Is there any way to safely convert a load in one powder to an equivalent load in another? I found a .41 Magnum load that requires 8 gr of Unique...but since I only have AAC-2 & 5 I'm wondering how to duplicate the load.
Thanks.

The simple answer is "NO".

While it may be POSSIBLE to use a different weight charge of another powder to give you the same velocity, there is NO way to predict with safety what the chamber pressure will be.

There is NO such thing as a charge of another powder that will duplicate the performance of one given powder charge. Experiments like that is what causes blown up guns and injured shooters.

Please remember that excessive chamber pressure is what damages guns, and why we are under the strictest of safety observations to use ONLY documented loads from published powder and bullet manufacturers. They spend considerable time, effort, and money to develope and document safe working loads.

Thanks for your reply...I guess I'll be buying some Unique.

I guess I am cornfused. You don't need to duplicate the load like you describe. Going to the data for the Unique load, it will give you a velocity range for minimum and maximum. Then you go to the Accurate Arms data and see if there is something comparable for the same components and build your load from there.

Case in point:

220gr Speer softpoint with 8.5gr of Unique delivers 1030fps.
From the Accurate Arms data you can find a 220gr SRA Sil-FPJ and data to get you into the 1080fps range.

While it doesn't directly correlate from one weight of one powder to a weight of another, the velocity does make the load match.

Do you have any manuals? Do you know where to get data online from the powder manufacturers?

If not, you need to do both.

Hope this helps.

It would help to know what bullet type and weight.

As mentioned by others, you can not directly convert, but you can certainly find another powder that would be close using the other powders recipe.

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Still Running Against the Wind

I've checked lots of sources including LoadData.com and the Accurate website. The problem is there's not a lot of data for the .41 Magnum. I was looking for a lighter load...along the lines of 1000 fps with a 210gr SWC. The only one I found was for Unique.

As I understand it, AA#5 is close to Unique in terms of burn rate, maybe a little faster. So I'd use a little less AA#5 to get close to a given charge of Unique.

AA#2 is closer to Bullseye in terms of burn rate (a bit slower), so I'd use a little more AA#2 to get close to a given charge of Bullseye.

For a big (> .400"-dia.), long (Special or Magnum) casing, I'd go with the slower AA#5 or Unique.

HP38/231 is an excellent powder for medium loads in .357, .41, and .44 magnums.

7 to 8 gr of HP38 with 210 lead in .41 magnum gives around 1000 fps, depending on barrel.

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Science plus Art

The Accurate downloadable manual shows a load for a 200 gr MCB SWVBB(L) grain bullet using #5
And then a 240 gr bullet also using #5
So using the next higher bullet weight than your 210 it seems 10.8 grs would be a place to start.

Of course use at your own risk and all other disclaimers apply.

Download the pdf file and save it on your computer.

Accurate Arms Company, Inc.

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Still Running Against the Wind

Everyone should own unique. You can load just about any handgun caliber our there with it. Buy 4 pounds and it will last you a long time. I use it mostly in my 45lc and 44 special. 8grs of unique under a 255 gr bullet is happiness.

Baktersmith,

I just looked at my copy of Lee Modern Reloading 2nd addition.

For a 210gr LEAD bullet.

It lists Accurate #5 start 11.3 for 1264 fps starting load to 12.5 max for 1436fps

it list for Accurate #2, 8.3 grs start for 1158 fps to 9.2 grs max for 1315.

Unknown barrel length

Lee data tables are complied from other data sources

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Still Running Against the Wind

Here is a copy of the free Accurate Powders data circa '93 as shown in my One Book for the .41 magnum. The current data lists only slow powder mainly AA#9 and the other data from Accurate I have lists only heavy loads with all the Accurate powders at 1,100 fps or greater. This shows data at the level you want using Accurate Powders.

Wow, that is quite a difference than what is in the Lee data tables. Wonder if the powder formulation was different in 1993.? The current data for #5 for a 200gr bullet is close to what is in Lee. The current does not list #2

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Still Running Against the Wind

AA#2 is way faster than Unique. AA#5 is a closer match in burn rate. As for AA powders I would think AA#9 would be your best choice for full power .41 Magnum ammo.

If you're looking for an almost ballistic twin to Unique give Universal a try. It's cleaner and meters better.

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Freedom is never free!!
SWCA #3437

Thanks Steve C...that data you posted gives me exactly the lower power loads I was looking for.

Proceed with caution. That data is 17-18 years old. Has the formulation changed over that time?

Perhaps call Accurate before loading up a bunch of rounds.

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Still Running Against the Wind

I use both Unique and AA5 as midrange loads. I load 15 cartridges on a regular basis and use slow to fast burning powders for hot to target loads. I have found Unique very comparable to AA5 in load weight, but not performance. Although virtually all handguns will work with Bullseye, Unique and 2400, there are powders with characteristics that help in reloading.....esp.#5, which is spherical and meters precisely. This is a "dangerous" statement and should be approached carefully, but I have found that practically it works most of the time. Use a load guide to confirm or deny, but if you have good results with a given weight of Unique, I have found that a similar weight of AA5 is a good starting point. Normally they will correlate within 10%, even with huge caliber var.
380ACP ---90gr JHP 4.4gr. Unique, 4.6gr #5
.44 Mag mid-range load....215gr PbSWC: 8.5gr Unique, 9.2gr #5
If you are using #5, stay with it.....one of the best powders made.
The one cartridge that is very different, is the 9mm. Whatever the reason, the pressure curve building fast?, both Unique and AA5 work OK, but here is where a powder like VVN330 work so much better. In fact the VV powders work fabulously in the 9mm in its derivatives....38 super, 356TSW, 9x23, etc. VVN330, 3n37 are so much more accurate it is amazing.
Terry

The Accurate site has current load data for the .41 Magnum. You might want to cross reference the current data with the older data supplied in this thread.

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Freedom is never free!!
SWCA #3437

I use lots of Unique and also love AA5....
1st a note: the .41 Mag case is a relatively large one and therefore small loads of fast powder like AA2 are unpredictable. If you use a lead 210 gr. bullet, 4 gr of #2 will probably shoot great. You never know....

However, there is a correlation between Unique and AA5. I use both, load at least 11 different calibers (not .41) and found the 10% rule....usually, #5 is best at about 10% below the Unique load.....
Therefore, 7.3 - 7.5gr. or AA5 is where I would start. If it were me, I would load 10 rounds at .2gr. increments and check for accuracy. #5 is a great powder....it meters beautifully and shoots incredible groups. I use a similar load in my .44mag...... 9.7gr. AA5 with a 215gr. PbSWC while the .44spl requires 6.8gr. AA5 (these are one-hole accuracy @ 25yds.)
Terry