Heavy bullet charge data for lighter bullet.

[Eddy19]

I'm aware when you take the charge data for a heavier bullet and want to use a lighter bullet, you increase the charge.

Is there a rule of thumb or percentage to apply just how much to increase the charge?

ie: Say charge data for 44 mag with 240 gr. bullet and want to use it for a 200 gr. bullet.

UPDATE: I should add a clarification. I mean in many cases where the loading manuals do not show your particular bullet weight, but do show heavier bullets than you want to use.

 

[243winxb]

None that i know of.

If you list the components you want to use, others may have reloaded it already.

 

[Blue68f100]

Not that I know of. When working up the load you work up slowly looking for pressure signs then back off when high pressure signs show up.

 

[Lafitte]

A good rule of thumb in such conversions is to "refer to a loading manual".
Lafitte

 

[Eddy19]

Here's a load using Greendot I'd like to make only using a 200gr bullet which they don't list. For a 240gr bullet it's 7.0gr of Greendot. Since the lighter bullet takes more powder, just wondering how much more, 8gr? 9? I just need a ballpark figure then I can workup a load from there. Hoping there's a rule of thumb or something.

 

[Obturation]

No general rule for this that I've heard. Trouble is a heavier bullet will be seated deeper into the case, the lighter bullet less deep if the COAL is to be the same. The different bullets may not be designed to be seated to the same COAL as the cannalure or crimping groove may be located different distances from the ogive, that's why there can be no general rule. Only rule you should know and follow when developing loads and working with the unknown is what you already know - work your way up. A chronograph can help you make sure nothing crazy is going on too, but you can do fine without it. I may suggest using the max charge listed for the heavier bullet as a starting point but that is up to you to decide, if not using published data anything can happen. Be careful.

 

[243winxb]

CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

44 Magnum.
Alliant data from 1999 has a 200 gr JHP at 10.7 grs MAXIMUM , Green Dot. Federal 150 primer. 1370fps* . 34,500 psi.

Starting load 9.6 grs.

Your cast bullet may make less pressure, but not always.

Steves pages has Green Dot From 9.0 grains to 11.0 grains for bullets 200 to 210 grs.

With a cast bullet, i would stay far away from maximums with a fast burn rate shotgun powder.

* edit & add photo.

 

[Eddy19]

Thanks Obturation and 243winxb for the info. I'm just at the wondering stage with Greendot and 44 mag. I have my good loads for 44 mag with Unique and 2400. Also have other caliber loads for Greendot, 38 special and 357. I just have a lot of Greendot, WST, 700x, 800x, 231, from decades ago, I'd like to use them up if possible. I follow the manuals to the letter and always compare between manuals for certain loads. Been taking a new powder test load of 12 rounds each time I go to the range.

 

[rfwobbly]

The correct answer is to get on the phone and talk to the powder maker's Customer Service people. They'll email you about 3 pages of info not found on their web site. Just because you don't see it, doesn't mean they don't have the data.

Why anyone would prefer an answer from strangers on the internet as opposed to the powder maker is beyond me.

 

[Eddy19]

rfwobbly: good tip calling the mfg.

Why anyone would prefer an answer from strangers on the internet as opposed to the powder maker is beyond me.

Well, that's a good question and some people may take info and use it for their load data first hand, but not me. Like any info we get from various places, it has to be researched first. I do believe there is a very good reason to ask where knowledgeable people hang out, a lot of it comes from years of experience and I like to hear it. I'll decide after good research whether it's good to use or not, to remember or forget. So to me, asking on a forum is just one part of the mix, not the final answer.

 

[mdi]

My rule of thumb; don't try extrapolating load data. I have been reloading off and on for almost 50 years and steadily for 35+. I depend on my reloading manual(s) for any starting load data and my notes for subsequent loads. My Rule #1 is I pay no attention to any load data I come across, I see on my computer screen (!!), or hear at the range or gun shop...

 

[243winxb]

Max for me would be 9 grs with a cast 200 gr plain base, or use as a starting load and work up. See edit above. And corrected velocity/fps*. Was not 13,770 fps.

 

[Eddy19]

Max for me would be 9 grs with a cast 200 gr plain base, or use as a starting load and work up. See edit above. And corrected velocity/fps*. Was not 13,770 fps.

Thanks a lot 243winxb for looking that up. Over the weekend, I was looking through my very old notes before my long hiatus from shooting and found the last time I used the same 1992 Greendot / 200 gr. Lead SWC / 44mag was 5.4 gr. and noted it was a "very mild" load, clean, no unburn't flakes. So! guess I'll take off from where I left off and work up. I guess this is a case where keeping notes is a great thing.

 

[jmr40]

I use the data in the manuals.

 

[Eddy19]

Thanks jmr40, very true and I do to the letter, have several old and new manuals I refer to and compare between and now mfg's online data to study. But I feel, once a person uses the manuals as a starting point, making very careful and proven by shooting notes as one works up their "personal" load is perhaps more important than the initial manuals data as to what works for you.