Cast Boolit vs. J things

[Harv33]

I'm a bit slow so I figured some of you fellows can help me out here. I decided to try shooting cast boolits in my Finn 28/30. Here is my question: Using 16 to 18 grains of Alliant 2400 powder to shoot 100 yd. maybe 200 yd. targets works ok from what I read. Then why does it take say 35 grains (I'm guessing, never used it) of the same powder in a jacket bullet load to do the same thing. Are we looking at Mortar trajectory with the cast boolit ????.
Thanks,,, Harv..

[runfiverun]

please don't use 35 grs of 2400 in anything.
you will have much slower velocity's with most cast loads.
consequently you will have more drop over distance.

with my 308 using 18grs of 2400 and a 165 gr boolit my drop from 100 to 200 is 5 a moa change on the scope and from 200 to 300 it's another 5 moa change to the scope.
the difference in drop at 300 yds between that load and another 165 gr boolit going almost 2300 is 2'6".

[williamwaco]

please don't use 35 grs of 2400 in anything.
you will have much slower velocity's with most cast loads.
consequently you will have more drop over distance.

with my 308 using 18grs of 2400 and a 165 gr boolit my drop from 100 to 200 is 5 a moa change on the scope and from 200 to 300 it's another 5 moa change to the scope.
the difference in drop at 300 yds between that load and another 165 gr boolit going almost 2300 is 2'6".

Ditto !

[shredder]

Warnings aside, I think the answer to your question lies in the velocity you will drive the boolit/bullet.

For example: the reason a cast 30/06 180 grain load will be say 14 grains of some shotshell powder under your lead boolit while a full house jacketed load will use the same weight of bullet and 55+ grains of a coarse stick powder. Intended velocities: cast 1500-1700fps, Jacketed 2800fps. You can not drive cast boolets as fast as jacketed bullets. Under normal circumstances the best accuracy with cast for me is almost always in the velocity window mentioned above. Some times I will break the rule and get good groups at 1850-1950 with heavy cast hunting loads. Those are special though. For jacketed I have best accuracy very near max most of the time.

Two very different types of powder at work here. Rarely, if ever, would one powder be truly suitable (able to obtain typical velocites at typical operating pressures) for both cast and jacketed projectiles in the same weight in the same calibre. You could drive a jacketed bullet faster with the same charge as a cast boolit load as I understand it. Trouble is the typical cast powders are fast burners and pressure start going sky high if you try to get jacketed velocities or even close. Once they reach a certain point only a tiny bit more powder and things get dangerous. You will have much better results using a typical slow burninig rifle powder for jacketed.

[BruceB]

I think shredder sells the cast bullet a little bit short, although the basic principles he lays out are correct.

Loads at over 2000 fps with excellent accuracy are not all that difficult, but loads going much above that figure WITH ACCURACY are tougher to attain.

My Ruger #1 in .416 Rigby is a primo cast-bullet rifle; my standard load with the RCBS 216-350 runs at 2050 fps and easily makes 1" groups of five rounds at 100 yards..... and has grouped inside that figure with TEN rounds on occasion. Likewise, my M1A has done the same 1"/5/100 at over 2000 fps with IRON SIGHTS. Other rifles here will also shoot cast loads with similar results.

Anyway, the cast loads will generally be a good bit slower than jacketed bullets of the same weight, mostly because the jacketed bullets are much stronger in construction and withstand the stresses better than cast bullets do.

This definitely means that sight settings and trajectories will be much different to compensate for the different velocities. It's up to each shooter to identify and apply the required changes. Keeping notes isn't a bad idea, if one intends to switch back and forth.

[Harv33]

No, Like I said, I've never used 2400 but if I did I would naturally use proper load data. That answers my question then,, it amounts to sight correction to compensate for the slower bullet and amount of drop..(Mortar trajectory)!! . I was just curious as to how you can get a c/b to do with one third the powder that it takes a jacket to do the same.. Thanks

[texassako]

1/3 the powder does not mean 1/3 the speed with different powders. Jacketed also has more friction to overcome, copper vs. lubed lead. Also, the cartridge and firearm design means difference. It would be very hard to match jacketed loads in my .25-06, but my .32 Remington has its best accuracy at a 1 grain more of the same powder that jacketed accuracy falls apart with similar weight bullets; so it is actually travelling faster than jacketed. In the 28/30, you will notice that the fps of the published loads for a 200gr is pretty similar for jacketed and cast resulting in similar trajectories.

[Harter66]

And there are exceptions. For example I have a 32 Rem (very similar to the 32 Win spl) that produces near maximum j velocities w/a plain based cast below starting charges of the same powder w/acceptable accuracy.

[waksupi]

I've said it before, and I'll say it again. Look at my tag line. Cast Boolits are NOT jacketed bullets. They may seem kinda the same, but they ain't.

[Harv33]

No reason to get your back up Pal !!!, I was attempting to compare cast boolits vs. jacket bullets as you notice in my topic heading !!!!!!!!!

[waksupi]

No reason to get your back up Pal !!!, I was attempting to compare cast boolits vs. jacket bullets as you notice in my topic heading !!!!!!!!!

Not at all! It is just hard to break some people of pre-conceived notions.

[Harv33]

Thanks a lot fellow's for the help, tips and explanation. I savvy now !! Your never too old to learn and you learn a lot by asking questions. I've been reloading for my rifles for many years but this c/b is a new angle for me and interesting. Sure has another big plus seeing as how j/b's are hard to find now.. Thanks again and I hope I watched my language ,,,, Harv..

[DrCaveman]

Harv33

I think there may be more to your question than you realize.
The main thing you may be taking for granted is that all smokeless powders are similar
They are pretty different really

The example you gave initially might be valid if you are talking 35 grains of a SLOW rifle powder

My load manuals are like yours though: most cast boolit rifle loads use fast-medium powders shot at a pretty low velocity because that can reduce fit & leading issues hence most people find better accuracy there

Jacketed have no leading issues so the manuals 'let' us push em fast

Lately I've been using a lot more near-jacketed level data in my 30-30 and 30-06 since I am getting a handle on boolit fit and proper lube

In my 45 acp and 357 mag, I pretty much use jacketed data. Not exactly but pretty close

Hope that helps. Good shooting