Has anyone noticed this? I was loading some 6.5 Creeds using Federal brass, all cases pictured are loaded with 43.2g of IMR-4350. Very surprised at the amount of variation. Weighed the brass, varied from 155g to 181g. The heavier the case the fuller it looked.
I can't imagine getting anything consistent out of this batch. Normally I use Hornady brass and have never seen anything like this.
Wow. No, but then I don't have very much Federal 6.5 CM brass; so haven't paid a lot of attention. But wow, I think I wouldn't bother picking that up again.
That is the reason that you really need to use the same lot number of cases if you can and weight sort all cases to narrow this problem if you want consistency of accuracy. All cases need to be trimmed to the same length and have the inside of the case primer hole de-burred to get the weight of the batch of cases as close as you can make them. Then weight sort them. Laupa case are expensive but you most likely will not have this problem with them like with those Federal.
Of course there are differences across brands of cases but they should be pretty consistent in the same brand. If not, this is dangerous.
Exactly.
My new Hornady brass cases have a 1-2 g variance.After I fire them,I may get up to a 6 g variance. trimming them all down to the same size usually helps, a 20+ grain variance is scary .Im thinking the case walls are different thicknesses thats why some look fuller than others when you add powder.You will have inconsistent pressure.That is dangerous.
For bolt gunners who run multiple firings with neck-sizing only should be concerned about a build-up of burnt powder messing with case capacity. I find that when you full-size a case that has been neck-sized only you get scabs of burnt powder breaking off the inside walls. Tap this on the bench and there can be a fair amount of soot.
Weighing cases is a good start, but still a proxy for what we are really talking about which is case capacity. I am thinking that filling with water and weighing is a closer understanding of what you want to know.
65,
What do you think the variation in case capacity is across this batch of cases? With water it eliminates the possibility some cases have been filled with powder quickly or slowly causing a few to settle high and low (but still have the same case capacity). We all know how to settle powder more efficiently in a case if you want to cram more in; hold it against a tumbler or use a drop tube. Do you think something similar to this might have happened.
I hang out on some long range and target forums. Most guys will cull brass that is off by more than a few grains. Typically they are using Lapua or Adg so there is not much difference. There is also some difference of opinion as to wether case weight is directly related to internal capacity. With cheap brass you may find a fairly wide range from lightest to heaviest. Winchester has seriously gone down hill in this regard. I will usually kick out the high and low outliers and the ones in the middle are fairly close.
[QUOTE=Winchester has seriously gone down hill in this regard. I will usually kick out the high and low outliers and the ones in the middle are fairly close.[/QUOTE]
I stopped using Winchester cases a few years ago after I began finding cases with weird creases in the necks etc. in almost every batch of new brass. It's not such a good deal when you have to throw away several cases from every bag. It used to be all I loaded, but I've switched to Hornady brass. It's not as consistent as Lapua brass, but it's much less expensive. It's a decent compromise.
FloorPoor Wrote:I stopped using Winchester cases a few years ago after I began finding cases with weird creases in the necks etc. in almost every batch of new brass. It's not such a good deal when you have to throw away several cases from every bag. It used to be all I loaded, but I've switched to Hornady brass. It's not as consistent as Lapua brass, but it's much less expensive. It's a decent compromise.
I forgot to mention the crazy amount of brass trimmed off of new Winchester cases to get them in spec.....
It used to be high quality stuff. Now I consider it garbage grade and will only use it for .357/.44 mag. Precision accuracy is not a high priority for the revolvers.
I weighed the brass using water capacity. I weighed three different brass, Hornady and two different batches of Federal.
One batch of Federal and Hornady brass had 53.7-54.0g of water. The other Federal batch which had a slightly different head stamp had 50.3g of water. So, from now on when using Federal brass I'll be weighing and sorting.
Sounds like you are weighing the case with the water. Grendel case capacity is between 35-36gns of water. I plug the primer pocket with a used primer then weigh the case empty. Then fill with water and shave off the top so it's level (no meniscus). Do this a couple of times and take the average. Then subtract the weight with water from the empty case.
These are 6.5 Creedmoors. Sorry for the confusion but when it comes to reloading advice, from past experience, I trust this group. The Creedmoor holds approximately 52.5 grains of water. First I calibrated my scale, added one case, zeroed the scale, added water to level top which gave me the water weight.
