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OK guys, I'm a bit irritated, So I'm loading for a new 243 and have been having trouble with runout, but not the usual banana shaped neck variation type. The barrel is a Shilen select and was chambered SAAMI minimum It's Lapua brass, and it's happening with both new and once fired cases that show around .0015 outside neck runout after sizing. Even the new brass out of the box shows almost no runout at the neck. I've tried two different seaters, a forster benchrest and a Hornady sleeve type. I've used two different presses, an older O pacific and a Forster Co-Ax. Runout is sometimes 6 or 7 thou, and I double check it at the neck and the necks are less than 1.5 thou as mentioned above. It seems worse with flat base bullets, and it's quite inconsistent. Some come out less than a thou. I'm seating at least bullet diameter deep, and the bullets range from 58 gr Vmax's to 90 gr. Ballistic tips. It seems a little worse with the shorter bullets. This seems unique to this caliber, I was reloading some 40gr. BT's in .223 last night and they all come out less than 2 thou runout over and over again...using the CO-Ax and a Forster seater. I tried the "rotate the case 180 degrees" trick, tried very slow gentle ram pressure, etc., doesn't seem to increase consistency. I'm chamfering the necks with a VLD tool and I polish the inside of my necks with steel wool spun on old brush chucked in a drill. I'm about read to buy a Redding Competition seater just to satisfy my curiosity! I know it's not necessary because I've loaded plenty of strait ammo without one in other guns/calibers... Ideas? The two most abundant elements in the universe are Hydrogen and Stupidity | ||
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Roger check your case mouths after sizeing. You want about .002 neck tension. Then crimp with a Lee factory crimp die. JD DRSS 9.3X74 tika 512 9.3X74 SXS Merkel 140 in 470 Nitro | |||
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JD, Both new brass and full length sized are .270 and loaded rounds are .272/.2725 Roger The two most abundant elements in the universe are Hydrogen and Stupidity | |||
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Just some suggestions: 1) sloppy seater plugs in both dies 2) sloppy bullet chambers in both dies Maybe a chamber cast using cerrosafe could tell you something about the bullet chamber diameters. Sure would be low odds of the same or similar problem in 2 dies of different brands though. What a puzzle. | |||
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I have had a shell holder that was not right and that did the same thing.  | |||
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make sure the die is adjusted correctly. are you are using the correct shell holder? Adj the die according. screw in until it touches the shell holder, then back off 1/4 turn if there is a build in crip. this gives complete support for the case. next screw in/out the seater for length. Check the seater plug make sure it contacts the type of bullet you are seating at a point evenly all the way around and does not seat from the point of the bullet. this should get the run out in side .003" Dave | |||
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you can also take a bit of non-embedding lapping compound, apply it to the bullet you are using or wish to use, chuck the bullet in a drill, and insert it into the seater plug. Spin it for about 30sec holding it firmly in the plug. Then run some 600grit sandpaper into it to really slick it up. That should allow a bit more uniform fit of plug and bullet. Difficulty is inevitable Misery is optional | |||
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Could be due to variations in neck wall thickness. The outside of the necks can be perfectly concentric, but if the case walls are not uniform, then this variance will show up when you measure concentricity on the bullet. You can sort your brass by neck thickness or neck turn your brass to correct it. I don't do much of either myself, but then I don't have to because I use Lee collet neck dies which index on the inside of the neck rather than the outside. Since I started using these dies I have yet to have a cartridge with more than .0035" runout measured on the bullet. Between .000 and 0015" is the norm. BTW, that's with using either the Forster benchrest or Redding competition seater. | |||
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I've gotten my worse problems with plastic tipped bullets not fitting the profile of the seater plug. BUT....never that bad. I've had seaters that seat lead tipped bullets perfectly wind up with .002-.003" with plastic tips but .006" runnout I've never seen. I can guarantee its not your press, shell holder etc. It's pretty much gotta be the seater unless the trim/chamfering is done crooked. | |||
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Make sure that yours rings (dies) dont move;also that yours dies are well "tight" on the press;something is not set correctly, | |||
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Rogerinneb, sounds like you need to square your seating die before you start. Place a resized empty case in the shell holder and lower the press handle all the way down, then screw the seating die down till it is snug on the empty case mouth. Now raise the ram handle and remove the empty case and place some flat shims on top of the shell plate. Now lower the ram handle till the flat shims makes firm pressure contact with the base of the seating die, then tighten down the locking ring on the seating die. This will square the seating die with the ram. Next loosen the seating plug lock ring and back the seating plug out almost all the way. Place a loaded round with “little or no run-out†and “proper length and seating depth†in the shell holder and run it all the way up in the die. Now screw the seating plug all the way down good and snug and lock the seating plug lock ring. This should square the seating plug with the bullet of the loaded round. Properly adjusted dies should give very little to no run-out if adjusted correctly. If you need a crimp seat you can adjust this before you square the seating die with the shims. Hope this helps! Wouldn't you know it! Some smart ass punk from Colorado stirring up shtuff...DaMan!  Dumbman | |||
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What run-out gauge are you using and where are you measuring? Using the Forster (which I do) you are supporting the cartridge between the tip of the bullet and the base of the case, and measuring either at the neck of the cartidge, or at the shoulder of the body. I prefer the shoulder because it gives a larger reading (a bigger bend in the banana). In either method I think it is the wrong way to measure the run-out. Using the Sinclair you support the cartridge at the base and at the shoulder, and measure the bullet's eccentricity. I believe this is the correct way. as you are seeing the true effect of the case's dimensional faults on the seated bullet. Unfortunately I cannot get access to a Sinclair. Whichever way, you are seeing a problem caused by the inside of the case neck not being concentric to the outside. This will explain the inconsistency you are seeing. The only way to fix that is to neck turn the cases, with a tight mandrel. Then you would have to resize again to square things up. You have to conquer run-out your own way, and everybody has a different way of doing it, it seems. The Forster Benchrest Seat die is a good die, I am thinking of trading up to a Redding. If Chuck Norris dives into a swimming pool, he does not get wet. The swimming pool gets Chuck Norris. | |||
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here are a couple ways to look at it. drives you crazy. you can get possesed.   | |||
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Freebird, Using the Co-Ax press it is not possible to make the corrections you suggest. The die floats via the snap in locking ring setup. I would think the springloaded sleeve of the Forster seating die would center everything but hey, obviously SOMETHING isn't working. The seating stem squaring process should work. I'll try it! Pete, I'm using the Sinclair tool, and I measure both the runout of the case as well as the bullet. If the case neck has runout surely the bullet will follow. I'm still not tracking on why OUTSIDE neck turning will help if the outside neck runout is .0015? I'm not set up to measure neck wall thinkness variation but with new/once fired Lapua brass I'd be shocked if that's where the problem lies...but again, I guess I'll have to try some of these things to see what works! I appreciate everyone's thoughtful input and ideas The two most abundant elements in the universe are Hydrogen and Stupidity | |||
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roger,..lets look at it this way and see if we can get to the reasoning behind neck turning. You have a case right? and that case has wall thickness variations,..that means you will already have runout of the amount that the thickness varies by, even if you have a PERFECT seating die arrangement. Now, when you run the expander ball inside that neck, the ball pushes the high spots to the OUTSIDE of the neck because the internal dimension has been uniformed by the ball. Now those high spots when turned down, will REDUCE the variance in thickness around the circumference outside as they are removed. NOW, when you fire that round, the expansion of the case neck under that amount of pressure, slams the nk against the internal surface of the chamber neck. That then uniforms the OUTSIDE of the neck and sends the high spots to the INSIDE of the neck since the chamber neck will be uniform in it's circumference. soooo when you measure that runout on a fired case neck, you will find it to be greatly uniform (assuming a non-botched chamber) Now, you resize the case and the expander ball sends those high spots back to the outside of the case again. Any high spots not ironed out by the ball will then affect the way the bullet enters that hole. The bullet being perfectly round, and being stuffed into that hole will "cant" when contacting the thicker portions as will the die interior push harder on one side of the neck. Those high spots when removed, will not affect the STRAIGHT alignment of that bullet as it is forced into the opening and the interanl surface of the die will also not have the high spots to push the neck/case body off center. You are now working with a case having a much more concentric and uniform thickness all the way around, eliminating some of the mis-alignment and therfore allowng a straighter seating process. make sense? Difficulty is inevitable Misery is optional | |||
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Thanks JC, How would you describe the process if we're talking bushing die with NO expander ball? Reason for asking, as I mentioned above I've been loading 223 for my Cooper all week (PD's next week in SD!) and I'm using a Redding bushing die with no expander and Forster benchrest seater, and am getting most rounds well under .002 runout and many rounds darn less than .001. Another interesting item of note is that these are moly coated Nosler BT's...they sure go in smooth and easy... 223 is Winchester brass, not neck turned. Roger The two most abundant elements in the universe are Hydrogen and Stupidity | |||
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well roger, let me take a stab at it.. the lack of expander ball makes for the high spots being pushed to the inside of the neck, however, as you may expect, the bullet will be more dense that the brass, and therefore it may be pushing the high spots a bit toward the outside when seated in the neck. This may make for a little less disturbance with no expander, but any high spot has to affect something, and in this case, if you have .002" and less, I would go shooting or just barely knock the very highest spots off. I would bet they all uniform into the .001" range. I would however run with the .002" and forget it. Difficulty is inevitable Misery is optional | |||
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You mentioned you were using a VLD tool on your case necks. I read somewhere, I think it was a Varmint Hunter magazine that you should only use this tool (made by Tubbs?) on cases in which you're using VLD bullets. Could this be affecting your concentricity measurements? Best wishes. Cal - Montreal Cal Sibley | |||
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You might want to check and make sure your casemouths are square. When you seat a bullet in a casemouth that is not trimmed square the bullet will hit the longest or highest side of the casemouth first and will tip or cant to the opposite side and will continue to seat crooked even if the case neck was concentric before you started seating. aka. bushrat | |||
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