Factory Chamber specs on proof 223 comp 1:7 prefit

[FimRire RongLifle]

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?

 

[Rob01]

You don't have to be close to the lands for bullets to shoot well. The 80 ELDs don't mind a jump.

 

[FimRire RongLifle]

Thanks, I'm not worried about the jump actually was just surprised nearly mag length was clear already with an 80. I will measure just to know what the jump actually is.

 

[Niles Coyote]

Berger 85.5's and 88 ELD's have worked well in mine with N150, sorry I have no chamber specs.

 

[FimRire RongLifle]

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.

 

[Baron85]

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.

 

[Niles Coyote]

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.

 

[Shoots 700's]

Proof prefit and 85.5 with n140. First 5 rounds out of the barrel