Trimming straightwalled cases

[Black Jaque Janaviac]

I've seen threads asking a similar question about trimming straightwalled revolver cases and it seems that most people don't bother. But since the question was posted in sections where those cases are typically fired from pistols I thought maybe the question might be more valuable to straightwalled cases from rifles.

I shoot a lot of .357 mag from lever actions. I don't trim them, mainly because the cheap little Lee trimmer doesn't touch the case mouth on most of the cases. I think the Lee timmer is set up to just make sure that cases are not too long for safety reasons.

But there are other reasons for trimming a case - even length cases produce a more consistent crimp. And consistent crimp yields consistent velocities. . .

So do rifle shooters trim their straightwalled cases to a consistent length?

[Themoose]

I do for 44 mag... for reasons you listed... consistent crimp

[MostlyLeverGuns]

I trim 444 and 45-70 for uniform crimp. I measure the actual chamber length before picking a trim length. Multiple ways to do this, NOE makes a Case Lebgth Button that is handy. I will use the shortest case in a lot of 50 or 100 to set the trim diameter unless the chamber is shorter, the chamber length minus .005 to start. New cases will often shorten slightly on first firing so sometimes I will until fired before trimming. I normally crimp only tubular feed rifle cartridges or revolver cartridges with auto pistol getting a slight taper crimp. I haven't trimmed 45 ACP, 40 S&W, or 9mm. 44 Magnum, 45 Colt and 357 for crimp uniformity. I use a Wilson trimmer for most, have used the LEE hand trimmer, have a Forster for some. I also anneal rifle cases for consistent crimp and bullet pull.

[EDG]

Long straight rifle cases expand when fired like any other case.
If you fire and resize them they stretch diametrally - across the diameter.
When they are sized the FL die squeezes the stretched brass back to the original diameter. But the brass cannot be compressed. The stretched material flows up the die to make the case gradually get longer.
Eventually some of the longer cases become either too long or uneven in length or both. When that happens I like a minimum clean up. For revolver ammo you need an even consistent case length for a good crimp. I don't crimp BPCR straight walled rifle cases much but I still like to have even case mouths that match the length of my chambers.
When sizing .45-70 down to fit the .40-65 the cases get longer and are some times uneven. It is good to trim those cases to make sure they are not too long for my chamber.
.45-70 brass is about 2.100" long. 40-65 cases usually wind up about 2.125". If any are longer than 2.125" they are longer than my chamber and need to be trimmed.

[stubshaft]

I trim all of my straight wall cases to insure a uniform crimp.

[country gent]

I trim 38-55, 40-65,45-70, and 45-90 first when new to square mouth and make the same length I then deburr and chamfer. This gives me consistent cases all the same. O then trom when length is to long or the batch starts to vary by .005 or so from each other. O seldom crimp but want te evenness this provides.

Even on cases that don't stretch a lot this first trimming to square the mouth and et length the same gives some benefits. Loads can be done to feed and function smoother. Crimps are more consistent. Bells and expanding stay more accurate making bullet seating easier. I think this also has a direct effect on neck tension.

On the lee studs they can be adjusted to trim to min length or in-between max and min Its not hard but a lot of trial and error. The pin in the end of the stud and its length set the cut length. With a medium grit stone lightly stone the studs length shorter. Take 8-10 even passes with the stone and trim a couple cases see what change you made and work from there.

[Black Jaque Janaviac]

The stretched material flows up the die to make the case gradually get longer.
Eventually some of the longer cases become either too long or uneven in length or both.

Perhaps this is different with straightwalled rifle cases, but it doesn't appear to match the experience of straightwalled revolver reloaders. There are so many pistol-caliber reloaders that never trim brass because it doesn't stretch in length.

Country Gent:

The pin in the end of the stud and its length set the cut length.

Oh. I thought the length was set by the shank of the stud where it tapers to hold the pin. I thought the pin just centered it on the primer hole. But if all I need to do is grind down the pin - that's easy-peasy. I'll sort my .357 brass to get an idea how short the shortest brass is, then I'll modify the stud to match that length and then I can make all my cases uniform length. Should be interesting to see if I note an improvement in velocity and accuracy out of my Rossi '92s.

[Walks]

I've always trimmed my cases, regardless of caliber. It may only the first time, with new or once fired cases or it may be every 2nd or 3rd time as in high pressure cartridges such as .25-06 & .270WCF.

But cases like .45ACP & light .38 or .32 loads only need that first trim. And if you neck or partial size bottleneck brass, that cuts trimming in half.

[bikerbeans]

I trim straight wall rifle brass for uniform crimp.

I don't trim revolver or pistol brass, mostly because my kid shoots it and leaves it on the ground at his pistol shoots. I do allow him to spend his money to replace the lost brass.

BB

[country gent]

The pin bottoms on the solid center of the shell holder, If you look at the face of the holder in the center after running a few you will see the bright spot in the center where the pin hits. A neat way to make them adjustable is to install a set screw at this point with a hole thru the stem to adjust ( easier said than done as these are hard parts) then the allen screw can be adjusted t set cut depth.

[JBinMN]

BJJ,

When you said in the other topic about Variance in Velocity that you were going to post up a topic about what we started to discuss about trimming Straight walled cases I never thought you would get so many replies in favor of trimming straight wall cases for conformity. Like you mentioned there in the other topic, I too have seen mostly topics where folks say they never trim straight wall cases and in particular handgun calibers. I guess I just never understood why they would say that for the handgun calibers, but for a couple reasons, which I mentioned in the other topic...

So, I am a bit surprised, but happily surprised, as I thought there were not very many who thought it can improve crimp setting to a set length in the crimp die( or seat/crimp die)& prevent too much variance on velocity & likely accuracy, due to some cases being shorter & having less crimp & the longer cases having more crimp from a die setting, regardless of if the first case was short or long when the die is first set up.

Knowing the cases are all the same length, means a uniform crimp on all & should make for more uniform performance when fired for both velocity & accuracy.

Like I mentioned in the other topic, it is perhaps because of the range distances many folks shoot handguns vs. rifles. The ones shooting handguns at lets say, 25 yds, or less may not be as concerned with the possibilities of different velocities & accuracy due to different crimps. While those who are shooting longer distances know that, ( just for example purposes & not for accurate measurements>) a couple hundredths " at bbl. might be 5 inches out from the bull at 200 yds , as well as if one is crimped with a shorter case and less crimp than a round loaded & crimped to a deeper setting in the die for a heavier crimp & it likely changes the pressure in the case before release, or at least not the same as the shorter rounds & can cause issues out at the target depending on how distant the range is at the time.

Anyway, Glad ya took the time to ask folks here! It appears it is turning out to be a pretty good topic!

[Bazoo]

I trim all my revolver brass for consistency. I don't trim 45 auto unless it's long, but that's because the taper crimp is more forgiving of case length.

[dragon813gt]

I trim all straight wall cases that require a roll crimp. This insures he crimp is applied in the same spot every time. This is also important w/ a Lee collet crimp die. And while I should trim every case that requires a taper crimp. I have no desire to do this w/ 9mm and the likes. I do trim 357AR which requires a taper crimp. It gets treated like every bottle neck rifle cartridge even though it’s straight wall.

[Black Jaque Janaviac]

JB

BJJ,
Like I mentioned in the other topic, it is perhaps because of the range distances many folks shoot handguns vs. rifles.

Anyway, Glad ya took the time to ask folks here! It appears it is turning out to be a pretty good topic!

Yeah, I am pleasantly surprised at the response as well as the fact that rifle-shooters seem to answer the question differently. I think you are right, variations in velocity must not translate into poor performance at pistol distances.

My problem was that the Lee case-length gauges were all too long to be of use to me so I never bothered (and I didn't feel like spending $50 on a horizontal trimmer). So the added bonus of this thread is that I now know the Lee gauge can be altered easily (kind of embarrassed that I didn't figure it out years ago).

Dragon

This is also important w/ a Lee collet crimp die.

OK. Good to know.

[indian joe]

Somebody needs to be odd man out here

I never trimmed a case in my life until I started making brass for my 45/75

Always ran the crimp die by FEEL on the 32/20 and 44/40 stuff - have loaded thousands of them that way without perticular problems

Wore the barrel out of my 22/250 without trimming a case - but - I never full length sized one for it either.

All the FL size dies I ever saw take brass down way smaller than needed (ditto for neck size dies) - it takes very little reduction (in the right place!!) to get sticky brass back where it chambers easily -

the overworking from too small dies gives us shorter life, stretched cases, split necks, the need to trim cases, and eventually caes head separations.

[bobthenailer]

I first resize my straight walled brass before trimming my brass because it usually grows about 0.010 longer after sizing , then trim to trim to length spec. the crimps are all the same with better accuracy !

[Dieselhorses]

I crimp using the torque wrench (inch/lbs.) I have built into my right arm. They all come out the same.

[Black Jaque Janaviac]

I crimp using the torque wrench (inch/lbs.) I have built into my right arm. They all come out the same.

ok. Does anyone just bite the brass a few times around the casemouth?

[tazman]

I would consider trimming my 357 mag brass so I could get the longer nosed boolits I like to use to feed through my Henry. Some of them are just a tiny bit too long to function properly.
Of course, I would adjust the powder charge appropriately.

[indian joe]

I crimp using the torque wrench (inch/lbs.) I have built into my right arm. They all come out the same.

Yep ! that works -- gotta be fingers not fist tho - lotta fellers dont get that - so a longish case goes scrunch and ya gotta pull it to pieces before ya bin it.