Pursuit of .357 Magnum Cast Bullet Accuracy

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Coote
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Pursuit of .357 Magnum Cast Bullet Accuracy

Post by Coote »

Howdy. It has been a while since I've posted. I'm still experimenting with loads for my .357 magnum rifles. I have eight different types of lead bullets that I've been playing with. I have moulds for seven of them, and the eighth is a round-nosed 158g swaged projectile from Speer.

While I have some acceptable hunting loads, I've had some perplexing results. Here are pictures of the bullets:

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Four of the bullets work pretty well for me. Here is a list of loads that give me acceptable groups. I am shooting these in a Bergara BA13 single-shot.

1. Lee 358-125-RF. I have some subsonic loads using 38 special brass and 4 grains of Trail Boss. I seat the bullets to the top of the crimp ring (I don't crimp because I use these in a single-shot). I'd seldom use them beyond thirty yards. Nice and quiet too, travelling at around 1000 fps. I've also loaded these bullets with 5.7 grains of Trail Boss (in magnum brass), but this means I can't fully seat them. This load gives me pleasing accuracy and a velocity of around 1160fps. Using up to 7.4g of ADI AP70N powder (similar burn rate to Unique), I get up to around 1500 fps. I don't shoot many of these in one session, but I've never noticed any leading from them. These worked well in my Rossi 92 also. I shot a feral goat with one of these faster loads and the result was impressive.

2. Speer RN 158grain. These factory-made bullets shot well out of the Rossi and my Bergara. I only ever loaded them at subsonic speeds, mainly using about 4.2g of Trail Boss. Not my first choice for a hunting bullet, but they do the job when used carefully.

3. Lee C358-200-RF. These possibly give me my most accurate .357 load. But only at one speed, and they didn't work in the Rossi (they went sideways). I use 4.8g of AP70N which gives a velocity around 960 fps. Faster or slower than this the groups open up. When I found this accuracy I thought I had an ideal, quiet cartridge for hunting around inhabited areas. However its terminal performance on my first hunt with it was just awful. The goat I shot didn't seem to know it was hit and just walked away. I had to follow it into the thick, thorny scrub and shoot twice more. I'd have been better off with my .22 and Winchester subsonic ammo which I have used successfully on goats many times. The meplat on this bullet is smaller than the meplat on the 125g RF. If I had to pick one of my current bullets for rabbit shooting accuracy to maybe 75 yards, this would be it.

4. Cast Bullet Engineering (Australia) 360-210-SWCPB (plain base). This mould was relatively expensive, but it is heirloom quality. Simply beautiful. Never have to hit it with a stick, I simply nudge any stuck bullets with the finger of an old leather glove and they fall out. These bullets sit quite deep in the case, but I can fit 12.5g of ADI AR2205 under them (closely related to Hodgdon H110). Using standard small rifle primers, this load gives me about 1300 fps and although I haven't shot a lot of groups, they seem to shoot under a two inch group at 55 yards.... which is great for bush stalking. This is my serious hunting load. It makes a heck of a bang though.

I'd like to be able to use these 210g bullets at subsonic speeds, but they don't group nearly as well.

All the other bullets shown in the photos have not grouped well enough for me. I've been a target shooter, but I realise that I will be too frustrated if I will only settle for target accuracy with my hunting bullets. So I've told myself that anything under 4MOA is worth pursuing. 2MOA or less would be wonderful.

I think it is odd that my C358-200-RF groups so well at 960 fps and won't group well at faster speeds. Yet the 210g SWC groups pleasingly at 1300 fps while it is rubbish at slower speeds.

I also like the look of the Lee 358-158-RF with its nice big meplat. I've shot some good groups with it, but not every time I try it. I wish I knew why.

If anyone has any thoughts on achieving better accuracy with either the 210g SWC or the 158g RF, I'd love to read them.

The poor old three-legged boar in the photo below was shot with a 358-125-RF powered by 5.7g of Trail Boss. It was too tough for human consumption so I boiled it up and cut into small chunks for pet food.

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Best wishes from New Zealand... Stephen Coote.
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Re: Pursuit of .357 Magnum Cast Bullet Accuracy

Post by GasGuzzler »

I would think the 125 over 5.7 of TB might be accurate at close range but pack little punch. The 1:30 twist on the R92 usually requires velocity up there scooting well to be accurate. I have a NOE 360180GC I size to .358-.359 and load over a bunch 0f 2400 or LilGun and it does well. I have both of those Lee 158 molds and they both work great in my Blackhawk and my R92. You're using a gas check with the 358-158-RF, right? I probably do not proof my loads as meticulously as you. Never said what rifle, barrel length, twist rate...
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Coote
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Re: Pursuit of .357 Magnum Cast Bullet Accuracy

Post by Coote »

Thanks for the reply.

I don't use gas checks on any of my bullets. I may do one day, but meanwhile I prefer to use lower velocities.

I live in a hilly, semi-rural area where I have the opportunity to hunt on lifestyle blocks. Generally I am never further than maybe 300 yards from the nearest homestead.... and in the bottom of the valley there are a number of houses. While my hunting is perfectly legal, I don't like to disturb or frighten people. I used a suppressed .22 rimfire for a long time, but this meant there were some opportunities for shots that I couldn't really take advantage of. So I got the .357 rifles and reloading gear. This enables me to have a bit more power than the .22, but at moderate speeds which means the bullets can be relatively quiet and drop safely to earth much quicker.

The rifle I use the most now is a Bergara BA13 single-shot with a break action. It has a 1:16 twist in its 16" barrel.

I can't remember whether I've already posted the photo below.... forgive me if I have. I would have used a subsonic load for this, but I can't remember whether it was a 158 or 125g. It was at close range. That tape around the rifle is the supply I keep for covering the muzzle to stop leaves and other rubbish getting in to the barrel. I've sold that Rossi now. It had a 16" barrel. If I get another I would be inclined to get a longer barrel so the bang is further from my ears.
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I've shot several goats and pigs with subsonic loads, and I have not yet recovered a bullet. They penetrate a long way.
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Re: Pursuit of .357 Magnum Cast Bullet Accuracy

Post by Missionary »

Good morning
First... Coote thank you for that fine hog photo !!! Good write-up also.

With all firearms since they all are individuals just like us, my first task is find out what diameter will shoot the best. For .357mag rifles we start at .359 and go fatter.
We may try some .358 diameter but so far we have not found any advantage with that smaller diameter. But then we have only had 3 .357 mag rifles and plan on no more. .41 mag is our #1 grab.
Way down south in Arequipa, Peru till June 2020.
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Re: Pursuit of .357 Magnum Cast Bullet Accuracy

Post by Coote »

Thanks Missionary. The cast projectile that has given the best accuracy so far is around .357 - .3595 (it is out of round). The bullets from my 158g RF mould are a similar diameter but I don't seem to get consistent accuracy. And the swaged Speer round nosed 158 grainers typically measure .356 - .358 (which is smaller), but they are reasonably accurate most of the time.

The big CBE 360-210-SWCPB are a whopping .362" in diameter and they are the closest to perfectly cylindrical out of all the bullets I cast. With care I can coax them into unsized fired brass and they group pretty well... at what seems to be their only favourite velocity from my rifle - around 1300 fps.

It is all a bit mysterious, but it is fun trying to figure it out. Best wishes.
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Re: Pursuit of .357 Magnum Cast Bullet Accuracy

Post by LittleBill »

358156 and 358429 are what you seek. Best (in my 5 357's) Ive found.
Coote
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Re: Pursuit of .357 Magnum Cast Bullet Accuracy

Post by Coote »

Thanks LIttleBill. 5 .357s is a good number. Best wishes.
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