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Discussion Starter #1
I was wanting to try some of the Lyman 375449 bullets in my 375 Win. They are dropping from my mold at 278 grains. I was hoping someone has used this combo and could pass along their experience and some load data. What velocity is possible with that heavy of a bullet? Thanks, Ted
 

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That's a bit heavier than my example of that mold will throw unless the alloy is a bit soft....not too far off the normal, and a useable weight.

Personally, I'd use 38/55 cast bullet data and you'll still probably rind that accuracy goes south before top listed loads are aproached. Part of that is due to the faster twist of the .375's barrel in comparison to the 38/55's....somewhere near 1600fps may be your limit. Yours may be the exception, but that's what I've found.
 

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ribbonstone,
This was the first time I used this mold. The alloy is just plain wheelweights. I suppose it would be better with some lino or tin added. Actually, this is the first rife caliber that I have cast bullets for. Any other advice would be helpful. What powder do you prefer with this bullet? Thanks, Ted
 

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If the bullets look good...all the gooves well filled out, no big wrinkles, and the base filled out well (the edges not rounded off or ineven) then you cast them right reguardless of the weight.

Loading is pretty much idential to the manual instructions for loading straight walled pistol cases...same idea, need a three die set.

Had a .375W and a 38/55...ended up keeping the 38/55. I would load to two levels: full power and low power plinking. For full power for me was 32gr. of 3031...some loading manuals will go a good bit higher, but past this point (about 1555fps) the 375 would make improved cylinder patterns. Oddly the 38/55 would toss the same bullet accuratly at about 150fps more velocity...cold be a gun to gun variation, or it could be the slower rifling twist of the 38/55.

The light "plinking" load was the same for either the 38/55 or the 375W. Taken from the RCBS Cast Bullet manual (#1), I use 7gr. of red Dot for all of 1025fps. I still use theat load for most of my off-hand practice, rolling tin cans for fun, and general fun.
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if you want to use jacketed bullets, will direct you to the "Hawk" line (they are on line)...about perfect bullets for the velocity.
 

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Hello Ted-

I have a .375 Win. also and have been working on developing a CB load for it. I'm an avid caster and shoot a variety of claibers - CB's mostly.

The .375 Win has turned out to be a serious challenge. Problem for CB's in this chambering appears to be related to it's very long freebore. The bullet has to jump well over .250" for my bullet (a 300gr. gas checked design). It leads like nobody's business - huge slivers of lead after only 10 shots all coming from the area just ahead of the chamber. Different hardness bullets, different velocity ranges, different sizing diameters, nothing seems to help.

The reason to comment is that CB's are very fun and rewarding to shoot and usually not much trouble to get to work. Since you commented that this will be your first attempt for CB's in rifles - I thought you ought to know that this chambering is not representative and may proove to be very difficult.

Re: loads...
Once you stuff a large bullet in the .375 Win - it leaves limited powder space. AA 1680 is a very fine ball powder that works well in the available space to reach top velocities and does so at lower pressures (according to the load manuals) than most other powders. For reference - I'm at the 1850fps range with no signs of pressure with this powder & bullet combo.

Best regards-

Sky C.
Longmont, CO
 

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Discussion Starter #6
Well, I finally got out and shot some of those Lyman cast bullets in my 375 Win. Let me tell you, I was one happy camper! I had four different loads with two different powders. I was happy with all of them, but the one that really shined was 24 gr. of IMR-4227. I shot two, three shot groups at 50 yards that were less than 1.5 inches. There was no lead left in the barrel at all. I am suprised at how much lower they shoot than my regular load with the 220 gr. Hornady. Like 7-8 inches lower at 50 yds. It is not a problem though as I have plenty of adjustment in the Lyman sight. I forgot my crony today but going by the load data from the RCBS cast bullet manual, they should be around 1700 fps. Regards, Ted
 
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