How to measure neck diameter in chamber.

[Robertdillon]

To measure the neck diameter in your chamber and check if your loaded round has enough clearance to release the bullet properly, follow these steps:

1- Measure Neck Diameter: Use a caliper or micrometer to measure the neck diameter of your fired brass (freshly fired is .2950 inches).

2- Calculate Clearance: Subtract the neck diameter of your loaded round (.2920 inches) from the freshly fired neck diameter (.2950 inches) to find the clearance (3 thousandths or .003 inches in your case).

3- Assess Clearance: A clearance of .003 inches is typically enough, but check your specific rifle's requirements.

4- Consider Neck Turning: If your brass varies significantly in neck thickness, neck turning may help ensure uniform clearance and improve consistency in your loads.

5- Further Suggestions: Seek advice from experienced reloaders or forums for alternative methods to measure and confirm neck clearance, especially if you're facing high extreme spreads (ES) or standard deviations (SD) during load development.

Always prioritize safety and precision when reloading ammunition.

 

[Paulstarr]

Brass when fired, expands, then contracts, .003" growth IMO seems fine, it is growing at least .004", maybe more. Take a pic of the carbon ring on the neck of the brass, the closer it is to the shoulder may help us determine the actual close off point of a fired rd.

Not trying to be negative, shoot it some more, new barrels act funny, and break in can be different in brands-barrels, some it is a one shot process, others a circus.

Milo could be right,It took me 4 months to run in my 223, I started with 60gn V max and RE 10 powder and Fed match primers.It was very disappointing when I finally finished a 50 round run in but I stuck with it after 300 rounds it vastly improved now it repeatably shoots 5 shot bug holes at 100 Mts.

 

[Charles Duke]

You misunderstand; clearance is not measured from diameter, but rather is measured as headspace (how far bullet is backed-off from firm contact with the lands), which is usually .020-.080”. Any less can cause dangerous high-pressure spikes. This usually means that total diameter clearance is AT LEAST .005”, depending on shape of bullet nose.

What? clearance is not measured from diameter- but - diameter clearance is least ????
You must be having a serious Biden brain fog. Please retract or correct.

 

[pdog shooter]

I agree with the “spring” in brass to an extent but unless you have the exact same alloy, thickness and all variables exactly the same, it stands to reason that the spring back will be different. This is why I turn all brass after first firing. Induction annealing will demonstrate the different alloys, hornady takes 3 seconds lapua 7 seconds on the same machine.

Are we talking about 3” groups at 1000 yards or hitting a mule dear at 100?

Bullet falling into brass is a safety check not an accuracy test.

Pouring that lead stuff in the chamber gets my vote.

thunderstorm and winds on the first round
f class

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