16ga.com ~ View topic - Effect of slightly different powder amount?

Joined: 26 Apr 2010 Posts: 3178 Location: NCWa

I use PW equipment for loading several different gauges but I note that there are several load listings in various manuals where the listed load falls between the amounts from the bushings. I see three options. Use a bushing where the load is short. Use a bushing where the load is over; or get an extra bushing of the smaller size and hone out the bushing a little at a time until it yields a load that matches the book. Number 3 would be best but the question is are the effects of a load being slightly under or over a big deal?

Joined: 04 Mar 2019 Posts: 1844 Location: Central ND

If you are within 0.3 grain, you are wasting time and effort trying to be exact. Why? First, because most printed velocities are rounded up or down. Second, because +/- 20 FPS isn't going to affect breaking targets or killing game.

IMHO, when using bushings and you have a choice of being over or under err on the high side, not the low side.

Honing bushings, only makes that bushing good if every lot of a specific powder you buy never changes.....and the density of powder lots always varies to some degree.

You can prove what I have said by loading 10 rounds with 16.0 grains and loading another 10 rounds with 16.3 grains and running the loads over a chronograph. If there is 20 FPS between the two test strings, that will be a big deal.

Joined: 09 Aug 2007 Posts: 445 Location: WI

I have an adjustable charge bar on my MEC Sizemaster, and it is surprisingly consistent. But yes, when measuring by volume using bushings or an adjustable charge bar, close enough is still good enough.

I don't disagree that there is some fudge factor in the amount that is dropped. When I want to adjust to a "between the two sizes" I use the larger and "paint" nail polish (a color she no longer wants) inside to shrink the bigger one. Easy to remove with acetone and a Q-tip when you are done.