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Old February 10, 2013, 07:52 AM   #1
Lost Sheep
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Join Date: January 24, 2009
Location: Anchorage Alaska
Posts: 2,996
Rounds per hour: Sustained vs Cyclical rate

Rounds per hour: Sustained vs Cyclical rate

Just for curiosity's sake and for another thread I discussed the production rate achievable and commented on the claims of some loaders of excess of 250 rounds an hour on Lee's Turret Presses. That's doable. But can you keep it up indefinitely?

If a loader can drop one finished round every 15 seconds, that is 240 RPH (Rounds Per Hour) cyclical rate (3600 seconds divided by 15 seconds = 240). But you can't do that forever without interruptions. You have to stop every once in a while.

So, I knocked out a spreadsheet to allow comparing the two rates depending on the factors that separate the cyclical and sustained rates, namely; Interruptions for checking the powder drop, refilling powder hopper and primer feeder and to stretch your legs and bathroom breaks.

The first set of figures below, I believe, are reasonable for a smooth-running auto-indexing turret press with an automatic powder drop. For progressive presses, the figures are much higher but the principles are the same.

If the process is interrupted once
every 25 rounds for 45 seconds to check the powder drop and
every 100 rounds for 60 seconds to replenish the primer dispenser,
every 50 rounds for 10 seconds to replenish the powder hopper,
every hour for 5 minutes break to stretch your legs

A smooth-running turret press with an automatic powder drop
then 240 RPH cyclic/188 RPH sustained (205 RPH without a break).

Without an automatic powder drop, one round every 30 seconds.
120 RPH/102 RPH/110 RPH

if 20 seconds per,
180 RPH/146 RPH/159 RPH)

A 500 RPH cyclical progressive pencils out at
500 RPH/337 RPH/367 RPH

On a progressive press with a case and bullet feeder), these figures are similarly reasonable by my reckoning
720 RPH/434 RPH/474 RPH

So, when you read anyone's report (boast or complaint) of their throughput, ask yourself how they measured it, what they included and what they left out.

Obviously, I've been bored. Off work sick for a few days. Getting better now, though.

Lost Sheep

edit: My formulas don't work well for batch processing, as done on a single stage.

Last edited by Lost Sheep; February 10, 2013 at 09:00 AM.
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