new and wet powder,

[constructor]

When you buy a new lb or keg of powder and it's 100fps slower than your last batch do you try to dry it or just adjust your loads to get back up to the vel and in your node and then check the load for vel before you load for each match?

 

[bheadboy]

I would never recomend altering a powders charcter, either adjust loads, contact manufacturer, or set aside,

you are messing with a complex chemistry and can cause worse problems for your self if you try "drying the powder"

Bob

 

[kitsap]

I am curious where the idea came from to "try to dry it" in response to manufacturing variances in smokeless powder ??

Were the rest of the components used in your reloads the same manufacturer and lot number ??

The end result of 100 fps slower is not very large. What caliber are you talking about and what velocity range ??

Were the environmental variables the same when you measured the velocity difference ?? Such as temperature, humidity, air pressure, etc.

Did you use the same chronograph to measure the different velocities ??

 

[RDavies]

I have seen 100 fps difference in different powder lots. If I have an accurate load with one lot, when I have nearly run out, I load some cases with the previous lot, and some with the new lot, to see what happens velocity wise. I shoot both lots at the same time, so temp, sunlight, crony angle etc are the same. With my new lot of powder, I have had to increase the load by .75- 1gn to stay in the same velocity.
In short, just bump up (or down) the powder level to stay in the node.

 

[constructor]

I am curious where the idea came from to "try to dry it" in response to manufacturing variances in smokeless powder ??

Were the rest of the components used in your reloads the same manufacturer and lot number ??

The end result of 100 fps slower is not very large. What caliber are you talking about and what velocity range ??

Were the environmental variables the same when you measured the velocity difference ?? Such as temperature, humidity, air pressure, etc.

Did you use the same chronograph to measure the different velocities ??

When you buy powder it is definitely wet and starts to dry as soon as the container is opened, the acetone, ether or alcohol used in manufacturing or washing the powder evaporates.
Dry powder will bounce when it hits the pan new wet powder is darker, it just hits and sticks. I see 100fps difference with several powders, this recent was RE15 in a BRX, 95SMK at 3070 is center of my middle node from a 22" barrel, same chrono inside my shop under controlled lighting, tested at the range and hit much lower at 300. The first time I saw it I just left it open on the bench for a week and would shake it as I passed, the next weekend it was much closer to the vel of the last container so I didn't need to adjust much. 100fps can make the difference in hitting the high node and not also if someone is just using the same charge without checking vel it could drop out of the node. Same thing with Varget using an 8lb keg the vel gets higher as one uses it over a period of time, then when you get a new keg the charge needs to be adjusted to get back to the same vel. So I guess from the replies most just adjust the charge before each match to stay in the node.

 

[rcw3]

When you buy powder it is definitely wet and starts to dry as soon as the container is opened, the acetone, ether or alcohol used in manufacturing or washing the powder evaporates.
Dry powder will bounce when it hits the pan new wet powder is darker, it just hits and sticks. I see 100fps difference with several powders, this recent was RE15 in a BRX, 95SMK at 3070 is center of my middle node from a 22" barrel, same chrono inside my shop under controlled lighting, tested at the range and hit much lower at 300. The first time I saw it I just left it open on the bench for a week and would shake it as I passed, the next weekend it was much closer to the vel of the last container so I didn't need to adjust much. 100fps can make the difference in hitting the high node and not also if someone is just using the same charge without checking vel it could drop out of the node. Same thing with Varget using an 8lb keg the vel gets higher as one uses it over a period of time, then when you get a new keg the charge needs to be adjusted to get back to the same vel. So I guess from the replies most just adjust the charge before each match to stay in the node.

Constructor

Great post! You are one of the first people I have seen to have noticed this condition and to have brought this issue "to the light of day" on a forum. I have seen this condition before myself numerous times and make adjustments in my loading routine to account for it. The interesting powders are the Hodgdon Extreme powders that are supposed to be extremely stable and not affected to any degree by such things, yet in my experience are affected to a significant degree by a "drying out" over time. The powders I have seen to be affected by this are H4831SC, H4350 and Varget, and the longer I keep an 8 lb jug around in my reloading room and use it, the more I have to cut back on the charge weights to retain the same velocity and accuracy. What tipped me off was I had a new jug of H4831SC and in a 6mm I had it shot great with 43.5 gr of powder and the 115's (just under 3000 fps). After I had the jug 6 months or so, I went to go shoot a match with the same load as before and it shot awful, it baffled me until I ran the load over a chrono again and found it was going around 75 fps faster and was now out of the "sweet spot". I dropped the load back about 1 full grain and everything was good again at just under 3000 fps. This also happened to me in a 6.5 x 284 with H4350 powder and H4831SC (i.e. worked up a good load with a new jug of powder but if I did not use it up right away the powder changed over time and burned faster and made it so the load I had did not shoot well anymore unless I cut back the charge weight).

Robert Whitley

 

[constructor]

Well Robert you know I don't shoot benchrest, I am lucky to get 2 hrs a week out of the shop to shoot for personal amusement. I was just curious as to what the big trigger pullers were doing because I have read several times about the variance in lots of Varget, I'm not so sure it is manufacturing variance in product but how wet the product is.