Bullet runout

[bozo699]

Are you inside my brain??? Because you wrote exactly what I do in my OCD reloading practices and what I stopped caring about with regard to concentricity a long time ago.
Dave

I shoot F-Open. When I reload for a match I am fanatical about headspace and bullet seating depth as they go hand in hand and are critical to accuracy. I trim cases to +/- 0.001 and carefully chamfer. I uniform primer pockets, weigh and sort my primers. I use a Sinclair priming tool and seat my primers within +/- .001. I sort my bullets by OAL trim and point them and then resort by OAL. I measure powder to 0.02 gn. or 1 kernel whichever comes first. Am I nuts ABSOLUTELY. But being really fanatical with this along with a lot of luck has eliminated flyers and allowed me to shoot a few 600 scores. The one thing I do not do is measure bullet runout. If your dies are working properly BULLET RUNOUT doesn’t matter. If you really want to eliminate any effects of bullet runout do as most of the benchrest shooters do and slightly jam your bullets.

pretty much spot on with my process, I’m also extremely picky with my necks , the carbon in them, the amount of times I brush them and so on.
I hate when someone reaches over and takes a piece of brass or cartridge outta my box!…. Keep your meat beating hooks off my brass!….
Wayne

 

[F Class John]

I'll say with the caveat of F-Open and in my experience, I'm with the crowd that says as long as you're doing everything else right, runout/concentricity has a near minimal effect. I used to say that I only measured when setting up new dies but I don't honestly even do that anymore. I did this test a while ago and while I agree with the people who say that the chamber does a lot of straightening, but there's still a lot of runout across this test. I know it's only one test and one point in time but I can tell you I know a fair number of Open shooters who treat runout as one of the lowest priorities when reloading.

 

[Dave M.]

I sold my Sinclair concetrisity gauge couple years ago once I figured out it didn't show up on paper.
Just the other day I bought a new to me concenrisity gauge because a buddy told me they work great for coloring tips with a sharpie for testing.
Ymmv

Brett, I saved mine on the shelf in hopes that some day it is worth big money like my Stretch Arm Strong guy, my original IPhone (1), or my old Gary Fisher steel frame mountain bike.
Dave

 

[Dave M.]

pretty much spot on with my process, I’m also extremely picky with my necks , the carbon in them, the amount of times I brush them and so on.
I hate when someone reaches over and takes a piece of brass or cartridge outta my box!…. Keep your meat beating hooks off my brass!….
Wayne

Sounds like me. Iosso blue nylon brush once in and then removed after annealing.

 

[Dave M.]

I'll say with the caveat of F-Open and in my experience, I'm with the crowd that says as long as you're doing everything else right, runout/concentricity has a near minimal effect. I used to say that I only measured when setting up new dies but I don't honestly even do that anymore. I did this test a while ago and while I agree with the people who say that the chamber does a lot of straightening, but there's still a lot of runout across this test. I know it's only one test and one point in time but I can tell you I know a fair number of Open shooters who treat runout as one of the lowest priorities when reloading.

John, I love the work you do and I froze the target picture of you runout test and although the group size improves in just about every aspect going from your 0.035” runout rounds to you 0.003” runout rounds, the number of shots in each group were not the same:
.030” rounds had 13 shots
.020” rounds had 9 shots
.003” rounds had only 6 shots.

In order to have done a more direct “apples to apples” comparison, I would have liked to have seen the same number of shots in each group. Obviously, the more shots you take in a group, it can only get larger (or at best stay the same size). I would love to see this test again with 10 or 15 shots per group. I will say that your findings seem to mimic my testing two years ago.
Dave

 

[Bc'z]

John, I love the work you do and I froze the target picture of you runout test and although the group size improves in just about every aspect going from your 0.035” runout rounds to you 0.003” runout rounds, the number of shots in each group were not the same:
.030” rounds had 13 shots
.020” rounds had 9 shots
.003” rounds had only 6 shots.

In order to have done a more direct “apples to apples” comparison, I would have liked to have seen the same number of shots in each group. Obviously, the more shots you take in a group, it can only get larger (or at best stay the same size). I would love to see this test again with 10 or 15 shots per group. I will say that your findings seem to mimic my testing two years ago.
Dave

Hey brother, excuse me a minute while I runout and get some more beer. Lol

What do you guys expect from me ...
All alone, late at nite, sitting in my shop watching primer dry...
Oh yeah run out....
I'mma runout and relieve the last beer..

 

[Dave M.]

Hey brother, excuse me a minute while I runout and get some more beer. Lol

What do you guys expect from me ...
All alone, late at nite, sitting in my shop watching primer dry...View attachment 1532648
Oh yeah run out....
I'mma runout and relieve the last beer..

Brett, you are just teasing us by sending us pictures that show some orange peel when we all know darn well those will be gone and the final product will look like mirror. I’m shocked how poor the finish on our new $60K+ trucks are. They all show tons of orange peel and require the full Megs 105/205/M21 treatment before they meet my standards. Love your work brother, keep it up.
Dave

 

[Bc'z]

Brett, you are just teasing us by sending us pictures that show some orange peel when we all know darn well those will be gone and the final product will look like mirror. I’m shocked how poor the finish on our new $60K+ trucks are. They all show tons of orange peel and require the full Megs 105/205/M21 treatment before they meet my standards. Love your work brother, keep it up.
Dave

Isn't that the prettiest laminate color combination?
I think it's rather striking, anyhow as for the orange peel your looking at my polyester primer.

 

[Dave M.]

Isn't that the prettiest laminate color combination?
I think it's rather striking, anyhow as for the orange peel your looking at my polyester primer.

Which I’m sure will be polished out before leaving the shop.
Dave

 

[Zero333]

 

[FrankG]

I'm going off of memory but I want to say the spec for NM ammo was like .005" for runout... again going off of memory.

Does runout or if you want... I'll throw crappy bullets in there matter? You bet it does. Any runout the loaded ammo has and if you will the only way I can describe it... when the bullet is making the jump from the case into the rifling... and the more runout you have the barrel has to try and straighten the bullet out per se and it doesn't always straighten out. So in essence a loaded round with more runout or crappy bullets with a lot of runout in them and it gets worse with a faster twist... your amplifying the runout which in turn has a negative effect on accuracy.

A good barrel and good gunsmithing can help poorer quality ammo to shoot better but it won't solve everything all the time.

If runout doesn't matter than when you get that flier on the target that you cannot call where it came from....? Was it this... was it the conditions... was it the guy pulling the trigger and not reading the wind good? Why put a variable into the equation.

What is your accuracy requirement?

What type of match shooting are you doing? I think this is a big one when I see a guy yelling at another hi power shooter for stepping on his neck turned brass but we are shooting offhand at 200 yards at a 1 moa target. You have to keep some of this in perspective.

No I don't have a magic number that is the limit or anything like for runout etc... but I will say typically the runout on my cases/loaded ammo is no more than .003". Up to .005" your probably o.k. but once you start hitting .006" or more... again that will cause the unexplained fliers and it gets worse the further down range your target is.

Runout is just one variable to think about....

 

[markm87]

As many have posted... my concentricity gauge has a thick coat of dust on it.

 

[cooperve]

It seems to me (the un-trained), runout of .005, .010 or more ( just an example) would magnify the accuracy of groups dependent of the bullet jump. I definitely improved my 40xb 22-250 varmint rifle’s groups with an extreme worn out throat from ~1-inch to ~5/8-inch groups by using .001/.002 runout loadings vs. .010’s or up.
If your loaded bullets are .001 to .005 from the lands to start the chamber/barrel would probably straighten a bullet rather quickly. More accurate.
I have also seen test results in Small Caliber News where rimfire ammunition definitely shoots better groups the less the runout. But, we're talking soft lead bullets which is a different animal.

 

[Zero333]

The video in post # 22 by @F Class John kind of says it all.

Using standard green box RCBS FL dies I get no worst than 0.007" runout once in a blue moon, and 99.9 % are within 0.004"

For whatever reason, the least runout I get is with 300 pieces of Winchester 308win brass that's been used in 3 barrels and has well over 30 reloads. Pretty much all the time all the brass is within 0.002" runout. I anneal it every several reloads.

 

[barefooter56]

So I finally got my Sinclair concentricity gauge. (Backordered for 4 months.) I went to measure some of my 6br reloads, and to my surprise I had maybe about 1 thou run out give or take. Measured a few more and they were about the same. Figured I'm doing something wrong. So I took some 6.5 Grendel American Gunner ammo, and it was getting like 6 to 7 thou run out.

They never shot great out of my gun. I know there could be a million reasons why, but could that kind of number degrade accuracy? What exactly is the end result if your concentricity is off by a good bit?

Per FRED SINCALIR. " ACCURACY IS NOT AFFECTED TILL THE RUNOUT IS OVER .005" Now, where are measuring on the bullet? The probe should be as close to the neck/bullet junction without touching the neck as you rotate the cartridge on the tool. Also.. do not measure this using NEW/UNFIRED BRASS! Use fired/ sized brass or fired unsized brass.

 

[quest450]

/\ /\ /\ interesting, I always measure around where ogive contacts the lands in my barrel
I get .0015" closer to neck and .003" at the ogive measuring the same round

 

[fkimble@charter.net]

Obviously, if it ain't perfect, then the further out you measure, the bigger you number will be!

Frank

 

[liseo]

As a newbie to precision shooting, I have a question.
If high runout does not interfere with accuracy, why do gunsmiths care so much about perfect alignment between the barrel and the chamber, to the point of using the indicator at the throat and a point forward, to guarantee perfect alignment between the first point of contact of the bullet and a section ahead?
Or are they different situations?

 

[drop_point]

As a newbie to precision shooting, I have a question.
If high runout does not interfere with accuracy, why do gunsmiths care so much about perfect alignment between the barrel and the chamber, to the point of using the indicator at the throat and a point forward, to guarantee perfect alignment between the first point of contact of the bullet and a section ahead?
Or are they different situations?

Apples and oranges comparison.

 

[rwj]

As a newbie to precision shooting, I have a question.
If high runout does not interfere with accuracy, why do gunsmiths care so much about perfect alignment between the barrel and the chamber, to the point of using the indicator at the throat and a point forward, to guarantee perfect alignment between the first point of contact of the bullet and a section ahead?
Or are they different situations?

I’m not a gunsmith… but the clearances for the case neck and bullet in the free bore can be quite small. If the chamber/barrel bore concentricity exceeds these, chambering a round could be difficult.