223AI Neck Clearance

[tooter]

I'm seeking experienced advice while preparing my new 223AI for a maiden run to the range. Here's my situation:

- The chamber was cut with a brand new PTG .251 neck reamer; Dave Kiff recommended this for no-turn
- I fireformed 20 virgin Lapua cases with unturned necks using 8gr. of Bullseye and COW
- Necks were partial sized with Redding Competition die and .248 bushing
- 20 rounds were loaded with 69 gr. SMKs
- Loaded round necks measure .2500 across sized area,measured with a Starrett Mic)
- Measurement consistency is dead on .2500 diameter round to round,only 20 rounds though)

From your experience is .001 neck to chamber clearance too risky?

Should I remove a half a thou off neck wall thickness,280 remaining virgin cases)to be safe going forward with successive loadings?

I've read that some BR shooters prefer such a tight clearance, but I'm assuming they are also religiously neck turning.

Advice is appreciated, as I'm a newbie just getting into this whole BR experience.

Thanks,

Tooter

 

[tooter]

Correction:

Loaded necks measure .2494 to .2500 --- meant that none are over .2500.

tooter

 

[Link]

I just had a 223 AI contender barrel built.
It is my understanding that after reaming the chamber is polished? Mine should be around .253
after polishing?
I am going to make another post maybe you want to check it out?

Link

 

[Link]

PS my fired cases measure .2525

How about yours?

Link

 

[ronemus]

0.001' clearance means you'll have to be VERY attentive to your reloading, and will probably have to turn necks after a few firings because any less clearance could result in an 'event.' Did you measure the diameter where the pressure ring on the bullet is seated? If the ring bumps the diameter up, you'll have problems. I use 0.003' clearance in my rifles because I'm not a benchrester and don't want to be quite so close to the edge.

 

[tooter]

Link,

I have only fireformed the Lapua cases using Bullseye and Cream of Wheat. They form pretty complete with the neck outside dia. measuring .2504 uniformly.

Based on input and judgment, I turned 50 new Lapua cases to a neck thickness of .0122. I will fireform,COW)these over the weekend and ready them for loading with 69 gr. SMKs.