One in a row....

As my long time reader (Hi Cary!) knows, I am an avid reloader. I still shoot factory shells occasionally, but the vast majority of my shooting is done with ammo assembled by my own pudgy little hands. Over the years I've developed a preference for powder measures that use a bushing system as opposed to an adjustable measure. I have an adjustable measure that I use for load development, but as soon as I find a load that I intend to shoot a lot of I switch to a bushing measure for consistency. Why? One word: visitors. Visitors are the scourge of any person who uses tools that can be adjusted. The mere sight of an adjustment knob creates an uncontrollable urge to twiddle with it in most people. I use bushings simply because they can't be screwed with.

( This is great Len....you go away for 6 freakin' months and come back to tell us about knobs. Gee, thanks. )

Anyway.........my reliance on bushings was recently put to the test when I purchased a new lot of IMR 700x powder. The two 12 gauge loads that I use most are 17.5 grains of 700x with 1 1/8 ounces of shot (MEC #28 bushing) and 16.1 grains of 700x with 1 ounce of shot (MEC #27 bushing). Remember, these are weights thrown in my bushings...not the factory guesstimate of what the bushing will throw. I think my #27 bushing is slightly undersized, but that's beside the point. The point is that these two bushings always have thrown exactly what I wanted, every time I wanted it, for years. Until my last powder purchase, that is.

I've heard tales about people who buy a new lot of powder and find horrible differences between the new lot and the old lot, but I've never experienced it. Ever. I habitually weigh the first few throws out of a new lot just because of the magazine and internet horror stories, but it has never been an issue before. So there I was, new keg of powder in hand, setting up to load a batch of shells, when I decided to weigh a shell at random out of the new lot. Zero the scale, drop the powder, empty the shell into the pan, adjust the scale to 17.5 grains.........and watch in amazement as the beam bangs into the stop. What the heck is this? Re-zero the scale, throw another powder charge, put it on the scale........BAM! The beam slams into the stop again. That bushing has thrown the proper amount of powder for so long that I did this 3 times before it occured to me that I should actually move the balance weights on the scale and find out what was in the pan.

16.5 grains. One full grain less than normal. Now what should I do?

I pulled out the bushing to verify that it really was the #28 bushing with "17.5 700x" written on it in black marker. It was. I replaced the bushing and weighed 3 more charges. They all came out to 16.5 grains, plus/minus .1 grain.

After much head scratching I changed the setup on the press to my 1 ounce load to see what came out of that bushing. Instead of the 16.1 grains I was expecting I got 15.3 grains. Lovely. The bushings hadn't changed, so the density (fluffiness?) of the powder must have changed. Should I press on with pride and keep using the same bushings I always have? Should I change to a different set of bushings that throw the actual weight I was used to? Research on the web and in my reloading manuals resulted in support for both methods. Some shooters swear by the volume of powder....others by the weight. There was only one thing to do: load some samples, break out the chronograph, and find out what was what. Everything stopped on the reloading line until I had a chance to test the new loads.

The results were quite surprising:

Old load 17.5 gr 700x 1 1/8 oz #8
avg velocity: 1170 fps
standard deviation 5.54

New load 16.5 gr 700x 1 1/8 oz #8
avg velocity: 1197 fps
standard deviation 5.26

Old load 16.1 gr 700x 1 oz #8
avg velocity: 1166 fps
standard deviation: 6.83

New load 15.3 gr 700x 1 oz #8
avg velocity: 1206 fps
standard deviation: 3.78

Hmmmm......less powder (by weight), but both loads are faster. I suppose it's possible that IMR changed the formula for 700x, but I really don't know. What I do know is that I'm going to keep my same bushings in the machine and just act like I know what I'm doing. I broke a 95/100 with the "new" 1 ounce load on the same day I did the chrono testing, so I have no complaints there. I guess I'll just shut up and shoot.

How can this help people out there in internet land? That's simple: trust no one. In the age of the sub-$100 chronograph, there is no reason for any reloader to not have one. Don't assume that the velocities in the reloading manuals are what you are getting. Don't believe any of what you read on the internet or in magazines of how a certain load will perform. Buy a chronograph and use it. Test your load in your gun under the conditions where you shoot. That's the only way you'll really know what is going on.