RCBS Presision Mic

Lilswede1 · November 19, 2008, 12:14 AM

Just ordered the RBS Precision Mic for .223 from Cabelas.
Could someone give me a blow by blow description of the process so I will be a little bit ahead of the game when it gets here?
Also ordered the Hornaday Lock-N-Load OAL Guage in several different calipers and would like to know, step by step, how it will work.
Thanks

Tex S · November 19, 2008, 12:46 AM

I would also like to know how the Precision Mic. works.

rg1 · November 19, 2008, 04:13 AM

Detailed use of the Precision Mic here with pics:
http://www.realguns.com/archives/035.htm
Check a few factory rounds to check if your headspace nut actually stops at zero on the dial. They sometimes can be off just a little. In other words your mic may show a minus .001 instead of stopping exactly on zero. Just to let you know that it's not always exact. My 30-06 Mic stops on zero on factory cases while my .223 stops at minus .001. Using the freebore tool to check distance to the barrel lands is tricky. Takes some experimenting with tension and several tests loading and measuring to get good results. Great tool for checking headspace but not quite so great for checking freebore but it will give you useful results.

F. Guffey · November 19, 2008, 10:34 AM

Lilswede1, I can not help you, I started doing it wrong a long time ago, I made my own gages, I am not inhibited or restricted with specific adapters for each chamber and or caliber, tools are tools, the difference is in how the tool is used and who is using them, and I have nothing to gain by selling you on the ideal 'purchase' another tool is the answer.

MAX OAL is obtainable in .000 thousands without consideration to head space and a head space does not tell the user the amount of head space a chamber has, if the go-head space goes, it only tells the user the gage will go, it does not indicate the amount of head space the chamber has. MAXIMUM OAL for a chamber can exceed the maximum length that can be feed through the magazine.

Max OAL without consideration to powder charge and the ability of the bullet to conform to the diameter of the barrel can have disastrous results, Remember, some rifles were designed for free bore for the designers HOT loads, inadvertently the designer protected the re-loader from himself by building the rifle with a short magazine, it is not easy to protect one from one self.

F. Guffey

jaguarxk120 · November 19, 2008, 11:03 AM

You can go to the RCBS web site and they have the instructions you are looking for in pdf. format. Download and print them off.

Tom F

November 19, 2008, 12:14 AM	#1
Lilswede1 Senior Member Join Date: September 8, 2008 Location: NW Wash State Posts: 216	RCBS Presision Mic Just ordered the RBS Precision Mic for .223 from Cabelas. Could someone give me a blow by blow description of the process so I will be a little bit ahead of the game when it gets here? Also ordered the Hornaday Lock-N-Load OAL Guage in several different calipers and would like to know, step by step, how it will work. Thanks

November 19, 2008, 04:13 AM	#3
rg1 Senior Member Join Date: November 6, 2001 Posts: 1,125	Detailed use of the Precision Mic here with pics: http://www.realguns.com/archives/035.htm Check a few factory rounds to check if your headspace nut actually stops at zero on the dial. They sometimes can be off just a little. In other words your mic may show a minus .001 instead of stopping exactly on zero. Just to let you know that it's not always exact. My 30-06 Mic stops on zero on factory cases while my .223 stops at minus .001. Using the freebore tool to check distance to the barrel lands is tricky. Takes some experimenting with tension and several tests loading and measuring to get good results. Great tool for checking headspace but not quite so great for checking freebore but it will give you useful results. Last edited by rg1; November 19, 2008 at 04:21 AM.

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November 19, 2008, 12:46 AM	#2
Tex S Senior Member Join Date: November 12, 2008 Location: Fort Worth, TEXAS Posts: 909	I would also like to know how the Precision Mic. works.

November 19, 2008, 10:34 AM	#4
F. Guffey Senior Member Join Date: July 18, 2008 Posts: 7,249	Lilswede1, I can not help you, I started doing it wrong a long time ago, I made my own gages, I am not inhibited or restricted with specific adapters for each chamber and or caliber, tools are tools, the difference is in how the tool is used and who is using them, and I have nothing to gain by selling you on the ideal 'purchase' another tool is the answer. MAX OAL is obtainable in .000 thousands without consideration to head space and a head space does not tell the user the amount of head space a chamber has, if the go-head space goes, it only tells the user the gage will go, it does not indicate the amount of head space the chamber has. MAXIMUM OAL for a chamber can exceed the maximum length that can be feed through the magazine. Max OAL without consideration to powder charge and the ability of the bullet to conform to the diameter of the barrel can have disastrous results, Remember, some rifles were designed for free bore for the designers HOT loads, inadvertently the designer protected the re-loader from himself by building the rifle with a short magazine, it is not easy to protect one from one self. F. Guffey

November 19, 2008, 11:03 AM	#5
jaguarxk120 Senior Member Join Date: February 28, 2008 Location: Michigan Posts: 2,619	You can go to the RCBS web site and they have the instructions you are looking for in pdf. format. Download and print them off. Tom F