Don't bother weighing cases

TheCanAm

TheCanAm

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I've wasted too much time weighing cases. I have read many postings on CGN and on reloading specific forums talking about how case weight correlates to case volume. It simply does not! The following image is just a small sample but it is representative of the many cases I weighed and checked the volume of. There is simply too many other variables affecting the weight.

case%20wt%20to%20vol.png


If you are going to take the time to weigh your brass, then take the time consuming step of checking volume... or don't bother at all.
 
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I recently did a test in 223. I weighed a bunch of cases to make a matched set of cases that all weighed the same and saw no difference in accuracy.

Mind you, I can't be sure if the gun I was using is capable of making the best use of the matched brass.
 
Oddly, i found the weight of all my fired brass perfectly reflects what their internal volume regardless of manufacture with the exception of norma, which has a shallow extractor groove.

Since all brass makes are of the same alloy, same density, the same weight brass regardless of sizing/fitment will take up the same volume in the chamber. However depending on the casings dimensions it may have a different internal volume, but once fireformed to that chamber if it weighs the same, itll have the same volume. Doesnt matter if it has more material in the web, neck, shoulder or body, it all takes upthe same space in the chamber.
 
TheCanAm said:
I've wasted too much time weighing cases. I have read many postings on CGN and on reloading specific forums talking about how case weight correlates to case volume. It simply does not! The following image is just a small sample but it is representative of the many cases I weighed and checked the volume of. There is simply too many other variables affecting the weight.

If you are going to take the time to weigh your brass, then take the time consuming step of checking volume... or don't bother at all.
Click to expand...

You're correct - it's internal volume, not weight that matters, so if there's not a 1:1 relationship of weight to internal volume, there's no point in weighing, you should check internal volume.

The problems are:

- there is not an exact 1:1 relationship, even within a single manufacturer or batch, to the level of accuracy that's expected (i.e. better than 0.5%);
- weighing is easy and can be done to +/- 0.1 grs;
- but if you choose to measure internal volume, it's slow, messy and much less accurate.

So I agree that it's pointless.

Other will argue it's not, and claim that their groupings are better by 1/2" at 1000 yds when they weight brass, but there are so many variables in taking a single shot that the claim can't be substantiated.
 
So, do you mean we can mix brass of different manufacturers without changing accuracy, or are you taking about weighing and sorting brass of the same manufacturer?
 
Great article that talked about that in Varmint magazine on brass prep and sorting brass. Basically the author sorted brass samples from most of the brass companies (Rem, Win, Nosler, Lapua and Norma) by case weight, neck thickness and primer pocket depth to see what kind of spread was present in the brass from each manufacturer, and then fire 25 rounds from each brass manufacturer (unsorted) with his best known load. Results where inconclusive and the average grouping from each manufacturer ranged from .444 for remington to .594 for lapua (which actually had the best consistency). Not sure what it really tells us and if the rifle and process he was using are precise enough to produce the desired effect but anyhow, it convinced me that at my level, as long as I shoot brass of the same manufacturer in a same batch, I should be fine :p If any one is interested in seeing the actual article, send me a PM.

Cheers!
 
TheCanAm said:
I've wasted too much time weighing cases. I have read many postings on CGN and on reloading specific forums talking about how case weight correlates to case volume. It simply does not! The following image is just a small sample but it is representative of the many cases I weighed and checked the volume of. There is simply too many other variables affecting the weight.

case%20wt%20to%20vol.png


If you are going to take the time to weigh your brass, then take the time consuming step of checking volume... or don't bother at all.
Click to expand...

Thank-you for your expert opinion on cases, just wish you had of told me about that 35 years ago so I wouldn't have wasted so much time making my benchrest guns shoot through one hole.
 
Let's say that it probably will not make a difference unless you are winning competitions.
Then maybe it's a bit of a mental thing. If it makes you think your loads are superior, you might actually be shooting better.
Tiger woods has had issues with golf since his scandal, and he has not changed brand of golf balls, or clubs, as far as I know.

Buy hey, why not.
 
Those procedures are important, Norma case, sorted by weight after, neck sizing only, concentrity, lenght, tumbling, prime pocket thightness, after that powder charge weight 2 times, OAL from the ogive diameter not the tip, very light uniform crimp = SD 4--- ES 4 === .3 MOA or less... JP.
 
Internal case capacity effects chamber pressure, if internal volume varies so does chamber pressure, velocity and accuracy. There is a reason why competitive shooters buy Lapua brass. ;)

Below, .223/5.56 brass by manufacture, as you can see Winchester brass has the most case weight variations and Lapua the least.





Quickload requires internal case volume in grains of water, case length and bullet seating depth to compute chamber pressure based on your "fired" cases capacity. Just changing the bullet seating depth effects chamber pressure because the internal volume of the case changes.

 
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The OP is correct in that it makes little sense for most people to weigh cases for their rifles. There are however a handful of guys where this type of sorting makes a noticeable difference in their rifles, as in the difference between winning and losing. Read some of the articles on 6mmbr.com or better yet tell some of the fellas over there that weight sorting makes no difference... but put your Nomex on before you do!
 
So if I wanted to check the volume of cases, do you use really fine sand or wiegh water. If you were to weigh water how could you do it cleanly without making a mess or my dripping some everywhere. I would assume that using really fine sand scraped off at the top would be easiest. After seeing some of Caramels groups it might be a worthwhile task.

Evan
 
Caramel could shoot a 1" group at 200 yards with an airsoft pistol.

I havn't bothered weight sorting any brass for my bench gun but I'm getting to the point where I think I should.
Weighing case volume is the only way to go IMO
 
I thinks it helps when being consistent. I purchased some match 308 brass (was originally used for police sniper ammo) on the EE a while back and all cases weigh 168 grains. I suspect that this is very much intentional and that the 168 grain weight is designed to be matched with an equivalent (165/168gr) bullet weight.
 
I have a Lapua cases that run from 170gr to 174gr. They are trimmed to the same length and the extractor groove is between .0005" to .001 difference in diameter from the 170's to the 174's. The neck thickness is the same on all cases. The .001" difference in the extractor does not make up 4 gr, so I would assume the extra weight is on the web of the case. Meaning the heavier cases have less volume. For anyone wanting to shoot groups (not benchrest shooters) at ranges up to 300 yards this 4 gr difference might not mean anything. However a 1000 yards it could mean as much a 1 MOA difference and throw your nice waterline group into something that doesn't fit inside the bull anymore.
 
"...case weight correlates to case volume..." Yep. Total waste of time unless you're a bench rest shooter.
"...unless you are winning competitions..." Doesn't make a lick of difference.
 
sunray said:
"...case weight correlates to case volume..." Yep. Total waste of time unless you're a bench rest shooter.
"...unless you are winning competitions..." Doesn't make a lick of difference.
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So you think the winners don't weigh their cases? Long gone are the days of issued DA or IVI for fullbore competition when you shot what you were issued at the match.

I was down in Barbados for the West Indies Fullbore Championships last May. Even though is was issued match ammo, the Brits, who won everything weighed and batched every round they fired in the team matches.
 
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