Accumeasure throwing 3/10's low?

[drklynoon]

Hi all I just received a Lyman Accumeasure off of fleebay. I like the simplicity and it so far it seems to be durn consistent but I have found that it throws 3/10's low with Unique with all three starter drums. If this is the consensus then I will be doing a little polishing on one of them to get it up too 5.5 gr Unique. If not and it is merely a matter of weather and it will correct itself then I will probably leave it alone. Does anyone have a similar experience with this powder measure?

[Maven]

Nathan, I have one of those too with a complete set of rotors and find that Lyman's data, which came with the measure, was typically 0.5gr. less than it was supposed to be. Btw, this is true regardless of powder brand and type or rotor number. What you need to determine is exactly the charge of Unique, et al., thrown by a given rotor before you begin polishing, reaming, or enlarging the cavity. You do this by consistently dropping 5 sets of 10 charges of powder, Unique in this instance, into your scale pan and averaging the result. This has worked perfectly for me for throwing pistol and some rifle charges.

[Green Frog]

It seems like many of the fixed cavity rotors (not just those from Lyman) tend to go a little lighter than advertised... my Little Dandy rotors suffer from this malady as well. I think they did that intentionally so folks who didn't check their drops against a scale would err on the side of safety. (That's just my educated guess, however.) I have a complete set of rotors for an Accumeasure I bought several years ago, but haven't used it much so don't know for sure that mine follows that same trend. I like to work out a load that works with a rotor that is just below the "desired" amount... just a fuzz low, but that's just me. :roll:

Froggie

[MtGun44]

Seems like it is what it is, not adjustable unless you drill out the cavities.

Bill

[drklynoon]

Thanks for the feedback guys. I tested the weight many times on two different beam scales to be sure with each rotor. I usually develop my loads a little on the light side so I don't really want to go lighter and with only having three rotors I'm going to have to make some modifications to get it to throw a few of my most used loads. I usually use a Lyman 55 but I thought this was a good deal and it has to be more consistent than my 55, so why not. I've looked for rotors online but have come up empty except the three that come with the measure. I filled one cavity half up with epoxy today and am going work with it to throw my .357 loads. I'll polish on one this weekend to get it up to 5.5 gr of Unique for my .45 acp load. Fortunately the largest rotor works for a trail boss load for .45 colt so I won't monkey with that one. This measure is really consistent and may become a highly used tool.

[drklynoon]

Wow, I just read my first post and boy was that disjointed. I was worried that my results were skewed because it was a sticky, cool, and half rainy morning. I would think that high moisture content and high barometric pressure would give higher scale readings than clear dry days but I haven't done any tests to prove it. So I was attempting to verify the measures propensity for dropping light.

[EDG]

If you polish the rotors out, the next lot of powder you buy may throw heavier.

[drklynoon]

Yeah EDG, it is possible. I tried other powders to see if it threw them low as well and it did so I am hoping it won't be too bad.

[Maven]

Nathan, There's another possibility, which doesn't involve the mess and semi-permanence (or at least inconvenience) of epoxy. You can cut paper discs from magazine subscription cards or paper of that weight with an arch punch that's the same diameter as the one in the rotor. (You'd be surprised how much one such disc reduces the charge weight.) Add (or subtract) as many as you need, as they're easily removed.

[MtGun44]

My bet is that since all manufactured items have tolerances in the
manufacture, they probably made darned sure that the tolerance band
was ALL on the too light side, for safety. I think this is the reason
that most fixed rotor designs have been out of production for a
while.

Bill

[Ben]

I tried to drill out an RCBS Little Dandy rotor on my drill press.

After ruining 3 drill bits , I gave up.

Ben

[drklynoon]

That's an interesting idea about the subscription cards Maven. Yeah Bill I think you are right and they were designed that way for added safety. Ben, the Lyman rotors are made of brass, I'm not sure if the dandy's were steel or not but I'm hoping the brass will be easy to polish/ drill.

[drklynoon]

Just to update my experiment everything went swimmingly. The epoxy trick worked like a charm. I drilled the epoxy until it threw exactly what I wanted. I then remarked the rotor so I don't get cornfused later. I also opened up the 6L cavity a little with a drill bit. It worked as well. So now I have a cavity for .45 acp, .45 colt, .357 mag. I'm load developing for my .32 H&R Mag but when I'm done I'll fill a cavity with epoxy and drill it. I also made a stand for it today that should be pretty awesome. I like being able to move things around my bench without drilling holes everywhere so the powder measure stand uses a piece of 1" x 1/8" flat stock bent to slip over the front of my bench. It fits tight and doesn't move around at all. I may put a picture up tomorrow after paint dries.

[o6Patient]

The most important part to me and maybe some one mentioned it already and I missed it,
would be are the light charges consistent? A cavity can always be hogged out a little.
If your drill won't drill it you could always use a harder drill ..or maybe even a die grinder
used judiciously.

[drklynoon]

06, every charge outta this measure seems consistent. I wouldn't have believed it to start. I did drill out my one rotor until it threw the desired amount. The brass is easy to drill if one is patient. I'm a pretty big fan of this measure and besides having to be creative with the rotors it is a sound little measure.

[o6Patient]

That's terrific, ...yeah I saw were Ben was drilling out a little dandy rotor and forgot we were talking
about a lyman brass rotor, early onset senility.:veryconfu

[Maven]

"The most important part to me and maybe some one mentioned it already and I missed it,
would be are the light charges consistent?"

o6Patient, Every powder I've tried in the Lyman Accumeasure, from B'eye and Clays (original) to WC 820 has been consistent to within 0.1 grain IF you operate it consistently.

[o6Patient]

If I were making a fixed rotor and the measure was a plus or minus .1 grain
(which in my book is excellent)
...I would make the rotor one tenth under to start with..just a thought.
What I'm saying it is better to be one or two tenths under a max load
than be over max even if a just tenth. make sense..does to me(lol

[Maven]

If I were making a fixed rotor and the measure was a plus or minus .1 grain
(which in my book is excellent)
...I would make the rotor one tenth under to start with..just a thought.
What I'm saying it is better to be one or two tenths under a max load
than be over max even if a just tenth. make sense..does to me(lol

o6P, See post #2 above.

[o6Patient]

Maven: I re-read post #2 and it is a very nice post!