Strange findings.

[Brick]

I only recently started reloading for .357 Magnum rifle and revolver. I had a collection of once fired factory brass, but limited in number. So I just took possession of 500 once fired mixed headstamp cases from The Brassman. I tumbled them all and now they're nice and clean and since it is winter and I've enough time I've been sizing and trimming them as I go along. I'm finding a pretty wide range of case lengths as I go. Some are over 1.590" (maximum length) many are right at the 1.585" "trim to" length and there's even a bunch that run as short as 1.570" (notably Aguila and some Starline).

So I'm going to stake things out like this: 1.584" - 1.586" goes right into the pile with no further processing. >1.585" gets trimmed, chamfered and primer pocket cleaned. <1.584" gets tossed into a separate pile for use in light lead bullet loads. Probably to be loaded with A#5 so I can use up my current supply.

Any thoughts?

GRRRR! Too damn many numbers running around in my head! Max case length for .357 Mag. is 1.290" so the numbers I show should be 1.285" (trim length), 1.284" - 1.286", >1.585" and <1.284"

[abner13]

I trim my fired brass .005 under nominal and virgin brass to .010 under. They do grow in time. A uniform crimp is essential for accurate sixgun loads and consistent length is the key to that.

[Walleye Hunter]

I'm new to it all but...people have said that straight walled brass doesn't need trimmed. What, does that exclude .357 mag?

[frankski]

I think your plan is fine for now. However, I agree with Abner that even length cases are necessary for consistent crimping and best accuracy.

I found a lot of variation in .357 once fired brass when I started reloading it. Now I only use Starline which I bought in bulk a few years ago. You will find stretch varies with potency of the load. So I measure brass at every loading and set aside outliers to trim in batches when I have nothing better to do the dead of winter. That said, I don’t personally fuss with pistol brass as much as precision rifle loads.

[chp1911]

I'm new to it all but...people have said that straight walled brass doesn't need trimmed. What, does that exclude .357 mag?

ALL straight walled brass will stretch at some point. It all depends on how hot of a load that you shoot. I have been using Starline brass exclusively for my .357 and 45 Colt loads for about 20 years and the hot loads get trimmed after 5-6 loadings.

[markshere2]

I think your plan is fine for now. However, I agree with Abner that even length cases are necessary for consistent crimping and best accuracy.

I found a lot of variation in .357 once fired brass when I started reloading it. Now I only use Starline which I bought in bulk a few years ago. You will find stretch varies with potency of the load. So I measure brass at every loading and set aside outliers to trim in batches when I have nothing better to do the dead of winter. That said, I don’t personally fuss with pistol brass as much as precision rifle loads.

For rifle accuracy and consistent chambering, sizing a necked down cartridge for length is important.

For a straight wall revolver round, not really necessary.

There are many factors in pistol shooting that play a far bigger role in accuracy than consistent case length. Start with the gun being held at arms length by 2 hands instead of having 3 or 4 points of contact with your body.

Then, consider the short barrel. Its not going to be as accurate as a 16 to 24 inch barrel.

Then consider the short sight radius (distance between rear and front sight). Way less accurate than a rifle.

If you feel better by doing it, please, by all means, trim it. But its not a big factor. If you use that time practicing your draw and dry firing with snap caps, it will prolly help you a lot more.

[frankski]

For rifle accuracy and consistent chambering, sizing a necked down cartridge for length is important.

For a straight wall revolver round, not really necessary.

There are many factors in pistol shooting that play a far bigger role in accuracy than consistent case length. Start with the gun being held at arms length by 2 hands instead of having 3 or 4 points of contact with your body.

Then, consider the ehort barrel. Its not going to be as accurate as a 16 to 24 inch barrel.

Then consider the short sight radius (distance between rear and front sight). Way less accurate than a rifle.

If you feel better by doing it, please, by all means, trim it. But its not a big factor. If you use that time practicing your draw and dry firing with snap caps, it will prolly help you a lot more.

As I said, consistent length and consistent crimp leads to better accuracy, for me, other things being equal. Even more so in .357 rifle.

But thanks for the pistol shooting 101 tips anyway.

[Delkal]

For a straight walled case that headspaces on the rim the actual trim length is unimportant. You just want it consistent so the crimps are all at the same spot on the bullet. Measuring each case individually would be a pain and then you will have 2-3 different batches of brass to keep track of and some rejects. I would trim them all to one length with a Lee trimmer with the cutter chucked in a drillpress. You can trim them as fast as you can insert them into the shellholder. Any case that doesn't bump the cutter can be separated out and the rest will be identical.

With a 1.590" (maximum length) I am not sure where you got the 1.585" "trim to" length. Usually trim lengths are 0.010 shorter for bottlenecked cartridges. And it is less important with a straight walled case. I would trim them all down to 1.575 so you don't have to trash as many perfectly good cases.

And you did size them all before you measured them. Didn't you?

[Brick]

Thanks for all the answers. Part of my issue is I'm loading for both revolver and rifle (in this case a Winchester Model 92). Consequently I load the lighter rifle charges. I had an issue with Blue Dot last year that leads me to believe that compression of that powder is bad and bullet shank length and case length can affect compression.

WRT Delkal's comment above GRRRR! Too damn many numbers running around in my head! Max case length for .357 Mag. is 1.290" so the numbers I show should be 1.285" (trim length), 1.284" - 1.286", >1.285" and <1.284".

[Delkal]

Thanks for all the answers. Part of my issue is I'm loading for both revolver and rifle (in this case a Winchester Model 92). Consequently I load the lighter rifle charges. I had an issue with Blue Dot last year that leads me to believe that compression of that powder is bad and bullet shank length and case length can affect compression.

WRT Delkal's comment above GRRRR! Too damn many numbers running around in my head! Max case length for .357 Mag. is 1.290" so the numbers I show should be 1.285" (trim length), 1.284" - 1.286", >1.285" and <1.284".

Trim all to 1.575 after you resize them. I never saw anyone recommend 0.005 shorter trim length than max (even for bottlenecked rifle cartridges). The standard is 0.010 shorter. Sizing all of your cases to 1.575 is a little shorter than the standard recommendation but you won't have to waste perfectly good brass because they are "too short". If some of the brass doesn't bump the cutter you can segregate them (or not worry about it)

There is not minimum length (within reason) for straight walled cartridges that headspace on the rim. You won't blow up.