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Posted: 10/16/2008 9:26:58 AM EST
I'm working on some match-grade 175gr. .308 rounds. I plan on deburring the flash holes, uniforming the primer pockets, weight sorting, checking length at the ogive with a comparator and seating a few .001's off the lands. Is it necessary to turn the neck of the case? I've heard it helps with accuracy, but others say it weakens the case. What are your opinions on neck turning? MJD
Link Posted: 10/16/2008 9:29:56 AM EST
[Last Edit: 10/16/2008 9:30:28 AM EST by scuba_ed]
Since you're interested in match loads, it's likely something you may wish to consider. Check your fired brass before reloading--it will be helpful if you keep your lots together and sorted by manufacturer, times reloaded, etc.

Periodically check to see if the neck needs turning...may as well do the whole lot then for consistency.

Enjoy!



Link Posted: 10/16/2008 10:36:42 AM EST

Originally Posted By highwayman:
I'm working on some match-grade 175gr. .308 rounds. I plan on deburring the flash holes, uniforming the primer pockets, weight sorting, checking length at the ogive with a comparator and seating a few .001's off the lands. Is it necessary to turn the neck of the case? I've heard it helps with accuracy, but others say it weakens the case. What are your opinions on neck turning? MJD


With a factory rifle and a sloppy chamber/throat, I'd say no, don't bother. If you have a barrel with a tightly reamed throat, you might have to. You have most of the bases covered it seems, so spend your time playing with neck tension, COAL, powder, primers and practice. You can even jump the 175s a bit farther with nary a penalty. With VLDs, you'd want to jam the lands.

Also if you're going to be turning the outside of the necks, you'd also want to ream the inside of the necks as well, to get any high spots removed. It's really a two step process. At that point, you'd want to be using bushing dies to get about .001"-.002" of neck tension for bolt guns, a tad more for gas guns.

Chris
Link Posted: 10/16/2008 1:36:32 PM EST
Link Posted: 10/16/2008 1:41:38 PM EST
Best reason to turn:

With the bullet loaded, the neck exceeds SAMMI MAX spec's.
Link Posted: 10/17/2008 3:54:32 AM EST

Originally Posted By ChrisGarrett:
With a factory rifle and a sloppy chamber/throat, I'd say no, don't bother. If you have a barrel with a tightly reamed throat, you might have to. You have most of the bases covered it seems, so spend your time playing with neck tension, COAL, powder, primers and practice. You can even jump the 175s a bit farther with nary a penalty. With VLDs, you'd want to jam the lands.

Also if you're going to be turning the outside of the necks, you'd also want to ream the inside of the necks as well, to get any high spots removed. It's really a two step process. At that point, you'd want to be using bushing dies to get about .001"-.002" of neck tension for bolt guns, a tad more for gas guns.

Chris


I have a factory Remington 700P DM that has a very sloppy throat. It's REALLY long. I'm not even sure I can seat to .005" off the lands without exceeding maximum COAL. I plan on changing the barrel out relatively soon and putting a high-quality tight tolerance barrel on it, maybe Krieger, Hart or Lilja. I also plan on having the action trued, oversized recoil lug and Badger Big Knob installed. My rifle seems to like 168's a lot better than 175's and that's a problem for long distance shooting. It'll leave 1 ragged hole at 100 yards with 168's but 175's shoot ~1 MOA for some reason. I don't plan on shooting VLD's right now but may go to them later. I'll stick with SMK's for now.
Maybe I should get all my rifle mods done first and then work up the loads for the new barrel. No sense in doing double work. MJD
Link Posted: 10/17/2008 7:00:04 AM EST
About the only way neck-turning weakens the case is if you get stupid about it. Get a cutter w/ a bevel on it that matches the shoulder angle so you don't gouge the shoulder region when turning the necks.

BR shooters turn the necks of some calibers down to as little as ~9 thou - coming from ~13 thou or so. Thats one hell of a lot compared to what I've seen most people do, and can be an invitation for donuts in the shoulder/neck region. Most folks, even with 'target', but non-BR rifles don't have fitted chambers where you have to turn the necks to fit the chamber. They may be snugger than SAAMI spec, but usually not that tight.

Turning for a light clean up as mentioned, or to a specifc neck diameter for consistency, is one of those things that can't hurt. More consistent neck thickness generally equals more consistent neck tension, and more consistent bullet release. It is a matter of increasingly small benefit, though, and you probably need a gun/load/trigger puller that are working really well in the first place to be able to really tell the difference in sheer accuracy. The other place it may show some benefit is in more consistent muzzle velocities. Again, the gains are small, but generally real - if you sample a large enough population of cases. Shooting 5-10 of turned and 5-10 of un-turned might give you different results than say, 50-100 of each. It also depends on how consistent your original brass is to begin with. Traditionally, Lapua match brass is very consistent, and a lot of folks load it and shoot it and have excellent results. The batch I got this year (900 cases straight from the importer) were... not so good. Then again, my standards are a bit higher than some. Neck turning to clean up inconsistent cases is one way of *making* the necks consistent. Others say (and I can't entirely disagree) that those thick/thin spots don't stop at the bottom of the neck - they likely go some distance down the case shoulder and body, and may affect how the case as a whole expands during firing (getting really nit-picky here). Some folks sort cases by runout (measuring that thick/thin ratio) first, *then* neck turn.

Me, I neck turn pretty much all my match cases because as mentioned, done right it can't hurt and it *should* help.
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