Need help "matching" a charge

[JATA]

Hope you guys can give me some insight.

(9mm) I've been pushing a 130gr cast Truncated Cone bullet with 3.9gr of Bullseye. I am out of Bullseye and have a can of BE86.

Alliant lists 5.7gr (I realize that is max) and, on another forum, someone told me they ran 4.7 of it. So I felt pretty comfortable starting at 5.0gr. Here's the thing though - My last load ran so good out of my new pistol that I want to try to use a charge of BE86 that will be as close as possible to 3.9 of Bullseye.

I guess what I'm asking is - how do I replicate my load with this powder? I know 5.0gr would be a good starting point but I don't know how it compares to 3.9gr of Bullseye. Unfortunately, I no longer have a backstop in my backyard, to test loads, and am going to load a couple hundred (at least) before I can pop the first one. I don't want mess with a load that works, but this is the powder I have on hand. So....

Thanks

[country gent]

Easiest way is to chronograph the old load ( if you have some left) and then work up to it with the BE86. Or there is a lot of data out there for bullseye a average of 4-5 manuals data for velocity of 3.9 grns bullseye will also get you close. But the new powder may or may not perform with the older powder.

[Texas by God]

Welcome to the forum!
I would just load 20 or so and test them before I ended up with 200 of a sub par load.
Don't ask how I know this.

[John Boy]

how do I replicate my load with this powder?

Your gonna be in a guessing game because the relative burn rate differences between Bullseye & BE-86 are substantially different:
Burn Rates:
18 - Bullseye
31 -Unique
34 - Power Pistol
BE-86 burn rate is between Unique and Power Pistol. Unless you are a very experienced reloader and have a chronograph - I would forget trying to duplicate Bullseye with your one can of BE-86. Best advice - buy another can of Bullseye because for comparisons ... you don't even know the fps of your existing Bullseye reload for a base line velocity to start with

[Wayne Smith]

I agree with John. This is your first post, we don't know you or your experience or your equipment. To give specific advise would be literally irresponsible. You are talking about walking into unknown territory in a high pressure cartridge. Use your manuals to come up with a reasonable load with the BE86 and call it good. Otherwise you are attempting the very difficult with very little data and apparently less ability to collected real data.

[dverna]

Both are made by Alliant. Contact them (I have had good experience with a guy named Ben Amonette there). Tell him the particulars of your load, (COL, bullet) and he will get you close. It is after all just pistol ammunition and unless you are shooting Bullseye competition a gnats hair difference in accuracy is irrelevant.

Ben's email is Ben.Amonette@ATK.COM. Last time I emailed him was a few years ago. If he is no longer there, send the question to their "Ask the Expert" link on their home page.