Reply with quote #1
I was looking at the 223 page and it gives a measurement of .253
with the bullet seated at the neck. [neck diam.]
I measured one at the local gun shop and it was .2495 with lapua brass.
What's up with that? What do you guys get on yours?
Reply with quote #2
I just measured 3 randomly from the loads I finished tonight.....mine are all .2495 as well (Lapua twice fired brass loaded with 80g Bergers)
Reply with quote #3
Link: The dimensions shown on the 223 page are all maximum ctg. dimensions that can be chambered in a SAAMI spec chamber. As an example, case length is shown as 1.7598", and we all "round up" to 1.760". Same for ctg O.A.L., shown as 2.2598"/ rounded up to 2.260". Every commercial 22 c.f. chamber neck dia. I've ever measured is .256"/.257", so again, the .2532" would "fit". And, yes, my Lapua 223 loaded neck diameters are around .249"/.2495", the reason my spec'ed chambering reamers include a neck diameter of .253", a good dia. for a tight, no-turn neck. Loaded 223 with Winchester brass will have a neck dia. of approx. .246" for a really sloppy fit in a "large" chamber. Good observations on your part: you are on top of it.
Reply with quote #4
MMmmmm Thanks guys.
The reason for asking is I want to order my neck dies with the bushing. Should I order 2 bushings?
1 at .247 for the Lapua that measures .2495
& 1 at .244 for the L.C. brass?
And as for the neck size in my new chamber maybe a .252 or .253?
this is a .223 A.I. I am having built for my Contender.
Reply with quote #5
Link: Again, you are on top of it. Thats the combination I use: .247" for Lapua brass and .244" for Winchester, Lake City, and "other". I actually have several other sizes, a few thousandths smaller & larger, but seldom use them. I think the only way you would get a smaller chamber neck dia. than "standard" is if it's specified when the chambering reamer is cut, otherwise it will be .256"/.257". With the neck bushing die, and the proper sized bushing you will be able to control the minimum as sized diameter, ( a standard die will radically oversize/squeeze-down) and the big advantage remains in not having to use the inside neck expander. But, with a saami spec chamber neck dia., the necks will still be expanded to the .256"/.257" diameter., so you will be "working" the brass approx. .010".: .257" to .247". With a tight, no-turn neck dia. of .253"/ .252" the brass will be worked around .005"/.006". And that's the main reason I specify a tight,no-turn neck on my chambering reamers.