, 250AB loaded to 3.385 OAL. Averages 2700 fps with lots of variation (65 fps or so).

All were done with a lee collet neck die and a lee factory crimp die. Both seem to group well, about 1.5" for a 10 shot group that was 5 of each load.
 

Leverwalker

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I haven't annealed anything. I might try it with some of the old school techniques I've read about, like a candle and bare fingers, just to try it. I've honestly got a fairly healthy pile of oddball brass ill likely never use so if I ruin some it won't really matter. I'm planning to try it after I shoot my most recent batch. I've yet to touch the 338 brass with a FL die yet, so I haven't thought hard about annealing yet either.

I've got my notebook here finally. My last time out. Norma brass, CCI mag primers, 250gr grand slam. Loaded 66.5gr RL17 at 3.315" OAL got me 2785fps. Jam length in this rifle is 3.464" for that bullet and mag length is 3.409"

My accubond / 4831 load was norma brass, cci mag primer, 70gr of IMR4831, 250AB loaded to 3.385 OAL. Averages 2700 fps with lots of variation (65 fps or so).

All were done with a lee collet neck die and a lee factory crimp die. Both seem to group well, about 1.5" for a 10 shot group that was 5 of each load.
I think your goal to get consistent results is at odds with using odd brass, etc., so totally honest not quite sure where you're heading at this point. Just a note, but for annealing I use a propane torch, hold my cases by the bottom, rotate in my fingers in the "middle" flame until they get hot to the touch, and drop them on a cotton towel. Not the best method, but cheaper than a dedicated annealer and it gets me where I'm going well enough.

Your 66.5 gr RE 17 is approximately 97% of max. If that works, awesome, whatever works. For many of my loads, I don't hit the sweet spot until 98.5% to max. And again, the I 4831 max doesn't show as compressed, according to Speer.
 
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Choupique

Choupique

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Ah, I meant use the oddball stuff just to figure out a technique or whatever. Its all .30-30 brass that I'm planning to work up cast loads for playing around with eventually. That way I don't screw up my $2/case .338 brass trying to learn how to do it.

So, being faster than max at less than max doesn't seem weird? I know my charge weights are right, I verify with a check-weight set starting out and every couple loads. I know my measurements are right, I used to be a machinest. Being faster than book max just makes me a little nervous, since that's got to mean I'm over max pressure? Even if there are no "pressure signs?"
 

Leverwalker

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Ah, I meant use the oddball stuff just to figure out a technique or whatever. Its all .30-30 brass that I'm planning to work up cast loads for playing around with eventually. That way I don't screw up my $2/case .338 brass trying to learn how to do it.

So, being faster than max at less than max doesn't seem weird? I know my charge weights are right, I verify with a check-weight set starting out and every couple loads. I know my measurements are right, I used to be a machinest. Being faster than book max just makes me a little nervous, since that's got to mean I'm over max pressure? Even if there are no "pressure signs?"
Ah, gotcha. I'm stumped on the velocity exceeding the stated book, to be honest. I can't answer for you and the usual caveats (at your own risk, etc.) apply, but if it were me, I'd feel comfortable going to Speers's own stated values. In fact, I do go to max (and compressed) on many loads. For me, especially on 100-125 yard shots (i.e., my 45-70), chrono data doesn't mean anything compared to what's on paper. Totally different game on long distance, obviously, but even then, if I want to know what shoots at 200, 300 yards, etc. - shoot 300 yards.
 

BigNate

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Did you track the velocity changes as you worked up?

A big jump in velocity for a small change in charge weight is where it gets dangerous as it represents a pressure change that is exponential to previous charge increases.

I've been loading for my .338WM for a long time and have not used RL17 ever. I'd have to check my notes but I believe RL19, IMR4350, and H4831(and now the sc version) have been my main powders.
 
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Choupique

Choupique

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I'd feel comfortable going to Speers's own stated values

Yea, I think I'm going to stick with that charge for now. I can't imagine they'd publish stuff that is so tached out that it'd be a risk of blowing stuff apart even with tight chambers or stuff like that. I don't have any way to prove it, but I get the feeling my chamber is probably pretty loose just because it's a factory barrel chambered for a belted mag, and it definitely has a long throat.


Did you track the velocity changes as you worked up?

A big jump in velocity for a small change in charge weight is where it gets dangerous as it represents a pressure change that is exponential to previous charge increases.

I've been loading for my .338WM for a long time and have not used RL17 ever. I'd have to check my notes but I believe RL19, IMR4350, and H4831(and now the sc version) have been my main powders.

Yea, it was fairly linear on the way up. How do you size your brass and has it served you well?

I'm going to burn through this pound of RL17 and see how it goes. So far, I like it. It's damn fast at 4 grains less than with IMR4831. I figured 4831 would be faster with the heavy bullets and long barrels.
 

OMF

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Regarding the velocity difference, not all guns shoot/measure the same and not all chronographs measure the same with the same load. I would say it is just a variance in how that load shoots in your gun and how your chrono measures vs theirs.
 
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Choupique

Choupique

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I went burn some powder on my lunch break today. It was raining, and I said screw the chronograph I'm just going shoot to make sure I can kill stuff this weekend.

Factory norma oryx (6 shots) reloaded 250gr accubond (3 shots) and reloaded speer grand slam 250gr (6 shots). Total group size was about 4" at 100 yards, one sailed way way high and I don't think it was me that did it. The grand slams really opened the whole group up a lot, with the high one and the farthest left both being grand slams. I think I'm going to ditch the lee crimp die, load up 10 more and roll crimp them, and see if that makes a difference. Speer recommends not using a lee factory crimp die, which I just learned today.

Not necessarily any usable information, but fun to shoot. I thought it was pretty cool that I could kill deer to 200 yards with any of these loads without changing zero. Interesting that a few weeks ago I took the scope off the rifle, took it out the stock, spray painted it, reassembled it, remounted the scope, and had the EXACT SAME zero - 0.5 mil high and a little right - as prior to doing all that work. I thought that was pretty neat.
 

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