Trimming 38 spl cases

[alor_swe]

When trimming 38 spl cases, which measurement is most important to get right?

http://stevespages.com/jpg/cd38special.jpg

Is it the over all length (1.155") or is it from the top of the rim to the case mouth?
My guess would be the latter but as I've never trimmed a single case in my life I thought I'd ask before I destroy any cases.

Is it important to size the case before trimming or is it ok to trim unsized cases?

[Three-Fifty-Seven]

I trim them to 1.148" to make them all even, that way it makes crimping them easier, as they are all the same, measure yours, and see which are the shortest, then trim to that length, since I shoot mine in 357 mag I don't really care how long they are, and I usually load 38's light anyways, so once I've trimmed them, they stay that way.

[oldtoolsniper]

You are looking for the entire case length for your overall length. I trim after I full length size as there is a possibility that you may stretch the case during sizing.

[DLCTEX]

If you use the Lee case trimmer you trim post sizing to eliminate wobble of the cutter.

[Echo]

Really a good question. Are we concerned with the depth the cartridge goes into the chamber (in which case we would trim to a uniform length from front of rim to case mouth) or are we concerned with OAL (in which case we would trim to uniform length from base to mouth).

I believe we are concerned with OAL, so that flaring, seating, and crimping will be uniform, as those procedures are performed locating on the base of the case.

I theeenk...

[HeavyMetal]

Size first then trim.

This eliminates "wobble" as previously posted and, ths is a big plus, you will occasionally find a case with a very tight "mouth" on it. Eliminating this case from the loading cycle removes one more cause of "flyers"!

I use the Lee trimmer set up with the ball handle cutter and the collet chuck held in a 24 volt cordless drill works great and you will have sore hands before you run out of battery.

Don't use a drill of less than 18 volts for this as this is a lot of drain on a battery and 8 and 9 volt drills I've had just run dead real quick!

As for a trim length? I touch the "pin" on a new Lee trimmer to a cut off wheel in my dremel tool to take just a "hair" off the end of it.

I've found these are usually to long to trim all the case's and it's very important to have them all the same length for both boolit"pull" and crimp strength.

The length itself is does not have to be specific, it just all has to be the same!

[DLCTEX]

A DeWalt 12 volt cordless drill has more power than some brands 18 volt. I can trim and chamfer 1000 cases with a full charge for the battery. I need recharging more often.

[10mmShooter]

I only load .38 specials to the original velocity of 975 fps for my 150g SWC or so I use 4.8 of WW231. I only shoot them in my 686(.38/357). So as mentioned above OAL is a non-issue. Also I taper crimp thereby avoiding the need to trim cases for a proper roll crimp. But thats just me.:Fire:

Winchester Load manual(page 43) says "Trim to lenght" for .38 Spec is 1.149

[Charlie Two Tracks]

I believe it is a OAL that is most important using mixed brass. If you are using just one make of brass, then you can get as technical as you want to. IMO

[alor_swe]

In my current load I use a lee 358-158-RF sized to .358 in a .357 match barrel with 4.6gr of VV N320, moderate roll crimp and home made lube (have tried different lubes to no avail). It keeps me just shy of 2 inch groups at 50 meters (about 55yards) from a ransom rest.

I only use norma brass but my brass supply is mixed in years (some are made in the 60s and 70s) all mixed when I bought them. All the head stamps looks the same, some cases have a slight discoloration that might be from weather and wind as well to be from a different decade.

So I got an idea, if I trim all cases to spec I might improve my groping.
Is it worth the investment, time and effort to trim 5K cases or should I try something different?

[crabo]

So I got an idea, if I trim all cases to spec I might improve my groping.
Is it worth the investment, time and effort to trim 5K cases or should I try something different?

Why don't you try 50 trimmed and 50 untrimmed to see how much pain you want to endure.

I would certainly use the Lee trimmer with my home made handle and a drill press if I was going to trim that many. You only have to twist the collet a 1/4 turn, to open or close. I deburr in and out while still in the handle.

[HeavyMetal]

Crabo's got the right idea!

select 100 random case's and trim 50 and then use the same lot number primer powder and boolits from the same pot of alloy if you can.

Like I said be aware of to tight case mouths in the 50 you trim. You'll know these because they will want to spin the trimmer in your hand rather than fit into the case.

Get replacements rather than force these to work for you.

Looking forward to a post with the results of your experiment.

[lwknight]

Why?
I have neve found a 38spl case that needed trimming.
It aint like your going to a 100 yard turkey shoot with a 38spl.
Are you?

[HeavyMetal]

Jeff Cooper once told a story about Jack Weaver that I find rather pertanent at this point.

Seems Jeff and Jack were competing in one of the legendary Big Bear leatherslap compatitions and one stage had a 100 yard B-27 target to shoot at during the stage.

The Colonel was up first and says he went prone and managed a "fair" score on that leg of the stage.

Jack Weaver followed him and during that leg of the stage fire his two rounds STANDING using his now famous weaver stance, Dead center five's that were touching each other!

At One hundred yards.

Not saying I could do it but I'd like to think my ammo can!

So ya I might have to do a 100 yard turkey shoot some day.

[shooting on a shoestring]

My opinion, for .38s/.357s (and any straight walled revolver case), the length is not important, the consistency is. I trim mine in lots (box of 50 to start with) and keep them together. They don't get a second trimming until I start seeing variation in crimps, then they all get shortened to the same lenght.

I don't try to completely clean up all the cases, but choose a length that will get all the cases showing at least 50% new metal on the cut. This keeps all my role crimps working nicely.

As for repeated trimming leaving cases short...no problem. Yes if you get drastic, the pressures will go up, but not much, and I don't run mine to the ragged edge, so its not a problem for me. I do have some very old military .38s that are down to about 1.300 or so. They won't seat full wadcutters anymore, but I still use them, mostly for shot loads, but sometimes SWCs, just not to full max loads.

[alor_swe]

Why don't you try 50 trimmed and 50 untrimmed to see how much pain you want to endure.

I'll have to try that, just got to borrow a trimmer as I'd rather not invest in more equipment until I know it makes a difference worth investing in [smilie=1: (yes I'm a cheapskate, more money for powder and primers)


Why?
I have neve found a 38spl case that needed trimming.
It aint like your going to a 100 yard turkey shoot with a 38spl.
Are you?

I'm not familiar with the term "turkey shoot" but i do routinely shoot at ranges up to about 120 yards both for practice and competition.
But I'm mainly interested to get a tighter group at 50 yards.

[DLCTEX]

At a Turkey Shoot you shoot at a turkeys head at 100 yds. so accuracy is a must. Why would anyone not want to produce the most accurate ammo possible even for plinking?

[alor_swe]

Just talked to a friend who has a case trimmer that I can borrow a few weeks from now, I'll update with the results when I've had the time to trim and test.

[686]

if the different case lengths are a problum with a rool crimp, try a taper crimp die. it would be less work for the money. i use to shoot ppc matches with 38spl. i have shoot over 100.000 rds and have nevet trimed a 38 spl case. i did try something one time. i wanted to see how many loads i could get be fore the case split. i started with 6 new ww brass. loades 158 swc 2.7 gr be. i would load the 6 , shoot them, load again, and so on. the first case got a very small split at 26 loads. i measured the length of all 6 and checked others from the same box of brass. the fired cases were shorter.

[MtGun44]

I'd try the test AND with a TC die which is much less sensitive to case length.

I will guess that the difference will be very small, but that is a guess. If you fire
five 10 round groups from your ransome rest with each type, you will KNOW the
answer.

With the question properly posed Mr. Target ALWAYS answers truthfully. ;-)

Bill