RCBS Chargemaster Question

I am hoping to get some other opinions on the auto dispensers.
I bought a RCBS Chargemaster and later on bought a Competition Pro Chronograph.
My question is, I am sometimes getting extreme spreads of 100 to 200 fpm when using either w231, clays, tightgroup with 50 shot groups.
Is that normal? I haven't gone back to my old volumetric dropper to check any velocities but I figure it would be worse.
I have paid extra special attention to the scale to make sure it is calibrated.
I am also wondering if it couldn't be my chronograph. The reason I say this is because it started "missing" shots when this happened, so maybe it could be the battery needs to be replaced?
Thanks [:D]


  • charliemeyer007charliemeyer007 Member Posts: 7,348 ✭✭✭
    edited November -1
    200 feet per minute? I would think you could test the chargemaster repeatability with your scales. Make sure you settle the powder in the hopper before testing. If you are shooting lead bullets make sure the base is free of lube. Primer brand and seating technique could easily cause problems. Case length and brand could also affect the crimp. just my thoughts.
  • Rocky RaabRocky Raab Member Posts: 10,891 ✭✭✭✭
    edited November -1
    It's probably not the powder dispenser. It would warn you if there was a problem with a charge.

    I assume you are chronographing handgun loads (based on your powder choices) but it sounds a lot like read errors. You may be too close to the chronograph and muzzle blast is causing errors. Or the sun may be at a bad angle. Or - as you suspect - the battery may be low. The "missed" readings are the major clue that you have a chronograph problem of some kind.
    I may be a bit crazy - but I didn't drive myself.
  • bryan6842003bryan6842003 Member Posts: 25 ✭✭
    edited November -1
    You are correct that it is pistol loads.45 ACP to be exact. They are the Ranier plated bullets, but I dont think that would matter that much.
    If you guys chronograph, how long do you think the batteries would last in a chrony? They are only a few months old. I disconect the battery between uses, and have only used it a couple of times for maybe 2 hours at a time.
  • Rocky RaabRocky Raab Member Posts: 10,891 ✭✭✭✭
    edited November -1
    First, the reason I mentioned handguns is because the muzzle blast from rifles can seriously disrupt chrono readings. With the 45 ACP, that particular problem can be eliminated from consideration - unless you have the muzzle a foot from the first screen!

    A new alkaline battery should last eight hours of "on" time, but batteries do weaken on their own even if not connected. That's the very first thing to change out when a chronograph is acting weird.

    I added a second battery to my chronograph to double the run time. Get a connector from Radio Shack and wire it red to red and black to black so you get double the capacity but still at nine volts.

    I had a marathon range day yesterday because it was the first nice weather in a week. I ran my Oehler 35P for six hours straight and never missed a shot. I won't say how much shooting that was, but I ran off almost ten feet of printer tape. 100% perfect readings.
    I may be a bit crazy - but I didn't drive myself.
  • bryan6842003bryan6842003 Member Posts: 25 ✭✭
    edited November -1
    I didnt realize they would drain a battery so fast. I keep a spare with me all the time, but didnt dream it could be gone so fast.
    I do keep back about 10 feet from it when I shoot with my pistol just to make sure I am not getting any gasses interefering with the readings.
  • jonkjonk Member Posts: 10,121
    edited November -1
    I've had the same battery in my chrono for 4 years without issue. I use it maybe twice a year, hour at a time, so maybe mine is due to die.

    Assuming the Chargemaster is working properly I'd look at consistent crimp (there really shouldn't be any roll crimp with a .45), uniformity of bullet diameter, uniform seating depth, and make sure you use the same brass brand if you want repeatability.

    It could however be the charge too; too light a charge leads to erratic velocity sometimes, as does too slow a powder. With the powders you list the latter shouldn't be an issue and if it is cycling probably not the former.

    Are you using the sun screens with the chrono? Could be the issue if you aren't esp. on a partly cloudy day.
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