Unable to crimp 38-40 cases after trimming them to trim to length

I have been loading 38-40 for 22 years using a Redding FL die set. I was shooting an original Winchester 1873 with a 24" barrel in that caliber up until a 1 1/2 years ago when I bought a Uberti 73 from Taylors with a 20" barrel in 38-40. I found that when I when I loaded 10 rnds (the max that we ever load for a stage) into it some of the bullets would get pushed back into the case. This never happened with my older gun which had a longer mag and an old spring so I realized that the rnds needed a firmer crimp and finally started seating the bullets with the Redding die and crimping them with a Lee Factory Crimp Die. This was working and I bought some new Starline brass and measured it. It was way longer than the max length so I trimmed it to the recommended length of 1.295" and loaded it but I saw that the crimp was not enough either with the Lee die or the Redding built in roll crimp. Under pressure the bullets could get pushed into the case. I measured my old brass and found that it was around 1.32" to 1.34" in length and over the published max length of 1.305". I have not measured or trimmed the cases in a long time and did not have any problems chambrering them in either gun. The problem seems to be that when I trimmed the new cases to the published spec I cannot get a good crimp on them due to the length of the brass even if I set the dies down to where they touch the shell holder at its peak. Someone said at my club that I should shorten the die but I don't have a lathe to do that so I am trying if all of the brands of the dies are going to have the same problem. It seems like the dies would be made so that you could roll crimp even when the brass is trimmed to the trim to length.

thanks,

Mike

Pick up a 7/8 14 nut, some 120 grit emery paper and you can shorten it by hand. working slow and easy.

Screw the die into the nut. This helps to keep it square and even. Lay the emery paper on a hard flat surface. A piece of steel flat stock or plate works good here. In a figure 8 pattern work the die around on the emery cloth cutting the die and nut both. rotate your grip on the nut occasionally and work it around for a while. A little oil helps with the cutting also and helps to finish. Once close to where you want a few finer grits and oil to finish it. .010-.015 should do the trick for you. If your careful you can remove most with a bench girnder and just square it up and finish it with the nut. Dress the wheel on the bench grinder ( this sharpens the wheel so it cuts a little cooler and makes it flat) roll the end of the die against the running wheel keeping it as even as possible. When your close switch to the nut and paper.

Get a Lee shell holder & sand the face down to where the crimp die will engage the brass.

The Lee factory crimp die in .44WCF & .38WCF won't work on MINIMUM LENGTH BRASS. I ran into the very same problem with new starline brass. It's also to thick to chamber a .427 bullet in my 1st GEN COLT.

Either shorten the lee die or clip a couple coils off the new rifle's spring, a coil at a time.

I have shortened an older rcbs 44 mag seat die so it will crimp 44 special by holding it on the side of a bench grinder. It only took a little grinding and follow up with some fine files.

I don't know why Lee insists on making seat/crimp dies so that they just barely work with minimum length brass but that has been my experience with them. Maybe all the makers do this. But you can rapidly shorten the die on a bench grinder, and since once it is short enough it will never contact the shell holder before you get the desired amount of crimp there is no reason to worry about the die being kept perfectly square at the bottom. Just grind plenty off and go back to work like smkummer did.

As stated above, the mag is probably over sprung and can clip 3-4 coils off it easily, a coil at a time to insure reliable feeding of the last couple of rounds. I found the same problem with a Lee FCD and threw it away. If a crimp die does work right, I look to Redding for a specialty crimp die.

Seating dies are not hardened like sizing dies, so are much easier to shorten. Just take it to a bench grinder or a belt grinder and have at it. It does have to be pretty or even square on the bottom.

I’ve sanded down shell holders to get more crimp. Lay some 400 grit aluminium oxide paper on a sheet of glass and slide the shell holder, die body or both back and forth. Give the part a ¼ turn every few strokes. Micrometer measure the length and sand off enough metal for a firm crimp. The sanding is easy to do, it just takes a little while. Take frequent measurements to see how your progressing and test crimp a load to see if the case mouth is now getting tucked under the edge of the crimp groove.
Or you could load full charges of compressed BP, bullets won’t sink into the cases if their sitting on precompressed black powder. Old style bullets with out a actual crimp groove required a bed of compressed BP to sit on to prevent the bullet from collapsing into the case.

Well I found out what caused this. I was looking at my dial calipers and noticed that when completely closed the dial was showing 0.04 which meant that I measured my new brass a being too long and consequently trimmed it too short. It was too short to reach the crimp inside the die. My calipers are old and cheap so I could not reset it so I just bought a new digital one and remeasured everything. I am not sure when the old one got off but from now I will always check the zero. Now I am stuck with 100 rnds of new too short brass that I cannot use. Lesson Learned and I am glad that I had not trimmed my older brass yet because when I measured it with the new calipers it is setting at the right length even though some of them have been reloaded for more than 20 years.

Thanks,
Mike

It happens. I work at a job that uses calipers everyday, sometimes, unknowingly they can be off for whatever reason. Crud, bumped, humidity, whatever. Things like this always remind me to zero my powder scale every time also.

Being a good Scotsman I wouldn't toss those "too short" cases. Do like clum553946 suggested -- get a second shellholder and grind off about .04" (I have a couple of these made for certain cases and just color the top red with a Sharpie marker to keep from using them for normal stuff). Then you will be able to use both the regular crimp and the Lee FCD for your short brass without needing to grind any off the bottom of the die.

I asked "QuickLoad" how much this .04" shorter round would raise pressures of my standard 38/40 load of 7 grains TrailBoss with 175 grain boolit and QL says "about 500 psi" which is pretty negligible. This would be nullified (if so desired) by dropping the load by a tenth of a grain.

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Originally Posted by mrappe

Well I found out what caused this. I was looking at my dial calipers and noticed that when completely closed the dial was showing 0.04 which meant that I measured my new brass a being too long and consequently trimmed it too short. It was too short to reach the crimp inside the die. My calipers are old and cheap so I could not reset it so I just bought a new digital one and remeasured everything. I am not sure when the old one got off but from now I will always check the zero. Now I am stuck with 100 rnds of new too short brass that I cannot use. Lesson Learned and I am glad that I had not trimmed my older brass yet because when I measured it with the new calipers it is setting at the right length even though some of them have been reloaded for more than 20 year

Thanks,
Mike

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Send them to me! I’d love to have them!