I think. 6.5CM. A new case is my "zero". A fired case is only .002 bigger than the brand new case. A fired, sized case is only .001 bigger than a brand new case and .001 smaller then a fired case. Sounds sweet right? Until I get 1 out of 3 that are hard to chamber. Would it fix the problem if I took .002 off the top of the shell holder so it would push the case up .002 higher? AND...I am not measuring the shoulder on the .400 datum line. I dont know what the bore is of the "comparitor" that i have but as long as I use the same tool on all the cases does it have to be measured on the .400 datum line?
- Thread starter 105gr
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It's really difficult to get consistent shoulder bumps if you're not properly annealing every firing as the springback of unannealed brass can result in what you're experiencing.
The ones that are hard to chamber, have you measured the headspace measurement on those as well? You may not be getting consistent enough to run only 1k of bump.
Re: measuring - It doesn't have to be exactly on the datum. As long as you are using the same comparator, you'll get a measurement that's good enough for what we use it for- Comparing.
Re: measuring - It doesn't have to be exactly on the datum. As long as you are using the same comparator, you'll get a measurement that's good enough for what we use it for- Comparing.
How are you lubing the brass? Better lube means more shoulder bump.
I do not anneal every firing. And yes thats what it seems like is happening, especially since this brass is still being used for load development so the charges and pressures arent the same
How do you mean? I have seen no difference in the amount of shoulder bump, for the same die setting, between redding sizing die wax and lanolin lube.
I have seen inconsistencies and bumps if too much lube has been used, but that is a different issue.
One shot spray
I was asking the OP.
That is the OP...
I wasn’t talking to you
HOS is not as consistent as imperial sizing wax. Try it, you’ll bump better and more consistently.
I set my headspace to be about a thousandth over new brass on multiple barrels with no issues.
I suspect you have a resizing issues.
die setting?
Annealing?
Lube?
I suspect you have a resizing issues.
die setting?
Annealing?
Lube?
That wasn't clear.
My question still stands - how does better lube make for shoulder bump with the same die setting?
The die is a full length RCBS die set up the way the manual says. Run the die down till it touches the top of the shell holder.
I have not annealed this brass. It is on it 3rd firing I think.
The lube is Hornady One Shot
Turn the die in more. The press could be springing away from the shell holder under pressure from sizing.
You probably need to screw the die a bit more.
You have to account for slack and deflection.
Also at about the 3-5 firing brass definitely gets hard enough to require another die adjustment.
I’m not a fan of one shot for medium to large cases.
Nothing catastrophic will happen with 4k bump.
Don't rely on the "touch the shellholder + x turn" setup. You can run the die in further to get the bump you want.
And yes lube does matter... More lube=more bump
The statement was "better lube means more shoulder bump." I have never seen a difference in bump due to the type or brand of lube I used, as long as it's not excessive. I would like to know if people have seen a difference in amount of bump due to type of lube that was not due to inconsistent application.
Not arguing for one lube being better than another.
Better lube allows the case to go in deeper into the die. Worse lube causes more drag on the die walls. The case body is forced outwards and the shoulder doesn’t get bumped as much.
I cant run the down farther. Its as far as it goes. On the hornady single stage press it has a "cam over" so at the top of the stroke before it drops back down slightly the bump against the die is pretty stout. Thats why I thought about taking .002 off the top of the shell holder because I cant screw the die down any farther.
You can set it so it just smashes it more.
A better lube might help, but when not annealing, trying to keep within .001 with all that spring back it's just a difficult fight. You're got 3 firings and the brass is becoming more and more work hardened each time you fire them. If you're not going to anneal, then you may want to consider increasing you shoulder bump to allow for the springback.
Don’t anneal when easier solutions exist
Not everyone does and it's not necessary depending on the type and level of shooting you do. But, if you're after "precision" and go by objective test results, then . . .
You might like to read this below and take note of the numbers as to how hardness increases with each firing. As harness increases, there's more springback and more grip on the bullet with each firing, which does effect performance.
How Induction Annealing Works | Under The Microscope | AMP
View the latest articles from AMP Annealing. Get tips and tricks from our R&D. Here we upload articles to provide your the best possible information on innovations in the annealing process.
www.ampannealing.com I still think this is more a die set up issue than anything else.
without a case to size my body die smashes into the shell holder pretty solidly when the ram goes up.
I remember long ago just following the directions and having issues, the directions are really just a baseline setting.
without a case to size my body die smashes into the shell holder pretty solidly when the ram goes up.
I remember long ago just following the directions and having issues, the directions are really just a baseline setting.
I had a similar issue recently and found that setting the die up like the directions said did not work out.
Like others have said, I turned it 1/4 turns until I got the desired shoulder bump and all casings chambered correctly. I’m using a rock chucker and it did have more cam over than normal.
Like others have said, I turned it 1/4 turns until I got the desired shoulder bump and all casings chambered correctly. I’m using a rock chucker and it did have more cam over than normal.
Either do as someone said above, and screw the die down when the ram is not all the way up and cam it over, or you can remove a couple thousandths of material from the bottom of the die with some sandpaper and a flat surface.
I wouldn't take too much off the shellholder, because you need the material there to help pull the brass back out of the die, in case you get one that isn't sufficiently lubed.
I would try a little more cam over on the die before I took some off the shell holder. Your bump will change from touching the shell holder to camming over on it, to camming over on it a little harder.
D
Deleted member 10043
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BS. That doesn't happen if you don't anneal after every compulsive firing.
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D
Deleted member 10043
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No, I never got into annealing brass. You got a short chamber. On the press side bump .004" as already mentioned. In the chamber it equates to .002. BTW, the latest fade is to bump up to .003. Won't be long before we are just using the die instructions. More important what is your COAL and CBTO for the same cartridge jammed into the lands. Are they on the short side as well?
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So, you're saying measuring headspace off a fired case is about 1.4921?
No. Because I'm not measuring on the .400 datum line.
Thank you for posting this - been looking for a SAAMI cartridge and chamber drawings for the 6.5 CMoor...I have a Proof SS petit for my AXMC and in a discussion with proof, they advised their chambers are on the short side; my fired case CH- Shoulder is 1.554 using Hornady’s headspace gauge.
@105gr - what are you using to measure your fired case case headspace? Can you post a pic? Just curious what you’re using...
Its a home made CBTO comparitor insert I was using for my 338. So the bore is probably around .336
I wonder what your measurement would be if you used the Hornady tool.
I size mine to 1.551”, measured using the Hornady tool...FGMM 130 Berger chambers with resistance and have to crank down on the bolt to get them in there...They all measure 1.554/1.555 as factory new. At 1.551” I get only a slight hint of resistance to no resistance. 1.552” a tad more resistance. Resistance starts to become real noticeable at 1.553”+.
Not sure if any of that helps you but perhaps your chamber is on the shorter side of SAAMI like mine.
Here’s one of my fired cases. Spent primer removed before measuring.
OP, I would suggested getting this tool or something similar that measures cases at the same place on the brass simply because it's how most folks measure for headspace. Otherwise it’s all apples to oranges...
OP, I would suggested getting this tool or something similar that measures cases at the same place on the brass simply because it's how most folks measure for headspace. Otherwise it’s all apples to oranges...
I had problems like this with a RCBS 7mm rem mag full length die. I couldn't get enough bump. If it's already camming over pretty hard, the die is already mashed up against the shell holder. No amount of screwing it down "a little further" is going to make a difference. You'll have to shave a little off the top of the shell holder or the bottom of the die. The shell holder it probably preferred. I just put some sandpaper flat on my bench and rubbed the top of the shell holder back and forth on it. It doesn't take long to shave a couple thousandths off.
