Bullet runout question

M

model14

Guest
I just started using my new Sinclair concentricity tool to measure bullet runout on some newly reloaded .223 rounds. These are accurate target rounds based on past experience using the same die setup and procedures, but I was surprised to measure as much runout as I did. Average runout for 30 rounds was .0038. Max runout was .007 and min was .001 (one round), with four having .002. I ran them all back through the die and achieved an average of .0033. Max was .006 and nine were at .002. I am measuring at the bullet ogive. Neck runouts are about half these values measured at the center of the neck. Are these values normal, should I be concerned about accuracy affects? What is your experience, please? Bullets are 52 grn Sierra MK's and the die is an older Redding Competition Seating Die (has a mic on top).
Thanks, M14
 
Runnout

It has been noted that it does little good to machine barrels and actions to the "nth degree"only to chamber rounds that runnout in numbers that would be considered atrocious in barrel work.

I have delibertly taken rounds and sorted them by the smallest runnout to the largest, (we are talking a spread of between .0005 and .003), and they all went in the group. This was with my Rail Gun.

That being said, it sure doesn't hurt anything to strive for the least amount of runnout as possible. My dies habitually produce 6PPC rounds, or 30BR rounds, that will measure .0015 or less.

For what it is worth, I have found that most runnout that is induced during the loading proccess is a product of the Sizing Operation, not the seater...........jackie
 
My experience and finding with runout is it occurs when we size the neck during the sizing process. As a test, measure a fired round, diameter and RO, now measure a sized round, diameter and RO. Bet the RO changes on you. How much did you size the neck down? More than .005"?

If I size the neck down more than .005" at a time I've found that is when the RO occurs. If using bushing dies experiment with varying sizes of bushings to size no more than .005" at a time. Measure again but RO only. If using an expander ball die, change to bushing dies. Good luck to you. I chased this beast for several months before I found what worked for me.
 
runnout:

model14: Like you I'm also using the Sinclair coincintricity tool, with the RCBS also, and I have been getting "numbers" similar to yours for years: drives me nuts! I personally believe much of it depends on the quality of the brass. How else to explain 20 or 40 cases, all fired in the same chamber, all sized with the same die, all seated with the same seater die, all loaded with the same components. As an example, 2 or 3 may have r/o of around .004" or .005", another 4 or 5 may be at "0" r/o, and the remainder somewhere in between. If I mark the "bad ones" ( black magic marker on the case head), fire and reload, the "bad" will be "bad" again, and the "zeros" will also be "zeros" again. I use those with .004" or more for close range, basic scope adjustment, first round foulers, and practice, keeping the best for more serious work. Price of the brass ( Lapua vs Winchester) does not seem to be the complete answer, as I've good and bad with both. I've also had some unacceptable r/o using the Wilson chamber seater dies, and neck bushing dies, and Have had plenty of "zero" r/o using the standard $25 2 die sets. Go figure. Not all brass is created equal, I guess.:(
 
Chasing the dog

I chased this dog long and hard for some time.

Here is what I found:

It could be your sizing die.

It could be your "touch" on the press.

It could be many other different things.

HOWEVER once I started using quality brass such as Lapua I have no problems getting .0015 runout or less on the bullet at the Ogive.

One other thing you did say "newly reloaded". If the brass has not be once fired then that could be the run out problem. Check a fired case before and cleaning or sizing. I bet it's close to being deadnuts.

I have my best results using Lee Collet dies (FOLLOW THE INSTRUCTIONS!) for neck sizing and Redding Benchrest Seating dies. However for tight necks I use a bushing die to size the necks.

And yes runout does matter and is something a hand loader should address and fix.
 
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Runnout, part 2

model14: Yes, to all the other postings also, and the inside neck expander can and will pull the necks out of alignment. If I must use an inside expander, for my "conventional" dies, the floating carbide button seems to do the least damage, the tapered expander is "not bad", but the worst is the rigid, parallel sided expander. I've opened a factory sealed box of dies and looked at the bottom of the sizer, and the de-capping pin will be off-center. I also agree, Lapua is top quality, and runout is seldom a problem, but I recently bought a bag of 100 Winchester 22-250 (lot# 2BD10), and it is outstanding. Loaded round r/o are .002" maximum, and many are around zero. After 6 firings, primer pockets remain tight, and neck walls vary no more than .001". On the opposite side, I bought a bag of very expensive brass from one of the Scandanavian producers (big name) and r/o on the majority are .005" +. Thus my belief that price does not always guarantee quality.
 
Standard, one-piece, FL dies, that require considerable effort to pull their expander balls through unturned case necks are the primary reason for crooked cases. Avoid them.
The question of how to do that has several possible answers. You are trying to putt with a ball that is out of round and balance. Get a better ball.
 
After reading your posts I went back to my bench and took some more measurements. Loaded case concentricity is not the problem. All loaded case necks had less than .002" runout. My neck sizer is the Lee collet type.

I found what is probably the culprit. I thought my seater was a Redding. It is not, it is an old Hornady with mic adjustment on top. I took it apart and took some measurements. The floating neck guide throat measures .247". My outside neck diameters on the loaded .223 are .227". That is a whopping
.020" difference. At the top of the seater is a bullet tip cavity pin that provides a stop for the seating up-motion in my RCBS press. The bullet tip can move all over in this cavity. I can see that if the bullet starts up the neck throat and into the seating cavity crooked, it is pretty much going to stay crooked, especially with the Sierra MK HPBT's I use. They have a very narrow and sharp tip that doesn't begin to fill the Hornady bullet stop cavity.

Is the Redding seating die different from the Hornady, is it a better design.?Should I go with a Wilson? Comments and suggestions would be appreciated.

I think how dumb and happy I was before I bought the Concentricity Gage :D
 
Get the Wilson and an arbor press. Just for grins I compared the Hornady seater to my Wilson and it gave me twice the runout with cases with identical neck runout. I know that others will point you at the Redding or Forster dies. They will do the job, but friends who use this type have ogive to case head variance issues that I don't have with the arbor press dies. Another thing, the seater stem should not touch the very end of the bullet. It should make contact in a circle around the point. If the tip of the bullet bottoms, your stem needs fixing.
 
Runnout, part 3

model14: I really like the Forster benchrest micrometer seater die, have a few Reddings, and also have and use the Wilson chamber seaters with an arbor press. All work fine, but my favorite remains the Forster. I also make it a practice to inside taper neck ream the mouth of the case, using the K&M tool, ($24). The bullet seats smoothly into the case mouth without any damage, or undue force required. I only taper to the recommended depth of 1/32", just enough to cut the sharp edge that is sometimes left there with the standard de-burring ( shaped like a rocket ship) tool. Unless your brass is stretching a lot, it's usually a one time operation.
 
If a bullet tried to run out on me I would never take it back.
Ted
 
Loaded neck measurement

model14 said:
. The floating neck guide throat measures .247". My outside neck diameters on the loaded .223 are .227". That is a whopping
.020" difference. :D
Click to expand...

model14,
Are you sure about that loaded neck measurement? .227 only leaves neck wall thickness of .0015.
Jerry
 
Jerry,
Thanks for catching my error!
Let's start all over again:
For my Hornady bullet seater the neck of the .223 loaded case (.247 outer diameter) slips into a .259 diameter cavity, and the seated bullet slips into a
.226 hole above that. So that is only a .012" difference in diameters, not
.020".
The bullet has no choice (+/- .002") but to be held straight in the die, but the case can still be at a significant angle when the bullet is pushed down by the stem. In any event I don't like the system since it does not hold the case in alignment with the bullet as it is seated.

How does the Wilson or Forsner system work compared to what I have with the Hornady? From the cutaway drawing in my Sinclair catologue of the Redding die, it looks like the Redding holds the cse while seating the bullet.

Thanks, M14
 
I have a Bersin reloading tool , bought it from K & M , measures and adjusts runout ,kinda pricey , but i have gotten runout to .02mm or less. I neck turn using sinclair nt, and their expander. I've noticed some cases , espically 223s that just dont seem to straighten up. I have also noticed that the bersin device seems to pull the bullet out alittle after adjusting runoff. , oal increases by .002 or so , not much but its clear its happening.

I also think case neck tension may play a role. I believe tighter inside diameter , ( say bushing dia .322 instead of .327) produce more runout and make it more difficult to reduce it. Futhermore i believe once you've reduced it , if you let the ammo sit awhile it will bounce back to orignal postion. This happened to me a few times were i loaded up, adjusted r/o , went to the range a week later , checked it on the spot at the range and it was like i didnt even check it. I noticed doing a good job annealing seems to help "control" runoff. I usually take my bersin device to the range and double check just befor firing. Just my 2 cents
 
We could write a thin book on this topic of the cause! But, I no longer care what causes it because I know that no die can consistantly eliminate it. I simply have learned to use methods to reduce it down to next-to-nothing to obtain my one-hole groups.

After spending much time having never discovered the miracle die, I have found that by employing the right methods will I consistanly reduce it's occurence to a minimum of .001 to .004 readings. These kind of readings shoot as perfect as I can handle my rifle. (groups in the ones and two's)

I have to disagree with others who say that you will be fine if your case starts straight out of the chamber. These are often the same people who say concentricity gages are not needed and are primarilly the tools for neourotics and other masochistic people. You can start with a perfect "zero" reading case, only to end up with an accentrically seated bullet that gives a .009 or worse reading. A straight case is ONLY a great start. I'd love to check a handful of their finished and ready to fire cartridges on my gage!!! NEAR-PERFECTION DOESN'T OCCUR EASILLY OR NATURALLY. :p

My seating procedure entails 7-10 ram presses of the bullet before it is fully concentrically seated. (I use a method employing marks on the case holder.) I almost ALWAYS end up with .001 - .004 readings.
 
Bullet runout

I've never been able to get acceptable runout from any threaded seater die. For my accurate rifles with custom barrels smithed by one of the best, I use Wilson seaters. I'm able to keep bullet concentricity < .001 consistently.

Lou Baccino
 
chino69 said:
I've never been able to get acceptable runout from any threaded seater die. For my accurate rifles with custom barrels smithed by one of the best, I use Wilson seaters. I'm able to keep bullet concentricity < .001 consistently.

Lou Baccino
Click to expand...

Wilson "in-line" seaters are always my first choice. But, I still wish that I could get the same .001 consistancy you report. I'm not doubting your experience....I only know that I still get a periodic accentrically seated bullet with the Wilson seaters too. Maybe it's because my most accurate loads are often compressed loads, or they have a lot of bullet pull. (??)

As for my mentioned successful method using screw-in dies.....it is that I have no choice with custom calibers like the 22- 6.5x47 Lapua which Wilson makes no seater dies for.
 
Wilson

VaniB said:
Wilson "in-line" seaters are always my first choice. But, I still wish that I could get the same .001 consistancy you report. I'm not doubting your experience....I only know that I still get a periodic accentrically seated bullet with the Wilson seaters too. Maybe it's because my most accurate loads are often compressed loads, or they have a lot of bullet pull. (??)

As for my mentioned successful method using screw-in dies.....it is that I have no choice with custom calibers like the 22- 6.5x47 Lapua which Wilson makes no seater dies for.
Click to expand...

Vani,
You can buy a blank Wilson that your gunsmith can ream with the reamer that reamed your chamber or you gan go with a Newlon blank which is a threaded die. Maybe I just got lucky but the Wilson seaters I have all perform very well. I like to take the seater stem out of the die, with a loaded case, and watch the bullet float down on a cushion of air; that's precise. These are all neck turned cases that are sized using a modified Redding die by JLC Precision. Carstensen's modified dies (JLC Precision) are dead on and I believe this is one of the reasons I have success with the Wilson seater afterward. If you use a conventional sizing die with a neck sizing button, you may find the culprit to be the sizing die that is contributing to your eccentricity. This is where the concentricity gauge can help to determine where your problem lies. Assuming your chamber was reamed by a good smith and your neck thickness is consistent, a fireformed case in that chamber should show no deflection on your indicator. If after sizing you see runout, look to the sizing die.

Even with so-called threaded competition seaters, I've only been able to maintain .002 to .003, sometimes less.

Lou Baccino
 
Lou,

It's a given with me that I will not proceed to seat a bullet into a case unless I have first checked the sized case for concentricity. I have two Sinclair gages on my work bench.....one set at a length to check the bare sized case, and the other gage set to check the length of the finished cartridge at the bullet. I'm with you that I will not use a button sizer either.

HOWEVER, I do concede that you still would have me beat at the reloading bench! :) I will not fuss with having dies custom made. And as for the issue of turning case necks...... Last year for the first time I went and bought a K&M case turner just to satisfy my curiousity. I did my first couple of cases with it to see how it works and I reacted immediately to it with a grin and an exclamation "Boy, isn't this neat Randall!!"....... And then I proceeded to order my reamer from Dave at Pacific in a non-turn neck size. :D

Thanks for sharing that input with me. It's interesting to learn what other fellow precision hand-loaders are doing out there in this hobby.

Randall
 
Once you figure out what FL die neck ID you want, have a Forster FL die modified by them to that measurement. They don't charge much and that should give you low and consistent neck runout. Another way to go is to use your current die, without a bushing, as a body die, and size the neck with a Lee Collet Die. It is interesting to see how straight cases are out of a body die.
 
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