Armory Sponsor
Posted: 1/22/2017 11:02:17 PM EDT
I am trying to help my dad here. I have not reloaded in a few years. My dad has reloaded my whole life. He mostly loaded for his Rem 760 30-06 and when I got my M700 in '06. He recently got an M700 like mine. He is having issues with case size. He has been getting case separation when firing rounds that have been loaded a second time. The loaded rounds are falling just slightly below the case gage lip. Overall length is good. All measurements look good except where the shoulder starts. It is about .04 to .05 short. I am guessing this is where the problem is... He says the die is set up correctly, but I think he is missing something. I just don't know what. Here are two rounds that came out of the same gun. The load is 54 grains of IMR 4350 with a 165 gr Barns Tripleshock and Fed primers.
|
|
Quoted:
Your sizing die is over sizing the cases, creating too much headspace and causing the case separations. The red hot loads being used is another issue. That load is too hot for that rifle. According to the Barns loading book, that load is just above the min load. I think the max load for that powder is 56 or 57 grains of powder. Ill have to check, but I know it is not the max load. He never uses max loadings. |
|
Quoted:
Wow. That looks way over pressure. Are the new rifles the ones breaking the cases like that? Not the old 760? Might need to start low and work up the load again. Different chambers. It is his new rifle. I have not had any problems with mine. I gave him my rifle today to do some shooting. He fired some rounds out of each gun and measured each case and both were the same, and both fit low in the case gage. I don't think it is the gun. |
|
Quoted:
According to the Barns loading book, that load is just above the min load. I think the max load for that powder is 56 or 57 grains of powder. Ill have to check, but I know it is not the max load. He never uses max loadings. Quoted:
Quoted:
Your sizing die is over sizing the cases, creating too much headspace and causing the case separations. The red hot loads being used is another issue. That load is too hot for that rifle. According to the Barns loading book, that load is just above the min load. I think the max load for that powder is 56 or 57 grains of powder. Ill have to check, but I know it is not the max load. He never uses max loadings. BUT that load is too hot for that rifle. Wrong powder is being used, wrong bullet weight, scale is off or not set up correctly. Ect, ect. I'm thinking it's a set up issue as the sizing die is not set correctly. |
| Read this thread to learn how to properly set up a sizing die. |
|
Quoted:
That's nice and all. BUT that load is too hot for that rifle. Wrong powder is being used, wrong bullet weight, scale is off or not set up correctly. Ect, ect. I'm thinking it's a set up issue as the sizing die is not set correctly. I'm not arguing that point. I know he checks his scale with calibrating weights when he starts. I am just stating what is being used. I think it is just that the die is set up wrong. I was thinking the being to short was causing the head to be slammed into the bolt face causing the separation. Not all the primers are flat like that. Very few are. I just grabbed that one at random. |
|
Read the thread I linked. Learn how to set your sizing die. Your hot load is a separate issue.
Again, you sizing die is oversizing your cases causing excessive headspace. (it is too low in the press and needs to be screwed out) When cases are fired they have to stretch more than the normal .003 to .005 and since they are sized more than that, they separate as they have exceeded the elasticity of the brass case. |
|
The dies are over sizing the cases. Take a fired case, lube, and then smoke the neck/shoulder or color it with a sharpie marker. Set shell holder on the ram, lift ram, dial resize die down until it makes contact. Back it out abut a turn. Set the lock ring.
Now size the smoked or colored case. You'll see it resizes most of the case neck, but not the shoulder. Begin to resize that same case repeatedly until the neck is fully sized, but the case shoulder isn't set back. Those cases will not fit and function fine in that rifle without head separation. The case on the right shows DRAMATIC over pressure. Dad made a mistake of some kind.... If the loaded rounds run fine in two other rifles, but not dad's new 700, dads 700 is FUBAR. Which, if its a new 700, is quite likely... If one box of ammo, reloads, are showing one case is fine, and another is all blown to hell like that primer flattening and the ejector print on the case head, there is an issue in the ammo. Pull the bullets and check two things.... check powder type and charge, and check the bullet diameter. Its unlikely, but possible there is something like a .311 diameter bullet or two in with the .308's (that would be VERY unlike). Or more likely, you are going to see that powder charges are way off..... |
|
Originally Posted By dryflash3
Your sizing die is over sizing the cases, creating too much headspace and causing the case separations. To the OP- Case separations can give the appearance of over pressure but not normally that much. Your photo shows two different brands of twice fired cases. What do the cases look like on the first firing? |
|
Quoted:
Originally Posted By dryflash3 Your sizing die is over sizing the cases, creating too much headspace and causing the case separations. To the OP- Case separations can give the appearance of over pressure but not normally that much. Your photo shows two different brands of twice fired cases. What do the cases look like on the first firing? The cases look fine on the first firing. The first are also hand loads. |
|
Quoted:
Originally Posted By dryflash3 Your sizing die is over sizing the cases, creating too much headspace and causing the case separations. To the OP- Case separations can give the appearance of over pressure but not normally that much. Your photo shows two different brands of twice fired cases. What do the cases look like on the first firing? ThInk you hit on the problem and a good chance of the headspace looking like over pressure. The flattened primer in a long headspace setup is from the ejector holding the case forward to the chamber shoulder and upon firing the primer pops out to the bolt face the. When pressure inside the case builds further the brass stretches pushing the case head to the bolt face. That stretching is beyond design and why your case heads are tearing off. Your peimers are flat because they can't reseat under pressure, their side walls I believe grab under pressure. When the case head repeats the they mush out radiLly filling the pocket. Voila and now you have the appearance of over pressure. Now what I am not sure of is the button ejector mark. That usually is a sign of high pressure. Can you get an ejector Mark from the case head coming back hard? I am not comfortable saying that. It's just something to consider. New brass, properly set up die. (I suggest learning to use a hornady headspace kit) Then rework up the load. You may find you see pressure signs and you may not. Short of expensive pressure testing gear that's all you can do. |
Armory Sponsor