Help with 6XC Brass and Dimensions

[oklahomaboy]

I have ordered a PTG reamer with a .272 neck on Dave Kiff's recommendation. I find on forums that loaded round dimensions for Norma 6XC brass is .270, Win. 22/250 is .270, Rem. 22/250 is .270 and Norma 22/250 is .267 or .268. It would seem that the Norma 6xc would be the easiest path to follow but is that way the best to end up with good quality hard brass. Seems a bunch of folks chose the Norma 22/250. Why? I've considered buying a bunch of Winchester and weighing and sorting it to achieve the best batch. I have no objection to turning necks, so I am also considering dropping the neck dimension to .270. What think ye? Thanks so much for your time and opinion.

 

[WyleWD]

I went with the Norma 6XC brass. As you stated it just seemed the more simple way to go. I have NO regrets. There are numerous ways to make the 6XC brass and my philosophy is the more steps to making brass work the more opportunity for a mistake along the way or ending up with a cull for one reason or the other. And with the price of powder, bullets, and primers then fireforming isn't cheap either.

As far as dropping the neck diameter you mentioned, that is what I'd do too, take it to 270 or 271. Just my 2 cents worth. WD

 

[Bob3700]

Do yourself a favor and don't just look at the loaded neck dimension but also look at the reamer print for the base dimension.

6XC brass (Norma especially) is larger at the head than 22/250 brass. The Rem/Win brass will measure around.465-.466 vs the 6XC Norma will be up around .468. (this measurement is just above the extraction groove).

As long as the reamer is ground for the 6XC dimensions, you will be OK. If ground for Rem/Win brass you may run into issues.

My reamer was ground for Rem/Win brass and when I switched to Norma I started getting bolt clicks upon extraction. The extra diameter at the base was the culprit.

Bob

 

[mikecr]

My Norma 6xc brass measures .468 at the web, as mentioned. With this, I'd choose .4685, .200 from the heads. This way the brass stays well within spring back, and never yields on firing -beyond springback. Extraction would not be a problem with rational loads.

My 'new' necks measure a bit over 14thou thick.
.014x2+.243 =.271
I don't see a reason to go .270 unless you desire to turn anyway. In which case I'd turn to 12thou thickness and go ~.268-269 chamber neck.

Personally, I like em tight!
(that's what he said).

 

[oklahomaboy]

Thanks for all the responses. I got my new Norma 6XC brass and my necks measure .014 as indicated in a response. If I clean them up to .0135, I will have a loaded round diameter of approx. .270. So the .272 reamer diameter is perfect if using the norma xc brass. I would think the .270 or .271 might be better if using 22/250 brass as you might need to turn off a .001 to clean them up; but, the brass is here and that is what I will use. As a side note, the Norma brass necks seem to be fairly uniform, but the weight from case to case varies quite a bit from a low of 155.9 grains to a high of 160.1 or 4.2 grains difference. I purchased 300, weighed them all and segregated them into 3 lots. After culling 10 brass, the middle 100 is only .6 grains different and the lightest and heavyiest lots vary about 1 grain and 1.3 grains. It's not Lapua brass but it'll fit my chamber.

 

[mikecr]

Case weight don't mean diddly..
And Lapua brass ain't Norma either, despite herd assumptions.

Someday you might compare them hand in hand(maybe even in 6XC).
You'll likely find Lapua harder, Norma more consistent.
So if I were you, I would not push your Norma beyond 56Kpsi.

 

[spclark]

When the 6XC first came out there were no factory brass options available until D. Tubb had Silver States Armory begin custom production. His first lot was notoriously thick-walled & produced pressures beyond what could be considered normal with loads that worked fine in cases made from various (Winchester, Remington, Grafs, Norma etc.) 22-250 parent stock. Later runs were more suitable.

Norma is considered to be the best quality of what was then available, which is why you see references to it so often. They began making factory 6XC brass a few years ago which is of excellent quality. All work fine if you do your part in the forming & load testing but I suspect that from Norma and Lapua are the most consistent & will probably last longer with reasonable attention to annealing & sizing.

This year Lapua began making 22-250 available too, so that's now an option for those who are willing to put up with case forming.