2fg or 3fg

[roundball]

Roundball, do you (or any of those reading this) have any information on where this "10-15%" figure comes from? I haven't found any authoritative sources for it.

When I first started using BP and saw this rule-of-thumb referred to I wanted to get another source as well...and since I was into TC muzzleloaders I called TC...asked to speak to one of the longest time, most knowledgable employess in the repair department.

When I put the rule-of-thumb question to him he didn't even hesitate and confirnmed that it was indeed the industry rule-of-thumb when substituting 3F in place of 2F load data, to keep pressures approximately the same...which is the only point that the rule-of-thumb is intended to address.

It is not intended to be a precise substitute to duplicate POI or group size between the two powders...only to allow the interchange of granulations with respect to maintaining reasonably equivalent pressures for safety sake.

I've since followed this rule-of-thumb myself for several years now myself, so I now also have my own personal hands on experience as a source as well...it works as advertised.

So I use 3F in everything I can except with .58 & .62cal PRBs...and even then I'm only using 2F because I have a half case of it left to use up...have them already sighted in with 2F and it's not worth rezeroing them with 3F just to rezero them.

My .02 cents...

 

[Dave K]

I have always read that as well, but never really gave it allot of thought. Then one day I was testing powders in my gun. I had the same brand of powder, the only differenve being 2F and 3F. So in testing, I noticed to get the very same POI at 100yds, it took about 10% more 2F than 3F to do it. Not real scientfic, but it works.