Is Something Like A Rcbs Precision Micrometer Necessary For Case Prep

[WolfFox]

I will be using a Dillon 550 and/or a RCBS Rock Chucker for resizing my .223 and someone told that I need something like a RCBS Precision Micrometer for chamber headspace and bullet seating depth. Is this something that is good to have or do I need it? I don't mid getting one if I will need it. Thanks in advance

Edited February 15, 2006 by WolfFox

[ihatepickles]

The RCBS case micrometer is a good tool for accurate rifle reloading. The principle is this:

Fire some rounds in your .223, and then put them into the case mic. This will give you an imaginary number that indicates the max shoulder length for that particular rifle chamber. Now, when you goto reload those .223 cases, you can use the case mic to help setup your resizing die to only bump the shoulder back enough for safe feeding. Generally, a bolt gun only needs the shoulder bumped back .001" or possibly no bump back at all. An autoloader, will probably need .002 to .004 of a shoulder bump to reliably feed the case. When I was shooting NRA service rifle, I bumped my shoulders .002 and never had a misfeed. I had a very good chamber however, done by a very good gunsmith.

You'll save your brass some undue stress by following this proceedure as well as improving the accuracy. To what extent the accuracy is improved, I can't say. Basically, by only resizing the cases just enough to feed and chamber, you reduce one of the dynamic aspects of firing the round. The brass doesn't have to stretch as much to reach the shoulder of chamber.

You don't *need* this tool, but you'll find that it's not a time consuming process really. Once you know where a particular rifles shoulder is, you use the imaginary number to set the dies up and move ahead. Since it's not a huge hassle, I'd say go for it. It's not a total pain in the butt step like neck turning or bullet/case weighing so why not take the extra 10 minutes?

Oh, and I forgot to mention, I never used the RCBS case mic for bullet depth since I felt it was too slow. I prefer other tools for that, the Davidson bullet depth indicator is good and fast.

[AlamoShooter]

The RCBS case micrometer is a good tool for accurate rifle reloading. The principle is this:

Fire some rounds in your .223, and then put them into the case mic. This will give you an imaginary number that indicates the max shoulder length for that particular rifle chamber. Now, when you goto reload those .223 cases, you can use the case mic to help setup your resizing die to only bump the shoulder back enough for safe feeding. Generally, a bolt gun only needs the shoulder bumped back .001" or possibly no bump back at all. An autoloader, will probably need .002 to .004 of a shoulder bump to reliably feed the case. When I was shooting NRA service rifle, I bumped my shoulders .002 and never had a misfeed. I had a very good chamber however, done by a very good gunsmith.

You'll save your brass some undue stress by following this proceedure as well as improving the accuracy. To what extent the accuracy is improved, I can't say. Basically, by only resizing the cases just enough to feed and chamber, you reduce one of the dynamic aspects of firing the round. The brass doesn't have to stretch as much to reach the shoulder of chamber.

You don't *need* this tool, but you'll find that it's not a time consuming process really. Once you know where a particular rifles shoulder is, you use the imaginary number to set the dies up and move ahead. Since it's not a huge hassle, I'd say go for it. It's not a total pain in the butt step like neck turning or bullet/case weighing so why not take the extra 10 minutes?

Oh, and I forgot to mention, I never used the RCBS case mic for bullet depth since I felt it was too slow. I prefer other tools for that, the Davidson bullet depth indicator is good and fast.

+1 well said ...but, the last part about bullet depth. If you plan to shoot longe range & If you have a bull barrel with 1in 9 or 1in8 twist for shooitng out past 500 yards, the only way you will get the best results for 'long range' - over 500 - is by seatting the bullet out and useing 69gr-75 gr bullets.

The bullets will not fit in the magazine and will have to be shot one at a time.

a barrel with a 1-8 twist will not shoot the 55 gr bullets as good when you push them fast. You will probley have to keep them below 3,000fps to get a good group, the light bullets 50 and under are too short to matter much

Edited February 15, 2006 by AlamoShooter

[WolfFox]

The RCBS case micrometer is a good tool for accurate rifle reloading. The principle is this:

Fire some rounds in your .223, and then put them into the case mic. This will give you an imaginary number that indicates the max shoulder length for that particular rifle chamber. Now, when you goto reload those .223 cases, you can use the case mic to help setup your resizing die to only bump the shoulder back enough for safe feeding. Generally, a bolt gun only needs the shoulder bumped back .001" or possibly no bump back at all. An autoloader, will probably need .002 to .004 of a shoulder bump to reliably feed the case. When I was shooting NRA service rifle, I bumped my shoulders .002 and never had a misfeed. I had a very good chamber however, done by a very good gunsmith.

You'll save your brass some undue stress by following this proceedure as well as improving the accuracy. To what extent the accuracy is improved, I can't say. Basically, by only resizing the cases just enough to feed and chamber, you reduce one of the dynamic aspects of firing the round. The brass doesn't have to stretch as much to reach the shoulder of chamber.

You don't *need* this tool, but you'll find that it's not a time consuming process really. Once you know where a particular rifles shoulder is, you use the imaginary number to set the dies up and move ahead. Since it's not a huge hassle, I'd say go for it. It's not a total pain in the butt step like neck turning or bullet/case weighing so why not take the extra 10 minutes?

Oh, and I forgot to mention, I never used the RCBS case mic for bullet depth since I felt it was too slow. I prefer other tools for that, the Davidson bullet depth indicator is good and fast.

Thanks a bunch! That is what the other guy was telling me, but you put it into words to where I could understand it. This is a great site and being a newbee you guys will be hearing from me again!

Edited February 16, 2006 by WolfFox