6.5x284 loaded neck diameter

[dieselten]

Hello,

I have seen on this forum in a search that 6.5x284 Lapua brass with a Sierra 142 or a Hornady 140 Amax has a loaded case neck diameter anywhere from .294 - .296.

I would appreciate if someone would use an actual micrometer and mic the loaded neck diameter of a piece of new Lapua brass manufactured within the last year, and a 142 or 140 bullet, or even a Berger or Lapua bullet.

Thanks very much!

Nick

 

[watercam]

Lapua brass has .015" thick case neck walls. .264" bullet plus .030" combined case neck thickness gives one .294" total loaded round case neck diameter. When I outside turn my Lapua necks to 70% for a thickness of .0145" I measure .298". It will depend upon the lot of brass you have but you can measure the neck wall thickness. I felt I was better served buying more than one die bushing so that the neck tension could be easily adjusted depending upon whether or not the round was to be magazine fed or single loaded, just needed a bit more tension, etc.. Bushings are fairly inexpensive and you need not buy the coated ones - steel works just fine.

 

[dieselten]

Thank you. I am not concerned with neck tension, I am looking at chamber neck clearance. My rifle is being cut with a reamer with a .2972 neck. I absolutely hate to turn brass necks unless necessary for safety. I want .003+ clearance. Sounds like it will be close

 

[cncmill]

I recently built a 6.5-284 for myself. First build ever. Talked with someone at Pacific Tool and Gauge where I got the reamer. They recommended a .297 neck since I told them I didn't want to turn the necks. I use Lapua brass (not turned), 142 Sierra, and 140 Amax. Loaded case neck is .293 - .294. Works perfect. I never shot anything so accurate. I also use a Match RCBS die with a .290 bushing. I tried a .291 bushing also but didn't work as nice. Hope this helps.