6mmBR brass neck thickness

[pintopete]

I have a Remington 700 Varmint style rifle with a Hart barrel that I bought used. For it I bought new Lapua brass. The chamber on the rifle was described as a no turn neck. When loaded with the Lapua brass it chambers tightly on the necks. I would rather not turn the Lapua brass. I was wondering if the Norma or Remington brass have necks that are slightly thinner out of the box than the Lapua. Thanks, Peter

 

[cmillard]

there are different specs for a no turn neck. a common one for 6BR is .272. my barrel has a .271 no turn neck. there are others as well. if you know the person you bought it from, ask them what the chamber spec is if you dont already know it. you can call up bruno shooters supply and buy some lapua brass that they can neck turn for you.

 

[blawton]

The thickness on the necks should be close to .013". So if you chamber is really a no turn neck then a .271 should give you .002" clearance. A easy fix for this i have found is just to us some inside neck reamers on your case trimmer. After you run them through your neck or FL die then run a reamers on the inside like .240, .2405, .241 and so forth. I think i always start with the .240 and work my way up until i like how it performs. Hope this helps...

bobby

 

[golfer2b2000]

Peter, I am not a fan of turning the necks of brass, but just bought a 6 dasher and I have had to form the brass, and also neck turn them. Once you nect turn them you are done. There is no need to do it again. And I understand that it does imporve accuracy, but myself I cant tell because I am not that good of a shooter as some people are. You can get set up to turn brass for probably less than 75 dollars.You can just take .001 or .002 off just to true them. I would have to believe that it would give you better accuracy.

 

[fdshuster]

pintopete: It's been my experience that Norma 6BR neck walls will be appox. .001" thinner than Lapua, my present lots of Lapua being just a few ten thousandths under .0135", for a loaded neck dia. of .269" plus maybe a few ten thousandths ( I cannot accurately measure to 4 decimals). Have been using this unturned Lapua brass in 2 of my .272" no-turn chamber necks for several years now, problem free. If you measure the as-fired case neck diameter and add .001", you will have the neck diameter of your chamber, the added .001" taking into account the springback. For example: my 272 chamber necks will have as fired case neck diameters of .271". Both of my .265" chamber necks will be as-fired at .264". The 22BR .251" chamber neck will be as-fired at .250". Sounds like your chamber may be the before-mentioned .271" that probably would require one light clean-up cut, really no big deal to do. All good advice from "golfer" above.

 

[CJ6]

Try candleing a case maybe it's not the NK dia. could be the shoulder needs a bump

 

[P1ZombieKiller]

Peter,

If you want a few old Laupa 6br cases that have been turned down for a .269 neck, shoot me over your address, and I'll send you a few. load those, and see if that works out better for ya. If you are able to get a round loaded in there, I would measure the OD of the neck of a fired case and see what it measures. I think normal spring back would be .02. so if the case measured .270 after firing, you most likely have a .272 neck. If it measured .269, than possible you have a .271 neck.

 

[pintopete]

Thanks for all the replies. I found I have two loaded rounds left. They are with new unfired Lapua brass and 65gr V-Max bullets. The loaded necks measure about .2694 - .2695 max. The neck walls on some once fired brass measure .0133 - .0134 on average with my Fowler tube micrometer. My best try at measuring the fired neck OD is .269. They distort very easily with the micrometer. When shooting the rifle the rounds frequently need "encouragement" to chamber and I am not a big fan of having to force them in to lock the bolt. The rifle does shoot very well though. When I bought the rifle the only description referencing the neck was the terminology "factory neck". It is probably a used Hart barrel from a competition rifle, shortened and re-chambered for my purpose as a varmint/hobby target rifle. I knew this much when I bought it but was a little naive about the chamber neck. Thanks again, Peter.

 

[fdshuster]

Peter: When you say "encouragement to chamber", (just a little resistance when closing the bolt?), it could be your headspace length, and it would only take .001" or .002" longer than "as-fired" length to cause that. Actually a good thing, since it proves you are locking up the case in the chamber, front to rear. Two critical dimensions are the chamber/cartridge neck diameters, and the headspace length. You can learn a lot by taking measurements from a case, as-fired. Measure the fired case neck dia. and add .001" ( or .002" as previously mentioned, although mine are always .001" smaller), and that will be the chamber neck dia. Take the same case, and with the Stoney Point/Hornady, or any other type gauge, measure the as-fired headspace length, and compare it with one that has been loaded, ready to fire. The length should be the same, or .001" or .002" shorter, never longer. I keep a clean, empty fired case with each die set, for each rifle chamber if I ever need to verify chamber specs, as may happen when adjusting dies, forming new brass, etc.

 

[wapiti25]

I would run a chamber cast, keep it for reference.