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Rifles, Reloading, Optics, Equipment
Reloading
How do you eliminate runout
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<blockquote data-quote="Savage 12BVSS" data-source="post: 1912052" data-attributes="member: 112413"><p>Concentricity is a pet subject of mine, spent a long time getting a handle on it and find it to be ignored or sought after among accuracy shooters. It takes an accurate rifle to really show its effect and it won't make up for limitations of rifle or shooter.</p><p></p><p>First thing to do and you have the equipment to check it, is fire some rounds in your rifle and check this fired brass for neck runout. I prefer once fired brass for this and write down what your rifle chamber produces in neck runout. Thats your starting point, now resize some of this brass with your chosen die. This is where it gets tricky.....what die do you use and are you going to neck size or bump the shoulder, or full length resize? I've been down this road and the neck runout you measure should lead you to the best set-up for your shooting. I reload brass 3 times and then full length shoulder bump, then three more loadings to next shoulder bump. I use a lee collet neck die for the between bump loadings and a forster benchrest FL die with expander and spindle removed for the bump loadings. I get a dozen or more loadings from quality brass (lapua and norma) so thats about primer pocket life. Here is what I've experienced at this point, my lee collet neck mandrel die produces .0005 neck runout when set up 1 1/4-1 1/2 turns after touching shellholder. THIS IS NOT what lee suggests as a starting point in their die instructions. A search on lee collet neck die adjustment will bring up a detailed way to do it by J Valentine from 2008 on a benchrest forum. This is the way to adjust it trust me. Now if I can replicate the neck runout from the chamber after bump or neck sizing by using the collet die in either case as the final sizing step, then where I fight runout is in the seating step.</p><p></p><p>I use the forster benchrest seaters with the sleeve, I turn the cartridge twice during the seating stroke and then measure final runout on the finished cartridge. Out of 40 loads on average about 15 will, on average, exceed .001.......up to as much as .0015, these I will tweak down to .001 or less on a hornady concentricity gauge. The remaining 25 will run between .0003 and .001. There are collet supported mandrels and straight mandrels as well as bushing dies, all improve runout over pulling a resizer button thru the neck. For me .001 or less is the number I look for <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile :)" loading="lazy" data-shortname=":)" /> Good Shooting!</p></blockquote><p></p>
[QUOTE="Savage 12BVSS, post: 1912052, member: 112413"] Concentricity is a pet subject of mine, spent a long time getting a handle on it and find it to be ignored or sought after among accuracy shooters. It takes an accurate rifle to really show its effect and it won't make up for limitations of rifle or shooter. First thing to do and you have the equipment to check it, is fire some rounds in your rifle and check this fired brass for neck runout. I prefer once fired brass for this and write down what your rifle chamber produces in neck runout. Thats your starting point, now resize some of this brass with your chosen die. This is where it gets tricky.....what die do you use and are you going to neck size or bump the shoulder, or full length resize? I've been down this road and the neck runout you measure should lead you to the best set-up for your shooting. I reload brass 3 times and then full length shoulder bump, then three more loadings to next shoulder bump. I use a lee collet neck die for the between bump loadings and a forster benchrest FL die with expander and spindle removed for the bump loadings. I get a dozen or more loadings from quality brass (lapua and norma) so thats about primer pocket life. Here is what I've experienced at this point, my lee collet neck mandrel die produces .0005 neck runout when set up 1 1/4-1 1/2 turns after touching shellholder. THIS IS NOT what lee suggests as a starting point in their die instructions. A search on lee collet neck die adjustment will bring up a detailed way to do it by J Valentine from 2008 on a benchrest forum. This is the way to adjust it trust me. Now if I can replicate the neck runout from the chamber after bump or neck sizing by using the collet die in either case as the final sizing step, then where I fight runout is in the seating step. I use the forster benchrest seaters with the sleeve, I turn the cartridge twice during the seating stroke and then measure final runout on the finished cartridge. Out of 40 loads on average about 15 will, on average, exceed .001.......up to as much as .0015, these I will tweak down to .001 or less on a hornady concentricity gauge. The remaining 25 will run between .0003 and .001. There are collet supported mandrels and straight mandrels as well as bushing dies, all improve runout over pulling a resizer button thru the neck. For me .001 or less is the number I look for :) Good Shooting! [/QUOTE]
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