OK, seems my no-turn neck chamber in my new 6Br barrel may need just a little turning.

[fkimble@charter.net]

If fired brass, poor test.

Low pressure starting load, slow burn rate powder, light for caliber bullets may not expand fired case necks fully.

If running a tight neck chamber, know the diameter.

Fired brass, no ejector so neck doesn't get knocked out of round. Not a low starting load. Not a slow powder. Not a light for caliber load. I know the diameter but am questioning it!

Frank

 

[AlNyhus]

You need to know two exact dimensions:
-Chamber neck diameter
-Chamber length
Neck diameter can be determined by pin gauges. It's best to take the barrel off for this. Chamber length is easily determined by using a Sinclair Chamber Length Guage.

Hope this helps. -Al

 

[fkimble@charter.net]

Also, check and make sure you do not have a carbon ring or build up.

Only just over 100 rounds, not a carbon ring. I think I confused folks with my description. The shank of the bullet is a snug fit. Have to line it up square to get it to slide in. The ring at the heel of the bullet where the boat tail starts is very snug. Can force it in if rotating it as I push hard.

Don't see how a carbon ring in barrel would keep a bullet from sliding in a neck of fired case.

What's the carbon look like, on fired necks?

What's the carbon look like, on fired necks?

Good question Nat! First glance there appears to be no carbon. Comparing the fired case to a new case shows the fainted line at the neck shoulder junction. Actually just a hair up the neck from the junction. If I did not have a new case to compare I would swear there was no carbon line. So makes me think my case neck diameter before firing is very close to my to my chamber diameter.

Frank

 

[fkimble@charter.net]

No burrs on the inside or outside of the case mouth? You need a mic for this not a caliper.

No burrs, chamfered inside and out before loading! Got a mike coming per Tims suggestion. What is the neck diameter on your 6 Br reamer, I think you told me .272 but its been a couple years, covid, prostate cancer, and a double hernia! It was the cone bolt for an Atlas action.
We missed you at Atterbury this year.

Frank

 

[Walt Krafft]

I believe 0.272 is the standard no turn neck diameter. Looking at some 6BR reamer prints, commonly the neck tapers from 0.271 at the mouth to 0.272 at the end of the neck. I am still not getting around good enough after knee surgery to go to the shop and measure my reamer and a couple of sample chambers.

 

[fkimble@charter.net]

I believe 0.272 is the standard no turn neck diameter. Looking at some 6BR reamer prints, commonly the neck tapers from 0.271 at the mouth to 0.272 at the end of the neck. I am still not getting around good enough after knee surgery to go to the shop and measure my reamer and a couple of sample chambers.

No problem. Had not heard of your surgery. Hope everything works out OK. Only advise I can give you is to do you therapy and not wimp out on it. Wife had a total knee replacement many years ago. Came home from work to find her walker in the middle of the living room floor. Found her in the back room. Said it was just slowing her down! Happy holidays may see at Perry next year. Lodi is a bridge too far, plus the schedule takes 5 days to shoot XTC!

Frank

 

[jackieschmidt]

Most custom reamers have a straight neck.

I use a .272 neck in my 6BRA no turn, and it is perfect. The 80 grn Barts Dominator measures .2431.

This is what the soot on your fired round should look like. Sort of a sine wave pattern.