Mixing powder

[ihmsakiwi]

Hi Guys,

Don't flame me too much, but......

Newby F-Class shooter here. Transfered recently from Silhouette pistol shooting where 1 MOA was all you really needed to be competative. As i have only shot one F-Class club day to date before our club closed for the wet-season I don't have the chance to bounce this off my new club members

I have 3 x 500gr ADI 2208 cannisters and just been given 3 500gr "tins" of AR2208. My question is due to the time difference in manufacturing am I best to keep them separate and work up loads for both powders or how problematic would it be to mix them and have one powder to again work up loads on? Feeding a 30" 6mmBR rifle for 300 & 600yd shooting. I'm pretty sure I know the answer but thoight I would check anyway.
Peter

[saum2]

This not a recommendation but, I know someone who always mixes powder. ie, when getting low on the current 4kg jug mixes in with the new powder of the same type. doesn't seem to affect scores in any way. I've been known to mix 3 small lots of the same type into one container, no problems
Your tins would be a lot older than the current plastic bottles so maybe keep them seperate.

[Rich4]

Depends on storage conditions of old batches? Perhaps do a parallel max pressure exploratory workup with both in a single case each and see if the the velocity’s are similar.

[ajvanwyk]

Peter,

Its probably the right, risk free answer to say dont do it....

For the best part of two years I have taken every new 500g tin, bought or won and mixed it into my 4kg jug of 2209. If I bought a new 4kg jug, I mixed both of together with a few shakes and continued along my way.

I'm by no means at the pointy end of the spectrum and have to say that for me, I couldn't tell you what or if the difference was meaningful enough to worry about it.

Best to get a broad range of opinions and make up your own mind...

[bruce moulds]

how do you know that it is absolutely evenly mixed?
that is the question I ask myself when I do it.
bruce.

[williada]

If you have the luxury of a pressure trace and past data you can detect significant change. Using a lab radar is probably the next best thing to check velocities. The burn rates between batches are meant to be formulated to velocity and pressure in standardised test barrels by manufacturers, but as we know batches may differ a tad but should remain within safe limits as determined by the manufacturer. Perhaps powder gets stale when it is stored inappropriately or the air gets to it. ADI powder is designed to have years of shelf life. However, I take Bruce's point made earlier about intelligent loads on a previous thread. Loading near the upper limits could be problematic with fresh powder if loads were based on stale powder but not a problem if loads are backed off a bit for accuracy as Albert may do.

I take the view it would matter not much in the accuracy stakes at club level mixing powders based on the manufactures designation,but for an important shoot at long range variables should be minimised by sticking with an unmixed and tested batch. The serious shooter for long range shooting weigh primers.

[bruce moulds]

williada,
what do you weigh when you weigh a primer?
anvil + cup + propellent + other.
too many variables here and all could be null and void by stacking in various directions.
the primer is one thing we have no control over period.
when compared to poi changes due to bending light on the way to the target, how much difference will weighing primers make.
how do we learn to deal with bending light, which can be up to 1 moa?
stack oto this elevation changes due to change in wind direction and speed, and you have a far greater potential way to minimize vert.
learning and understanding this could be far greater advantage.
and if you get a batch of primers that seem better, stick to them.
bruce.

[Cliff Austen]

I would be contacting ADI and seek their technical advice and not that of all us 'arm chair' experts, in this case. Doing the wrong will have devastating results. Keep safe. Cheers Cliff

[bruce moulds]

cliff,
they might say throw out the old powder and buy some more to replace it.
why would one suspect such a thing?
bruce.

[KHGS]

I would be contacting ADI and seek their technical advice and not that of all us 'arm chair' experts, in this case. Doing the wrong will have devastating results. Keep safe. Cheers Cliff

ADI blend batches of bulk powder to create canister lots for retail sale, this is done to keep burning rates to their acceptable level from canister batch lot to lot. I read somewhere that this acceptable variation was held to something like 3.5%, don't quote me on that though. This is why there can be wild variations in the charge rates in factory ammunition with a given powder to achieve a given velocity/pressure rating. Ammunition factories load with bulk powder not canister grade powder so the burning rate variation is much greater than canister lots of the same powder. I blend every time I buy a 4kg canister with the old batch at the rate of about 50% so I never have to load test with a new lot of powder.
Keith H.

[williada]

Bruce the statistical bias is with the propellant.

[Cliff Austen]

Bruce, yes i agree.
Keith, they would have every piece of anti static device and earthing straps in play that one could think of.
Only yesterday I blended 6 x 500 gram bottles of 2213SC in a 4 kg bottle. All of this was done by bringing the 500 gm bottle in contact with a 4kg black ADI bottle and slowly running it into the 4kg bottle. I also wore a full face mask/goggle. i then slowly rotated the 4 kg bottle in a few different directions for 5 minutes to mix/blend the powder. No vigorous shaking.
It is important to use the Black ADI bottles as the are designed to be static free.
From this I will be loading 300 rounds in 7mm/284 to use in the Match Rifle Long Range F Class Championships in SA and then the Ultra Long Range Challenge at Coonabarabran.
Cheers
Cliff

[ihmsakiwi]

Thank you all for your inputs. I have the feeling I may be better to keep them apart and just do a accuracy test with each to check pressures & any change of height variance.
I willemail ADI though to see what they suggest and I will post their reply.
Peter

[AlanF]

I cannot see any safety problems with mixing batches of the same powder if you don't exceed maximum recommended loads, even if you fail to mix them thoroughly. The worst that can happen is that performance will be inconsistent. I've mixed different batches often (dregs or salvaged from dismantled cases etc.), but never use it for serious competition, just for fire-forming cases , running in barrels etc. Powder is one of the least expensive inputs to shooting F-Class so don't risk competition performance by mixing it.

[KHGS]

I cannot see any safety problems with mixing batches of the same powder if you don't exceed maximum recommended loads, even if you fail to mix them thoroughly. The worst that can happen is that performance will be inconsistent. I've mixed different batches often (dregs or salvaged from dismantled cases etc.), but never use it for serious competition, just for fire-forming cases , running in barrels etc. Powder is one of the least expensive inputs to shooting F-Class so don't risk competition performance by mixing it.

Alan, perhaps you should tell the powder manufacturers that, they don't seem to know that because every canister of powder you buy from any powder manufacturer has been blended.
Keith H.