Correct "Trim To Length?"

[traub]

I would like to know if anyone knows the correct "trim to length" of 3 different cartridges? I've noticed the lengths seem to vary depending on the loading manual and it's vintage.

I feel that is necessary to have consistent and correct lengths since I roll crimp these cartridges.

I am loading .357 Magnum, .41 Magnum and .44 Magnum.

The Speer manual lists the .357 & .41 Trim Length at 1.280"and the Max Length at 1.290".

The .44 Trim Length is 1.280" and the Max Length is 1.285," however, some references list the Trim Length for the .44 to be at 1.275" and the Max Length at 1.285."

Does anyone have the definitive minimum & maximum correct trim lengths of these cartridge casings?

My typical load for the .357 mag with a 158 gr. lswc is 6.5 grains of Unique and for the .41 mag with a 215 gr lswc is 8.0 grains of Unique. Does anyone have a favorite load for the .44 mag with a 240 gr lswc using Unique?

 

[OKFC05]

These are the only "definitive standards" I know that apply.
SAAMI

 

[Rule3]

5/1,000ths does not matter.

 

[SMSgt]

If you need to trim at all.

 

[forestswin]

SAAMI gives the minimum case lengths as follows:

357 and 41 = 1.270" [1.290" (- 0.020")]

44 mag = 1.265" [1.285" (-0.020")]

so what I see is SAAMI states the maximum case length.... and then says its okay for it to be 0.020" shorter to function properly - but never exceed the maximum

so it seems what the load data charts (books, manuals, etc) give you is a "trim to" length that has a +/- tolerance of 0.010" nice of them huh?

SO....to get that +/- 0.010" tolerance
trim to length for .357 is 1.280"
and
for 44 mag trim to length is 1.275"


by the way - you have to open OKFC05's link to the SAAMI cartridge drawings in INTERNET EXPLORER to get to the caliber specific drawings that are linked in the Table of Contents that you first see.

THE NUMBERS ARE WHAT THE NUMBERS ARE

 

[MichiganScott]

I like 10gr of Unique under a 240gr SWC in a .44mag. It's not a powderpuff load by any means. IIRC, I get about 1150-1200fps in my 8 3/8" M29.

 

[Pondoro]

1) You can trim to anything between the max and the min. If you think your brass grows quickly trimming lower in the range will give you longer before you need to trim again. But if you trim below min you cannot go back. I do not think my 38 special or 357 mag brass grows. I have not had much growth with my 44. I think bottleneck rifle cartridges grow more but I have never reloaded them.

2) When you ask anything about trimming on any forum lots of people say, "I never trim."

 

[fixitfred]

I don't trim my 357 or 44 mag or any handgun cartridge for that matter.

 

[Geo. T.]

Well!

As far as 38 and 357 go I have found that most is very close to the same length. I have never loaded 41 magnum.

When it comes 44 magnum I have found that length varies a lot. I load on an RCBS Ammo Master and to get a good crimp I trim to the shortest cases I have. IMI is the shortest that I have found so I trim all of the cases to that length.

 

[H Richard]

The important thing is that all the brass be consistently "the same" length.

 

[Ole Joe Clark]

On rimmed pistol/revolver hulls I use mixed brass and have never trimmed one in 30 plus years of reloading. I currently load .38 Spec, .357 Mag, .44 Mag., and .40 S&W in a rimless shell. Can't remember if I ever checked the O/L (probably have) of a rimmed hull.

I do check and trim rifle brass.

 

[Just another 22 shooter]

In 40+ years of reloading, I have trimmed a lot of rifle brass.
I have never trimmed straight case handgun brass of any flavor.

 

[W.E.G.]

I trimmed some straight-wall pistol cases once in 1985.

Got that out of my system.

I only trim rifle brass now.

 

[tug700]

I use the old Elmer Keith load of 8.5 grains Unique with a 240 SWC. Been using it for 35 plus years and enjoy good mid range loads with great accuracy.

 

[Moe Mentum]

Never trimmed handgun brass at all.

 

[ggibson511960]

Important on Heavy Roll Crimps

I've always thought it important to check case lengths and trim to the exact same measurement for heavy loads fueled by slow burning powder, 2400, H110, & 296. Makes sense. These powders need a lot of pressure to burn uniformly and efficiently, and manuals warn of reduced loads. The severity of a roll crimp depends on the case length, not so much with a profile or taper crimp. I wouldn't think you would ever get in trouble with erratic roll crimps, excepting bad accuracy, and that could be hard to see with all the other variables in handgun ammo. I rarely trim any more. Target and midrange loads, my mainstay these days instead of the rhino-rollers, stop stretching after a few reloads when they work harden a bit. Back when I was more zealous about trimming, I ended up over-trimming just to get the cutter to take a uniform trim from the shortest case in a lot, way overkill except for heavy loads.

 

[Engineer1911]

The Exception -- there is always one

I trim 357 mag and 44 mag brass to 1.250" length in the fired condition. I don't have to trim again because the brass splits before it grows too long. I accumulate range brass until there is enough to make trimming worth while.

I trim fired brass rather than resized brass because the pilot doesn't bind in fired brass.

I get a consistent crimp and never had a case stuck in a chamber because it was too long.

EDIT: I trim 357 / 44 mag brass because of problems with brass sticking in cylinders, flattened primers, and irregular crimp. You don't want to pound on ejector rods to remove fired brass from a cylinder. Even an engineer recognizes "close enough" isn't working when 5 out of 6 cases are stuck in the cylinder. Most of my brass at the time was 4 to 5 years old and had been reloaded 8 times or more. Measured cases were 0.020"+ over max case length.

 

[forestswin]

I trim 357 mag and 44 mag brass to 1.250" length in the fired condition. I don't have to trim again because the brass splits before it grows too long. I accumulate range brass until there is enough to make trimming worth while.

I trim fired brass rather than resized brass because the pilot doesn't bind in fired brass.

I get a consistent crimp and never had a case stuck in a chamber because it was too long.

This method makes more sense then any other method I've read...in many ways...

 

[mikld]

Like many of the above posters, I don't trim handgun brass (I did once in '70 but my "extensive" testing showed no difference). Some say getting the revolver brass all to the same length makes a difference in crimping. Well, mebbe, but in 30 years of using untrimmed brass there has been no noticable difference in accuracy from my .38 Specials, .357 Magnums, .44 Specials and Magnums (in my good shootin' days I was getting -1 1/2" groups @50' with my .44 Magnums shooting LSWC ammo.). Now I sometimes used mixed brass for my .44s (I have 5 of them) and accuracy seems to be unaffected by any case length variation...

 

[Rule3]

If shooting lead bullets with such a LARGE crimp groove, there is so much room to "play" with that a few thousandths trimmed on the brass makes no difference to me. The crimp groove is MUCH bigger than the tiny bit of brass trimmed off.

Even a cannelure on a FMJ is wider than the variance.

But i do not clean primer pockets or flash holes either.