Home Forums Reloading Big Game Rifles .348 Win with cast bullets -- powder selection?

My .348 handloading restart project continues apace, at least with the Hornady 200-gr JFP so far. Detoured by needing a taller front sight, since changed. Hampered a bit by only having one suitable powder on hand, and supply chain difficulties with other powder options...

But now I'm looking further ahead to the next part of the project whenever I can get around to that, using a 200-grain cast/gas-checked RNFP from Montana Bullet Works (cast from RCBS #57911). My goal is NOT a particularly "reduced" load. Instead, I just want decent accuracy at just under whatever velocity ceiling it takes to give no significant barrel leading. If that means 1800 FPS, 1900, 2000, whatever... so be it. WITH a temperature-insensitive powder. WITH a load/fill ratio of 90% or better.

A cursory powder survey suggests the best temp stable powders these days for this application could be Reloder 23, H4831/4831SC, H1000T, IMR 7977, and IMR 8133. Of those, it also looks like 7977 would be best "higher velocity" choice, and H1000 might be best "lower velocity" choice. (In this case, "higher" and "lower" are only significant to me as it might impact that leading issue.)

I welcome commentary, suggestions, critique, etc... especially if I might be missing something altogether.

-Chris

None of those powders are recommended by Lyman's cast bullet handbook for any cartridge firing cast bullets. These most likely would have wide standard deviations in velocity at reduced charges and may even be unsafe to reduce. Best stay with recommended cast bullet powders. I'd recommend anything from 32.0grs to 37.0grs of IMR-4198 with that there 200 gr cast gas checked bullet. You'll have excellent results, no leading, velocities from 2000 to 2300 fps

Thanks. Did any of these powders exist when that Lyman's handbook was published? IOW, were they not recommended because they're too new?

Interesting to see 2000-2300 FPS with no leading. I've not worked with gas-checked bullets before, didn't realize they can be pushed that fast without smearing.

Note that I'm NOT looking at reduced charges; QuickLoad suggests I could run any of these powders at over 90% fill...

-Chris

H4831 has been around for over 70 years, so yes Lyman could have used it but chose not to, probably because at reasonable cast bullet velocities the pressures are too low for consistent ignition/burning. Ditto most of the other powders listed. I suppose you could use the slow powders and get them to work at some level, but decades of experience has shown that faster powders work better. 90%+ case fill isn’t required either. No need to reinvent the wheel here.

I take your point. I have some cast load recipes, mostly from Pet Loads (including Ken Waters) but also from a few others... but I don't have the Lyman book. Can you guys tell me what other powders they recommend, and at what pressures?

-Chris

Chris,
Using cast lead bullets definitely implies reducing the powder charge for two reasons (at least) 1.Cast bullets cannot be driven as fast as copper jackets. 2. Cast bullets are considerably softer plus lubed, so there's way less friction. Less friction means more efficiency so you'll need less powder to reach the same speeds. I suppose this all depends on what the purpose is for these loads. If you want to see a group size measured by the county simply keep the powder charge at full power and simply replace the copper bullet with the lead one. 😀

FWIW older Lyman reloading handbooks provided cast bullet loads for the 348 using slower powders up to 4350 and H380.

In general cast bullets for me tend to provide good accuracy with loads up to the 1600-1800 FPS range. You can achieve accurate loads at faster speeds but it becomes more difficult to achieve. It is because of this that burning rate powder recommendations tend to be on the faster side.

However if you do have a good design, the right alloy, use a high speed lube, fit a gas check and it’s sized correctly you can achieve higher velocities accurately. I think with newer PC and Hitek coated cast pills we could see higher velocity loads but this is not an area I dabbled in yet.

From the Lyman manuals I have one lists the following loads for their light 187gr pill (#350447).

Start 25gr IMR 4198 1672fps
Max. 35gr IMR 4198 2150fps

Start 35gr IMR 3031 1828fps
Max. 47gr IMR 3031 2338fps

They also list their best accuracy was achieved using 41gr 3031 developing 2060fps.

Yep, got that. Maybe useful if I hum a few bars about "reduced." When I've said I'm not looking for "reduced" loads, I've been meaning loads using something like 5744... with velocities down around 1200 FPS or less...

Using 2500 FPS as a plausible reference for some loads with 200-grain jacketed bullets... I recognize cast lead/gas-checked bullets should be loaded to lower velocities. I'd been guessing, based on loading articles I've read, maybe 1800-1900 FPS (???) max to avoid leading... another reason I was surprised by that 2300 figure. But anyway, I just haven't been meaning to apply the word "reduced" to 1800-1900 FPS loads. Sorry if confusion...

-Chris

Thanks, that helps.

I see QL predicts 41-gr of 3031 gives 19955 PSI and 2047 FPS. 47-gr gives 29088 PSI and 2340 FPS. 35-gr of 4198 gives 23577 PSI and 2060 FPS.

For temp stable powders in roughly the same pressure and velocity areas, QL seems to home in on 7977 Enduron or H1000. For example, 58-gr of 7977 (96% fill) gives 23716 PSI and 1982 FPS. Or 60-gr H1000 (99% fill) gives 20626 PSI and 1916 FPS.

I'd think temperature stability would be a good thing. What kind of "swing" (?) from those powders do you guys get from temps ranging between 0°F and 90°F or so? Accuracy differences a lower vs. higher temps? Point of aim shifts? Or nothing much? Or...?

-Chris

Most of Hodgdon’s rifle powders are temperature stable. I’d look for some Benchmark which is about the same burning rate as IMR 3031. If you want to try slower powders, then try H4895 or even Varget.

Chris,
With my alloy plus homemade bullet lube I have no trouble keeping accurate groups with no leading at 2300 fps. I've been molding Lee 170-309 in gas checks with excellent results. I recently cut one ragged hole with 4 shots at 100 yds. I mostly use recommended powders for cast bullets as listed in the Lyman cast bullet handbook. This book is very informative on the metallurgy involved in making a suitable alloy for cast bullets. I have as close as I can get to the lyman #2 alloy then they fall from the mold into ice water to quench harden. I hope you enjoy the cast bullets as much as I do. It's an excellent way to conserve resources and still obtain useful performance at reasonable ranges all the greatly reduced barrel wear and tear

Thank, JFE, I'll check those out.

Gas, the cast/gas-checked bullets I have are commercial, so I dunno hardness and they're lubed with whatever. (Look good, though.) I guess I'll just have to experiment with velocities, whenever I get around to this part of my .348 project.

I don't have very much experience with large rifle cases, but I'm surprised you guys get good accuracy and consistent velocities from loads only a little over half full of powder. With smaller handgun/rifle cases (e.g., .44 WCF) I didn't really start getting best consistency and accuracy with faster powders until powder charges got up to about 90% or so... and even that wasn't great until Trail Boss came along. Light charges of Unique, Red Dot, and Clays weren't horrible... just not as good...

-Chris

You will need a neck expanding die to properly seat cast bullets. RCBS make one and Buffalo Arms makes a range of custom neck expander plugs to fit the Lee die.

You should also aim to buy a Lee factory crimp die as the 348 has no throat.

Got those. Sorta. I've removed the RCBS decapping/neck expander pin for resizing -- after using a universal decapper. Then I'm re-inserting the decapping/neck expander pin to expand the neck during the press downstroke. Seems to be straight, i.e., only minimal run-out.

It's a .348 expander, though. Works well enough with the .348 cast bullets I have on hand (at least for a dummy round). I guess I'd probably need larger if I had .349 or .350 cast bullets, though...

I am using the Lee FCD, but... "no throat?"

-Chris

Good call JFE! I use the Lyman "M" die in all the calibers that use cast bullets. This die will expand the neck diameter to the proper diameter for cast bullets.

Most levergun rifle calibres have little to no throat. There are exceptions like 375 Win and 450 Marlin and rifles in pistol calibres are different. What you might detect as a throat is likely to be a slightly longer neck. With any levergun cartridge it’s a good idea to have a Lee FCD on hand.

Your cast pills should be 0.349 or 0.350 in diameter. The regular neck expander in your die set will likely be 0.347 or maybe 0.346. Lyman’s M die is a two step expander, though not sure if Lyman currently make one for the 348Win. In this case the first stage should ideally be 0.350/0.351 and the second stage 0.348/0.349. This is so you can fit the cast pill in the neck with perfect alignment and apply just enough neck tension to secure the bullet without distortion.The Buffalo Arms custom expanders come in a wide range of sizes and IIRC are a two step design like the M-die.

Thanks for the wake-up call. I hadn't thought far enough ahead about actual bullet diameters. Yep, sure enough, one is .349 and the other is .350, and you're right, the RCBS expander button is .347. So I'll get on with shopping for a better neck expander system.

Got it, ref throating. Didn't know that, but I had already decided to use the Lee FCD anyway... at least on whatever bullets have crimping grooves. (And all my various .348s do.)

-Chris

I think I'd forgotten to mention there was an additional reason I started looking at the original 5 (6? 5½?) powders I originally named: Reloder 23, H4831/4831SC, H1000, IMR 7977, and IMR 8133. And then maybe my original focus on 7977 and H1000 maybe sort of caused me to wander off target a bit more (than usual).

That extra reason was that R. L. VanDenburg in Handloader #52, December 2017, suggested the following Hodgdon (now Extreme) powders with 200-gr cast/GC RCBS (with some informal QuickLoad computations that I've added here):
- H4895, 42.0-gr, 1999 FPS (QL = 68.7% fill, 20433 psi, 2011 fps)
- H4895, 43.0-gr, 2143 FPS (QL = 70.3% fill, 21735 psi, 2059 fps)
- H4350, 52.0-gr, 2132 FPS (QL = 86.9% fill, 24156 psi, 2104 fps)
- H4350, 53.0-gr, 2153 FPS (QL = 88.6% fill, 25511 psi, 2148 fps
- H4831, 59.0-gr, 2145 FPS (QL = 99.3% fill, 26866 psi, 2171 fps)
- H4831, 60.0-gr, 2176 FPS (QL = 101.0% fill, 28395 psi, 2216 fps)
But “best this bullet” was with 21.0-gr SR-4759 at 1624 fps. (IMR SR-4759, apparently discontinued, isn't in my QuickLoad powder tables...) I don't see a quantification of what "best this bullet" means, just the broad brush "in terms of extreme spread and group sizes." I don't see his goal specifically cited, either; seems almost like just testing a bunch of likely powders with a bunch of likely bullets... without mentioning specific interest in best accuracy, highest velocity, stability or consistency, lowest recoil, etc. (Closest he comes to that is about backing off from max loads to minimize case stretching; seems a good idea.)

QuickLoad comparisons to those Lyman loads, above, simply 'cause it was easy to do:
- IMR-3031, 35.0-gr, 23577 psi, 2060 fps
- IMR-3031, 47.0-gr, 29088 psi, 2340 fps
- IMR-4198, 25.0-gr, 11417 psi, 1550 fps
- IMR-4198, 35.0-gr, 23577 psi, 2060 fps

Anyway, I had originally homed in on H1000 and 7977 simply because I was thinking cast/gas-checked loads should maybe fall below 2000 fps somewhere, to avoid barrel leading. Without knowing any better. Certainly without knowing you guys are getting 2300 or so without leading. And figuring a mostly-full-ish case would give better consistency/accuracy than a half-full case with powder just sloshing around in the "somewhere" when ignition begins.

FWIW, I can't see a pressure "target" in the Lyman loads. Under 12000 psi to over 23000. It's easy enough to imagine modulating VanDenburg to fall in that range... but I don't know enough to suggest that'd be a good approach or not. Maybe pressures aren't static targets? So 23000 psi from an H4831 load (~56.5-gr, 95.1% fill, 23405 psi, 2059 fps) may be quite different from 23000 psi from an IMR-4198 load (for example)?

-Chris

I have had excellent results using Varget in my .348's with cast bullets.. I have also found Benchmark to be another excellent choice with cast bullets and am currently using it in my .450 marlin. I don't use 3031 after having a run of IMR powders that went bad. Reloader 7 is another choice but I feel like it gives a little higher recoil- personal opinion, though.

Interesting thread. Ken Waters got the best accuracy with cast bullets and H4831.
The 200 grain bullets I ordered from Montana Bullet works arrived today. I’ll hope to get shooting the M71 soon.
If I can get 1,700 fps with cast bullets and no leading and less than 3" MOA, I'll be really happy. I also have some Barnes 250 grain bullets, but I am thinking the rifle is a cast bullet shooter until proven otherwise.