6XC Neck Tension

[VooDooMagic]

OK, I ordered the reamer with a .272 neck for use with current Norma brass. Using Redding type "S" Match neck dies which bushing size should work best. I'm thinking .267, especially if I use coated bullets. What say you...and also do you think the titanium nitride coating is really worth twice the money? The standard heat treated steel has a surface hardness of Rc 60-62, I don't think brass is going to know the difference...

 

[Laurie]

Assuming 0.0130" neck wall thickness, a 0.268" bushing for naked bullets, and 0.267" for coated examples should be OK. Going up 0.001" in bushing size might or might not work giving a bit less (but not too little) grip depending on the brass hardness. Sometimes 0.001" below nominal loaded round neck O/D works in my experience, other times it produces too little grip and you can move the bullet in the neck with your fingers. You don't say what kind of rifle you're loading for and its intended use - magazine feed and rapid bolt manipulation for XTC or tactical shooting need a tighter grip than you might get away with on a single-shot bench gun.

With a 0.272" neck (which I have on my 6XC), I assume you're checking your Norma brass thoroughly, or neck turning. (I had to turn every case in my lot.) It may be a 'belt and braces job' as we say on this side of the Atlantic, but I always pay out for an extra bushing in the chamber neck diameter to slip over every loaded round as a quick check that none are oversize when running at 0.002" overall clearance. Quicker, easier, and less prone to a mistake than checking each round neck O/D with callipers.

Laurie,
York, England

 

[Obtunded]

I skim turn all my brass which results in about 12 thou neck thickness. I like to use 2 thou neck tension, therefore .012+.012+.243= .267

Subtract 2 thou neck tension and you have a .265 bushing

If you use a .013" neck wall, you would go .267

 

[spclark]

Which bushing depends on several factors: your chamber's neck diameter, your brass neck thickness, your preference for neck tension, and the degree of hardness (temper) of your case necks.

Over time & with one or more firings, case necks will work harden whether they've been turned or not. A selection of bushings is useful to enable a choice of one (maybe two) sizes smaller as you find your necks not sizing enough as they get harder.

I like the idea of having an additional bushing to check sized neck diameter but keep in mind brass spring-back; you'll want one that's larger than your sizing bushing because of it.

Unless you over-anneal your brass (probably ruining it) you won't be able to slip the same size bushing over sized necks as you used in your press. I prefer the nitride-coated type if only because they tend not to rust.

Some gunsmiths will provide you with a custom chamber gauge made from the cut-off from chambering your barrel. Made at the same time & with the same reamer, it's a useful gauge to check case neck fit as well as how far your barrel's throat has moved once you begin using it.

 

[WyleWD]

In my experience with the 6xc, the best neck tension will vary. For the 95's I use a .268 and for the 80's I use a .267. And use the same powder charge in both of them..... and belive it or not, the amount of click up from 100-300-400yds is exactly the same.

My barrel is a 9 twist Kreiger that is 27" long. Using the Norma brass, R-17, CCI BR primers and just "skimming" the necks to make them all as close as possible to equal. WD

 

[bozo699]

VooDooMagic,
I am shooting 115 bergers from a Krieger 1:7.5 barrel @ 3050fps w/.001 neck tension.
Wayne.

 

[Scott Harris]

Yes, the titan. nitride coating is worth the cash. Your bushing size is related to your loaded round neck diameter and has nothing to do with the reamer you chose.....you choose the reamer to match the cartridge. Without knowing your brass neck thickness, it's hard to give you a specific bushing recommendation, but .002 & .003 below loaded cartridge diameter is the standard.

 

[Joe O]

With a 0.272" neck (which I have on my 6XC), I assume you're checking your Norma brass thoroughly, or neck turning. (I had to turn every case in my lot.) It may be a 'belt and braces job' as we say on this side of the Atlantic, but I always pay out for an extra bushing in the chamber neck diameter to slip over every loaded round as a quick check that none are oversize when running at 0.002" overall clearance. Quicker, easier, and less prone to a mistake than checking each round neck O/D with callipers.

Laurie,
York, England

Good tip Laurie.Would have saved me allot of time pulling bullets ,re-turning necks,etc.Thanks.

 

[VooDooMagic]

Exactly. I'm having my 'smith' make me one using the same finisher as for the chamber. Super tip from Laurie...