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conflicting load data
Posted:
Sat Jan 23, 2016 10:17 am
by Slugger
What do yall do when you find conflicting load data. I'm getting ready to do some .223 loads with IMR 4198 and hornady 55gr SP for my 20" varmint rifle chambered in .223 wylde.
my issue is I really don't know where to start. The Hornady manual shows start load of 17.4 gr with a max load of 20.0 gr. The Nosler data is starting at 19.5 going up to 21.5 and the sierra (AR-15 DATA) starts at 20.1 and goes to 22.5 . I have noticed that it seems Hornady data seems to almost always be on the more conservative side with most of their data. So after seeing all of that I went to the IMR data and they show max of 21.5 I'm thinking I will just start 10% below the IMR data and work up in .5 gr increments from there. what do you think?
Re: conflicting load data
Posted:
Sat Jan 23, 2016 12:32 pm
by Al in Mi
better safe and start low.
Re: conflicting load data
Posted:
Sat Jan 23, 2016 12:57 pm
by Jim in Houston
Or you could pick the low end of where they all overlap. I would do this rather than take an arbitrary 10% off one of the recommendations. But start low is always good advice.
Re: conflicting load data
Posted:
Sat Jan 23, 2016 1:17 pm
by m113103
Re: conflicting load data
Posted:
Sat Jan 23, 2016 3:07 pm
by Slugger
I have no intentions of pushing MAX pressures. I'm using matching headstamp range brass. I weigh each charge and sort cases by length. I'm just wanting to work up an accurate load for punching paper and yotes. I will start at the Hornady starting point of 17.4 and go up from there picking the best load for my gun. I was just confused on why the start load from one manual would be within .3 grains of the max in another. I understand that different barrels will produce different pressures as well as air temp, different batches of powder ect. I just didn't realize it would be such a dramatic swing.
Thanks
Re: conflicting load data
Posted:
Sat Jan 23, 2016 5:45 pm
by Hoot
FWIW, QuickLoad modeling software agrees with Nosler, based on loading them to 2.26 COL. What you can not add to the calculation though is what kind of primer you are using. That can account for the differences from one source's range to the other. I do believe Hornady bases many of their loads on the Winchester Small Rifle primer, which like Remington 7 1/2's are pretty peppy compared to say Federal or CCI plain Jane primers. Not to distract from the topic with primer debates.
Hoot
Re: conflicting load data
Posted:
Sat Jan 23, 2016 6:39 pm
by lungingturtle2
Please be aware that military headstamp brass is thicker brass which decreases internal volume and will drive pressures up. Max loads of some bulkier powder in commercial .223 cases can over flow military cases.
Re: conflicting load data
Posted:
Sat Jan 23, 2016 7:55 pm
by m113103
Re: conflicting load data
Posted:
Sat Jan 23, 2016 8:04 pm
by m113103
Re: conflicting load data
Posted:
Sat Jan 23, 2016 11:02 pm
by Hoot
Being the rifle range coordinator at my local club, I get lots of LEO practice brass pickups. Believe it or not, the heaviest deprimed brass award goes to PMC. Yes PMC, not LC or IMI. Go figure...
Hoot