How often to trim 223?

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"...after every reload..." Isn't necessary. You trim only when its required. You check case lengths every time though. Lock your calipres at 1.750". If the thing is shorter than that it doesn't need trimming.
Do not forget that you must chamfer and deburr after trimming too.
 
Sunray said:
"...after every reload..." Isn't necessary. You trim only when its required.
Click to expand...
Necessary for what? To fire safety? That is true, but some folks want more consistent brass length for a couple of reasons. It certainly doesn't hurt. It's a personal choice depending on your wants and perceived needs.
 
I've reloaded several bottleneck cartridges from 22 to 32 caliber, rimless and belted ones. When fired, they all shortened 2 to 3 thousandths inch. After full length sizing, they grew about a thousandth more compared to last time. After the cases grew about .001" each shoot then reload cycle and lengthened about .010", I trimed them back. How much they grow when full length resized depends on how much fired case diameters get sized down then lengthens the case.

Never saw any accuracy difference in a .010" spread of case length for any of them. While the common reason to have case length the same for best accuracy is popular, how much difference in how tight the case neck grips the bullet (bullet release force is the standard) if it's contact area is that much shorter? How much does it change muzzle velocity or anything else you can measure repeatable? If the neck grips the bullet for .15" contact length, that's less than 7% difference across a .010" spread. Does bullet pull force and velocity change that much? There's typically that much and more spread in bullet pull force with all neck grip area the same.

What's a neck length gauge? Wilson case gauge or anything to measure from shoulder to mouth. That's what controls where the case mouth is relative to the chamber mouth. Rimless case length doesn't matter because the case head ain't against the bolt face when the round fires. If it's neck is too long, the chamber mouth angle works like conventional seating dies and it crimps case mouths into bullets from firing pin impact.
 
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I don't see in Sinclair's info for how much clearance is required between case mouth and chamber mouth. SAAMI specs for those dimensions can be calculated easy from their chamber and cartridge diagrams. Too bad that's not mentioned in that info. It's usually about .010 inch.
 
In my limited personal experience, I have found the following.

SAAMI specs are for maximum length of a cartridge to enable it to be used in a magazine.

One can go much shorter or much longer as long as the cases are sorted accordingly.
 
I don't understand where some people come up with this idea that SAAMI specs are "max" dimentions only, is this just an example of how some uninformed person spreads false information and it's simply repeated by others who don't bother to verify what they were told?

Look at the cartridge and chamber drawings and you'll see how wrong this "maximum" idea is. You can readily see that the cartridge maximum length is too long for most detachable magazines so that idea isn't valid and the fact that minimum specs are shown also debunks this rumor.

The dimensions shown in the SAAMI standards are based on a concensus of ammo and firearms manufacturers. These specs allow for safe pressures and more universal parts dimensions. The existence of SAAMI standards helped drive the Wylde chamber that enables AR owners to use both 5.56 and .223 ammo in the same chamber.
 
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I trim for length EVERYTIME. This is a safety issue. Why would I want to mess around with case gauges and calipers when I can just run every case very quickly thru my WTF2 trimmer? If the case needs trimming, its done, if it doesnt, it wont trim anything. It literally takes 2 seconds to do it.

Some guys always try to make everything difficult when its really not that hard.
 
Kaldor said:
I trim for length EVERYTIME. This is a safety issue. Why would I want to mess around with case gauges and calipers when I can just run every case very quickly thru my WTF2 trimmer? If the case needs trimming, its done, if it doesnt, it wont trim anything. It literally takes 2 seconds to do it.

Some guys always try to make everything difficult when its really not that hard.
Click to expand...

Same here, just run them all through the Frankford Arsenal case prep center after sizing........Done and doesn't hurt a thing or cost anything
 
Quote “The dimensions shown in the SAAMI standards are based on a consensus of ammo and firearms manufacturers. These specs allow for safe pressures and more universal parts dimensions.”


The above is true, and further, SAMMI specifications are designed to ensure all ammunition made will fit into all firearms manufactured for that particular round. They are a guideline which gives a min/max range between which everything remains safe. If you are really anal, you need to make a chamber cast of YOUR firearm and then you will know the maximum safe chamber clearance available in YOUR firearm. Armed with that knowledge, the maximum length you can allow your case to safely (without risking a pressure spike) grow is the point that the case mouth comes in contact with the front end of the chamber (neck) cut into your firearm. If you trim each and every time the case is fired, you can safely trim your cases to about 1 or 2 thousandths less than this maximum chamber measurement. Will that assist accuracy?? Maybe it will but you need to try in YOUR firearm to see. Except (perhaps) in a custom made firearm, SAMMI measurements will still leave a safety margin with respect to the maximum OAL case length that can safely be used.
 
I have WFT so any more I don't bother to measure them to see if they need to be trimmed, faster to just run them all thru the WFT (set to 1.750) If they are long they get trimmed if not they don't.
You
I always resize/deprime before trimming.
 
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