neck diameter reamed for a 280 ackley

The Accurate Reloading Forums

This topic can be found at:
https://forums.accuratereloading.com/eve/forums/a/tpc/f/9411043/m/767109701

12 December 2003, 12:05

Jameister

neck diameter reamed for a 280 ackley

I am looking at a custom 280 Ackley. builder deceased.
the barrel is stamped 280 Ackley X 311 Neck.

I take this to show that the neck is .311

Can it take factory 280 ammo? or must unfired brass be used and have it all be neck sized before fireforming?

thanks

12 December 2003, 13:57

DigitalDan

Factory ammo MAY be a risk you don't need. .311"-.284"=.027" Subtract .002" for release and you wind up with .025" for two neck wall thicknesses(is that a word?). Anyway, that's .0125" per wall, and I've seen a fair amount of brass at .013-.014" thick. Measure your neck walls, turn if needed.

12 December 2003, 14:04

tiggertate

I don't know DD. Thicknesses.. thicknessi..??

13 December 2003, 03:21

Jim Kobe

Apparently you have a "tight neck" chamber on your 280 Ackley. According to the specs, the neck diameter of the chamber should measure .3176-.3196. Your loaded rounds should not exceed at least .003" under the neck diameter and that may be a little tight for some. I am quoting from memory, so my figures may be off. Someone chime in if they are.

13 December 2003, 04:56

JustC

You will be needing to turn the necks,..I am betting a factory case will not even chamber in that gun. Turn the necks down so that there is .0005" - .001" clearance between the neck and the chamber neck,..and you'll be good. Your brass should last longer with this set-up due to not being worked as much. It can only stretch .0005" -.001" upon firing,.instead of the normal .003"-.006".

14 December 2003, 18:02

Jameister

Quote:

I have a 280AI with a .311 neck, the brass should be thinned to the .0125 that DD suggested, it is a very accurate round with many 5 shot groups in the .4`s. I had my reamer made by JGS and the smith wanted it badly so we traded out for him to keep it.

I just micrometered a bunch of factory loads. the necks are from .311 to .313.

If I pulled the 313's, and just shot the .311 and .312 that will chamber, this will give .001 to .002 for bullet release, assuming the chamber itself is .311.

BUT another question that is really only answered by a chamber cast, is: Do gunsmiths properly stamp the reamer dimensions, or do they stamp the approved bullet dimensions?

I will do a chamber cast...

thansk for the help. And I do look forward to groups in the .4's, if my skills are up to it.

Jameister

15 December 2003, 03:40

Tim in TN

You will need a finished loaded round to measure .309" to safely fire the rifle, get a quality neck turning tool. I have about 100 Remington cases that are already turned to the proper dimention, flash holes deburred and primer pockets uniformed, that I would sell if interested, but it must not be a giveaway price as this is labor intensive to get all done right. The .311" stamped is the actual neck dia. for that chamber, the loaded round must be less than that. Also I have been able to use standard Redding dies to resize, there is still enough meat in the neck for bullet grip after resize, no need for bushing type die. You will like this round, The bullet I use is a Nosler 140gr. Ballistc Tip, the barrel is right at 25" long and get 3206 fps with 63.5 gr N165, best load I found. Top speed and great accuracy. Seat .010" off the lands. You are informed!!!