Armory Sponsor
Posted: 6/3/2016 9:43:29 PM EDT
|
Haven't seen this before. While seating bullets for my 6mm Rem I had one slide rather far into the case mouth. Usually they sit right on top or just barely inside. This one slid in and out by hand about 1/4" in before the case seemed tighter. I tried a few different bullets but same result. I thought maybe it somehow didn't get resized so ran it through the sizing die again and still loose. I took out the expander ball and still loose.
This was one of the 6mm cases that I had extraction issue with after firing. I realize some of these cases are done for, but curious if this might suggest anything regarding that issue. |
|
Quoted: Haven't seen this before. While seating bullets for my 6mm Rem I had one slide rather far into the case mouth. Usually they sit right on top or just barely inside. This one slid in and out by hand about 1/4" in before the case seemed tighter. I tried a few different bullets but same result. I thought maybe it somehow didn't get resized so ran it through the sizing die again and still loose. I took out the expander ball and still loose. This was one of the 6mm cases that I had extraction issue with after firing. I realize some of these cases are done for, but curious if this might suggest anything regarding that issue. The neck is work hardened, it needs to be annealed. Like I told you in your first thread on this subject. |
|
Quoted:
The neck is work hardened, it needs to be annealed. Like I told you in your first thread on this subject. Well, that's what I'm trying to figure out - if this is somehow related to the other issue. Oddly, the case chambers just fine which it wouldn't do before sizing so clearly whatever was causing it to stick was fixed during sizing. Just the case mouth is too loose. I've never annealed brass other than a brief experiment and hadn't seen this symptom before. Usually the mouth just cracks and I toss it. I'll experiment with this one and see if annealing fixes it. I thought work hardening meant the brass had lost its "springiness". This seems the opposite as it "springs back" after sizing. EDIT: I attempted to anneal the suspect case and then resized again. No change. Neck is still too loose. I realize annealing is an art and just heating up the neck isn't enough. I tried twice. The first time I heated it just until it started to change colors. This might not have been hot enough so that could be the reason it didn't help. The second time I heated just until it started to show a slight orange hue. This might be too hot but this should at least ensure it's annealed. Still no change. After resizing the case mouth is still loose. |
|
Tempilaq is what you need. Midway
Search Google or Youtube for a how to video. |
|
|
|
Hard extraction = tight neck= high pressure."Case head" Larger in diameter? If we look at the SAAMI drawing http://www.saami.org/PubResources/CC_Drawings/Rifle/6mm%20Remington.pdf in the neck area, both chamber and sized brass, i see very little clearance of a loaded round. This is if the loaded rounds neck diameter is .276" or more. Note the taper on the chamber. I suggest you measure the loaded rounds necks, before firing. See if the rounds that are close to .276" are the problem brass. Your chambers neck may be tighter than normal or the brass neck wall thickness is heavier. Do measure loaded rounds neck before firing and measure fired necks outside diameters after firing. Spring back of the fired brass, i would want it a least .001" larger than the loaded rounds neck diameter. Note that light loads may NOT expand the case neck, using slow powders. So not a 100% good test. A chamber cast may be needed?? Has the trim length been checked AFTER FL sizing? Thats my guess. |
|
Thanks. Obviously the unknown temperature is a major factor, but I'm not sure this particular issue is about annealing. No doubt annealing will help all my brass, but I think something else is going on here. l'm not worried about saving this one case so heated it again to orange hot. That should have over annealed the case making the brass too soft. Nevertheless, after running through the sizing die the case mouth is still too loose even when not using the expander ball. It's like it just formed to the current size and will spring back no matter what. Or, is it not possible to bring back a work hardened case? From what I've read you can so that's why I'm confused. |
|
"Brass getting shorter after firing" A light load will expand the case body and pull the shoulder and neck back/shorter trim length. You may want to try loading hotter, if there is no problem with neck diameters, chamber and brass. A hotter load will expand the brass fully to the chamber. This hotter load will produce more spring back of the brass after firing. May solve the extraction problem?? Does factory fired ammo stick? |
|
Quoted:
I thought work hardening meant the brass had lost its "springiness". This seems the opposite as it "springs back" after sizing. Hard brass is stiffer, springier and stronger. You can bend them but they spring back (or break). Annealing softens brass and allows it to be bent and stay bent. As you size and resize a case you work harden it, making it stiffer and springier , again. I don't think this is a work hardening problem. Check your die. My experience has been that standard dies size the neck down a LOT! They rely on the expander ball to return the internal neck dimension to a useable size. Check the diameter of your expander ball. It may be the wrong size. At least, that's where I'd start. As a follow-up, I would size a case without the expander ball and see how much the die is shrinking the neck's OD. If the die is taking the neck down, the expander ball is the problem. Finally, measure the OD of the bullets. Be sure they are the proper caliber. |
|
Quoted:
Hard extraction = tight neck= high pressure."Case head" Larger in diameter? If we look at the SAAMI drawing http://www.saami.org/PubResources/CC_Drawings/Rifle/6mm%20Remington.pdf in the neck area, both chamber and sized brass, i see very little clearance of a loaded round. This is if the loaded rounds neck diameter is .276" or more. Note the taper on the chamber. I suggest you measure the loaded rounds necks, before firing. See if the rounds that are close to .276" are the problem brass. Your chambers neck may be tighter than normal or the brass neck wall thickness is heavier. Do measure loaded rounds neck before firing and measure fired necks outside diameters after firing. Spring back of the fired brass, i would want it a least .001" larger than the loaded rounds neck diameter. Note that light loads may NOT expand the case neck, using slow powders. So not a 100% good test. A chamber cast may be needed?? Has the trim length been checked AFTER FL sizing? Thats my guess. Thanks for this. I did some measuring. For the OD I used both a micrometer and a digital caliper. They were in agreement. Had to use just the caliper to measure the ID and brass thickness as the mic I have won't do ID. Newly loaded rounds measure .271" (+/- .001) at the neck. Resized brass measures .270" outside and .239 inside. Thickness is .016". Something is probably off though as those don't add up. The problem case measures .267" outside and .241" inside. Thickness is .013". If I'm reading that drawing right, looks like the ID of the case should be .237 so my problem case is at least .004 too big and probably a bit more given the difficulty of measuring ID of a circle. Assuming the measurements are accurate, the thinner brass on the problem case along with the larger ID could be the issue. Also, according to the mic the bullet diameter is .2427 or just a hair under .243. |
|
Dude.... You're killing me man. Really...
I'm coming up on thirty years of reloading. I've never had this much trouble reloading. Seriously. One reason is this.... sooner or later, you simply look at a batch of brass, realize its been thru the wringer and accept the fact that its "done". You pick the whole batch up, and dump it in the trash. Seriously, you;re way over doing this. You are making reloading 100 times harder than need be. And instead of becoming familiar with the basic operations and mastering the fundamental skills, you're getting sidetracked trying to track down esoteric causes of problems created by crapped out brass. Give up already. In well over two decades I've never annealed a case. Not once. I get four or five or size firings out of stuff like 308 and 556 cases, then I start to see the occasional neck split, and chuck it. I;ve got my money's worth. Pistol cases just keep going and going and going. But Ive never needed to anneal a case. Only now, after all this time, would I remotely consider it. I'm fire forming 280 Ackley Improved from Norma 280 cases, and have a fair 'investment" in these in terms of time and money. Annealling MIGHT be worthwhile. But a 6mm rem case? Nope. www.midwyusa.com, www.natchezss.com, or Grafs.com. Order a new bag of brass and get on already. |
|
Yeah, maybe I do overthink things, but I prefer to call it research. I'm just trying to track down an issue with the rifle which I've had ever since I got it in the early 80s. We first started reloading for it then and I recall having the occasional stuck case even then. We just didn't really pay it any mind.
I haven't reloaded for it in over 10 years and only recently dug the stuff out again. I decided to try and track down what's going on. I didn't think old brass was the issue but given that wasn't something we tracked maybe that's it. |
|
Your thickness readings are off but what is most important is the difference you found.
The case that won't hold a bullet has thinner walls thus it's ID ends up larger. It's hard to measure wall thickness because of the radius inside the case. The smaller the ID the less accurate the measurement UNLESS you have the proper measuring equipment. As touched on before, I think your brass is worn out. Time for some new stuff. 
Motor |
| Loaded round neck diameter .271" - .243" bullet diameter = .028" รท 2 = .014" neck wall thickness. Looks Ok. The problem case at .267" is not. In 243 win, its nearly impossible to get a loaded rounds neck diameter at the SAAMI listed .276". Happened 1 time and over working from the die made case walls thinner. |
|
Quoted:
If you have two gages (calipers and/or micrometer) you do some trigonometry and develop a correction for your measurements of internal diameter. The math is simple and reliable. Start by measuring the width of the flats on your calipers. I mentioned this in the other thread, I may start advocating for machinist ball gages in the reloader's tool box. They're at least as useful as some of the other junk we buy. |
Armory Sponsor