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Rcbs Precision Mic Neccesary?


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With an acurate = sub MOA rifle amoe you want the bullet out long almost touching the rifleling in the barrel. with an AR that means it will not fit in the magazien = So ... You probly are not intersted in bullets that will not fit in your mag...? right?

Some Ar's are built to shoot long range = Glen D. Zediker's Book is very good

What you most likely want is a bullet that will shoot good out to 300 yards and fits and feeds from a 20 round mag... right?

and you will want to put a crimp on it so that it will not change when it gets bumped in the mag. .. so you may want to just set it in the Cannalure ...If the bullet has one.

So don't worry be happy just lube the brass and load like pistole bullets.

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The RCBS precision mic is used to measure the headspace of you chamber. You take a measurement with a fired case and compare that to the measurement off a resized case. By adjusting the sizing die, you can still have the sized cases fit in your chamber without sizing them more than you have to.

So, no, you don't have to have one. That being said, I use the same type gizmo from Stoney Point. For ARs, I use the most conservative figure for all my chambers so the ammo will work in any of them. For my National Match AR, I set the sizing die to bump the shoulder back just enough to ensure function.

Like AlamoShooter said, probably more appropriate in a bolt. Get Glen Z's books on ARs and Handloading. Money well spent.

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The RCBS precision mic is used to measure the headspace of you chamber. You take a measurement with a fired case and compare that to the measurement off a resized case. By adjusting the sizing die, you can still have the sized cases fit in your chamber without sizing them more than you have to.

So, no, you don't have to have one. That being said, I use the same type gizmo from Stoney Point. For ARs, I use the most conservative figure for all my chambers so the ammo will work in any of them. For my National Match AR, I set the sizing die to bump the shoulder back just enough to ensure function.

Like AlamoShooter said, probably more appropriate in a bolt. Get Glen Z's books on ARs and Handloading. Money well spent.

Can you still get your rounds in the mag? I had to go singal shot with the 75s

But my chamber is "Wilde'/? did I say that right.

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I don't have a lot of use for the RCBS Precision Mic. The bullet seating 'tool' is largely useless (doesn't accurately relate to any bullet profile I use), and for $35-40, you get to measure the headspace of *one* cartridge type (outside of some 'families' like .243/.260/.308, but RCBS wants you to buy one of each... yeah, right). With a Stoney Point tool... you can measure the headspace using your dial calipers (which every reloader has, right?) or accurately measure your seating depth, etc.

For mag length AR stuff... I'd measure the headspace of your fired cases, then set your sizing die so it bumps the shoulder back several (3-4) thousandths, less (1-2) in a bolt gun. Should work well, last long time, etc.

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  • 11 months later...

The precision mic is very helpful for loading belted magnums (300 win mag ) where the excess headspace creates a donut at the base of the brass. For the 223 I would guess it is not necessary. It is usually only needed after 3-4 firings anyway. My 223 brass never lasts that long not to mention I have not heard of many people shooting 223 enough times to get the case to stretch far enough for there to be a need.

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Smoknshawn,

What are you doing to your cases that they only last 3-4 firings?? Got WAY more than that when I was shooting an AR in highpower but only set the shoulder back 3-4 thou as measured with the RCBS Precision mike. IMHO, it is a very useful tool to maximize case life in any caliber.

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