I've had pretty good luck with cast bullets in the 348. I can attest to Doudna's good bullets. I've also used some from Old Western Scrounger in the 185-190 grain size - likely cast in the 350447 mould.
If Brushbuster sees this he has taken a deer with cast and a moose with jacketed factory loads.
here is a little bit of data from some work I did a year or more ago. Please approach with caution as your gun may be different.
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Test day was March 5 afternoon about 3 pm to 5:30 pm. Temps about 25-30 F, very light breeze that died by about 4:30.
Bright sunny with high sparse clouds. The chrono screens were set so the instrumental velocity is about 15 feet from the muzzle. I ran 2 fouling shots with 190 gr cast gc bullets through the gun to warm up the barrel and clear out the oil etc.
BTW my gun is the Win 71, 24 in barrel. All testing today 3-5-04 was at 75 yard target, using a new Williams aperture of .05?? whatever the smallest opening is - shot at standard 25 yd slow fire pistol target.
load 1, test order 1
3-5-04 (loaded date) 59 gr H 4831 std not short cut, 250 gc Custom Cast Douda, CCI 200, WW case trimmed to min, Lee crimp 4 rounds only - one bullet shaved a little on loading - didn't have expander die adjusted deep enough.
chron 3-5-04, 4 shots, 2013-2028, 15 es, 2021 avg, 6 SD
3 shots TOUCHING 4th shot spread to 4+ inches. easily able to increase - High accuracy potential if I can keep consistent sight picture. I'll enclose a scan of this test target. Could be good hunting load too. I doubt I could do this regularly but I might try.
load 2, test order 2
3-5-04 (loaded date) 60 gr H 4831 std not short cut, 250 gc Custom Cast Douda, CCI 200, WW case trimmed to min, Lee crimp 4rounds only.
chron 3-5-04, 4 shots, 2035-2095, 60 es, 2061 avg, 25 SD not as consistent as 59 gr,
I think I was flinching badly - horizontal stringing of 8-9 inches but vertical dispersion of only 3 inches and slightly higher than test 1 on target. Work up from 59 by .25 gr if seek more vel.
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here are some other notes from my 348 work:
Chrono 3 Ancient Win factory 150 gr loads on 7-26-92 (likely 50-60+ degrees) 2559-2640, 81 es, 2610 avg, 44 sd
F
As I am getting back in touch with this gun and cartridge I come up with some thoughts, that I think I had when I was first busy with it in the early 90's. For fun shooting with this, a light kicking cast bullet load in the 1650-1800 fps range might be nice. Even the heavy hunting cast loads whack pretty hard. Lighter loads would be much easier on the gun as well. I think that's where Ken Waters was going with his mild cast bullet loads. A 200-220 cast bullet, while having more whomp on the shoulder than a 180-190, might be better on the target and better for light big game with those sub 1800 velocities.
G
Also, the different bullet weights hit way different on the target with one sight setting. So its real tempting to find one bullet weight and one load if you don't like all the work resighting your gun.
H
Cases stretch a lot especially with full power loads. I think I'll try to be more careful to record the number of trims and use new brass for hunting. Another argument for using mild loads if you want to plink with this gun. Also plan to discard brass after 4-5 ?? trims or at least keep a very close eye on the case stretch and potential head separation.
I
A new butt stock with recoil pad would be real nice.
J
Its not too hard to nearly match jacketed velocities with same weight cast bullets, especially in the heavy bullets - and my barrel doesn't seem to be leading up much.
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I might be able to dredge up more stuff later.
I encourage you to use those moulds - you can have a lot of fun and be easier on your fine old rifle.