I am not OVERLY worried about he runout in my 25-06, it is my mid range coyote and deer gun.
What I am worried about it in is my 270 AM and another gun project I have in the works. For these guns I want evry peice of ammo I load for it to be the absolute best it can be. So that any mistake that is made I know will be my fault.
For these guns .003-.008 runout aint gonna cut it.
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Being that Kirby cut the chamber in your 270AM, I doubt there will be any problem with the gun [img]/ubbthreads/images/graemlins/smile.gif[/img] Consequently, you just need to focus on not screwing up the fireformed-straight neck while sizing. Have you tried sizing any brass without the expander to see how much constriction is taking place? Not saying that the expander is nessicarily the culprit, but it tends to drag problems to light. What trimmer are you using? Ive seen unsquare case mouths and expanders cause runout problems.
The "best" solution may well be a lee collet die as Jim mentioned. .001" and under is common on everything I load with them. Naturally, you would have to have a custome one, but,even then, its only $50. Id also suggest that you specify a pair of mandrels that are undersized when you order it. It will come with one thats .0015" or so under bullet diameter. you will probably want one thats .0025, and .0035" under, so you can have more controll over neck tension. Even with the custom mandrels, it should be under $70.
Give it some thought [img]/ubbthreads/images/graemlins/smile.gif[/img]
Its $70, but it will pretty much whup your runout problems.
As UncleB already mentioned, the expander stem creates about 85% of all Run out problems in ammo using conventional dies.
Here are a few tips to try using conventional dies that will help with your run out issues.
First do as Uncle B stated and try sizing some cases in the FL die with the expander stem removed, it will surpise you!! Generally run outs drop to 0.001" or less instantly. Only problem is these dies reduce the neck diameter to much and require the case necks to be expanded back to the proper dimension.
First thing is to get the case deprimed without sizing the case. You can do this by dropping the expander/depriming stem as low as possible to deprime the case before it contact the die body, or use a smaller diameter expander stem. Whatever you use, we need the cases deprimed before starting this process.
Now, with the cases deprimed, and the expander stem installed back in the FL die, adjust the FL die down to size the proper amount on your case, generally I like 2/3 to 3/4 the neck sized when partial full length sizing.
First thing to do now is to determine how the FL die body is effecting neck run outs. Try sizing some cases. With the die lock ring loose, run a case up to the point that you want it sized to. Lock the die body lock ring down and then withdraw the sized case. This should hold the die in proper alignment.
Size another case and then measure the neck run out on this case. If it is 0.001" or less, your ready for step 2. If it is not, untighten the die lock ring and repeat the test but with the lock ring loose instead of tightened. SOme die threads are not perfectly true, as are some press threads off a bit. If they are and you tighten the die lock ring down you will pick up run out.
Run a properly lubed case up into the FL die until the ram is at the top of its travel.
Then raise(unscrew) the expander stem up until it stops against the inside of the case mouth that is in the die. Then turn the expander back down 1/2 rotation just to give it some breathing room.
DO NOT tighten the lock ring on the expander stem!!! Very important, let her float!! THis will allow it to self align with the case as it is pulled over the expander ball.
The benefit here is similiar to a sliding sleeve inline sizing die. The Inside of the case mouth engages the expander ball before the case is released by the die body in the neck area. Basically, the die body is true in most cases, since the case held in position by the die body, the expander stem is required to center itself to the position of the held case mouth. Leaving the stem floating allows it to do this. And generally the finished expanded case neck will have a dramatically lowered neck run out.
-Deprime cases without sizing the case
-Adjust the die body so it is producing good low runouts
-Leave that expander stem floating so it can self align
YOu will see a dramatic decrease in your neck run outs using this system with conventional dies.
The next issue is the conventional seating die. We need neck run outs as true as possible and the case mouths perfectly square and evenly chamfered or bullet runout will increase during the seating process.
Using conventional seaters, you can expect to see the neck run out value at least doubled in the bullet run out. Point being you need your neck run outs as low as possible for any hope of getting sub 0.003" bullet run outs.
There is no real good way improve the conventional seating die. Basically, get that brass as square and even in the case mouth as possible, get the neck run outs as low as possible and you get what you get.
To greatly improve the bullet run out, you really need an inline seating die. Forunately, Forster makes a great inline seater that is very reasonably priced. I think they run about $30 for the more popular chamberings.
These will really help the run out of finished ammo.
When using an inline seater you will generally see the same bullet run out as the neck run outs you started with, or in some cases slightly better.
There are more expensive inline seaters like the Redding Comp dies but they all do the same thing, hold the bullet and case in the same axial alignment while the bullet is seated. This is key to low bullet run outs!!
Try that set up with your sizing die and I assure you your neck run outs will drop significantly on average.
You've started down that slippery slope of run out!!! Kind of like getting a chronograph. All was well before you knew the true!!!
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