Has anyone who experimented with Lil Gun also tried 1680? Is this a good alternative since the burn rates are very close?

You may want to look at the posting by me dated 2/11/14, 4th page of shooter's bench, before you consider Lil'Gun. Good luck.

FAH,,,,,,, I haven't used LIL GUN because of the warnings I read. I can't help wonder about 1680 because the burn rate is so close. Before I would start a search for more powder, I was trying to draw on others experience. Does anyone know if you can get LIL GUN velocities and pressures from 1680 without the extremes of the former?

From what data that I have found to cross-reference, it depends on the chambering. What is your flavor?

When I get down to caliber it would be 45 colt, 454, and 475 L.

"since the burn rates are very close"

Where did you get they "are very close"?
1680 is several grains slower. It is at least 4 grains slower than H110/W296.
It would make more "sense" to compare it to 2400 since they are closer.

Very close to LIL GUN at least in my Lyman cast book.

I have the Lyman 49th book. What cartridge? What bullet weight?
Have you checked any other books? I like to consult several books before I make a decision on things. I know from using AA1680 in the past it is roughly 4 grains slower than W296/H110.
Maybe a tad slower than that.
Since Lil-Gun is faster than W296/H110 by a tad then I don't understand. Generally when dealing with "small" charges a couple or four grains is a larger difference than two or four grains are compared to a "much larger" charge.
4 grains are a higher percentage of 25 grains than 4 grains are to a 60 gr powder charge.
4 grs to 25 is 16 percent. 4 grains to 60 is 6.7 percent.
I am sure you know this. Keep this in mind when looking at relationships from one powder to another.
I see the calibers now. What I said still holds true. Consult more then one source.
1680 is farther from H110/W296 than Lil-Gun is from H110/W296 in burn rate and load data.

MePLAT,,,,,,,,,,,I did some checking with other reloading books and you are correct. The listed burn rates very between them. I was just looking at burn rates in the Lyman cast book. The burn rates seem to be all over the place. I wonder why so many variations?

Contrary to popular belief pressure is not the only criteria that labs use to determine maximum load.
It can be compression of the load, is adding more powder getting anywhere, consistency, and a host of other things many of which we don't know about.
That is the reason we consult several sources.
AA1680 is a good powder but it fills a position that makes it slower than some cartridge and bullet weights need.