I did a partial length (P/L) resize on a batch of PPU .303 cases that have had quite a few reloads as the bolt was getting to the point of a slight resistance to fully locking.  Rolling the reloaded cases on the bench was rather shocking, the bullet tip wobbled around in a large arc.  I hadn’t noticed this before on my .303 reloads.  

I also loaded up some new PPU cases and had some Canadian DI’43 cases I had neck sized on my Lee Collet neck sizing die.

The results were pretty interesting. 

First, the P/L sized PPU reloaded cases.  Considerable variation, all above 0.005 inches, the one below had a whopping 0.011 inch runout.  No wonder these P/L reloads shoot like crap. 

Then, I checked new PPU cases, and they ran from 0.003 to 0.004.  Fairly respectable. 

Last, was necked sized DI ‘43 cases done on my Lee Collet die.  They ran .002 or less.  And I think most of that is variation in case neck thickness.  At last, the secret of the collet neck sizing die is revealed.  I get excellent accuracy with these neck sized only cases.  

So, my old RCBS FL sizer is going in the trash.  I bought a new Forester “Benchrest” FL sizer and I’ll report on how well it does to keep necks concentric with the case body. 

The reason I ask is because I have been purposely using a Lee Loader (whack-a-mole) for my .243W and seat the bullets out to 10 thousandths over what is considered standard and have almost zero run out.

My "BR" acquaintance however is consistently plagued with bullet runout issues because he his always seating his loads to just 5 thousandths of an inch from touching the rifling. He's shooting a .220 Swift chambered Weatherby and replaces the barrel every 500 rounds as well. 

The only time I have ever experienced a bullet runout issue with my 303 is when I attempted to seat the bullets 20 thousandths of an inch off of the rifling.  Accuracy was severely affected and pressure spikes were an added nightmare.

I reset everything back to military specs and the accuracy returned with no unusual pressure spikes with abnormal runout becoming nonexistent...

I think the only reason that the partial length resized cases can even be chambered is that the die reduced the case body diameter near the shoulder by a lot, and the bullet will somewhat self align in the bore.  But, I’ve always had best accuracy when neck sizing only with the Lee Collet die, and now I know why that is.  The collet die will not move the neck centerline position, it squeezes the neck onto a mandrel with no subsequent expansion of the neck as it is drawn out of the case.  

You mentioned that you are, "throwing away" your RCBS FL die? Is there something inherently wrong with it?

I ask because the RCBS .303B FL, Neck, and Seating Dies are all I have been using since I started reloading in the mid 1980's.

Originally, I used just the FL die for everything until my BR acquaintance insisted that I get a Neck sizer with a 7.62 expander ball in place of the original 303 expander. For general purpose work using projectiles without a cannelure, I have stayed with a C.O.L. of 3.075". With a cannelure, I seat the projectile to 3.115". This seats the projectiles just past the cannelure while still allowing for reliable feeding and safe chamber pressures. Case and Bullet runout have never been a primary issue in the nearly 4 decades I have been reloading for the venerable 303 British. Runout became an issue only when the bullet was seated out past safe and prudent tolerances. The truly ironic item here is that I have had absolutely zero issues reloading any caliber I have when using the Lee Loader Whack-A-Mole. Just like that Rotisserie commercial, you just, "Set it and forget it."

You mention the "centerline" of the case being "Off"? 

I can picture that happening after a round has been fired and (before reloading) inside a chamber with an amplitude of "generous" spacing but, even with neck sizing only, the case centerline should never be, "Off." 

I should mention here that,

I had a Hornady Seating Die for my 7.62 that was machined wrong from the factory. It would seat the bullet at an angle that provided the bullet runout you described at the start of this thread which is why I asked about you throwing away the RCBS die and it possibly having a factory defect...

I only use this die to bump the shoulder back, ala partial length resize.  About once every 12 to 15 reloads.  I think the only reason why accuracy is not terrible with it is it sizes the body of the case considerably, increasing the taper such that there is sufficient clearance at the shoulder of the case with the chamber and the bullet doesn’t get too far out of alignment with the bore.  

The new .303 Forester Benchrest die is giving me .002 runout. Much much better. 

I also checked my .223 reloads, and those new Wilson dies (full length bushing sizer and in-line seater) produce very concentric cartridges.  The Dillon dies I was using gave .015 inch runout at the bullet.  They just would not get the 80 gr SMK concentric to the case body.  The difference at the target was very noticeable.  Went from 9 ring to X ring at 600 yds just by changing out these dies. 

A cartridge case concentricity gage won’t fix the problem, but it’s sure a good way find out if case neck/bullet runout is the cause of accuracy issues.  It’s not necessary to check your loads with one, unless you’re having unexplained accuracy problems. Some shooters will use them to sort long range loads and set aside those for matches having runout less than .002 inches. 

Sapper, if you’re getting 1 to 2 MOA, that’s as good as it gets, particularly if you’re shooting with the original sights. 

Yes, after some research, I chose the RCBS gage,  it even checks for case web thinning. I’m very pleased with it. 

Its a decent gauge.

I added a couple of strips of Teflon tape (not plumbers Teflon, the stuff used to make feed chutes more slick.) to the V  blocks, It makes rotating cases much smoother & less "jaggy"

  20 < 0.001

  40 < 0.002

  60 < 0.003

  85 < 0.004

  95 < 0.005

100 < 0.009

I ran the cases that had neck runout > 0.005 into the sizing die again, and this reduced the runout.  2 cases I sized a third time which brought the runout down to < 0.003 inches.  

What I’ve not isolated yet is why the variability.  I suspect it has to do with expanding the necks as the case is withdrawn from the die.  Doing this slowly and not letting the case head slide in the she!! holder seemed to help reduce runout.  

I plan to sort a batch of loaded rounds by the amount of bullet runout and test fire to see if the ones with large runout results in fliers.  

So far, the only objective evidence I have that large runout values are detrimental to accuracy is my 600 yd results with the AR-15.  My previous loading dies were giving bullet runout values above 0.010 inches and with the new dies, this runout dropped to .002 -0.003 Max with much improved accuracy.  The new dies increased my score from typically in the low 90’s to 100 with a high X count (ten shot groups fired prone).

Do you use any kind of lube inside the case neck when resizing?

A while back I polished all my expander balls & started using a dri-lube applied inside the neck with a cleaning brush.

The polishing is a "one step & done" thing. I just chucked the shaft in a power drill & spun it till it was mirror-bright in Green ScotchBrite pads. I cut a 1" strip off the narrow side of the pad & squeeze the ball from both sides for the most concentric polishing I could think of.

It made quite a difference to me.

I use a spray on lube that I make from Isopropyl Alcohol and liquid lanolin.  I set up the cases in a loading block and spray them such that the insides of the neck get lube as well.  

If I can't get it under 3 thou (average for a batch) then I start looking for troubles.

That was actually how I discovered my New (to me) RL550 was out of alignment!

.223 Cases FL sized in my new Wilson bushing type die in this press have a max neck runout of .002.  Most are .001.  But, I found that bullet runout is typically more than that, sometimes as much as another .006 to .008 more when bullets are seated in this press with my Dillon seater.   I’m measuring bullet runout 1/8 inch forward of the case mouth. 

Bullets seated on my arbor press with the new Wilson In-Line seater die are typically .002 max.  In checking 100 loaded cartridges, I found 10 that had bullet run out of .003 to .005, and this is maximum.  Certainly much better than I get using the Lee press with my Dillon dies, but still some variability.  

Wilson does not make an In-Line Seater die in .303, so I will need to find another solution. That might mean measuring and sorting cartridges for a match.  I’ll need to do some test firing to see how much runout results in fliers.  I’ll also need to measure more loaded .303 rounds to confirm that bullet runout is acceptable when seated in cases neck sized with the Lee Collet die, so far, that seems to be the case. 

Some of my loaded .223 cartridges have a neck runout of 0.002 (mid point in the neck) and a bullet runout of 0.008 (0.125 in fwd of case mouth).  If this is due to differences in neck thickness, that is an awful lot of neck thickness variation for match grade brass (.223 Lapua).  Using the neck thickness measuring tool on the RCBS Casemaster, I'm only seeing about 0.001 difference in neck thickness for this brass; most is less than 0.001. 

I think the bullets are going into the case at an angle and perhaps deforming the necks at an angle; seems odd, but I don't know how else this can happen. 

  

 

This was a partial length resized PPU case.  I can’t explain how it got so crooked, it’s plainly visible.  The average of ten rounds from that box was a case neck runout of .0057 and a bullet runout of .0117.  I’ve identified these and it will be interesting to see where they land up on the target. Suffice it to say, I won’t be using these in a match.

You have a case neck thickness gauge on the Case-master. I'd pull those bad boys & check that just in case.

Otherwise I'd be looking at the seating die?

I resized the case in my new Forster Bench Rest Sizing die.  That dropped the neck concentricity down from 0.010 to 0.003 inches (which matches the neck thickness variation).  I reseated the bullet, and the bullet runout dropped from 0.020 to 0.007.  Still a fair amount of runout, but much lower than it was. 

 I resized a batch of 50 cases this morning using the new .303 Forster Bench Rest FL sizing die.  The resulting case neck concentricity is much better than my old (circa 1960) RCBS FL sizer.  

It sounds like you have a handle on it.

Daft thought, what happens if you take the old die, unlock the locking screw, run it down into the primer hole of a known good case then re-tighten the lock ring?

I learned to do this years back as it acts a tail-stock center , for lack of a better term, aligning the decapping stem & rod?

I also only tighten the die body lock ring with pressure from a ram on the bottom (mouth) of the die! I use a washer if I'm seating backed off at all.

I loaded up 30 rounds this afternoon using the cases that were PL resized this AM in the new Forster die.  Bullet runout was much improved, not as good as it is with cases sized in the Lee Collet die, but much better than the old RCBS FL die.  The average bullet runout was .005 inches which I think will prove to be perfectly fine.  

I might have to dig out my Dad’s old Pacific C press and see if it makes any difference.  

Got out to the range today to test the bullet runout saga.  I must say, I did not expect this result.  It seems that the No. 4 and the 174 gr Sierra MatchKing can tolerate a LOT of bullet runout with no detrimental effects. 

And finally, Group 3) cases partial length sized in the new Forster Bench Rest FL die: 40.0 gr Varget behind 174 SMK. I moved the front sight to the left and the rear sight up one click before I shot this group. It’s a bit more scattered than Group 2). 

Here is another target with Group 3) loads, same as above.  Note another flier at 10:00.  But, a nice five shot cluster in the X ring. 

Conclusion: 

I will no longer worry about bullet runout in the No. 4.  It seems that the nose profile of the 174 SMK and the very long throat mitigate issues with bullet runout.  Bullet runout most certainly made a big difference in my AR 600 yard line load with long pointy bullets (80 gr SMK) that are seated close to the lands.  But, on this shot out barrel on my No. 4 with a whopping 1/2 inch jump to the lands, bullet runout does not seem to be a factor in 200 yard Service Rifle shooting accuracy. 

Well researched!

In an era of going by "feelings" its refreshing.

It almost exactly duplicates my results from years back, when I go into an "accuracy craze".

I think I posted the saga on here?

That was when I stopped all the absolute custom loading & just started making good loads that shot well.

My "Standard" loads, beat my "Custom Loads" by a respectable margin

I still do the "Once & done" steps, like flash hole reaming & primer pocket uniforming, & to me, "Partial Full Length resizing" but don't do the extreme steps. This may well not apply to the smaller & IMO more finicky 5.56/.223 reloading though.

Partial F/L resizing used to be a standard thing to match hand loads to individual guns. IMO it was a skill that should not have been relegated to the "extreme accuracy nutters" segment of reloaders.

No doubt in my mind that bullet runout is a big deal with some bullet types and some barrels.  I struggled to get good 600 yard scores with my AR and I’ve finally resolved that issue, it was because of poor bullet runout.  But, it seems to be a negligible variable in the No. 4 with the 174 SMK.  Now, that could be because I’m shootings these loads in a barrel that has a lot of rounds thru it and the throat has been blasted away.  On a new barrel, it may be a different outcome. 

I need to accept reality that this old shot out BSA 5 groove has served me well and it’s time to replace it.  The days of 10 consecutive shots in the X ring are now gone.  Today, my ten shot groups fired prone were 2.4 MOA and larger.  Just a year ago, it was still shooting under 2 MOA with a high X ring count.  I have a new Criterion and a new Lothar Walther barrel to choose from, so time to get on with the job before the next major match. 

In a scoped high precision rifle shot off the bench or bipod, I’d expect bullet runout to be important, but not with our Lee Enfield service rifles shooting in position with iron sights. Im convinced…

Oh absolutely!

When I got into my accuracy kick with the 101% custom Rem 700 with the Shilen bull barrel & all the other tricks it definitely made a difference!

But I was trying to improve on 1/3 MOA! A whole different world.

The reloads I’m particularly interested in are loads I worked up for long range shooting, 800 and 1000 yards. These are long pointy bullets, and seated longer than the 2.80 inch magazine length so that they are within .020 to .030 inches from the lands of the rifling (175 and 168 TMK).  

Had some time to kill yesterday, so I measured the bullet runout on each of the 50 rounds I had loaded for three different long range test loads:

Load 1:  Lapua cases neck sized in Lee Collet Neck Sizer Die, 155 Palma MK seated to 2.81 OAL.  Average bullet runout 0.0033 inches.

Load 2:  Lapua cases partial length sized in Lee Full Length Die, 175 Tipped MK seated to 2.935 OAL. Average bullet runout 0.0072 inches

Load 3:  Lapua cases neck sized in Lee Collet Neck Sizer Die, 168 gr Tipped MK seated to 2.950 OAL. Average bullet runout 0.0033 inches.

Similar to the .303 British loads, the lowest runout values were obtained with the Lee Collet Neck Sizer die. Load 1 and 3 had the same average runout, with a minimum of 0.000 inches and maximum of 0.006 inches. Out of 100 rounds, only three had a run out of .006 inches. 

All three of these loads use Varget powder, with charge weights set according to the bullet weight.  They are .308 Win published mid range loads, the maximum I’m comfortable with shooting in my No. 4 and strictly for the purposes of long range target shooting.  

The Lee FL sizer again gave the largest bullet runout, with a minimum of .002 inches and maximum of 0.011 inches out of 50 rounds loaded; 10 rounds have a runout of 0.009 or larger. 

I’ve recorded the runout on each round and I’ll be able to determine if it is a variable in individual shot accuracy, and accuracy of the load in general.  

I plan to go test these loads in the next week or two, and will shoot them at 600, 800 and 1000 yards along with a few sighters at the shorter ranges (100 and 300 yds). 

I have a Wilson .308 Bushing Type Full Length sizing die and a .308 Wilson In-Line Seater Die but have not tried them yet. That will be the next test.  

I’m expecting the accuracy edge on the three above loads to go to the 168 TMKs with cases that were neck sized in the Lee Collet die.  But what comes in second place, I don’t know…

How much bullet full diameter is inside the case neck?

I had a similar problem years back with 150 Gr Speers.

To get good feeding, jump to lands & so on they had minimal neck engagement.

It became a game of balancing choices, seat to lands stand off Vs case neck engagement.

Then I just quit using the Speer bullets.

Rule of thumb is to have one calibre of bullet diameter in the neck.  But, at the lengths I’m seating these bullets too, I don’t think I achieved that. 

The secant ogive of the 168’s and 175 TMKs do make these bullets very long for their weight, IIRC, they still have a fair bit of bullet held by the neck. 

That was what I was wondering.

What happens if you seat just deep enough to get one caliber in the neck?

I ended up favoring that over OAL & the longer jump to the lands.

My initial tests with these loads gave very satisfactory results (168 and 175 TMKs) at 800 and 1000 yds, i posted this over on the 7.62 Enfield Forum. Once I determine if bullet runout is a factor in long range accuracy, I’ll probably play with seating depth a bit.  These loads however are fairly warm for a No. 4, and I’m mindful of not wanting to wear out this barrel doing this.  I think shooting 150 rounds a year is OK, besides, my shooting days with irons are coming to an end, perhaps a few years left. 

I began this project to see how these DCRA conversions shoot out to 1000 yards, and to see how my own abilities compare with those that came before us. 

I did notice that bullet runout is typically 2x the runout of the case neck.  But I think that can be explained by where the runout is measured: at the mid point of the neck along its length and on the bullet approx 1/8 inch forward of the neck.  If the axis of the neck is slightly off at an angle relative to  the case body axis, then the runout increases the further forward you measure on the cartridge.

My oldest daughter asked me why it takes me so long to reload 50 to 100 cases. My response was to purposely try to make a question mark after I shot the cartridge case at a distance of 100 yards. The extra time involved with case prep and weighing out each charge is definitely worth the time and effort. The  Jap made Weatherby has been taken to Bergers 1000 yard range and produces sub-moa groups consistently and I truly believe that it is due largely in part to the bullet selection, weighing out of each charge and what some would call unnecessary case prep work with me being the redundant component. After the fire formed cases are set to be reloaded, it is then that I use the Lee-Loader "Whack-A-Mole" from that point forward.  My daughters targets they shot at a distance of 200 yards for reference......

Average runout for the two different loads were the same, 0.0033 inches with a max of .006 inches.  The two loads were with the Sierra 155 Palma MK and the Sierra 168 Tipped MK.

Great data & reporting.

Yeah I quit worrying about tiny variations in run-out & jump to lands a while back now I prioritize bullet seating mostly as it seems to male the most difference.

  

I found that my DCRA Long Branch barrel chamber neck is slightly off center with the axis of case body. A new case measuring zero runout comes out after being fired at .001 inches.  All the fired cases measured .001.  So, neck sizing these in the Lee Collet Die also gave .001 neck runout. I think this is still very good, and nothing to worry about.

My conclusions so far shooting the No. 4 .303 and 7.62 is that bullet runout as much as .006 is completely undetectable in the 7.62 out to 1000 yds and as much as .010 in the .303 was not detectable at 200 yards on the target.  .010 however on my .223 at 600 yards was a definite problem for me and the Wilson dies solved that for me. 

Check the neck runout on some of your fired cases, if the neck of the chamber is concentric with the body area, the runout should be less than .001, since the fire formed cases should be the shape of the chamber (with a slight bit of spring back).

The easiest way to check this is measure the neck OD on fired cases as add .001.  Compare that to the neck OD of loaded rounds.  There must be some clearance when the round is chambered, at least a few thousands, to ensure the chamber does not restrict release of the bullet.  All my LE’s have about .007 to .010 neck clearance with a loaded round, which is a fair amount.