Cast in a 270 Winchester help

[Colt1991]

As the title says I am in need of some help for the 270 Win. What I want to do is use IMR 4350 & AA 4350 with a cast bullet weighing about 150-165 grains. I am not looking for a reduced load. The molds that I have are A RCBS270-150-SP and NOE 279-165-FN.

[sigep1764]

The fastest I've gone with my 270 is about 2000fps with W748 and the RCBS 150 boolit. Faster I have not tried. Usually I shoot the 150 with 10 grains of Red Dot. It kills deer.

[Texas by God]

4350 is a great powder for jacketed. Not so much for cast however.
Starting loads are still too fast for normal cast bullets.


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[gewehrfreund]

I suspect you'll need a very hard bullet and a very smooth bore for that to even begin to work and achieve "acceptable" results. Buy a more suitable powder and lower your velocity expectations (see what I did there?) and life will be a lot easier.

[Colt1991]

Thanks for the reply's guys the only reason I wanted to use 4350 was I so much of it. I only have about a pound and a half of 4198 left which I did see some data for. I also have a bit of 3031 on hand if that would be a better powder.

[Colt1991]

4350 is a great powder for jacketed. Not so much for cast however.
Starting loads are still too fast for normal cast bullets.


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Why are starting loads to fast? Do you mean the velocity it would produce

[Texas by God]

Yes, I meant to say that the starting loads listed for 4350 have too much velocity for cast bullets.
Both 4198 and 3031 will be much better. They are listed in the Lyman Cast bullet handbook for .270 use.


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[Colt1991]

Texas by God thanks for your help.

[Colt1991]

So would anybody use 4350 in any cast bullet application

[Mr Peabody]

I wouldn't use 4350 in any cast bullet load that I can imagine

[Larry Gibson]

Why are starting loads to fast? Do you mean the velocity it would produce

Because most all 270s have 10" twist barrels. Thus, if driven over 1940 fps the RPM exceeds 140,00. To go above that (the RPM Threshold) takes specialized skill. Even then any success, as in "accuracy", beyond 50 yards will be difficult to obtain and maintain.

[Colt1991]

Because most all 270s have 10" twist barrels. Thus, if driven over 1940 fps the RPM exceeds 140,00. To go above that (the RPM Threshold) takes specialized skill. Even then any success, as in "accuracy", beyond 50 yards will be difficult to obtain and maintain.

In the post from Texas by God the 3031 data is above 2000fps so do you think i would run into accuracy issues? Would even recommend using 3031.

[Larry Gibson]

In the post from Texas by God the 3031 data is above 2000fps so do you think i would run into accuracy issues? Would even recommend using 3031.

Lyman does not test for accuracy on target. They list loads that have consistent internal ballistics. The start loads are where the powder begins to ignite and burn efficiently. Thus, the higher starting load velocities for the slower burning powders. The use of a dacron filler with those powders may allow a smaller start load and reduce velocity down into the "teens".

Yes, I do think you will run into accuracy problems above 2000 fps. Only way for you to know/learn is to try it. Other wise, note in Lyman's CBH #4 they no longer list those slower burning powders and the start loads are in the 1600 + fps range. That's where you should start if you're looking for accuracy. If you want speed and power then you might find a useful load in the 2000+ fps range for limited range shooting. If you want the full potential of the 270 for hunting then I suggest jacketed bullets.

[MostlyLeverGuns]

4350 can be useful in cast boolit loading, BUT mostly in the smaller cases, 30-30, 308, 300 Savage, where top velocity is under about 2200fps and the 'more gentle' bullet acceleration allows slighter higher velocities than faster powders. Many of the smaller bores have faster twist rates, making higher velocities harder to attain with even very hard cast bullets that do 'FIT' correctly. In the 270, reduced loads of 4350 have been blamed for the Secondary Explosion Effect(SEE), so most stay away from such reduced loads with slow powders. There are many theories about SEE, but less than 50-60-70% case fill with slow powders is one of them. Smaller cases using 4350 do not run into this. The 270 can be very accurate with cast boolits, using lower velocities and faster 'more conventional' cast bullet powders.

[TurnipEaterDown]

Found 4350 to work fine under cast in my 35 Whelen Improved (1:14), at 2100 ish. Issues arose 2200+. So, I'd use in some high expansion larger cases too.

[Colt1991]

Thanks for the info everybody. I was really hoping to use the 4350 but it looks like I'll just use this for my jacketed bullets for now and try some other powders. I see they also have Herco listed in the #3 manual posted above. With a charge like the ones listed would I need a filler?

[Larry Gibson]

No filler needed with those fast burning powders. Might use case with drilled flash holes if rifle is not a CRF and for better ignition with less powder position sensitivity.