Just got some new lapua 223 brass, the runout is less than a hundred K. When I seat 69 gn. Sierra Match Kings I get on average near of 4 hundred K using a Forester Ultra Mic Die and RCBS SS. I could sure use some help. Never check that close before the lapua brass just thought it was the LC brass causing the runout.
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Seating Issue
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I think you may want to recheck your numbers. "runout is less than a hundred K" are you saying < 0.100"? "average near of 4 hundred K" near 0.400"? Something is definitely not right.
Application??
I’d shoot them and see what happens. At .004” r/o, any number of things can be causing it, question is whether or not it’s worth trying to “fix” or tolerate assuming you can still do what you need to do with the gun while keeping an eye to make sure it isn’t getting progressively worse.
Doesnt the Forster MM seater come with a vld-style seater or no? If not, that should help, esp if he’s seeing little circular patterns towards the top of the bullet.
Maybe a little dykem or sharpie on the bullet can show where the seater stem is first making contact with it.
Im pretty sure not, but OP can disassemble pretty easily and put bullet in seating stem and look for excessive wobble
Jhonnies re-loadong bench on you tube did this test w/ 77smk, as part of mk 262 clone series IIRC
OP using 69 smk so maybe different, dunno
Yea true. Fwiw, I have about the same run out on avg loading 77smks for my mod1 and it holds .75moa at 100m and is good to 800. I use a standard RCBS seater as opposed to the Forster. I’m curious to see what his targets look like as is.
I feel it is holding a fair group on paper at 100 yds. 1/2 MOA 90% of the time. I was just looking to tighten it up a little more, that's what we all are trying to do just get that last little bit. That is why I when with the Forester Die and the Lupua brass. My load is 23.5 -IMR 4064 69 gn MK, CCi 400, and 1.9020 too OG. I feel that this is a light load for if I up the powder I start to get some crating issues with the RPR. Just want to fix what I can.
runout in your case is the LAST of the LAST thing to worry about...
Here what you do: go to auto zone and get valve grinding compound. Use a bullet seated into case. Put on bullet ogive and remove stem from die and start turning it by hand to it more conformed to bullet. Then use 600 grit, 1200grit and 2000grit sand paper to polish it smooth. Install back.
OR make sure when seating bullets the die isn’t hitting the shell holder. I’m betting it is. So get a diamond sharpening stone coarse and the remove sliding part of die and slide bottom across it evenly until you’ve ground it .007-015”. Where shoulder pushes the sleeve up and not shell holder. Polish it smooth. I did both of these and cut r/o to <0.002” TIR
In general if your seating die is hitting your shell holder, you can adjust your die. I.E unscrew it some, and move the lock ring down. Then follow that by screwing the seating stem in farther. I have never found a seating die that needed material removed. If I did, I would be much more likely to grind a shell holder than a die.
You’d never tell if you looked at mine it was ground. Anyway yes your option is good too. Mine works as needed and it’s mine.
First, I clean the die.
Second, I raise the ram with a case, screw the die down
to coil bind, then back it off, but only enough to position
the micrometer marks so I can read them. A 1/4 turn is
plenty. At this time I also check that the shell holder
does not contact the chamber sleve. If it does, I shorten
the sleve. I want the case shoulder to push the sleve up,
not the shell holder. I feel this centers the case better.
Third, I adjust the micrometer to zero, and turn the
seating stem all the way up. Fourth, I insert a case and
bullet and raise the ram, then turn the stem down until
you feel it touch the bullet firmly. Then lower the ram,
screw the stem down about 3 turns and seat the bullet.
At this point, measure the length
of the round, determine how much shorter you want it,
and use a caliper to lower the stem by that amount.
Then use the micrometer to fine tune.
People talk about it because it is pretty easy to measure. The more measurable something is, the more import people give it. But runout under .004 or so hasn't been shown to change anything on target.
Yup seat a little and spin case seat a bit more spin case will work 90% of the time
In my testing I could not see any difference on target till run out was over .007” measured on bullet At .010” groups opened only a tiny bit at 400 yards.
With .004” I wouldn’t worry about it
In my testing I could not see any difference on target till run out was over .007” measured on bullet At .010” groups opened only a tiny bit at 400 yards.
With .004” I wouldn’t worry about it
you should ''lean'' to straighter ammo, but just not to be concern about it in this phase.
because in your case it has ZERO efect on the target.
