Run out

[drop_point]

It all depends on your rifle's chamber dimensions. I think a match rifle it matters less than a hunting rifle due to chamber dimensions, seating depth, bullet designs.

 

[L.Sherm]

And F-class John did as well I believe up to .015 and saw no change.

It might have been F- Class John I was thinking of.

 

[L.Sherm]

It all depends on your rifle's chamber dimensions. I think a match rifle it matters less than a hunting rifle due to chamber dimensions, seating depth, bullet designs.

Are you saying custom chambered hunting rifles chambered differently than " match" ones?

 

[RustyInBend]

Here's my point in all this ... if you have one small variance from perfection, you probably won't notice a deleterious impact. If you have two, you might notice. If you have three, you'll likely notice. Etc. etc. etc. Sadly, the effect tends to be (a) negative, and (b) cumulative.

Doing all you can in every step of precision reloading to minimize the "offsets from perfection" is what makes the hobby so fun, and gives me great results.

Another way to look at it ... if I don't care about decreasing my run-out, what are the other 7 things I probably don't care about as well, and will those combined variations eventually present themselves on my 1-mile target (or "off" of it)?

 

[drop_point]

Are you saying custom chambered hunting rifles chambered differently than " match" ones?

I didn't mention custom hunting rifles specifically. Oftentimes they are different and we are shooting different bullets. Not always the case and the majority of hunting rifles are not "custom".

 

[markm87]

I've seen as much as .007 shoot .250 moa at 700 yards. So take what you want from it. My personal opinion its why I dont like resistance chambering a round, just my theory.

I agree. (I've posted this before, but..) I took the best and worst runout rounds out of a box of Black Hills 308 ammo with SMKs.

I shot them against each other expecting a revelation in accuracy/runout correlation. But at 100m, the groups were the same size. (tangent bullet ogive)

 

[drop_point]

I agree. (I've posted this before, but..) I took the best and worst runout rounds out of a box of Black Hills 308 ammo with SMKs.

I shot them against each other expecting a revelation in accuracy/runout correlation. But at 100m, the groups were the same size. (tangent bullet ogive)

I did this in a Rem 700 PSS with Federal Gold Medal Match 175 gr SMKs. I measured 40 rounds and put the best 20 and the worst 20 in separate lots. I shot a group with each lot. The difference was statistically insignificant. The best lot ranged from 0.001" to 0.005", the bad lot was 0.006" to 0.012" of runout.

 

[L.Sherm]

I didn't mention custom hunting rifles specifically. Oftentimes they are different and we are shooting different bullets. Not always the case and the majority of hunting rifles are not "custom".

My point of this there is a big difference in alot of factory " box" rifles vrs even just a hunting rifle that has a custom barrel, not in all cases but in alot.

 

[drop_point]

My point of this there is a big difference in alot of factory " box" rifles vrs even just a hunting rifle that has a custom barrel, not in all cases but in alot.

Many of the "customs" even have a generic chamber. You're talking about a fraction of a fraction of what is out there.

 

[L.Sherm]

Many of the "customs" even have a generic chamber. You're talking about a fraction of a fraction of what is out there.

What is Generic? Mass produced?
Theres a big difference in a smith who takes the time to dial in a barrel correctly than a mass produced one with with even a saami reamer. In my book Generic is not even semi- custom.

 

[drop_point]

Regardless of your opinion, a SAAMI chamber is much different than a chamber spec'ed for a target rifle, BR rifle, or F-Class rifle. Some of the newer chamberings are getting better in SAAMI configuration, but my .308 hunting rifles are much more finicky to banana rounds than is my F-TR rifle.

 

[Mulligan]

From my experience and testing.
No I did not run a half million tests in 47 barrels in 16 countries fired only by Swiss virgins!
Now that, that is out of the way.
If neck tension is a causal factor for accuracy in the discipline you shoot, then run-out of a loaded round is part of the puzzle. If neck tension is not "that big" of a consideration, then no worries for you.

If your loaded rounds are out just a tiny bit, then you are likely good. If they are out far enough to get straightened in your chamber, you could be changing the neck tension a tad when straightening the round?

Several years ago I asked the same question on this forum and received a multitude of answers. I actually was expecting the "guru's" to give me a unified and single answer. As an example, "X amount is problematic, less than that, no worries". That is not the answer I received and I set out to do some testing.
After ordering several sets of dies and using 3 different presses, and spending a plethora of time adjusting this and that......... I went to the range to test.

1.) Jumping bullets...... I just could not see a difference if less than .005" runout, however I did not test jumping very much.

2.) Jamming bullets, less that .003" you will very LIKELY have no worries. Less that .002" and you're golden. I tested this with actual die induced runout (the best a die and press could produce) and with intentional runout (me corrupting the system to make matters worse), and with rounds I buggered up making things worse. The worst case always shot like I was slightly out of tune. A .010" runout round nearly always landed out of the group.

NOTE:
This testing was done with a 6 Dasher at 600 yards.
It may have no value outside of that rifle and distance?

I have friends that check every round prior to a match and the straightest rounds are the record rounds. The banana shaped rounds are used for sighters and such. I built a system based on my testing and stick to it, but I check all the time. Unlike many folks on this forum, my concentricity gauge gets used plenty.


CW

 

[Alex Wheeler]

This is a really old topic thats been well hashed out. Nice thing about it is it one of the easiest tests you can do. Take your straightest and crookedest and shoot them. No need to ask the internet. We are not always right

 

[Mulligan]

This is a really old topic thats been well hashed out. Nice thing about it is it one of the easiest tests you can do. Take your straightest and crookedest and shoot them. No need to ask the internet. We are not always right

That is actually the perfect answer.
CW

 

[hoz53]

@hoz53 Merry Christmas Kim’
I can only speak for myself shooting several thousand Berger’s 108’s with jumps out to .030 will good accuracy and borderline excellent accuracy but my thinking is that even though the ogive is not touching the lands, the bearing surface is still in the throat.
I suppose a fella could record TIR before and after chambering a round just for knowledge.

hi jim — ive shot a few B 105s but no 108s- mabie im missing something there. anyway thanks for the exxplanation of the throat / bearing surface. even though my reamer is an off the shelf the chamber neck fits close enough to case neck if i get even a small ding in case mouth bolt wont close. so yes everything is lined up pretty close. we know the case body of chamber is very closely aligned with the neck of chamber and the neck of the chamber is closely aligned with the bore at the throat and aa little ways ahead of that. not much misalignment possable. I know ithas been said and proven cases with longer necks are more inherently accurate-
witness the 222 and 6br for a couple examples. mabie the bullet being a certain spot in the neck aligns it best with the neck and therefore the bore???? kim h

PS is that a Bar on ur porch?

 

[hoz53]

I agree. (I've posted this before, but..) I took the best and worst runout rounds out of a box of Black Hills 308 ammo with SMKs.

I shot them against each other expecting a revelation in accuracy/runout correlation. But at 100m, the groups were the same size. (tangent bullet ogive)

i think this is like ES at 100 yards. its to close to tell anything (ha ha) anyway it would be interesting to shoot those at 600 and see if there is a difference.

 

[hoz53]

That is actually the perfect answer.
CW

thats right—- har

 

[JFrank]

hi jim — ive shot a few B 105s but no 108s- mabie im missing something there. anyway thanks for the exxplanation of the throat / bearing surface. even though my reamer is an off the shelf the chamber neck fits close enough to case neck if i get even a small ding in case mouth bolt wont close. so yes everything is lined up pretty close. we know the case body of chamber is very closely aligned with the neck of chamber and the neck of the chamber is closely aligned with the bore at the throat and aa little ways ahead of that. not much misalignment possable. I know ithas been said and proven cases with longer necks are more inherently accurate-
witness the 222 and 6br for a couple examples. mabie the bullet being a certain spot in the neck aligns it best with the neck and therefore the bore???? kim h

PS is that a Bar on ur porch?

Kim, I have been wrong plenty of times and that’s why I don’t give advice. Lol
Btw that’s a Grizzly track about 150 yards from the cabin.
Mrs. SPJ comparing her foot to the Bear’s..

 

[hoz53]

Asking for some history here. Did the concentricity phase come before we saw so many super accurately/concentrically machined chambers?
I ask, wondering if more concentric rounds show an improvement over less concentric rounds in a looser chamber we see these days?
If that is the case, and chambering improved after, I could see the "old" work that showed improvement carrying on as an assumption until tested.

Or it's all just made up junk to sell gadgets from day one?

there is alot of “follow the money” in all of it thats for sure

 

[hoz53]

Kim, I have been wrong plenty of times and that’s why I don’t give advice. Lol
Btw that’s a Grizzly track about 150 yards from the cabin.
Mrs. SPJ comparing her foot to the Bear’s..

always good to get your thoughts— i never give advice i just state what i think- i never consider myself knowlegeable enough to give advice, im just trying to learn—- That is way cool youre living out there that close to Grizz