How much run out

[kokomokid]

When you guys check run out, how much do you allow? I marked a few rounds with .004 plus bullet run out when fire forming and they shot right with the rest of the group. I was loading out to bore rideing so maybe this corrected alignment? Most of my brass seperated by weight comes back to a good run out after fire forming.

[Kenny Wasserburger]

One way to tell is pull the round back out and check Run out again? But I suspect your right the bore riding bullet is correcting the run out to some extent. One of the great things about Paper Patching.

KW
The Lunger

[405]

You're right- bore riding or some contact into the leade can correct some runout. However, .004 runout doesn't mean a lot by itself. It all depends on HOW the runout is measured.

For instance when I measure runout it is an index or benchmark using my measuring technique against which other rounds in that particular cartridge are judged. For my bottlenecks: The cases are all supported near the base stop, a permanent setting on my gauge, then I support the case about 1/4" behind the shoulder and measure the runout about 1/8" behind the case mouth. If either of those two points are changed it will change the measured runout. Using those two indexing points my benchmark for most bottlenecks is less than .002" runout.

For most straight-walled cartridges I don't bother with measuring runout but, as a matter of course, load for minimal case resizing which will be about all that can be done for runout in addition to using a bore riding or leade seated bullet. Once in a while I'll check straight walls if I suspect something like irregular neck wall thickness.

[RMulhern]

If 7/8 of my bullet length is up inside the bore.....'runout' is the least of my worries!!

[oldracer]

This is one of the things I looked at since I started the black powder cartridge experience last month. One very knowledgeable shooter said he measured it but only if he crimped the cases which he did NOT do all the time. Another said it didn't matter no matter what you did since the trueness of the base of the bullet to powder charge (wad) was the important factor in how the bullet started off and if it was touching the lands were they all equal anyways?! There was also an article in one of the old issues of Black Powder Cartridge magazine that the writer said he did it all the time?!

So, as I have been finding out with this form of shooting, it may OR may not make a difference depending on many factors. Since both my guns seem to like the bullets finger seated on the wads with no crimp, the run out would tell me possibly if the ogive of the bullet was not concentric or that the case mouth of the fire formed case was somehow not concentric to the bore but so far I am not at that point of accuracy yet but it does give me another cool tool to have on my wish list!

[405]

oldracer,
Yes, the runout or concentricity gauges are interesting tools. If nothing else they can show or isolate a problem but they can't cure one. I've found I use them less when straight-walled loading than when bottleneck rimless loading. I've also found if I have runout at the neck/bullet with any cartridge it can usually be traced back to one of maybe 3 things: case re-sizing, neck expanding or neck thickness irregularities or uneven annealing at the neck. Sometimes bore riding type loads will correct some runout but if the bullet is canted/cocked or offset in the neck it may still have runout even when chambered with a bore riding bullet. In those instances almost a sure bet that it's NO GOOD for accuracy.

And, not everyone shoots every cartridge in every gun in each type of load with 7/8ths of the bullet length in the bore. About the only time I don't think too much about runout is when loading, shooting muzzleloaders. :)

[Kenny Wasserburger]

One thing I have done is check the run out of Sized cases, An issue with your press can be a root cause at times-ie Ram to die alignment.

Back when I shot GG's for the 2006 Nationals, Alliance 2005 and 2006 fall matches, I used a special Seating Die that BACO had made up by Reding, one of their inline Micrometer Bullet seaters made up for the 45-100 or 45-110. I still own the die, and If I decide to ever go back to GG Bullets it will be used.

Even with this die when seating bullets I took all the spring tension out of the die in the first stroke, then lowered the ram made a 45 deg turn of the shell in the shell holder ran the round back up into the die and seated about a 1/4 of the bullet depth, repeated lowering the ram and making the 45 deg turn, this was down till the final stroke seated the bullet to it's final depth.

The end result was a bullet to case run out of often .001 or less, seldom did I have over .002 of run out.

As 405 mentioned not many shoot Paper patch, nor did they need too, it in it's self is enough of a challenge for most and too much for many, when just getting BP loads to group well can be a tough road to hoe.

Even today I still anneal my PP Cases after each firing in the 45-110 for the simple reason to get consistant chamber seal. The Chronograph shows it is worth it to me, Last year at Raton a ES of 3 Fps was found.

Find a good inline seater and most of your Run out problems will go away, unless as I mentioned you have Press-Ram alignment problems.


These days I like Paper Patching for my long range stuff, Anneal-FL Size prime and load no belling or removing the bell after seating the bullet.

The Only real hard part with PP is a consistant Bore Condition, once you have that down, very good accuracy can be had.
KW

The Lunger

[oldracer]

Kenny mentioned "sized" cases and so far I have found both my Sharps and Rolling Block seem to like the fire formed cases with no sizing or other dies used once they get clean. I am super lucky I guess as the chamber on BOTH rifles measured out exactly the same when I did a chamber cast which really surprised me! The Sharps is Italian and the Rolling block is hand made with a hand cut badger barrel/chamber by a gunsmith here in the Chula Vista CA area and his cutting was pretty darn exact.

I am planning on getting a run out gauge to see what the case looks like after coming out of the chamber as far as roundness is if nothing else for references later on. So far both the Lee 500gn flat nose and 500gn pointed slide into a fire formed case with just a hint of resistance and the guns seem to really like them that way.

[kokomokid]

wish I could load fireformed without doing anything to the necks but I just do not have uniform neck tension until I rework them. Maybe if I annealed them that would help? I have expander plugs in .001 increments and use them to get a uniform tension across my 40/65 loads.