Cracked case and soot ??

kbis · Posted: Sun Jun 26, 2005 3:03 pm Post subject: Cracked case and soot ??

Being real new to reloading (about 300 rounds of 243 and 308) I thought I would ask your advice. I wanted to try my luck at reloading my 45/70 Sharps, I have never reloaded for a 45/70 and thought it can't be any harder than the other rounds, perhaps I was wrong Smile

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I am using Lee dies and a Lee factory crimp die. I loaded 5 rounds using 45 grains of IMR 3031, Rem. 300 grain JHP, Win. primers and once fire (by me) Win. brass.

I have 2 questions.

1. One of the cases now has a crack in it, starting about 5/8" up from the rim and about 1/4" long. Did I do something wrong or did I just get a weak case. I have never had this with my 243 or 308 rounds. 45 grains of powder is not a hot load and does not feel near as hot as the factory stuff.

2. One of the cases has soot half way around the case and about half way down the case, it almost looks like it was hit with a cutting torch. None of the other cases including the split one show any signs of soot. Any ideas what is up with the soot??

The group size was not bad, given that I am using peep sights and old eyes Smile

. At 50 yards I have 3 rounds touching and about 1/2" up I have 2 rounds touching.

Any insight to by questions would be greatly appreciated. Thanks

Ken

Bushmaster · Posted: Sun Jun 26, 2005 3:25 pm Post subject: Re: Cracked case and soot ??

Let's see what kind of a reaction I get with this...It is quite normal to experience a cracked straight wall case anywhere along the case. As long as you aren't experiencing it on all or most of the cases. As far as the blackened case. I assume that the soot is at the mouth of the case. This looks like the case isn't expanding against the chamber when fired and sealing the chamber (A small amount of blowback). Most often this is caused by cases that are work hardened, not high enough chamber pressure or if it isn't too bad, it might be the nature of the beast. You might try a faster powder. It would also be advantages to know what it is doing across a chronograph. If, as you say, it was only one case....I don't believe I would worry about it. Load data in my Lyman #48 says you are right on the low end of the charge weight if you are firing it in an 1873 Springfield. Be aware that there are two other load charts for this cartridge depending what rifle you are using. Recheck your load data to insure that you have the right one.

kbis · Posted: Sun Jun 26, 2005 4:03 pm Post subject: Re: Cracked case and soot ??

I rechecked a Hornady load sheet and it list min load at 40.9 grains (1300 fps) and max at 52 grains (1800 pfs), so my 45 grain is just about in the middle and is listed at 1500 fps. I am shooting it in a repro. Sharps. This my first try and I will probably kick the charge up a little (depending on accuracy). I am sure that the sharps could probably take the high load charts, but I am going to stick with trapdoor loads, I have several originals that I want to shoot and I sure don't need to get ammo mixed up, besides I am not sure my body could take the hot loads on the other charts Very Happy

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I presume what you are saying is increase powder a little and see what happens and not to worry to much unless it becomes a regular thing.
Thank for the info.
Ken

Blaine · Member Joined: Feb 24, 2005 Posts: 260 Location: Maine

Must be something in the weather..... Rolling Eyes

....I had a 308 case do the same thing this week. I loaded up 5 rounds exactly the same and the other 4 had no signs of excess pressure. They were all about the same velocity, too. This one's velocity dropped off about 200 fps, probably because of the leak. It had a crack around the circumference of the case that was all black. I was surprised that I didn't get the case stuck in the chamber with a full separation. This was with LC cases that I bought with some factory "re-manufactured" loads before I started loading my own. I guess it doesn't pay to load cases that "you don't know where that's been". Confused

Anyway, I thanked the good Lord that no harm was done, and tossed the rest of those LC's when I got home.

Blaine

kbis · Posted: Sun Jun 26, 2005 4:44 pm Post subject: Re: Cracked case and soot ??

I am a little leery of "once fired brass" unless I am the one that "once" fired it :). In this case all my 45/70 brass is stuff that I bought new and fired, some of it is pretty old but still it has only been shot one time by me and most of it has been shot in my Sharps. So I would not think that the brass has been work hardened, but you never know. I guess I need to go reload some more and see if I can get a few more rounds off before the sun goes down.

Flint54 · Posted: Tue Jun 28, 2005 12:22 am Post subject: Re: Cracked case and soot ??

Many times a split case can be attributed to brass that has "Age Hardened". If I'm not mistaken brass cartridge cases actually have 3 areas of hardening. The head is the hardest, the midportion is the second and the neck many times may even be in the soft range. With this in mind cases can split in the harder areas as there is not enough give in the grain structure to allow stretching, this is what causes cases that are work hardened to split in the neck area. Once a case has been sized many times the process of firing, then shrinking the neck and pulling it over an expander work hardens the brass in the neck area. Finally when it reaches that hardened point and you fire the case it splits instead of expanding to fill the chamber. Likewise in a sense with your splits although caused by another process.

As to the soot, your case mouth/neck is not expanding enough to seal the chamber and the soot is the by product of firing. I would use a bit faster powder and would suggest that you try some H322, I use this powder in my Contender with a 14" barrel and am getting 1500fps with the 300gr HP. 52.0gr with a WLRM primer and Rem. cases. Good luck and be safe, work up all loads from the starting point and use a manual for all loads. Wink

kbis · Posted: Tue Jun 28, 2005 5:50 pm Post subject: Re: Cracked case and soot ??

Thanks everyone for the input, I will try increasing the powder charge a little, about 4 grains , that should push the psf to about 1700 psf. It should still be well below max load for a Sharps and not high enough to beat the cr*p out of me. We shall see what happens this weekend, just to HOT to shoot after work.

calsibley · Super Member Joined: Jan 28, 2005 Posts: 317

You can't really tell how many times that brass has been fired. I'm often perplexed by that term, "once fired." It sounds to me like the brass was tired, overworked and about ready to go. You simply gave it the coup d' gras and sent it over the edge. This is why I'm reluctant to pick up brass at the range. When I buy a new rifle I always buy a couple hundred new cases to work with. Rarely does one split. Best wishes.

Cal - Montreal

kbis · Posted: Fri Jul 08, 2005 8:47 pm Post subject: Re: Cracked case and soot ??

When I said that I was using "once fired (by me) Win. brass. What I meant was that I went down to Wal-Mart and bought several boxes of Win. 45/70, took them home and fired them for the first time. I didn't go to the gun range and look for spent rounds.
I did try a few more round out of the same box, except this time instead of 45 grains of IMR 3031, I used 49.8 grains which should be about 1700 fps. I had now problems. No soot, no cracks. I have no idea, but I am not going to complain.

Flint54 · Posted: Fri Jul 08, 2005 10:00 pm Post subject: Re: Cracked case and soot ??

You have reached the level that your cases are expanding and sealing in the chamber, this is where you want to be. You should not have the problem any more. Cool

kbis · Posted: Sat Jul 09, 2005 7:36 am Post subject: Re: Cracked case and soot ??

Thanks, I sure hope so Very Happy

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