A complex headspace question

[problemchild]

FIRST ISSUE (solved see last post)

I have tons of LC once fired brass. Its all LC but the years are different. In one bucket I might have years 03,04,05,06. Those years do NOT headspace the same. I set the press up on year 04. As I cycle the press I will see my set headspace (1.610) and then see 1.605 (03 year) then 1.612 (06).

To add to the confusion the press seem to "flex" or "stretch" when all 3 stations are loaded up. I also must run the dies right against the shell plate to get the desired shoulder bump. When I push the handle down the press is sizing, trimming and M die expanding the neck back open.

If I set my shoulder bump at 1.607 when the press is loaded up it stretches to 1.610 which is my target headspace. So I have to set the bump smaller than I need it so the stretch is factored in.

I have tested lots of the brass and they cycle in my gun and fit the JP minimum Sami spec case gauge. Im not going to sort the brass by years so is this OK? My chamber is 1.614 (average of 10 fired casings)

SECOND ISSUE

When I tested my brass in my gun I noticed it bumps the shoulder back .005-.007 thousands just from slamming the bolt closed. Normal?

I measured a factory new FGMM and it was 1.606 headspace.

[Sub95]

first one should be fine. I test fit my cases in my rifle and set the die up just to let the bolt close nice and smooth, yes it takes a little time to do this but i am not pushing the shoulder back more then i have to.

second question, is it hard to close the bolt?

[EL_NinO619]

I dont understand what "headspace" your talking about..

[EL_NinO619]

As in, There is not measurement of 1.6xx for the .223.... What caliber are we talking about....

[Linkpimp]

I’ve guessing that you’ve never annealed your brass? IMO would not have this problem big guy if you annealed it once every 3-4 loads..

http://www.google.com/search?q=annealed+brass&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7GGLL_en

[joelogic]

What the heck does this matter? I screw die down until it touches the shell plate, size a case, verify with case gauge, and I am set. I only pick up range brass and never sort.

[ireload]

Since you are that anal then size them as you normally would then load them on the low side then shoot. You basically fire form them. The second time you resize the brass then they would be more uniform. The brass you purchased were propably fired from several guns hence the variations.

[FLIGHT762]

Zediker talks about this in his book. The standard recommendation is a sizing bump of .005"(which you're trying to get). He recommends at least a .003" bump for autoloaders. Another author recommended at least a .002" bump.

I have found different lots / manufacturers / types of brass will have different rates of "spring back" when sizing. The only way to be 100% consistent is to segregate the brass. If you don't want to do that, take 5 or so of your L C 06 brass that bumps at .002"-.003" and make some dummy rounds with the bullet you are going to be reloading. Chamber them and manually extract them. If they chamber and extract without difficulty, don't worry about it further, if they don't you're going to have to segregate and size the 06 a bit more. I've also found the amount and type of sizing lube can make a difference in shoulder bump. It's difficult to get within .001" of every case being bumped the same.

On your second issue, that's just what autoloaders do. I wouldn't worry about the shoulder bump when chambering.

When an auto chambers a round, it's like having the cartridge in an inertia bullet puller. If you don't have sufficient neck tension, the bullet can jump into the lands. With regular dies, it's usually not a problem. If you're going to use neck bushing dies, neck tension will have to be addressed.

[problemchild]

Zediker talks about this in his book. The standard recommendation is a sizing bump of .005"(which you're trying to get). He recommends at least a .003" bump for autoloaders. Another author recommended at least a .002" bump.

I have found different lots / manufacturers / types of brass will have different rates of "spring back" when sizing. The only way to be 100% consistent is to segregate the brass. If you don't want to do that, take 5 or so of your L C 06 brass that bumps at .002"-.003" and make some dummy rounds with the bullet you are going to be reloading. Chamber them and manually extract them. If they chamber and extract without difficulty, don't worry about it further, if they don't you're going to have to segregate and size the 06 a bit more. I've also found the amount and type of sizing lube can make a difference in shoulder bump. It's difficult to get within .001" of every case being bumped the same.

On your second issue, that's just what autoloaders do. I wouldn't worry about the shoulder bump when chambering.

When an auto chambers a round, it's like having the cartridge in an inertia bullet puller. If you don't have sufficient neck tension, the bullet can jump into the lands. With regular dies, it's usually not a problem. If you're going to use neck bushing dies, neck tension will have to be addressed.

I have 3 dies here and I have tried two of them. I am going to try the last small base die if I can find the primer punch for it.

[Anti-Hero]

http://www.google.com/search?q=annea...rlz=1I7GGLL_en

Lake City brass is annealed.

[kurac]

Maybe screw the die in another 1/8 to a 1/4 turn if the press is flexing, that might make them more uniform. Since I only reload autoloader brass about 5 times, I don't worry about neck hardening due to bumping the shoulder back or annealing, they get trashed or lost before they wear out so no big deal.

[sonnyt650]

First of all for .223 I don't keep track of the number of reloads per case and simply inspect them to determine whether they're "done", so I'm writing from a similar perspective to yours with your mixed buckets. I just measured a handful of brass from yesterday's brass prep session and found that they're all pretty much spot on at -.004" from zero with no variation according to my RCBS Precision Mic.

I think the difference is in the press used where I'm loading on a Lee Classic Turret on which the sizing die is in-line with the ram itself. It reads like you're loading on a progressive where the ram is offset from each of the stations, and there's enough play from the offset that you're getting these inconsistencies.

[problemchild]

SOLVED

The fricken primer punch rod had managed to spin down just enough to hit on the thicker web of the different year brass causing a backed off headspace sizing. Basically I had a moving target for headspace and I could not figure out what the heck was going on. Guess those swagged primers beat the ram enough to make it screw itself down even on a locked nut.

I started over from scratch on the die setup and that's when I figured it out.