Blending Powders

[rcar112]

I'm not one to want to blend powders but a question about blending the same powder, let's say Varget with different lot numbers.
If I blended different 1 lb cans into 8lbs of Varget with three different lot numbers and then did my load work ups. Would there be a reason this would not work?

 

[antelopedundee]

If each lot required about the same load amount to get the same performance I see no harm in blending them. Some say that some powder lots of the same kind [say IMR4831 for example] are hotter than others so your blended lot couldn't be any hotter that the hottest lot.

 

[RT2506]

No problem as long as you back off a known load and work back up seeing what happens. I do it all the time. It is just the same as if I changed lot numbers of powders.

 

[ButterBean]

No problem as long as you back off a known load and work back up seeing what happens. I do it all the time. It is just the same as if I changed lot numbers of powders.

^^^^^ I Concur

 

[rcar112]

Thanks, I have to do that now with every lb. or 2 because of how infrequently the same batch of powders show up!

 

[J E Custom]

In the past we had to use duplex or even triplex loads. we had to keep them separate and had to compress the powder charges to keep them in their proper place without mixing. some of us tried mixing Different powders and even the same lot numbered powders the results were all over the place. The conclusion we came to was that the blending process was not sufficient to get a perfect blend unless it was done for a long time.

So the best results were to first try to buy powder with the same batch numbers, and use each canister totally up if you had a good load. then when you went to the next canister start with a 1 grain less load if you were at max and adjust the weight by small increases until you have the same results. (Normally there will be a very small shift in POI and/or velocity) even with the same lot numbered powder. If you cant buy matching lot numbered powders, then it is recommended that you start testing the load when you start using out of the new canister.

If you mix/blend powders you will most likely see different SD,s and velocities even an occasional flier.

Many people blend or mix powders but if you are a accuracy nut you will find that the end results
are never as good when you mix powders.

As stated in the past, 1 MOA is easy, 1/2 MOA is hard, 1/4 moa Is very hard and accuracy in the .100's will have extreme consistency with no stone unturned, and nothing overlooked.

J E CUSTOM

 

[SilverbulletMAG]

With regard to blending same powders of different lots, I keep a constant "blend" or "Infinity Bottle", if you will. I work from 1lb cans and every time it gets to about the halfway point, I will top it off with something from an previously blended 8lb jug and give it all a good shake. Keeping 3 jugs of same powder in the rotation where possible and haven't noticed any appreciable difference on paper or velocity spreads doing it this way.

 

[cape cove]

When I mix like (same) powders of different lots I chrono a few rounds of each lot and if the vel is close then I mix. If not then I don't.

 

[243winxb]

Do a test by volume. Set the measure, run 20 to settle the power. Get the dropped weight of the old powder. Empty. Add new lot with same measure setting, run 20 to settle the powder. Compare both weights using the same volume. Any difference?

By volume,IMR4198, (not H) there can be as much as 1.1 gr difference in weight. 18.5 gr vs 19.6 gr. with the measure at the same setting. This was older Canada vs Australia. Mix if the same lot number. Other wise, work up a new loading.


https://apps.dtic.mil/docs/citations/ADA572333


"To consider the likely pressure variations, consider that QuickLoad V3.6 predicts a muzzle
velocity of 3174 ft/s and a peak pressure of 54371 psi for 79 grains of H4831 using the 155
grain AMAX in the .300 Win Mag. This is very close to the 3177.5 ft/s velocity that results from
averaging the measurements over all six lots of powder. However, compensating for possible
lot to lot velocity variations requires a range of powder charges spanning from 77.5 to 80.5
grains of powder and a range of pressures from 51063 psi to 57910 psi. It is possible that a
load showing no signs of pressure with one lot of powder might not be safe with another lot of
powder. At their web site, Hodgdon recommends working up new loads when the lot number
of any component is changed, and it is evident that this includes a new lot of Hodgdon."

 

[rsmithsr]

it is done all the time..just consider the new lot just that, a new lot.
so back up a bit, and workup/chrono so loads and keep good notes.
and in spite of an earlier comment, blended powders are used in competition bench rest. the most common today is lt31, 1/2 lt30 and 1/2 lt32.

 

[rcar112]

Please clarify your last sentence- kinda new to this.... thanks

 

[rsmithsr]

not typically used in hunting or long range target rifles.
was just saying in the sport of short range target shooting it is done...with real small cartridges...6ppc/6br,

Please clarify your last sentence- kinda new to this.... thanks

 

[Varmint Hunter]

I've done it a few times and have never had a problem or even noticed a discernible difference in velocity. I shoot all of my reloads over a chronograph.
You do, however, need to be extraordinarily careful to not make a mistake when mixing powders or transferring from one container to another. An oversight could be catastrophic.
My LGS use to sell one pound cans of powder that were relabeled. They were taking 8lb cans and repackaging them into 8-1lb cans using previously empty bottles that needed to be relabeled. I never purchased one of these bottles because there was always the possibility that a can could have been mislabeled or some other error made.

 

[GLTaylor]

Concur with earlier posts. When i can only get 1 lb containers from diff lots i buy several, pour in a clean bucket and stir, stir stir. I make a new lot of powder (of the same powder), label each jug, fill the containers to the top to exclude air and go from there.
I verify prior loads by working up again and make a notation in my loading journal. This load of 4831 is from Lot I, etc. Never really noticed much difference. If any, its usually small.