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Winchester Brass
Posted: Wed Jun 13, 2007 6:18 am
by Ken L
Cut and pasted from Long Range Target Forum as it is interesting.
Last year, I purchased a lot of Winchester brass (1,000 count) for Palma loads. Unfortunately, due to health issues, I didn't get a chance (or reason) to play with it until recently. This lot came in 20 bags of 50 ct each.
I began by selecting 500 pcs in order to cull them with the intention of dividing them in similar weight groups (but of course). Much to my surprise, after weighing the 600 pcs, I ended with a wide selection of cartridges weighing as little as 155.3 and as high as 159.8.
Needless to say, I haven't experienced such wide range of variation within Lapua and Norma brass, yet. Even Remington has done far better than this.
Percentage wise out of a total of 600 pcs weighed so far:
159.0 - 159.8 = 4%
158.5 - 158.9 = 13%
158.0 - 158.4 = 23%
157.5 - 157.9 = 17%
157.0 - 157.4 = 20%
156.5 - 156.9 = 19%
155.3 - 156.4 = 4%
I am going to continue weighing the remaining 400 pcs to see if the percentages remain the same, and so that I may have a good amount of median average to choose same weight brass out of.
Any similar findings out there with resent lots of Winchester brass?
By the way, pretty much ALL cartridge mouths are bent, crimped, out of round, etc, etc. Although I always neck size new brass, I am worried at the poor condition this brass was in.
Andy
Posted: Wed Jun 13, 2007 8:14 am
by Guest
That's a normal variation for Winchester brass ( 4.5 gns ). However it proves nothing other than one case is heavier ( or lighter ) than another.
The desire is to check case volume and unless a dimensional check is done on each case then there is no point weighing. Even a variation of 1% in relative density between cases will give a 1.6gn weight variation, and the R/D does vary.
So, what's the point in weighing?
I have seen factory loaded rounds weighed and batched accordingly. Now a factory load can vary up to 7or 8 tenths by virtue of 3 or 4 tenths variation in BOTH case and powder weights. So again what's the point of weighing when you have absolutely no idea where the weight variation is coming from?
After having fired a case and trimmed to length, probably the best check other than a volumetric measurement is to depth gauge from the case mouth to the internal bottom, but this is also rough as case walls may vary in thickness.
Barry
Posted: Wed Jun 13, 2007 12:08 pm
by Simon C
I agree Barry.
The other important factor is neck wall thickness and variation. I have found that the variation in Winchester brass (looking at neck wall thickness only) is quite evenly distributed. I have done this for 3 batches of 100 in 2 calibers. The volumes were pretty consistent though.
I think looking at the neck is a better measure. However, neck turning to skim off any high spots is a PITA but does help to enforce a consistent bullet tension.
Posted: Thu Jun 14, 2007 1:25 pm
by ned kelly
G'Day simon,
well to be different, I measured Win 223 brass and found the neck wall variations to be a max of 2.5thou over 50 cases with some having the full 2.5thou difference in one case.
In comparision, I measured 50 lapua .223 cases and they varied by no more than 0.5 thou max variation, with a good number being well below the 0.5thou max.
All of these cases were measured with the same 1/10,000 tubing micrometer (modified to measure at the neck/shoulder junction) and measured in 4 places around the neck. all cases came from the same batches from each manufacturer.
Naturally, I do not use Win cases for competion.
Cheerio Ned
Posted: Thu Jun 14, 2007 2:35 pm
by Simon C
Ned,
I too only use Lapua for competition. These are for a couple of varmint rifles
Posted: Fri Jun 22, 2007 9:02 pm
by Warwick Brown
I recently wieghed 200 winchester rounds that were once fired and found them to be 156.5 through to 160.3 gns. in wieght.
I have loaded them and found the neck tension average, but did have one case that was two button sizes smaller than the rest. They have been made up for my club 308 barrel for any new shooter that may come to the range to have a try of F Class, so my good brass does not do the clicks. The last lot of Winchester I did, I found that on the second reload (neck Sizing only) I had to drop one button size for all cases to achieve the required neck tension. On the 4th reload the neck tension varied cosiderably from case to case.
These cases are not made to reload time and time again.
Although I did shoot a 120 out of 120 @ 500yards with 2nd neck sized reloads last year.
I suggest that they are fine for varmiting but after two reloads, put them in the bullion bin.