Just got my new 21st century concentricity gauge from another member here and have been having quite a bit of fun with it. Measuring everything in sight. New case necks and case bodies, sized case necks and bodies, loaded cartridges measured between the end of case neck and tip of bullet, etc. Have found that most of my 6XC loads are within +/- .001" of runout but once in a while I'll find a few outside that spec. Thought I would try and straighten them out by reseating the bullet further in by .002" to see if that lessened the runout. Lo and behold when I remeasured the runout had been brought under the +/- .001" spec. Anybody else use this method to improve concentricity ?
Measuring concentricity
- Thread starter zipollini
- Start date
BoydAllen
Gold $$ Contributor
Good advice. If you want to try something, seat each bullet half way, then while the round is still in the press, lower the ram enough so that you can turn the case 180 degrees and finish seating. You can also stroke the case up into the die before putting the bullet on top, to better center it in the shell holder. Just be aware that at the level that your original runout was, none of this is likely to show up on your targets.
The only thing I check for concentricity is neck wall thickness after turning cases. Thats pretty important to me for even neck tension.
I believe concentricity is over rated. Now this was with neck turned cases with the bullet centered. I tested rounds with runout verses rounds with little or no runout at 1000 yards with a really good 300 WSM Heavy gun. I saw little difference in group sizes. I believe neck tension and seating depth play a bigger role. Matt
"I tested rounds with runout verses rounds with little or no runout"
What exactly {in thousandths} are you calling "runout"???? If you don't mind my asking....
I have fought the subject of bullet concentricity since I obtained a device to measure it. I do believe that a very accurate rifle with a good barrel and quality ammo {save the concentricity issue} can probably make it seem like the ammo has no problems.
I also agree that neck tension is probably more important as well, maybe seating depth too, but I think it is important when discussing this subject of concentricity to clarify just what or how much runout is acceptable. I was told by the folks at Redding and RCBS that it was hard to tell ammo with .003" or less runout from ammo with dead on zero. Is that what we are all talking about????? I should point out that I have found this to be true. I cannot tell, maybe some benchrester can...but not me.
I have found that getting a bullet seated to those specs is a matter of having good brass with a concentric neck to begin with {how many guys check the empty case necks for runout???} and either a L.E. Wilson straight line seater or a Forster benchrest seater die. In fact I have pretty much never been able to seat a bullet to within .003" with the standard seater die as included in a regular die set...I really don't know why they bother to make the things. Generally, I can average about .005" or more, the best I can do. Of course once in a while, less than 10% will be .003" or less.
I also have checked the case body as well because just like the neck, if it is out by say .003"-.005" then that will be the best you can seat a bullet to unless it goes in your favor by accident.
For some strange reason I have also noticed that the 243 Winchester and the 270 Winchester seem to be easier than others to get the case neck out of whack. Haven't nailed down why yet, but I am working on it. I will also say that Winchester brand cases seem to be worse for it as well. I have seen quite a few with as much as .012" runout at the neck. Anyone else out there see this too????? I can take these cases and run them through the resize die and sometimes they will come out perfect zero or very, very close...but then some come out with no change. They never end up worse.
I have to say with numbers like these, when it comes to which I'd rather have...I think I would rather have way closer to zero runout at the neck/bullet than a certain seating depth.
What exactly {in thousandths} are you calling "runout"???? If you don't mind my asking....
I have fought the subject of bullet concentricity since I obtained a device to measure it. I do believe that a very accurate rifle with a good barrel and quality ammo {save the concentricity issue} can probably make it seem like the ammo has no problems.
I also agree that neck tension is probably more important as well, maybe seating depth too, but I think it is important when discussing this subject of concentricity to clarify just what or how much runout is acceptable. I was told by the folks at Redding and RCBS that it was hard to tell ammo with .003" or less runout from ammo with dead on zero. Is that what we are all talking about????? I should point out that I have found this to be true. I cannot tell, maybe some benchrester can...but not me.
I have found that getting a bullet seated to those specs is a matter of having good brass with a concentric neck to begin with {how many guys check the empty case necks for runout???} and either a L.E. Wilson straight line seater or a Forster benchrest seater die. In fact I have pretty much never been able to seat a bullet to within .003" with the standard seater die as included in a regular die set...I really don't know why they bother to make the things. Generally, I can average about .005" or more, the best I can do. Of course once in a while, less than 10% will be .003" or less.
I also have checked the case body as well because just like the neck, if it is out by say .003"-.005" then that will be the best you can seat a bullet to unless it goes in your favor by accident.
For some strange reason I have also noticed that the 243 Winchester and the 270 Winchester seem to be easier than others to get the case neck out of whack. Haven't nailed down why yet, but I am working on it. I will also say that Winchester brand cases seem to be worse for it as well. I have seen quite a few with as much as .012" runout at the neck. Anyone else out there see this too????? I can take these cases and run them through the resize die and sometimes they will come out perfect zero or very, very close...but then some come out with no change. They never end up worse.
I have to say with numbers like these, when it comes to which I'd rather have...I think I would rather have way closer to zero runout at the neck/bullet than a certain seating depth.
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I am talking .003 plus. If you are in the lands it can't help but straighten them. If the chamber is straight the brass should be coming out the gun straight after fired. If you turning them they also will be centered. Like Alex said Tom broke the 1000yard records with ammo running out. I have also seen the same. Matt
dmoran, thanks for the nice comment!!! and amen to wanting both!!
The last two posts have a lot of "if's"....I agree with what you guys are saying, but I am not seeing it work that way. Straight chamber...check. Straight full length resize die...check. Straight brass case after resize...sometimes. L.E. Wilson straight line seater cut with the same reamer used to chamber the gun...check. Forester benchrest seater...check. Bullet concentricity less than .003" about 60% of the time.
Joe Salt, tell me what I should or should not be doing please.
The last two posts have a lot of "if's"....I agree with what you guys are saying, but I am not seeing it work that way. Straight chamber...check. Straight full length resize die...check. Straight brass case after resize...sometimes. L.E. Wilson straight line seater cut with the same reamer used to chamber the gun...check. Forester benchrest seater...check. Bullet concentricity less than .003" about 60% of the time.
Joe Salt, tell me what I should or should not be doing please.
Dusty Stevens
Shiner
Sounds to me like you need another seater die. Most times runout comes from the sizing die not the seater. Ive never seen a wilson make one runout but havent used one in quite a while. Maybe its your bullets or the forster. I use newlon seaters with the micrometer top as most short range br shooters do and newlon sizing dies i cut then melonite. But im with matt- dont really matter much. The wind is gonna get you way before your seater die.
Yep, the wind does more damage to shooters than a lot of things...usually for me it's the trigger that does it. I just shoot for fun and do a lot of hunting. I am like a junky on dope when it comes to the trigger...the lighter it can go the more I need it. Honestly, when it comes to shooting I need all the help I can get!!!
I did learn something yesterday in a phone call to Forester...I was having trouble with runout from the size die. I was told to make sure the die itself was good remove the entire expander ball assembly and see if the neck came out straight. Sure enough it did. Then the guy said make sure the expander is in the right place height wise. He said take the assembly and hold it next to the die where it would go, make sure the expander balls bottom 1/3 lines up with the vent hole in the die...it did not, it was all the way up as high as it could go, way too high. I also checked the assembly for runout. It was bent .004". I straightened it relocated the ball and he also said to loosen the locknut and let it float a little. Presto!!! Dead on necks.
Of course if the neck has runout then whatever it has will be the best you can seat a bullet. To me, dismissing bullet runout as no problem seems like admitting defeat...also, everyone probably wont admit this, but if someone came up with a die set that positively eliminated any and all neck and bullet runout.....they would ALL go out and buy a set today. I reload to improve on what the factory can do and their ammo don't have much runout, if any.
I did learn something yesterday in a phone call to Forester...I was having trouble with runout from the size die. I was told to make sure the die itself was good remove the entire expander ball assembly and see if the neck came out straight. Sure enough it did. Then the guy said make sure the expander is in the right place height wise. He said take the assembly and hold it next to the die where it would go, make sure the expander balls bottom 1/3 lines up with the vent hole in the die...it did not, it was all the way up as high as it could go, way too high. I also checked the assembly for runout. It was bent .004". I straightened it relocated the ball and he also said to loosen the locknut and let it float a little. Presto!!! Dead on necks.
Of course if the neck has runout then whatever it has will be the best you can seat a bullet. To me, dismissing bullet runout as no problem seems like admitting defeat...also, everyone probably wont admit this, but if someone came up with a die set that positively eliminated any and all neck and bullet runout.....they would ALL go out and buy a set today. I reload to improve on what the factory can do and their ammo don't have much runout, if any.
I don't like a lot of runout, but if I get a little it doesn't bother me. Like I said , my testing at 1000 don't show it made much difference. Tom M. and Alex W. say the same thing. I don't even check them anymore and haven't in awhile. If you do have runout, you need to find out what is causing it and where it is induced or you can't fix it. Matt
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