by Hoot » Mon Apr 23, 2018 8:19 am
I'm going to eat a little crow here. I throw around terms such as formula like I'm a chemist, which despite knowing a good deal about the subject, I'm Not. Like many other reloaders of Lil Gun in metallic jacketed cartridges, I noticed a change for the hotter around 2014-15. The assumption that they changed the formula was just that, an assumption. There are production variations with primers as well. I never took a look at whether I changed primer lots around that time however. I did com into several bricks of 7 1/2 primers in the same time frame, taking them wherever I could find them. There was a supply shortage going on at the time. Anyway, my assumption was anecdotal and not very scientifically based, to say the least. What threw a monkey wrench into my beliefs was when I found a 4-pound jug of Lil Gun at a small mom and pop reloading store. A very chance discovery when it was hard to find anywhere. The date code on the jug was March of 2009. It too shot a little hot in my tried and true recipes!
Some times, I forget the experiences in the past that are pertinent to a discussion I participate in. I admit to not paying much attention to date codes on the 1-pound bottles I used when I first got into this caliber. Who knows how old they were. Back in 2011, I was doing some workup on the Barnes XPB bullets and midway through, ran out of a bottle, necessitating buying another (from same local shop I always use). My resultant velocities dropped 2 grains worth. In that case, I was using the same primers.
The point I'm struggling to make is that variation exists and stacking tolerance variations from different primers and powders at the same time, not to mention other factors (see below), can "cloud the waters" of observation. I will try to be better going forward, not too throw around terms that are more opinion based than scientific. All I can honestly say is that where Lil Gun is concerned, something changed over the years. That should be of little consequence to the prudent reloader, who always starts low and works up to determine what their rig safely likes.
The following are factors that can affect resultant velocity and pressure for the same charge weight:
Powder characteristics
Primer characteristics
Barrel ID, finish, cleanliness
Bullet OD
Case capacity
COL (overall is one word)
Temperature
I'm probably missing a couple...
Hoot
In Theory, there is no difference between theory and practice. In Practice, there is.