Terrible runout on 308 cartriges

[Bulltipper]

I just got a Forster concentricity guage and put it to work, I had loaded a run of 308 recently and was checking bullet runout. I got varying readings, some good and some as bad as .015 out. I think I have tracked the source to a loose decapping rod in my sizing die. Has anyone had this problem before? I had finger tightened the locking knurled nut when it worked loose, but it seems I should have put a little more on it, like light pliers. Some of these cartriges are so bad that the bullet waggles visually (.015) when the cartrige is rolled on a smooth surface. I am wondering if I should shoot them and fire form the brass and try again or if I should pull them and salvage the FMJ and the powder, and scrap the brass. I love that new tool, wish I would have gotten it sooner...:sad:

[flashhole]

That's a lot of runout. I get upset when I see more than .002" runout. What kind of bullet are you loading? If it is a long pointy bullet you might also check the seating stem in your seat die to be sure the bullet is being captured on the ogive. If the tip of the bullet bottoms out on the inside of the seater stem you can badly cant the bullet. You would not be the first person scratching their head over that one.

I have the Forster guage too. Wonderful tool. I use it when setting up my sizing dies too to make sure I'm not inducing runout during the sizing step.

I found the Forster Benchrest Seat Die is just about the best there is for making concentric ammo. If you don't have one you might consider investing in one. They are worth every penny.

[405]

Back when I loaded a bunch of jbullet bottlenecks in various calibers I found that the 2 most likely sources of severe neck runout happened when: 1) pulling the neck expander button back out of the case after sizing 2) seating the bullet.

1) The 3 best die systems I found to help counteract the runout caused by neck expanding are the Redding Competition Bushing Neck sizer, Wilson Bushing Neck sizer (also called the hand die) and the Lee neck collet sizer with the full length mandrel. Of course the Lee is the least expensive but does an excellent job for most cartridges.

2) Bullet seating causing runout usually starts with the neck being sized down too much to begin with. It only needs to be .001-.002" less than bullet diameter for good neck tension. If that bullet has to expand/resize the neck more than that during seating.... there is much greater potential for excessive runout to be induced into the neck during bullet seating. The specialty neck dies that use different neck bushings are easy to change for best neck size and tend not to over-resize and induce runout. The same is true with the Lee neck collet sizer. The other way to minimize runout during bullet seating is to remove the decapper/neck button from the regular sizer die and use something like the Lyman M die. Use a universal decapper. I have removed most of the decappers/neck expand buttons from my regular sizer dies.

[Bulltipper]

Well the kicker is all cases with excessive runout were sized with the standard RCBS FL sizer, some I had primed over a year ago and just loaded them two weeks ago. last week I got my new RCBS competition die set and at first I thought it was to blame. I seated all bullets with the comp die and noticed the problem. then i used the old seating die, still had the problem. I tried to resize the brass and could not correct the problem. the brass seems to be bent at the shoulder, like the entire neck is bent. this is what is blowing me away, how did the whole neck get bent? I fired some today that i know were a little bent and they shot ok at 100yd. I am going to resize them tomorrow with the new dies and see if that and the fire forming straightens them out. then i guess i will work backward to try to figure this out for sure. I have so many dang variables here it makes it really muddy. all help,opinions and even raw criticism is welcome here by me...

[MtGun44]

Remove the expander button, size a case. Then replace the button and PUSH it into the
neck (in the press, of course), stop as soon as it goes past the neck and pull it out.

Check the neck runout. Should be massively improved. Try running the decapping/expanding
rod loose so it can wobble and self align on the pullout, but this may give you grief with
hitting the flash hole. Likely pulling the case crooked with the expander button.

If the case is straight before you seat a bullet, you may need a Forster or Redding or Hornady
type of seater with the floating alignment tube.

Bill

[liljohnnie]

I just had the same problem with a run of 270 Win. brass. I found out they were "a little wobbly" when i started to trim them. I had been using a set of used RCBS dies that i bought here and did not notice that the decapping stem on the FL sizer was bent until i had resized 500 rounds. I went to Cabelas and bought a set of Lee dies. I had to go back through the whole lot and resize,turn 180 degrees and size again,HUGE PITA.
In your case it sounds like you should have bought the Hornady concentricity unit that has the provision to true up a loaded round. As for me,i have had enough problems with RCBS dies in the past that i think i will steer clear of them from now on.

[bohica2xo]

You just need one more Forster tool. The bench rest seater.

Forster Bench Rest Seating Die instruction sheet (http://www.forsterproducts.com/client_images/catalog19938/pages/files/Bench_Rest_Seater_Die.pdf)

I have been using them for decades. No more seating errors.

B.

[DCM]

The replies so far are all very good information. Run-out starts with the case sizing. I am not quite sure who makes the best sizing die, but Forster makes the best seating die I know of. We tested it against some of the top brands a few years back and it always beat them.

[1hole]

Glad you got a concentricity gage, without one we are fanning the wind about straight ammo. Fifteen thou is a LOT of runout, you do know that your runout is half of the full range (Total Indicated Runout, or TIR) you see on the gage?

Necks can be concentric but have soft spots the metal. If so, the expander plug will run into the soft areas and bend what otherwise seems a good neck. Longer than usual expanders, cylinders actually, reduce that, at least somewhat. Lyman's "M" expander die and Lee's FL die's long expander designs seem to do a better job than any others, the long contact bearing surface uses the neck itself to help keep the expander centered.

Strongly doubt your semi-tight decap/expander rod had any significant effect on runout. That rod is too long and too small in diameter to be stiff enough to do much to a neck and no seater can seat staight in a bent neck. Another thing is the neck's inside can be out of line with its outside. The only thing that will 'straighten' that is to turn the necks (not ream) using a hand held turner and a snug fitting pilot that insures the cutter is making the outside match the inside. (I prefer the Forster HOT-100, it has several excellant features that are unique in a lower cost tool.) It's easy to remove more neck than is ideal, most of us seem happy to skim-turn necks over perhaps 60-80% of the circumference just to even things up a bit.

Second big thing that can produce runout even in a [perfectly concentric neck is high bullet "tension". Unless you have a full body sleeve seater that aligns the entire case and bullet before seating begins. (That seems to mean a Forster or Redding seater.) Otherwise the force required to seat into an undersized neck forces the case-bullet to tilt as far as the internal slop in the seater will allow even before seating starts. When a bullet starts crooked it tends to continue that way. Seaters are too loose for such 'tricks' as seating part way and turning it half around before finishing to make a significant difference, if any at all.

Having a neck smaller than about 1 to 1.5 thou under bullet diameter adds nothing to bullet grip, those who think a "tension" of 3-4 thou are kidding themselves, it only increases the seating effort but makes no difference to the neck's grip on the bullet. Some people like the various bushing type sizer so they can keep the neck at the right size (and some still make it much too small). Bushing dies work, or can, but I prefer to use Lee's Collet Neck Sizer because it tends to produce both straighter necks and the right size neck for straight seating without fussing with bushings. The Lee collet neck die has a moving part and requires a learning curve to get it right but it does a great job for those who take the time to learn to use it.

Good luck!

[Baron von Trollwhack]

To start working on run out problems you have to look at everything in the case sizing/bullet seating set up from the top of the ram to the expander.

Is the ram slot clean where the shell holder slides in or does it have crud not allowing the shellholder seat correctly?

Is the slot in the shell holder clean where the case slides in or does it have crud....... ? Does the case rim or base have interferring dings, dents, bends keeping it from seating fully?

Mount your sizing /neck expanding die on a Lee 0 ring so you can wobble the die a little without great force, yet the die setting will not move. This lets the press thread settings center better as the case is inserted. Then insert the case again and adjust the expander ball/tapered ball , not locked down yet, to just size the neck up to the depth you need for the boolit. Lock it down at some point in the withdrawal of the ball process. This involves both external sizing first then neck expansion, second, to set up the die.

Do not full length size as in 30-30, so the lower neck /shoulder junction stays fireformed, which helps center the case in the chamber, but the neck is sized down/ expanded, where the boolit will sit. Don't be afraid of letting that GC hang down . As in the 30-30 most boolits do not need the whole neck sized.

You cannot set and forget die settings. You must be able to duplicate good settings every die usage.

The F/L die on an 0 ring lets you do that. Get a way to measure case headspace (precision mic). You have to use good lube in case F/L work and internally in the neck size/expand process. Grind down larger expander balls to work for your lead bullet needs. Anneal for neck temper consistency(bullet pull). Use an "m" die instad of an expander ball. Size your 308 case in an 06 die to base size only(as an example). Remember that 4 different f/l dies will give you 4 different base, shoulder, and neck dimensions.

This is only a start. Your use must be perfected, unless minute of whitetail is ok for your shooting .

BvT

[August]

You just need one more Forster tool. The bench rest seater.

Forster Bench Rest Seating Die instruction sheet (http://www.forsterproducts.com/client_images/catalog19938/pages/files/Bench_Rest_Seater_Die.pdf)

I have been using them for decades. No more seating errors.

B.

Make that two more tools, you want the Forster Sizing die also. The Forster sizer has the expander ball way up in the die. The neck is still supported by the sizer as the expander draws through the case. I have had outstanding results with this die. It is adjustable with respect to the position of the expander vis-a-vis the sizing throat and you can get some dead-nuts concentric brass with this die.

[felix]

Especially if you have the folks there make them from your fired brass. ... felix

[Bulltipper]

Thanks guys! I am having a much better day in the loading room today, the 308 brass is squaring up after being resized in a freshly cleaned press, ram and shellholder. I have seated a few boolits and I am now less than .001 runout. I am still not 100% as to the cause (probably being less than meticulus or being in a hurry etc...) but at least now I know how to fix what is screwed up and what steps and tools are necesary to prevent this from happening to me again. (or at least catch it before loading 700 rounds) I learned a lot this week, thank you brothers for helping me with my schoolin' :-)

[flashhole]

Another thing you want to pay attention to when setting up your FL sizing die. The die threads have some side-to-side movement when screwed into the press. I will lube a case and run it up into the die prior to locking it down. This centers the die to the ram. My experience has been this eliminates a variable and helps reduce runout.

[GabbyM]

Another thing you want to pay attention to when setting up your FL sizing die. The die threads have some side-to-side movement when screwed into the press. I will lube a case and run it up into the die prior to locking it down. This centers the die to the ram. My experience has been this eliminates a variable and helps reduce runout.

Another method is to either run the die against the shell holder or if you want the die backed up use shims between the shell holder and die. Aim is to square the die up with the shell holder. Advantage of using a shim is once you put together a shim pack that fits your gun you can keep it in the die box for resetting your size die the next time around.

I’ll also agree with whomever stated in an above post about the Lee lock nuts with an O ring.

Also add my name to the list of satisfied Forester / Bonanza customer. RCBS dies will make good rounds also. Decap stems can get bent. The previous tip of locking your stem down while under up stoke tension is a good one and IIRC right out of some books I’ve read.

Unless you have a ten pound rifle with very high power scope which you intend on shooting targets like prairie dogs at 400 yards, which takes about a 3/8” MOA gun. I’d not get to ambitious about trading off RCBS dies. Myself and thousands of others have shot varmints at a quarter mile with ammo loaded with RCBS dies. Changing die brands or styles is no cure all to set up complications. You’re reporting huge run outs and that’s not the die design doing that. Hold off on throwing money at the issue. Bushing dies and such are as much to save brass life as anything. When you start plunking down $80 per 100 pcs for Lapua brass it makes sense.

One thing I’ve not noticed mentioned is brushing the inside neck then using a brush with motor mica for a neck lube to ease force from the expander. A bore brush chucked into a 110 volt electric drill clamped to a bench will make short order of a thousand bottle neck cases. Only time I run that many cases is to process Mil Surp brass. Do like to clean the carbon from the neck though. Not saying you must do that to get good ammo. Just that I’m not looking for production rate when loading bottle neck rifle rounds. I treat every round I load like it may be the one that changes my life. Even when I’m loading up M193 ball duplicate rounds for iron sighted AR’s. After all if I’ve time to blog around here on cast boolits I’ve time to load up quality ammo.

I’ve a book here I purchased a decade or so ago from Sinclair International.
Precision Reloading & Shooting Handbook 10th Edition. Fred Sinclair has since sold off to Brownells. Since none of us stay young for long. Books like that which detail bench rest load techniques give you a method (standard shop procedure) to follow. You don’t need to buy all the high price equipment to get the last .0002” of tolerance or all the micrometer setting dies and powder measures. Those are mostly gadgets that are not even needed in bench rest. IMHO. You get the idea. If you aspire to hit a target smaller than a gallon jug at 500 yards you need to know precession techniques. All that information absolutely transfers over to cast bullet shooting. All about fit and finish. You don’t have to have the most expensive tools to get good results. Good tools just make it easier. They do not guarantee good results. Most of the high price gadgets for setting up ammo can be home made from smiple items. Unless you just have to have all the best of evrything right now.