Reloading 308 caliber. 5 different brands with average weight listed. ADI 185.grains, HSM 180 . grains , FC 175. grains , Rem. 165 grains , Win. 157. grains . With all cases sized the same , using the same powder & charge, under the same bullet , same primer. Will all 5 shots group the same? In weighing brass, there could be a 5 grain spread in all brands.
Question on case weight
- Thread starter cw308
- Start date
Different weights mean different case volume.
Different case volume means different burn characteristics.
Different burn characteristics mean different velocities.
Different velocities generally mean different POI.
For target shooting, it would matter the most.
For hunting, not so much, with exceptions of course.
Different case volume means different burn characteristics.
Different burn characteristics mean different velocities.
Different velocities generally mean different POI.
For target shooting, it would matter the most.
For hunting, not so much, with exceptions of course.
Dufus
thanks for getting back so soon. That's exactly how I think. For benchrest shooting, missing one step can screw up your group. If the weights weren't so off, I wouldn't have posted this. The cases, even though they are the same brand, don't know if they came from the same box of 20. I get my brass from a friend that doesn't reload. If they are normally off by that much , that could be the reason for that unexplained flyer. I now will be separating my brass brands by weight in the 1 grain range.
thanks for getting back so soon. That's exactly how I think. For benchrest shooting, missing one step can screw up your group. If the weights weren't so off, I wouldn't have posted this. The cases, even though they are the same brand, don't know if they came from the same box of 20. I get my brass from a friend that doesn't reload. If they are normally off by that much , that could be the reason for that unexplained flyer. I now will be separating my brass brands by weight in the 1 grain range.
I don't weigh cases, but I also don't mix and match headstamps.
When I loaded .22 hornet, if I used REM cases, the loaded ammo shot great, no issues.
If I used WIN cases with the loads I worked up in REM cases, the WIN cases would show major primer signs immediately and have split necks much sooner.
I don't think the WIN brass wasn't as good, it just had less case volume, which translated into higher pressures, and the other warning signs of higher pressure.
When I loaded .22 hornet, if I used REM cases, the loaded ammo shot great, no issues.
If I used WIN cases with the loads I worked up in REM cases, the WIN cases would show major primer signs immediately and have split necks much sooner.
I don't think the WIN brass wasn't as good, it just had less case volume, which translated into higher pressures, and the other warning signs of higher pressure.
My K-Hornet likes Lil-Gun. I can get 99% on volume.
The Hornet cases are so thin that I suspect that volume variability would only change near the base so I don't weigh my Hornet cases normally although I always keep brass sorted by lot together.
I have found that weighing brass with my Rem. Varmint special in 222 dose seam to help.
There are a lot of things that can very in loading and then there are the variables with the rifle.
Although I am the largest variable.
The Hornet cases are so thin that I suspect that volume variability would only change near the base so I don't weigh my Hornet cases normally although I always keep brass sorted by lot together.
I have found that weighing brass with my Rem. Varmint special in 222 dose seam to help.
There are a lot of things that can very in loading and then there are the variables with the rifle.
Although I am the largest variable.
"With all cases sized the same , using the same powder & charge, under the same bullet , same primer. Will all 5 shots group the same?"
It's NOT a question of group size, but a question of load density. With moderate loads, the difference in internal volume probably isn't a safety hazard but may cause enough velocity variation to effect accuracy potential. This will be a factor of the rifle used.
It's NOT a question of group size, but a question of load density. With moderate loads, the difference in internal volume probably isn't a safety hazard but may cause enough velocity variation to effect accuracy potential. This will be a factor of the rifle used.
I agree with everyone. I was surprised there was such a range in weight in all. With the lighter cases I have to increase the load an average of 2 grains to have it group the same. I'm using the ADI brass for my next reloads, the range is 184.- 186 grains there are a few lower & higher. I will be loading only 30 rounds 185.0 - 185.9 grain range, to see how they group.
boondocker385
New member
I do weigh and for my hunting loads (to 300 yards ) it doesn't seem to matter much from the standpoint of needing rounds to fall in an 8"-10" zone. Past that, it does matter as velocity has a big change in POI and in the rounds I have tested using the biggest delta between capacities, YMMV.
The next reloads are going to be with cases weighed in the one grain range. My last fired cases on this range trip , had 6 out of 30 rounds grouped 1/2" out of the group. Weighed the fired cases 3 were 3 grains lighter , 3 were 3 grains heavier. Just found it interesting. Will see how they group with the weighed cases .
Got me curious enough to weigh some brass. The result surprised me somewhat. I used a small sample of 5 cases each of WCC (Western Cartridge Company) 10 military Winchester brass, R.P. (Remington Peters) and Lapua which I misspelled on the Excel sheet.
I was surprised the WCC brass once fired comes in almost 10 grains heavier than the Remington or Lapua and the Remington and Lapua are new factory brass never fired. All brass was sized and trimmed uniform. The Remington and WCC had the same standard deviation of 0.55gn both better than the Lapua. While I expected the military brass to weigh slightly more I did not expect it to outweigh the Lapua by as much as it did.
The WCC 10 brass I have been having some real good luck with in my bolt gun and M1A loading AA 2495 this past summer. I have not actually measured the case volume using the water method yet. I was looking to try something beyond my standard go to IMR 4895 and IMR 4064 powders so tried the AA 2495 I liked years ago under Sierra 150gn and 168gn Match King bullets.
Ron
I was surprised the WCC brass once fired comes in almost 10 grains heavier than the Remington or Lapua and the Remington and Lapua are new factory brass never fired. All brass was sized and trimmed uniform. The Remington and WCC had the same standard deviation of 0.55gn both better than the Lapua. While I expected the military brass to weigh slightly more I did not expect it to outweigh the Lapua by as much as it did.
The WCC 10 brass I have been having some real good luck with in my bolt gun and M1A loading AA 2495 this past summer. I have not actually measured the case volume using the water method yet. I was looking to try something beyond my standard go to IMR 4895 and IMR 4064 powders so tried the AA 2495 I liked years ago under Sierra 150gn and 168gn Match King bullets.
Ron
Reloadron
I have 200 cases on the average of each brand. When weighing 60 cases of each, there is an average weight of each group, but there is quite a few in each group with a big jump. Those I will weed out . I could see POI would be effected. Just another thing to check for. My RP & Win. brass are 5 years old, reloaded 5 times , still in good condition. Your RP are 10 grains heaver then mine. I will be shooting the weighed cases this weekend. Be Well , Chris
I have 200 cases on the average of each brand. When weighing 60 cases of each, there is an average weight of each group, but there is quite a few in each group with a big jump. Those I will weed out . I could see POI would be effected. Just another thing to check for. My RP & Win. brass are 5 years old, reloaded 5 times , still in good condition. Your RP are 10 grains heaver then mine. I will be shooting the weighed cases this weekend. Be Well , Chris
Chris
I should have mentioned the RP brass I used was at least 20 plus years old. New old brass.
Found a box that was originally 500 from decades ago. Your patience well exceed mine. I have been pleased with this WCC 10 brass from Brass Bombers. Keep everyone up on how things work out for you.
Thanks
Ron
I should have mentioned the RP brass I used was at least 20 plus years old. New old brass.
Found a box that was originally 500 from decades ago. Your patience well exceed mine. I have been pleased with this WCC 10 brass from Brass Bombers. Keep everyone up on how things work out for you.Thanks
Ron
If that happen to me I would think the cases were counterfeit. 'In the old days' WCC, WW, Winchester and WRA cases were consistently lighter than any other cases. They were in demand because of the light case/extra volume. And then there were the R-P cases; the R-P cases had a thick case head, when compared to military LC etc. cases the R-P case head was .060" thicker.
And then there was this saying that went around among reloaders about surplus cases were thicker because they were heavier and I wondered? How can a surplus case be thicker if the R-P case head measures .060" thicker than the LC case head? So I decided there could be a half truth, if the case head was thicker and heavier the case body had to be thinner and lighter. And the surplus case had to have a lighter case head because the case head was thinner, if there was any truth to that the case body had to be thicker and heavier.
And then I decided the powder columns could not be the same for both cases; after that someone decided it did not matter, they decided it was all that other stuff that mattered.
Anyhow, I sort cases by head stamp and by year and by weight.
F. Guffey
…And that's important. I've found the weight and capacity differences have varied over the years and lots and what plant they were produced in.
The weight itself is less important than where in the case it occurs. The head dimensions have tolerances, so it is possible to have a weight difference without an internal volume difference, as the 243 Win example below shows.
So, what you really need to look at is what is called case water overflow capacity. This is the amount of water the case will hold when the water is level with the case mouth. Also, you want this for a fired case, as it is the volume of the fired case that determines pressure and that should be compared.
To get this number, take a fired case and weigh it. Fill it with water and tap it to free bubbles and bring the water level with the mouth (no meniscus) and be sure no extra drops are on the outside and weigh it again. The difference in the two weights is the case water overflow capacity.
Do this for your different case headstamps. Make sure you compare cases of the same length. When done, you will be able to determine the difference in case water capacity. You will find each grain of difference requires about 0.7 grains of powder to bring pressure back to a match, and usually about 0.6 grains to keep barrel time close to better stay on a sweet spot.
The weight itself is less important than where in the case it occurs. The head dimensions have tolerances, so it is possible to have a weight difference without an internal volume difference, as the 243 Win example below shows.
So, what you really need to look at is what is called case water overflow capacity. This is the amount of water the case will hold when the water is level with the case mouth. Also, you want this for a fired case, as it is the volume of the fired case that determines pressure and that should be compared.
To get this number, take a fired case and weigh it. Fill it with water and tap it to free bubbles and bring the water level with the mouth (no meniscus) and be sure no extra drops are on the outside and weigh it again. The difference in the two weights is the case water overflow capacity.
Do this for your different case headstamps. Make sure you compare cases of the same length. When done, you will be able to determine the difference in case water capacity. You will find each grain of difference requires about 0.7 grains of powder to bring pressure back to a match, and usually about 0.6 grains to keep barrel time close to better stay on a sweet spot.
William T. Watts
New member
I agree with Guffy, over the years (about 45) I've separate by H/Stamp and by weight and times fired. I do not mix once separated, they stay in that group until they go in the recycle bin! William
So at what point is the case volume difference irreverent . .5 gr , .3gr ? This would be 308 . I ask because although I weigh my charges as close as possible . I've read many times that guys loading 308 have no accuracy issues when charge weights differ .3gr . So a .5gr difference in case volume would need a .35 change in powder weight . Should/would that need charge weight change ?
I'm asking because I do weigh case volume and separate my brass that way . How ever I don't weigh them all . Out of a 250ct lot I'll check water volume on 10 or 15 random pieces . If all 15 cases are under .5gr difference in water volume I consider that lot gtg . I'll add I'm not shooting benchrest and really the best I shoot is 1/2 moa using this process . I rarely have flyers because it's very rare for me to shoot 4 shots into one little hole and one shot off the group . My groups almost always are on the whole 1/2 moa with a pretty even spread . Because of this it makes it hard for me to say one specific piece of brass was the issue with a bad group .
I should add that it's really been maybe 2+ years since I really went rifle shooting and really tried shooting for accuracy for extended periods of time in multiple outings . I stared loading pistol about a year and a half or so ago and that takes up quite a bit of my reloading and shooting time . I have worked on some rifle loads in that time but really not like I was 2 and 3 years ago .
Not working today do to rain . I'll go do some water volume test and see at what point case weight changes water volume .5gr or more .
Well I remember why I don't check case volume on every case . That took longer then I thought it would and only checked 30 cases . Unfortunately I only had LC case to test because my other cases ( R.P. , WCC , Winchester ) all have been deprimed and in various states of case prep .
The cases I tested where . LC-10 , LC-12-LR and LC-14 in that order on the paper below .
Sorry for the colorful chart . I thought it would be easier to read if I highlighted each measurement . How ever about half way through I realized it was getting a little busy . There are a few interesting results there though .
Notable is the LC-14 set has some real issues . case 9 weighs 183.8gr with a volume of 554.3gr while case #3 weighs 183.4gr with a volume of 55.5gr . Case weight difference of .4gr and a case volume difference of 1.2gr
or how about 7 & 8 having a case volume difference of only .2gr yet the case weight difference is 2.2gr
How about if you throw out the 184.8gr case and use the other 9 . You get a case weight ES of .6gr but the case volume ES is 1.2gr . That's HUGE imo for just about a half grain difference in case weight .
The LC-10 had the lowest case volume ES of .6gr and the LC-14 had the highest of 1.2gr with the LR's coming in with an ES of .8gr
Anyways it's a lot of info to take in a process and compare . What do you guys see ?
The cases I tested where . LC-10 , LC-12-LR and LC-14 in that order on the paper below .
Sorry for the colorful chart . I thought it would be easier to read if I highlighted each measurement . How ever about half way through I realized it was getting a little busy . There are a few interesting results there though .
Notable is the LC-14 set has some real issues . case 9 weighs 183.8gr with a volume of 554.3gr while case #3 weighs 183.4gr with a volume of 55.5gr . Case weight difference of .4gr and a case volume difference of 1.2gr
or how about 7 & 8 having a case volume difference of only .2gr yet the case weight difference is 2.2gr How about if you throw out the 184.8gr case and use the other 9 . You get a case weight ES of .6gr but the case volume ES is 1.2gr . That's HUGE imo for just about a half grain difference in case weight .
The LC-10 had the lowest case volume ES of .6gr and the LC-14 had the highest of 1.2gr with the LR's coming in with an ES of .8gr
Anyways it's a lot of info to take in a process and compare . What do you guys see ?
Last edited: