Old Can of Worms - Ammo runout

[81STFACP]

I read all the bragging rights shooter's claim for the runout of their ammo, but I am not knowledgeable nor schooled enough to say - so what? I certainly understand the feel good factor, if you think it helps, therefore it does.

What does the run out affect, and how, and how much?

Who has meaningful data, not a three shot group, to back the claim?

In my short career in bench rest in the 80s, I never measured runout and rarely saw anyone who did. We loaded on the line between relays and just shot. In fact one of the scheme used back then was a step neck brass. This is done by turning just a portion of the brass to the point where the base of the bullet sits, so when you fireform the brass you create a step inside. On loading just prime, charge and just drop the bullet inside with no grip from the case, the base just stops at the step. You don't even want to know the runout of that case to the bullet. Cleans were shot in Hunter with this scheme in those days.

 

[Fuzzball]

Re: Old Can of Worms - Ammo runout

Runout shouldn't be a serious problem with your old soft seating method with turned necks in a tightly fitted chamber. But that sure isn't applicable to the loose chambered sporting rifles and ammo the rest of us use is it?

In our rifles, runout exceeding about 4-5 thou means little. Even a sloppy factory chamber will straighten out bullet tilt worse than that.

 

[5R Milspec]

Re: Old Can of Worms - Ammo runout

I would love to see a case if you still have one laying around.seeems like something I may want to play around with.
John

 

[81STFACP]

Re: Old Can of Worms - Ammo runout

Thank you.

Talking about chambers, I spec'd my reamers so the freebores are the same diameter as the bullet diameter. If indeeed, runout is real, the bullet being encapsulated in its own diameter should start straight, assuming the chamber is cut true to the bore. Check out the most popular 223 reamer, the Wylde reamer, the freebore is .2240.

Any more thoughts on reamers/chambers and runout?

 

[Greg Langelius *]

Re: Old Can of Worms - Ammo runout

Only that we make our own problems, and some of them are effectively little more than make-work.

For a BR shooter, all techniques are fair game.

For the practical shooter, I think in terms of surrendering that ultimate 1/2MOA of accuracy, going with the SAAMI chamber, and kissing off all that technique voodoo.

Greg

 

[Victor N TN]

Re: Old Can of Worms - Ammo runout

As a benchrest shooter, I was made aware of bullet runout at the World Firearms Industry Super Shoot when a friend asked me a question about runout when I spun my loaded rounds. I told him I didn't think it would matter. We tried a little test. Spin some loaded rounds and keep 5 of the best with low reading TIR. Then take 5 rounds and cut a small piece of masking tape (1/4" X 3/8") and stick it to the INSIDE of the case neck with it just overlapping out the case mouth. This should throw the bullet alignment off by .006 to .010" depending on the manufacturer of the tape and the original reading on the empty case necks. Fire the first 5 rounds into one group. Then fire the second 5 into a different group. The group with the bullets held off center will usually open up when compared to the first group. Give it an honest try and I think you'll see the difference for yourself.

Since then when I load for a centerfire match or shoot benchrest I always clean my case necks inside with a bore brush before loading.

This is all my speculation and test results. Whether or not your tests work the same way mine did I cannot say. But after shooting one afternoon we found out that .005" (I had the indicator tip placed halfway between the ogive of the bullet and the hollow point) is enough to cause the groups to open measurably at 100 yards. Likewise .002" or less will keep the groups in tight.

I was shooting the Hall rifle known as "Tony Boyer's Hall #130" with a Spencer barrel and my 6mm bullets. It had at that time a Leupold 36 X Tucker conversion scope. The temps were shirt sleeve tolerable in the afternoon. For north Ohio in May, not too bad I guess.

Good luck with your own tests.

 

[insight3b]

Re: Old Can of Worms - Ammo runout

I feel fancy tools to quell run-out are overrated. Set a few washers on top of the shell holder when the ram is raised and screw down the pre-set lock rings to the previously determined set-back/seating depth die('s) onto the the top of the washers resting on the shell holder and run-out is as limited as it is with the $$$ spent on fancy equipment. For $0.28 in washers you get excellent bang for your buck. Run-out does have a influence on accuracy IMHO but expensive tools to measure it and special dies only take cash from components and time from the trigger.

 

[Victor N TN]

Re: Old Can of Worms - Ammo runout

What do the washers have to do with keeping the bullet centered in the case mouth? A bore brush and handle with a little steel wool is all it takes to clean the inside of the case necks and remove the carbon that is 80% of the problem. If you have thin & thick places on the case neck then turning may be in order. Checking the runout is where tools can get as expensive and extravagant as you want to make them.

If it's something you have never checked or been aware of, chances are correcting it won't help you. In a benchrest match where the top 20 shooters are seperated by maybe .050" at 100 yards on a 5 or 10 shot group, you have to pay attention to things other than the wind. Not checking the brass for a 1,000 yard match can enlarge your group by an inch or more easily.

 

[Greg Langelius *]

Re: Old Can of Worms - Ammo runout

While I'm not busy measuring runout, I do pay some homage to the concept.

When I set up my dies, I loosen and retighten my lockrings at the top of the lever throw with cartridge components in place. I was told this would help.

Maybe it does, maybe...

 

[sandwarrior]

Re: Old Can of Worms - Ammo runout

81STFACP,

I'm finding it hard to believe you don't advocate using a system that helps true up the case to the rifle chamber.

In the BR world you usually, have tighter necks than what is typically encountered in a tactical rifle. The brass is also a tighter fit in the chamber. the problem in the tactical world of shooting is that fine fit as tight as benchresters do it isn't conducive to the function required of the tactical shooter. Otherwise we'd be bringing bench rifles to tactical competitions. The function we need doesn't allow for the form the BR world has brought on. Case runout is one of those things. the truer you get the better.

Personally, after only testing about 800 rounds I've found what eliminating runout does is eliminates the odd flyer that you couldn't explain. Meaning, my groups in the 1-1.5" range @ 300 yds. might have a 1" flyer opening the group up to 2-2.5" even 3.5" @ 300 yds. My goal is to keep the groups @ .5 MOA When you have these flyers it's hard to say your rifle continuously shoots .5 MOA when every 5th or 6th group is 1+ MOA.

insight3b,

I agree with Victor in TN. What does putting washers (of unknown size, quality, thickness, runout of their own, have to do with eliminating runout?

 

[polter71]

Re: Old Can of Worms - Ammo runout

The washers on top of the shell holder sguare the seating or resize die to the ram when the die nut is tightened down completly.Takeing out any runout that is introduced from the die thread and ram threads.Basically squareing everything up.

 

[Victor N TN]

Re: Old Can of Worms - Ammo runout

None of my presses have threads on the ram. And if your dies are crooked, you're using poorly made dies.

I have heard of turning the rounds 1/3 turn X 3 times as you seat the bullet. But I stand by my statement above.

 

[sandwarrior]

Re: Old Can of Worms - Ammo runout

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: polter71</div><div class="ubbcode-body">The washers on top of the shell holder sguare the seating or resize die to the ram when the die nut is tightened down completly.Takeing out any runout that is introduced from the die thread and ram threads.Basically squareing everything up. </div></div>


And how did you check those washers to make sure there was no run-out in them? Any pieces of metal clinging to them that might throw off their squareness to the die body bottom?

No more runout than to just bring the die to the shellholder then lock the ring down. Because personally for precision I'd trust RCBS and Redding to be more precise than whoever stamps out washers. Besides, if there's any play in the threads of a 14 tpi 7/8" dia. die body then the lock ring face should square that up anyways.

Now, if you suggested a small calibration block for a micrometer, then I would say that would be doing some good.

 

[Shady_Jay]

Re: Old Can of Worms - Ammo runout

I was always happy with the tight groups I shot off bench in load development (<.5MOA). Then, one day I was introduced to run-out, how to measure it, acceptable tolerances, and how inadequate my loads were because they had .003 run out and not <.002

I spent a lot of time, money and effort trying a make a tactical rifle shoot benchrest groups because I worried about runout.

Quality press + quality dies = forget runout.

You can't see it unless you are shooting BR.

 

[polter71]

Re: Old Can of Worms - Ammo runout

I use clinging metal washers.

 

[sandwarrior]

Re: Old Can of Worms - Ammo runout

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Captain Kick-Ass</div><div class="ubbcode-body">I was always happy with the tight groups I shot off bench in load development (<.5MOA). Then, one day I was introduced to run-out, how to measure it, acceptable tolerances, and how inadequate my loads were because they had .003 run out and not <.002

I spent a lot of time, money and effort trying a make a tactical rifle shoot benchrest groups because I worried about runout.

Quality press + quality dies = forget runout.

You can't see it unless you are shooting BR.

</div></div>

I'll agree, in LR BR it probably matters most

Also, quality dies and press make most of it go away. But it never hurts to check it with a new set of dies or dies that you haven't used in a while.

Bottom line: It matters if you are looking to split hairs. But if your loads are accurate with what you have and the way you are doing it, I wouldn't go hog wild on fixing run-out. In my case I think it corrected a small problem. If you have to check every case. And, that takes two extra hours a batch. Say you made (or cleared) $20 an hour. You'd pay for a good $40 die (Wilson) in one sitting.

 

[918v]

Re: Old Can of Worms - Ammo runout

I have found that even the best equipment will not guarrantee every round will have less than .003" of runout.

Runout can be caused by bad equipment, but it is mostly caused by bad brass. Every case is different. Some have more residual stress than others, and some cannot be cured by annealing.

Basically, out of a bag of 100, you should come out with 25 cases that will load under .003" TIR all the time. About half will load under .004" TIR and the rest will be .005" or more.

The reason benchrest shooters do not worry about runout is because their guns are so perfectly aligned and tight the brass does not have a chance to expand much. Less expansion = less stress = straighter neck = low runout.

Second, a round with say .005" TIR will not chamber in a benchrest rifle. The rounds have to be absolutely perfect to work. Therefore, if you are able to close the bolt, the round has low runout.

The other day I found it hard to close the bolt on my LTR factory chamber. I was using a 168gr A-Max loaded to 2.810" OAL. I noticed one side of the bullet shank (and the A-Max has alot of shank sticking out of the case mouth) was being severely scratched by the freebore. The round had .011" of runout. The case was bad. I annealed it, resized it, seated another bullet, but the runout remained. So that case ended up in the trashcan.

I have also found that a Redding Body Die coupled with a Lee Collet Neck Die produces straighter brass than a traditional FL die. Rotating the case 180 degrees half-way through seating will help to straighten out a bullet. A square case mouth chamfered with a VLD tool also helps to start the bullet straight.

Ultimately, however, the case itself will dictate how straight the round will be. So it basically comes down to those 25 special cases you sorted out of that expensive bag of brass.

 

[Victor N TN]

Re: Old Can of Worms - Ammo runout

In fired brass that has been fired 3 times or more the carbon burned inside the case necks can throw the bullet off by .006 to .008". And most people never check the case necks on the inside.

 

[kyreloader]

Re: Old Can of Worms - Ammo runout

Victor, I am currently using a brass brush to clean out my case necks prior to reloading to remove residual. In your opinion, is that sufficient or should I invest in some steel wool? It is really slick now because I just chuck the brass brush into the drill and turn a few turns to remove the black residual.

If you feel steel wool is better, what is your technique? Feel free to PM me if you do not want to divert the thread.

 

[Victor N TN]

Re: Old Can of Worms - Ammo runout

A bronze bore brush mounted on a RCBS screwdriver handle is what I use. I twist while pushing in and twist while pulling it out. Vary your technique a little and you'll get it down quickly. If you do that before each loading you'll cut out a lot of your run out problems. Especially if you have decent brass. I usually add some steel wool after the brush starts to wear. But it really isn't necessary if the brush is in good shape.

 

[Guest]

Re: Old Can of Worms - Ammo runout

For fired .308 win,.... 8mm brush on a cordless drill before an after walnut media. After resizing, then delubing with untreated corncob it's 7.62 brush on high after the VLD,... never a runout issue

 

[Victor N TN]

Re: Old Can of Worms - Ammo runout

Sounds like a good plan to me.

 

[427Cobra]

Re: Old Can of Worms - Ammo runout

I use 0000 steel wool to clean and polish the inside of case necks, while I think it helps reduce runout, I think it's more important to identify the cause so a correction can be sought, checking the runout at each step of the reloading operation will all but eliminate runout.

 

[Victor N TN]

Re: Old Can of Worms - Ammo runout

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 427Cobra</div><div class="ubbcode-body">I use 0000 steel wool to clean and polish the inside of case necks, while I think it helps reduce runout, I think it's more important to identify the cause so a correction can be sought, checking the runout at each step of the reloading operation will all but eliminate runout. </div></div>

I agree...

 

[JLM]

Re: Old Can of Worms - Ammo runout

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 427Cobra</div><div class="ubbcode-body">I use 0000 steel wool to clean and polish the inside of case necks, while I think it helps reduce runout, I think it's more important to identify the cause so a correction can be sought, checking the runout at each step of the reloading operation will all but eliminate runout. </div></div>

Ditto. Clean your necks.

 

[Shady_Jay]

Re: Old Can of Worms - Ammo runout

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 427Cobra</div><div class="ubbcode-body">I use 0000 steel wool to clean and polish the inside of case necks, while I think it helps reduce runout, I think it's more important to identify the cause so a correction can be sought, checking the runout at each step of the reloading operation will all but eliminate runout. </div></div>

you measure runout each step of reloading? How long does it take you to load, Brian? Because I haven't really seen the results.

 

[Winchester 69]

Re: Old Can of Worms - Ammo runout

Believe Brian is describing his analytic method for identifying sources of run-out.

+1