OCW increments

robtattoo

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Joined
Mar 17, 2015
Messages
14
So, math is not my strong point.

I'm wanting to work up loads for 6.5x55 using IMR7828ssc

I've read up on the OCW test sequence & I think I've confused myself a wee bit.

Working on a maximum charge of 50gn, could someone please tell me what my min-max increments (charge weights) should be please?
 

Mike 338

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Feb 4, 2012
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1,799
Location
Boise, ID
Newberry's instructions say to use 2% increments which would be 1.0 grains. Personally, I've always thought 2% seemed a little much so I use 1% increments which in your case would be .5 grains.
 

DocB

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Joined
Oct 7, 2012
Messages
454
Location
Windsor, VA (but heading for the Rockies)
So, math is not my strong point.

I'm wanting to work up loads for 6.5x55 using IMR7828ssc

I've read up on the OCW test sequence & I think I've confused myself a wee bit.

Working on a maximum charge of 50gn, could someone please tell me what my min-max increments (charge weights) should be please?
"...give a man a fish or teach him to fish" or thereabouts. So let's go fishin!

So for next time you can do this:
use a calculator ( on your phone, ipad, puter, somewhere) and either:

divide (/ sign) 50 (your max charge wt.) by 100 (50 / 100 = one percent of 50 or 0.5 gr.). So in this instance 1% of 50 gr = 0.5 gr.

or

multiply (* sign) 50.0 x .01 ( function of 1 part of 100 or 1%) = 0.5 gr

or

using your weight or whatever value, in this case 50.0 gr, simply move the decimal point 2 places to the left to get 1%. So moving like this ... one place left from 50.0 = 5.00, moving 2 places to the left from 50.0 = 0.500.

2% would be twice the value you receive in all cases above.

I hope this helps you in the future. Good luck amigo, enjoy and be safe!

DocB
 

8andbait

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Joined
Jan 14, 2012
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1,073
Location
ID
.3 or .4 grain increments will work best for that charge weight. Once you find the node do .2 on both sides and shoot them further.

100 yards is fine to start with but 300 or further is great for fine tuning.

Once I know the node from initial testing with OCW I load smaller increments and shoot them at 550. Because you are close to the node these should all have very similar vertical so at that point just look for group size.

Then fine tune seating depth of you haven't already.

It should look something like this.
50.4
50
49.6
49.2
48.8
48.4
48.0
So let's say 49.2, 49.6 and 50 all had the same verticals. Then load 49.4, 49.6 and 49.8.
These should all have the same elevation and just a small change in group size. I like to shoot these further out, preferably with little to no wind.
Good luck and let us know how it turns out.
 

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