357 magnum trim to length

[rdwarrior]

Need to know my correct trim to length for .357 magnum. 2 of my books say 1.285 and another 2 say 1.290. I looked at the SAAMI specs and it calls for 1.290 -.020. I am leaning towards 1.285 but could easily be talked into 1.290

Yes I know most folks do NOT trim pistol or straight wall cases. Well I have cases ranging from 1.280 to 1.298. That makes it hard to put the same crimp on each case as I reload, so I am trimming all to one length.

TIA
rdwarrior

[tazman]

Hodgdon site lists the trim length at 1.285. That should work pretty well with the brass you have.

[georgerkahn]

Need to know my correct trim to length for .357 magnum. 2 of my books say 1.285 and another 2 say 1.290. I looked at the SAAMI specs and it calls for 1.290 -.020. I am leaning towards 1.285 but could easily be talked into 1.290

Yes I know most folks do NOT trim pistol or straight wall cases. Well I have cases ranging from 1.280 to 1.298. That makes it hard to put the same crimp on each case as I reload, so I am trimming all to one length.

TIA
rdwarrior

tazman is right on -- same length as I trim to. Throwing something else I do is to use a VLD burr-remover on inside case mouths, which I lightly lub as well. Specially when loading jacketed bullets, I noted COAL differences -- which seemed to vanish when I used the de-burr tool on inside case mouth and either dipped case mouth in graphite (that Redding bottle with ceramic beads), graphite, or use a teeny-tiny amount of Imperial size wax on a Q-tip.
geo

[358429]

I trim to 1.22"

[tazman]

I trim to 1.22"

Let me guess.
That length allows you to crimp your 357429 boolits in the crimp groove and fit in the cylinders of model 27 S&W revolvers. Correct?

[243winxb]

1.285" should work with a .005" variance. For me, the crimp is still in the crimp groove of my 158 gr lswc, using this standards.

I try to match tbe shortest brass, AFTER fl sizing, of course.

[358429]

Let me guess.
That length allows you to crimp your 357429 boolits in the crimp groove and fit in the cylinders of model 27 S&W revolvers. Correct?

Almost correct it is so the loaded 358429 ww296 357 magnums fit my model 60 snubb nose yes recoil is brisk!
Hmm they also feed better from my 77-357 magazine.

[rdwarrior]

I did some more checks on all my 357 brass and found some interesting differences. As I mentioned in the first post depending on the source, 357 mag should be trimmed to 1.285 to 1.290. I had some new winchester brass and they all measured 1.280 +/- .002. I then checked a batch of mixed headstamp once fired brass (nickel). All the brass except hornady were within specs, but all the hornady were at 1.245-1.250. What gives with hornady? I have always noticed their brass is a few thousandths shorter than any other brass but lordy - .045 to .0450 shorter??? I have also noticed that hornady brass, no matter what caliber, has tighter primer pockets than anyone else. I have had to swage the primer pockets on hornady brass almost on a regular basis.

[243winxb]

Some Hornady- short brass, so when criming in the groove, the col is not to long, using some of there bullets. I seem to remember it being a rifle cartridge?

[358429]

Hornady ftx (those soft plastic tip jacketed hollow points, designed for tube fed lever action guns) are the reason for the short factory brass. They (hornady I would suppose) design for the loaded ammo to be the correct length to feed lever guns and fit revolver cylinders.

I have never shot any of those bullets to the best of my awareness.

(Unrelated)
(I wish they (hornady) did not crimp the primers for their 308 winchester brass.)

[1hole]

It's easy to overthink case length, especially "trim-to" length.

Maximum case length is determined by the minimum chamber length. SAMMI specifies minimum chamber length AND a maximum case length sufficient to prevent pinching bullets in place and raising chamber pressure out of sight; there is no other limit to case length.

Not all loading books give a suggested "Trim-to" length. Those who do hope to calm the concerns of the apprehensive. Since reloading book's "trim-to" lengths aren't valid SAAMI specifications any reloading manual can honestly list any case lengths that seem good to them. That's usually 10 thou shorter than the specified maximum case length for that chamber. BUT, for safety, most rimmed and bottle neck chambers are cut significantly deeper than the SAMMI minimum so, for them, even a "too long" case is very likely to be safe.

However, straight walled (rimless) cartridges headspace on the case mouths so their lengths - and light crimps - do need to be fairly uniform for consistent headspacing and powder ignition..

I've never had a straight wall case "stretch" much so all of my new batches of straight wall handgun cases are first length uniformed/trimmed to (or just below) max book length, then lightly deburred & chamfered. They work great and I never need to look at that stuff again.

[ioon44]

I would trim all of them to 1.280 and be done with it.

[carelesslove]

carelesslove, here !

Boolit Master ioon44 is right on target. "Trim all of them to 1.280" meets the trim-to-length recommended in most reloading manuals AND the SAAMI specifications.

Personally, I went for years and never checked case length - much less did any case trimming. I did notice crimping inconsistencies and that in my heavier loadings, I was getting pressure fluctuations, so I "invested" in a cheap plastic caliper (all I could afford, at the time) and found that all my .357 cases were exceeding 1.290", with some 1.310". The ones that exceeded 1.300" were all showing the pressure fluctuations. If you look closely at the SAAMI specifications, and the drawings for the cartridges, along with the chamber machining drawings, you can clearly see where case length can grow all the way to the machined taper of the cylinder throats and keep the case from fully "releasing" the bullet.

I only had one .357 Magnum in those days and I tried to shoot it to death. I burned off the back of the barrel and severely eroded the forcing cone. Somewhere in this same timeframe, I invested in a case trimmer and did what ioon44 recommended and trimmed all my .357's to 1.280" and my pressure fluctuations went away, my accuracy & shooting improved, and I had to re-barrel my first .357!

All of us should download and print out the SAAMI specifications. Reading them will reveal some true nuggets we would not know any other way.

Thanks, Tom "carelesslove" Love

[MostlyLeverGuns]

Your shortest case is 1.280, ioon44 is right, trim them all to 1.280. My process for all my brass is trim to the SHORTEST case length, unless my measured chamber length is shorter, VERY UNUSUAL, then I trim .005 under MEASURED chamber length. Uniform lengths more important than 'trim to' lengths in the manuals. I do measure all the chamber lengths in my firearms. Keeping handgun brass segregated by headstamp and batch keeps length and crimp uniform, usually avoiding trimming. SAAMI specs do make for interesting and surprising reading, I find headspace specs, particularly for rimmed cases to be remarkably generous from chamber to case rim. Google SAAMI to find your favorite.

[murf205]

rdwarrior, I "feel your pain", I fought the various case length problem for a long time and my collection of brass sounded just like yours. Being a super scrounger and living just a few minutes from a state run public range, I had a ton of once fired brass from every manufacturer you can think of and the lengths were all over the place. I found a friend in need of 357 brass and gifted him most of the brass and finally bought 500 Starline cases. All the same length, presto! That was pre-Obama, Biden,Covid but if you can afford it when they get production up again, you will spend much more time loading than trimming. BTW the advice to trim to 1.280 is sound advice and will get you consistency you are looking for. Good luck brother.

[rintinglen]

My own experience with Starline was less than outstanding. I wanted brass for accuracy loads for my S&W 52-2. I measured 100 38 Special cases-none of them were long enough to require trimming, but the shortest was 1.132" while the longest was 1.145". 13 1000Ths is a lot.

[murf205]

My own experience with Starline was less than outstanding. I wanted brass for accuracy loads for my S&W 52-2. I measured 100 38 Special cases-none of them were long enough to require trimming, but the shortest was 1.132" while the longest was 1.145". 13 1000Ths is a lot.

How long ago was that? I have heard others say the same thing but the Starlines I have came from 3-5 yrs ago and they are all spot on the same length in 32-20, 44 spl, 357, and 44 mag. Maybe the later one are the result of setting up the machines for different calibers while trying to keep up with demand, I dunno. Maybe I've just been lucky. I am a big fan of Winchester brass but in the LGS they are right beside the hens teeth display!

[megasupermagnum]

Not only is Starline length all over, but in all calibers I had, they are all short. 327 federal was 1.18" I don't remember if I ever had any 357 magnum. Both 41 and 44 magnum seem to be around 1.270". I didn't pay that close attention to how much variance I had, but for sure I had plus or minus .005" at least. It was bad enough I was trimming all brand new Starline cases for a while, making the already short cases, even shorter.

I know I used 327, 41, 44, and 45 acp Starline cases. If even one of those calibers had been decent, then I may have been willing to accept that I had some bad ones. The 327's I even exchanged all 2000 of them, for 2000 new straight from Starline after complaining. Nope, exactly the same. They are junk. The length is horrible, they are super thick which is not a good thing, and the annealing is the worst part. I did a side by side in 327, brand new Starline shot a 28-shot average group at 50 yards of around 5 1/2". I then did the same thing, same day, same bullets, new Federal brass shot a 28-shot average group at 50 yards of around 3 1/2". I later found my velocity ES's got cut by about 75% too. I then sold every single Starline case I had. Best thing I ever did for my handgun shooting. It is a true shame, but Starline makes garbage. I can get over the thick cases, most chambers can accept it, and it can work if you use the right expander plug. I don't know why they do it, but I could get over the cases being a little short. Its the total lack of annealing quality control that I can't get over. You can never make accurate ammo when you can feel from one case to the next how hard a bullet seats. And some of those bullets seat HARD in Starline cases, even if all are expanded with the same plug. Even if you don't care about accuracy that much, you can look everywhere. Tons of people have problems with Starline cases splitting. It is the only case I've ever seen split in a 44 magnum. I must have lost about 10% of all 327's due to splits.

Hornady brass is notorious for being short in a bunch of calibers. I've heard they do this for their special loads for lever guns. I don't really know why, that's just the word on the street. It is kind of a shame, as otherwise Hornady brass quality is top tier. I regularly load brass that had crimped primers, and even with swaging, sometimes one is a little tight, so if Hornady pockets are on the tight side, I haven't noticed.

To answer the original question, with Starline brass, 1.270" should make all the cases fairly consistent in length. That's what I used to trim the 44 and 41 mag to. Since then, I've replaced the 327, 357, and 44 magnums with Federal brand brass, and they come plus or minus .002", and I haven't trimmed any. The 327's I see from 1.192" to 1.195" ish. The 357's and 44 's were once fired, but are 1.285" plus or minus .002". Repeated firings have shown no meaningful growth or shrinkage yet. The 41 I went to Remington brass, and they too came new about 1.282", and consistent. The 45 acp I sorted out from once fired brass both Winchester and Federal. The 45 acp actually gets shorter as you use them.

[Char-Gar]

I am one of those reloading freaks that trim all revolver brass to a uniform length. That said, I can't see that .005" would make any difference. Not worth one second of fretting. Pick a number and trim, all will be good.

[rdwarrior]

Thank you everyone for your knowledge and comments. very interesting reading. IRT SAAMI specs, I printed out the spec sheets for every caliber I own and load for some time ago. Again thank you
rdwarrior