Substatuting powders

summerside sniper

summerside sniper

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I am trying to go through all the reload data I have so far, and I am having a small problem. I am using the VihtaVuori load data from the Lapua site and although its got a wealth of info for different bullets for each caliber, it only uses their powder in the lists. In their book they describe each of their powders with more common powders for burn rate.
For example:

.223 REM
55gr, FMJBT Hornady with a Cartridge Overall Length of 2.244" a person should use Powder N120 among others.

Thier burn rate chart (which says not to use to develop loads) and their rifle powder description states:
N120 is a "Slower burning powder for small capacity rifle cases and for lighter bullets in many .22 caliber loads. N120 needs higher pressure than N110 in order to optimize burning. Burning rate is near to Accurate 1680, IMR 4198 and Reloder 7. N120 is suitable also for 7.62x39 Winchester and .444 Marlin."

My question is, can the N120 powder be substatuted by IMR 4198 and still use the min and max loads described for the N120 powder? When if ever is it ok to substitute similar burn rate powders or do you blindly follow the load data given without question and go with the powder indicated?
 
I will thanks, but is it possible to do the substitution? After looking through all my reloading data, I found that not all bullet types are always given.

After looking at the online IMR data (Which is the Hogdon data in the sticky), I found that the bullet type/size that VihtaVuori has listed is not listed with Hogdon
 
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Substituting powders bassed on a burn rate chart is not a good practice. Powder burn rates can often change depending on cartridge construction , and normal operating pressurers.
Your better served to get data from multiple sources, and then work up your own loads for your rifle.
 
summerside sniper said:
My question is, can the N120 powder be substatuted by IMR 4198 and still use the min and max loads described for the N120 powder?
Click to expand...



NO! That is a good way to lose some fingers or an eye or two.


The published "burning rates" are very rough guidelines at best. The burning rates of the different powders are not static and the powders will change their positions on the table constantly based on both the size of cartridge it is loaded in and to what pressure level it is loaded. (The burning rate of smokeless powders increases as pressures increase.)
 
Thank you very much. I wasn't aware of that guys. So what do I do now? I have all the info I need on one chart but I don't want to use the powder. Can I write to IMR and ask them? What do most ppl do in cases like this where a chart for the powder they want doesn't contain the bullet type or style that you want to use? Do you substitute bullet types for one of equal weight?? ---but I guess that wouldn't work either would it....I'm very confused right now. It seems to me right now like you reference the charted data as you guestimate your way to your own min/max loads. This seems like a very dangerous act to me.
 
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Burn rates that are listed are only a guide and they are tested under lab conditions.

They will react diferently in different volume cases. At the same time the burn rates will change positions but there is no real way to predict this UNLESS you have access to some very spendy equipment and trained personnel.
 
Nosler lists .223 loads to 55 gr. for both Viht 120 & IMR 4198 with their bullets. Their "min" at 19.5 and "max" at 21.5 gr. with IMR 4198 is 0.5 gr. more than with Viht 120, - both ends. Velocities look to be very comparable.
Different bullets ca yield different results. As many have stated, straight out substitution is NOT recommended by any one, any where, for any purpose. Use the data cautiously and work your loads up looking for signs of pressure.
 
Might be a good idea to get a couple of books like the Nosler, Speer, Barnes etc so you can compare and find things like that. Lots of used ones around and Wholesale and Russels sell the new ones. Also check Ebay. Many good deals to be had for books. Just make sure they are recent enough to be useful. Mine are all 1994 issue and have been really helpful and a lot faster than posting on this site....:)
 
beretta boy said:
Nosler lists .223 loads to 55 gr. for both Viht 120 & IMR 4198 with their bullets. Their "min" at 19.5 and "max" at 21.5 gr. with IMR 4198 is 0.5 gr. more than with Viht 120, - both ends. Velocities look to be very comparable.
Different bullets ca yield different results. As many have stated, straight out substitution is NOT recommended by any one, any where, for any purpose. Use the data cautiously and work your loads up looking for signs of pressure.
Click to expand...

I did a comparison using "Quickload". A Hdy 55g FMJBT over 20.25g of N120 with COL= 2.244 gives chamber PMax of 46,845 psi.

Substituting 20.25g of IMR 4198 gives Chamber PMax of 46,525 psi.

This compares well with b boy's findings.

"Quickload" cites all the usual disclaimers and isn't a substitute for manuals but it sure is useful if you reload! :)
 
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