Concentricity Question

jreagle

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great learning experience so far from all that have contributed. best read in awhile!

would like to add some personal notes around the collet die experiences, etc ......... some is kind of a replay of what has been said here, only repeating for context. If we were standing at your reloading bench staring at your rifle, this is probably where the conversation would be headed.

the last 3 or 4 years have been using lee collet dies with a few different calibers, fired thousands of rounds in total. Have 8-10+ firings on some cases running accuracy loads (1.5-2 grains under max), 85%-90% of the cases have never seen a full sizer. Haven't had problems with run out with the collet dies; .001" max, mostly less than that, the needle on the gauge barely moves when rotating the case. I like the process; a lot of time saved using them; eliminating the case exterior lube and clean up steps. Any cases that show a more difficult bolt lift after firing, setting aside and will full resize, bumping the shoulder .0015"-.002" then shoot to fire form back to the chamber dimensions. have little pieces of paper in my reloading case trays for number of firings on the cases so i know where the necks are in relation to time for annealing.

Also have 1 rifle, a new caliber in the safe, that fl size cases only for it with a .0015" shoulder bump (slightest crush fit when closing bolt; slightly backed off .002" bump). Loaded 4 times fired cases with a proven load without annealing, at the 5th firing today groups opened up so i will anneal those cases as well as the 4 times fired cases in the tray and see if the groups come back down. Also, may have Lee make a custom collet die for me for this one; haven't decided yet. definitely notice the additional time at the loading bench with FL sizing and lube to get finished rounds to shoot though.

Seating the bullet seems to be where i can add to the most run out if not careful with my press handle speed and pressure. Seating in stages; lightly, 2-3 fingers on the handle, slowly just past boat tail, then twist case 1/2 turn and seat the bullet the rest of the way with a little firmer/quicker stroke. Case necks need a little lube to help seating uniformity, especially with an under sized mandrel; using graphite with pretty good results so far. Lee makes an undersize mandrel if more neck tension is needed.

Then i will sort the loaded rounds in the ammo case by run out measurement and shoot them that way in order to gauge how run out affects group size so far .003" or .004" run out, depending on the rifle (YMMV) seems to be the border where groups will start to open up.

really never use factory ammo when chasing problems; only because i dont spend much time and cost trying to see what brand works best in a particular rifle and the brass i am left with is probably something i don't use much. always use a reload that has shown some good results...... also not in the habit of using a bipod for chasing problems; a solid rest under the chamber (close to in line with the AO ring on the scope) of the rifle (where your stock narrows) at the range for firing groups. The bipod on a bench for me seemed to introduce another variable clouding group pattern results.

Make the jump; change the bases and rings. you wont regret it.
and re torque the receiver screws again, don't go too tight. No one ever goes too loose. Check torque after firing 3-5 rounds. Ran a torque test at the range with a couple of rifles last year. They seemed to group best somewhere between 35 inch pounds and 45 inch pounds depending on the rifle, surprisingly each one was different, maybe recoil level was a factor (and the shooter as the usual cause of trouble), not sure. Usually check screw torques each season when the rifles see daylight after storing in the safe. just a side note, alcohol cleaned receiver screws when installed, no extra lube on them (have read where some don't bother and have good results). Scope and ring mount screws are cleaned as well when installed and torqued to mfgr spec, check after firing as well.

Good luck.
Really enjoying the Olympics competitions so far... GO USA!!
 

Deputy819

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@jreagle
Wow...another good one. I'll have to add that in addition to the massive amount of GREAT info, the camaraderie/humor has really brightened my outlook on my "situation". Thanks guys! Once I get the ammo I'm cranking out to be as "consistent" as possible I'm definitely gonna look into the scope, bases and rings as a possible culprit. I only say this because the Smith who built this thing also did the base & ring installation as well as lapping the rings. So far, I cant find any fault in his work....and I don't want to either! And it seems that dreaded "A" word has popped up again so it looks as if I'm gonna have to follow suit on annealing as well. Another question: It seems that my brass has not quite stretched enough (from more than one firing) to completely fit my chamber. My question is if the brass I HAVE been working on the last couple days all have the same headspace, trimmed to uniform length, weigh within .5 gr of each other AND show a concentricity of NOT greater than .002 can I expect the same kind of consistency on paper (in theory)?-Disregard shooter error, bullet, powder and primer for the moment. :)
 

tnek13

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The tread is a great read. It has gone from Concentricity to torque – action, rings, bases, etc. Maybe, shooting position and rests should be thrown in, just to round out the discussion. Brass lot consistency or inconsistency should be mentioned, but it is a known that can further drive you mad because even in the same lot individual pieces react /act differently. Did not see brand of brass brought up or caliber or bullet type, tangent or VLD ogee. You have purchased a bunch of good equipment and can now go crazy measuring everything, be sure to write it all down with date etc. so later on you can maybe figure out that consistency is the key. So grab 10 pieces or so of fired brass find an average, set your full length sizing die to set back .002 and go from there. One other thing clean all lub off the bullets and use lighter fluid on a chamber mop to clean the chamber after cleaning to have even grab when firing. Make sure your shooting position is solid (find the rest the rifle likes) and shoot. Some rifles need several hundred rounds down the tube before they settle down. Have FUN.
 

jreagle

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@jreagle
My question is if the brass I HAVE been working on the last couple days all have the same headspace, trimmed to uniform length, weigh within .5 gr of each other AND show a concentricity of NOT greater than .002 can I expect the same kind of consistency on paper (in theory)?-Disregard shooter error, bullet, powder and primer for the moment. :)

IMO the .002" run out should not be a problem as long as it stays there with the bullet seated. Tight groups should be attainable.

Most times virgin fresh factory cases have more run out than that (measure some if you have time) and have had some good groups with them after just chamfering the case mouths (if they weren't already chamfered by the mfgr). The groups most of the time seem to tighten after the 1st or 2nd firing just collet neck sizing after firing.

every rifle is an individual though.....
 

ppoole

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I’m getting the exact same problems out of a custom 7 rem mag. I have changed all components multiple times and still getting results like yours. I think I have figured my problem out, Hornady brass. My gunsmith shot my gun for a .232 group with his Remington brass. I never could find Remington brass so I used Hornady brass and it went to crap. Since deer season ended Nosler brass came back in stock so I’m going to give this a try and possibly chan
 

Deputy819

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IMO the .002" run out should not be a problem as long as it stays there with the bullet seated. Tight groups should be attainable.

Most times virgin fresh factory cases have more run out than that (measure some if you have time) and have had some good groups with them after just chamfering the case mouths (if they weren't already chamfered by the mfgr). The groups most of the time seem to tighten after the 1st or 2nd firing just collet neck sizing after firing.

every rifle is an individual though.....
Measured some virgin brass today when I got home from work. It had more runout at the neck than my fired brass did.
 

Whitesheep

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Yes, nice thread. If this was a 1000 yard conversation I would not comment as there are others much more knowledgeable than me. However 200 yards is not that far and this is my experience for what it is worth.

#1 the nut behind the gun. Mentioned a couple of times, but a coach, even if video, is a help. A "retired" Marine Marksman has helped me a bunch, especially the physci stuff.
#2 a similar experience with an FNAR in .308 I think may help. Yeah, I know this is a semi auto, but it is basically a tacticalized browning and actually bolt action accurate.

With the FNAR my problem was exactly the same, at the same distance. The solution was seating depth, powder choice and bullet selection. Long story, but it is now an MOA simi auto.

I've chased the accuracy rabbit down the hole many times and in this case a simple back up to basic seating depth and powder/bullet weight choice made the difference.

As for concentricity, the start of this thread, I have a Hornady "correction" gauge and find that in a 50 round batch from the same die set up there are a few "flyers." However, after reading Bran Litz's book "Applied Balistics for Long Range Shooting" third edition, I am not sure minor concentricity errors are really that important. Most boat tailed high BC bullets stabilize quickly even if not concentric. I highly recommend Brian's book regardless what you think of Berger.

Good luck on your chase and thanks for bringing me along.
 

Deputy819

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@Whitesheep
Very True....so MANY variables. Might have to use my gunsmith as the "Nut behind the Gun" 'gauge', right? If my issues turn out to be bullet, powder and seating depth related I'm gonna have a new Birthday!! The things I've learned just on this thread have shown me that I'm NOT as consistent a hand-loader as I once thought I was. Fortunately my new "toys" are helping correct that! Thanks for chiming in. :)
 

JohnMill

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I've wondered about that....on a couple occasions I have had to adjust the eye-piece on the scope for some reason even though the distance between my 200 yard target and my bench hasn't changed. Could it be the "nut behind the trigger" is changing positions? I Checked all the rings and b much as we would like to think of parrallaase screws of course (they are solidly in place with blue loc-tite).
Hey Deputy,
As much as we would like to think of parrallax(sp) as a thing, it turns out to be more of a relationship. Your eyes today have much to do with it. My first coach told me to check my setting each time sat down to shoot a group. Some can do it instantly and others fiddle with it forever but the closer it is to right the better the group. You check by moving your head horizontally behind the scope. Amazingly there are folks who can not see the crosshair/dot move and have to use the focus of the image as a guide. I was fortunate enough to have anolder much more experienced hand to teach me. Another tidbit; The two things that are hardest for men to say ( and our biggest handicaps) are "I don't know" and " I need help". No Charge.
 

Rack

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Hey Deputy,
As much as we would like to think of parrallax(sp) as a thing, it turns out to be more of a relationship. Your eyes today have much to do with it. My first coach told me to check my setting each time sat down to shoot a group. Some can do it instantly and others fiddle with it forever but the closer it is to right the better the group. You check by moving your head horizontally behind the scope. Amazingly there are folks who can not see the crosshair/dot move and have to use the focus of the image as a guide. I was fortunate enough to have anolder much more experienced hand to teach me. Another tidbit; The two things that are hardest for men to say ( and our biggest handicaps) are "I don't know" and " I need help". No Charge.
 

Deputy819

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The weather finally let me shoot a little today. Decided to shoot over a chronograph to see what kind of numbers my "tuned" handloads kicked out. By tuned, I mean same headspace for all brass, concentricity was .002 or better, primer pockets reamed and uniformed and flash holes deburred and chamfered, brass weighed .2 -.3 grains of each other. Numbers were not that great. SD's 15-25 and ES 31-45. Groups not great either. Time for a different powder? 20180218_194938.jpg
 

Barrelnut

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Deputy, Last time I saw a rifle shoot like that it was a bad scope. I think the rifle is broken. It has a bedding problem and the action is shifting in the stock, the rings are allowing the scope to move, the scope internals are bad, or all three of the above in any combination. I would have the smith look at this rifle and shoot it.

What distance were these groups shot at? If at 1000 yards forget everything I just said. :)
 

ppoole

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1. Have you cleaned the rifle? If not you definitely need to clean it new rifles can develop copper fouling bad some worse than others. I like boretech copper or eliminator personally. Kg12 is good too and safe on stainless barrels.

2. shoot flyers?
3. Is your rifle bedded, does it have pillars or bedding block?
4. What inch lb is it torqued to?
5. Put two pieces of masking tape behind bolt head of unshot loaded cartridge see if it closes if so you have too much headspace.
6. Reattach scope base and rings and make sure they are torqued at appropriate inch lbs.
 
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