• Frank's Lesson's Contest

    We want to see your skills! Post a video between now and November 1st showing what you've learned from Frank's lessons and 3 people will be selected to win a free shirt. Good luck everyone!

    Create a channel Learn more
  • Having trouble using the site?

    Contact support

Factory Chamber specs on proof 223 comp 1:7 prefit

FimRire RongLifle

Sergeant of the Hide
Full Member
Minuteman
Apr 27, 2022
322
211
Florida, USA
Anyone have a link to info on the chamber specs on these? I picked up one for a Zues to play with and noticed a 80 ELDM at 2.540 COAL (was staying close to MDT plastic mag length) and 2.000 CBTO drops right in and easily does the pinky nail removal on bare barrel . I plan to measure it out however I'm thinking this needs 88-90s to even be close to the lands, or exceed the current mag length?
 
If anyone reads this later on my measurements were wrong, when testing on an assembled rifle with a bolt and using the Hornady OAL guage I got CTBO of 1.965 to lands with 80gr ELD on this barrel. The original measurements in post one was very heavy jam. I will be also trying the bergers shortly.
 
Berger 85.5's and 88 ELD's have worked well in mine with N150, sorry I have no chamber specs.
Mind sharing your load and velocity with the 88’s and n150? I’m running 88’s and n140 currently in a proof/origin.

I don’t have access to my load data but was running low 2800’s but primer pockets aren’t lasting long. Going to try and slow it down some.
 
Tried some 88 ELD'S and N150 today... made me look good 🤣

26" proof with whatever reamer proof uses in their prefits. COAL length to lands is around 2.518ish, these are jumping .030-.035. Charge weights above 23.25 grains were compressing enough to grow COAL.
View attachment 8316230
From the 5.56-223 reloading thread.
 
Proof prefit and 85.5 with n140. First 5 rounds out of the barrel
 

Attachments

  • 71011172251__436C1704-1DB6-48EC-9F6B-AF58B4975AFF.jpeg
    71011172251__436C1704-1DB6-48EC-9F6B-AF58B4975AFF.jpeg
    206.6 KB · Views: 32