Trying to learn ballistics

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DesertRatR

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I've got a load I like for 45 LC 200 gr LRNFP in a rifle. What can I expect if I use the same load with a 250 gr LRNFP?

I loaded some 200 gr LRNFP with 8.2 gr Unique. Average speed out of a Henry Big Boy is 1085 fps. If I use the same load with a 250 gr LRNFP I was wondering how it will perform. Faster, due to higher pressure? It isn't in my reloading manual. The manual reports a max of 8.5 gr Unique for a 230 gr out of a Winchester Model 95 Trapper. Alliant's website reports max Unique charge of 9.5 gr for 250 gr LSWC out of a 5.5" barrel. Reloadingammo.com reports 8.5 gr Unique for 250 gr LRNFP out of a Rossi carbine.
 
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You'll have to describe exactly what you mean. It can't be "the same load" because the two projectiles are obviously different.

Do you mean that you are handloading and you want to use the same exact powder and charge weight with a bullet that is a full 25% heavier? Because that is a bad idea and flies in the face of proper load work-up techniques. Pushing a heavier bullet will raise pressures and more bullet occupying internal combustion space inside the cartridge case will also raise pressures.

As for down-range ballistics, generally speaking, a heavier slug will move slower under similar pressure compared to a lighter one, but it will also lose downrange velocity at a slower rate than a lighter slug will.
 
That's a scary question but it's a good thing you asked before trying it.

If you make a change like that to a load recipe then it's no longer the same load. You'll need to start from scratch and find loading information for the new recipe you're interested in.
 
I've got a load I like for 45 LC 200 gr LRNFP in a rifle. What can I expect if I use the same load with a 250 gr LRNFP?
Click to expand...
If you mean "will it work just as well with the larger bullet?"--the type of powder might work well for both bullet weights; but the powder amount most certainly will not perform the same with the heavier bullet. (is this a trick question?)
 
Think of it this way its a balancing act. Imagine a bullet on one side of a scale & a pile of powder on the other.
There needs to be balance, if you change something on one side you also have to change on the other so you get a new balance. You can't just change on e side of the scale.

NB:
Before someone else points out the fact, this is just a visualization tool to help you get the concept. I am specifically NOT telling you to actually do this on a scale.
 
If you change to the 250 grain bullet, it will fall to the ground sooner.

If you mean by that that it will hit the ground at a shorter distance, you are correct. However all bullets and even baseballs fall at the same rate. The faster bullet just covers more ground in a given period of time. A bullet drops the same amount in two seconds as a fly ball does in baseball which is why all bullets drop like crazy beyond 300 yards.
 
If the loading data says that the 8.2 grains of powder is a max load for that bullet weight, going heavier will cause dangerous pressure.

So, check the loading data for that powder.
 
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