How much Runout is acceptable ?

[1000yardstare]

Have changed my mind 17 times about the importance of runout in target loads. Last Fall decided to do some testing. Used a Ruger .204 Hawkeye, stainless/synthetic. Not a benchrest rifle but very accurate for a sporter weight and a pleasure to shoot. Also cheap to reload.

Load was 28.5 gr H335, 32 gr Sierra BK, Win brass and primers. Chronod at 3950 fps. Sorted cartridges by runout.

Got the following results at 100 metres (110 yds). Each group size average of three 5 shot groups:

runout .001 group 7/16
.003 9/16
.005 9/16
.010 1/2

My interpretation is that for all intents and purposes with this particular rifle runout has no bearing on group size. Mind you this is with a 60 shot sample. If testing is done with 600 shots then a trend might be seen but who wants to go to that extent? A trade-off has to exist between meaningful results and shortened barrel life.

As a result I do not sort my 1000 yard F Class loads in 6AI by runout. Now and then I will run a check with a runout gauge. The 107 SMKs run pretty well between .001 and .003 and I have had good success at the long ranges in F Class without worrying about runout.

As a many times winner of the Ontario F Class Championship told me "Worry about reading the wind properly. All those gauges are just messing with your head." Anyway that is his opinion.

 

[short range]

Hi Johara1, the necks haven't been turned, so it's very possable that the wall thickness is uneven, I don't have a micrometer to check them, or a neck turning tool. I'm not working right now,the company that I worked for was in bussiness since 1954, and they closed the doors, so there has to be an end to some of the spending at some point. I might be able to borrow them from a friend.

 

[short range]

I have never used flags, all this advanced shooting a custom target rifle is new to me. I've only shot hunting rifles before I got this rifle about 6 or 7 week ago. I will start using them, but I'm sure it takes a while to learn how to read them very accurately. I only know two other guys that shoots custom rifles, and they are both about 1 1/2 hours away, so now I don't see them anymore because of the cost to drive there to shoot.

 

[alf]

the necks haven't been turned, so it's very possible that the wall thickness is uneven

The chamber has a .330" neck, which makes it a tight neck, which means you have to turn necks.

The brass has been turned to .0100" exactly.

 

[short range]

thanks alf, I didn't know that you had turned them, I didn't remember you mentioning that, I just probably forgot, I was going to check with you later today, so I'm glad that you read my post. I'm really enjoying shooting this rifle, It's great to have a rifle that's so accurate. One of these days I hope to get my groups tighter, but I'm getting there a little at a time, i think that's part of the fun, challenging myself to get better. I hope every thing is going well for you.

 

[short range]

Boyd, It helped seating the bullets 1/2 way and rotating the case 180 degrees, for the most part, it cut the bullet runout in half. I loaded 21 rounds today, and only 5 have a .002 bullet runout, all the rest are less than .002 and most of them are .001 bullet runout. Thanks for that hint.

 

[camac]

I actually agree with nearly everyone's comments here and do believe a lot of rifles show no significant impact on accuracy due to runout (doesn't mean there isn't a slight one but in the general magnitude of variation in wind, rifle and shooter accuracy it cannot be measured). At long distance (or any distance really) it is generally far more important to learn to shoot well, read wind and mirage and spend time on the trigger. I load much more meticulously than most people I compete with and they still give me a flogging. This might be a case of "can't shoot well so I may as well try and load well." Or alternatavely some would say I spend too much time loading and not enough time shooting - but in reality I have shot nearly every day of my life since the mid 70's - it is more than trigger time you need skill too. Like any top level athlete it is a combination of genetics and training that gets them there.

Some of my rifles have shown no "significant difference" so far in testing (namely 6.5 x 284, my 8 twist 6BR and one of my .308's) but I haven't done a lot of testing with these so far as they are my match rifles and I don't want to mess with barrel time -I may do more with .308 next. I always sort by runout for matches regardless (also sort shells and projectiles before loading).

However, the most significant rifle affected by runout is my 6mmBR 12 twist (not the same reamer as my other as is a "drop in barrel") it can be surprisingly accurate but does seem to suffer from runout issues. Not every time I have tested did it show up but I have recorded all the results (I keep big logs full of the stuff) and plugged them into a stats package and it is significant. A few others seem to show slight improvement but also not enough testing to show up as "significant" yet in a statistical package. I plan on rechambering with my reamer to see if it makes a difference.

When I test I also sort down to those that are very straight - that I can hardly see a flicker on the dial for my control group. I think even bullets with 1-2 thou runout will be "jammed" in these tight throated chambers we generally use (Most rifles have < 0.001 throat clearance anyway depending on projectile and can be much less than this). I also think a lot of modern projectiles are very well designed and tend to self straighten in barrel. I just measured a different brand of 80 gr flat based that I want to try in my 12 twist 6mm and it has a significant raised "ring" around base that measures .2435. Just forward of this measures .2428. I believe this will help straighten projectile in the barrel but may be wrong.

Ideally to test this sort of stuff you will cut out all variables and shoot in a tunnel/indoors and ensure everything else in your loading is identical (powder charge, shells sorted by weight, projectiles sorted by weight, bearing surface length and meplat, flashholes uniformed, annealed, neck turned etc etc.). You also should cut out the shooter error by using a shooting vise. But in the real world you can just try and do as much as possible but understand the effect of increasing variation (due to these factors and others.)

Short range you are on the right track. Just starting to measure this sort of thing will set you down a path that is very interesting and I have a feeling you will enjoy it. These guys tips are right. Try and do your testing in very low wind conditions and get some flags, start to learn to shoot with them. 5 shot groups are better than three but 10 are better again.
Also try and shoot them "round robbin" style. That is one shot from each group at each target then move onto next and come back again. This eliminates a few variables too such as barrel heating/fouling, increasing/ decreasing wind trends, increasing decreasing mirage etc.
Remember the most important rule - ENJOY it.
Cam

 

[short range]

Thanks cam for all of your input. The first test I did was with a very slight wind, so I don't think wind played any adverse part in the results. Your right it would be great if we could do our test inside with no wind and a gun vise, but for most of us that's not a possiblity, so we have to do our best to control all the factors that we can. I said this before, it's great to get all this input from all the great shooters on this forum, you all have been very helpful to me. I feel dumb asking some of the questions that I ask sometimes, but everyone is gracious about answering them. I am enjoying this new journey I've started on.for the test that I started today, I wonder if anyone wants to know the the measuements that I took threw the three stages of reloading like I did with the first test, or I they want just the bullet runout measurements and the results of the 5 or 10 shot groups that I shoot, or maybe nobody wants me to post them ? Let me know. I will try the Round Robin method, and see what happens. I'll also try the test on a day with no or very little wind. I'll try chambering a round at the range and rechecking the runout. After loading this time, I only have 3 rounds with runout greater than .002 and only 2 rounds with .003 runout, no rounds with any greater runout than that.

 

[alf]

Steve, if nothing else, get three arrow shafts or wooden dowells, tie surveyers tape on them, and space them out at intervals of 20-40-60 yards. Crude, but effective, and beats none.

 

[camac]

Keep posting... it is good and gives us all something to think about. I personally find other peoples comments and results very interesting and am still learning too. On this site we are all amongst great (and revered) company.
alfs tip for simple flags is a good one. Are you shooting on your own land (sounds like it)? - . If you have the room you can sometimes postion yourself to shoot straight into or downwind too. Upwind or downwind variations in speed will have a lot less effect on your projectile.

 

[short range]

alf, I will get some dowels today, I already have the tape.
cam, I'm shooting at a local Wild Life Conservation Club that has a range, I can only shoot out to 100 yards. Do you want me to post just the bullet runout and the group sizes, or do you want me to post the three reloading stages like my first test, and the group sizes ? It's raining here today for the third day in a row, probably no shooting today.

 

[short range]

for anyone that is interested, here is the measurments from the 3 stages of reloading for my second test. I know that I said that I loaded 21 rounds yesterday, but I only reloaded 20, numbers: 6,11,14,18 and 20 are left over from my first test rounds. For the rounds that I loaded yesterday, I seated the bullet 1/2 way, and turned the round 180 degrees, and finished seating the bullet, that reduced the bullet runout by almost 1/2 on most rounds compared to the measurements from the first test. I used the Sinclair concentricity gauge again, some of the measurements I took out 5 decimals again just for my use , so I know if the measurement was 1/4 way between .001 and .002, I put .00125 I put an "*" by the numbers of the rounds that were left over from my first test.


fired brass after neck sizing bullet runout
1. .00075 .001 .002
2. .00075 .001 .00125
3. .00075 .001 .00125
4. .001 .001 .001
5. .001 .001 .00175
*6. .001 .00125 .00125
7. .0005 .001 .001
8. .0005 .00125 .00125
9. .00075 .001 .0025
10. .001 .00125 .0015
*11. .001 .00125 .00225
12. .0005 .00075 .001
13. .00175 .00175 .0015
*14. .001 .00125 .0025
15. .001 .001 .0015
16. .001 .001 .00175
17. .001 .001 .002
*18. .00075 .00075 .00275
19. .00125 .00125 .002
*20. .0015 .001 .003
21. .001 .001 .002
22. .001 .001 .001
23. .001 .00125 .00125
24. .001 .002 .001
25. .001 .001 .001

I wonder if next time that I neck size these brass, if it will reduce neck runout if I size the neck, and then turn the case 180 degress and size the neck again, if it will reduce some of the neck runout at that stage of reloading ? After I shoot these rounds, I will post the results. I got wooden dowels to make flags today.

 

[LHSmith]

quote:"I bought a used 30BR, and 100 Lapua brass. 72 of the brass were loaded, and the rest were fireformed, resized and primed, none of the necks are turned. The rifle has a .330 bore, Al ( the guy I bought the rifle from) told me to buy a .325 bushing."


Actually, you most likely have a .330 NECK ( not .330 bore) which requires brass be neck-turned .
You are setting yourself up for information overload by your approach centering solely on concentricity.
You state this is your first BR rifle......you make no mention of the scope, rest set-up, bullets or powder your using, jam or jump.
Simple flags are a good start, but you will find there is more than just the wind component to adjust for.
Until you get some kind of handle on reading conditions, you will simply be wasting components without anything of value being learned. I do know that your 30 BR may well be capable of agging 1/4" all day long....it takes a lot of work (lots of bench time) on your part to know how to keep it in tune .
Don't insist on taking the decimal place to 4 places......that's ten-thousandths. , your calipers can't measure that small accurately and there is no reason to do so.

 

[camac]

LHSMITH - you are quite right - BUT........
I agree, some of the other things you mention are more important to initially improving accuracy (along with many others). I get the feeling though that ALF has set this rifle up well and he or shortrange have worked up the loads well too (group sizes are quite impressive for a self confessed "beginner" and no doubt these will improve as he gets more experience). Short range is obviously soaking up information quickly and well so I doubt he will get overload. Run out of time maybe? I also suspect he is not so much a beginner as he states - maybe BR but not shooting.
I believe what he is doing is a very, very good way of learning to shoot properly when he doesn't have access to training facilities. Not necessarily runout testing but just going through step by step testing all the possible influences on accuracy and learning to test properly cutting out the other variables as much as possible. It is far better for a beginner to be thinking of this sort of stuff properly rather than just going out and banging some down without training or guidance. The big difference between BR shooting and what he has probably been doing is "attention to detail". You start to concentrate so much more on consistency and variables. In the background of all this shortrange is learning about wind and other variables in his shooting as well as reloading. Tips are coming in from everyone on a lot of other issues. No doubt he is also learning to shoot more consistently. I would suggest one or two more trips to the range and he will have decided whether runout has an effect on his rifle or not and maybe can leave it alone. In the meantime he has learnt a lot of other stuff. Not only do I see no harm but I only see good coming from it. Unlike many others he will have tested it well instead of palming it off quickly.
I contest - he is not wasting components (and certainly not wasting barrel life with a 30BR) but is learning a lot on the way. He is getting shooting time and now starting to read the wind and control other variables too. Who knows, runout may actually have a big (or small) influence on his accuracy????
Back to his question - How much runout is acceptable - you are obviously saying it doesn't matter, and many agree with you - I recommend it is up for him (and his rifle/bullet combination) to decide.

 

[Benjerman08]

Never heard of anyone turning the brass 180 to size twice for the sake of runout, but maybe it would help for some depending on what dies. Shortgrange: even if your runout doesn't get better, it is quite good already. I will take .001 and .0015 anyday for long range competition. I have shot some good groups with 2 and 3 thou runout, but being superstitious, I like .001 or less. Time to go shoot them and learn the wind/mirage.

 

[LHSmith]

Suggestion: Sell that concentricity gauge and Redding "one size fits all" neck die and buy the properly sized FL die from Harrells, and a Wilson in-line seater. Sooner or later you'll encounter chambering problems by neck-sizing only...unless your running severely enemic loads....it will make life so much easier. If you must tinker between shooting sessions, there's always PRODUCTIVE work to be done like annealing cases, weighing cases, sorting bullets,making bullets, coating bullets, turning necks, perfecting powder throwing technique, analyzing previous targets, practice bench technique.

 

[LHSmith]

[quote

I contest - he is not wasting components (and certainly not wasting barrel life with a 30BR) but is learning a lot on the way. He is getting shooting time and now starting to read the wind and control other variables too. Who knows, runout may actually have a big (or small) influence on his accuracy????
Back to his question - How much runout is acceptable - you are obviously saying it doesn't matter, and many agree with you - I recommend it is up for him (and his rifle/bullet combination) to decide.
[/quote


I'm not saying R/O doesn't matter, but the values he measuring seem to be acceptable to those who responded. Albeit, he's accepting his values on a $14 R/o gauge as gospel.
We don't know if this is his first bench session with the rifle...if so, I would focus on a baseline of how the rifle and I perform with the ammo as supplied, then I would experiment with how the rifle wants to be held. Then I would load up my own using ALF's data. Then I would tweak this load one slight change at a time. I would not attempt to fix a perceived problem. Maintaining BR accuracy has more than enough variables.
IMHO -Any shooting done sans flags, renders useless target info.

 

[camac]

I actually agree with you on the most. (except I personally will make my own dies and worry about runout over and above making my own bullets as I can buy record breaking projectiles fairly cheaply but I am impressed you do it). I am sure shortrange will get to looking at most of it anyway especially if everyone keeps giving him good tips. He sounds like he is soaking it up like a sponge and yes now he has the gauge his measurements don't seem that bad but he would never have known beforehand and therefore not been confident. He has also already developed a few tricks for reducing the runout purely because he has the gauge. Whilst doing this he will be getting a baseline for ammo or load supplied anyway and learning more and more how the rifle likes being held, how to keep a consistent routine going etc etc.

Shortrange keep it up.

 

[LHSmith]

I did a search- you apparently have a Panda, 36x Leupold, and using 10x bullets.

Just learning..... get some Speer 125 TNT's, accuracy in my 30BR is right on the heels of custom bullets. Find out your specific reamer details and post here so you can get options on what bullets will most likely work.
The 36x will undoubtedly show mirage ..best to shoot when it is minimal until you have some grasp on the wind. Download the "windchart".... do a search.
Orange target dots are NFG....use black/white....preferably a BR target, nest the mothball (10 ring) in one of the corners of the crosshair.
What bag/ rest set-up do you have?
It would serve you well to attend (and shoot) a Benchrest match. I'm sure people on this site could direct you to something close.

 

[camac]

10X bullets have a very good reputation - I wouldn't change them in a hurry if they are shooting well and your groups indicate good accuracy is achievable. With practice group sizes will undoubtedly come down.


But heh, This is a thread on RUNOUT - I keep forgetting.