Minimum case length for precision .223 rem?

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prairieguy

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Hello CGN.

I have a question about what the minimum case length of a .223 Remington case can be and while still being useful for precision reloading.

I recently obtained a large batch of once fired brass which I intended to use for loading in a precision / varmint rifle.

All brass is the same manufacturer and most from same lot# of ammo.

I went to start prepping the cases and have discovered that about 90% are shorter than the "trim to" length specified in most reloading manuals. Lapua and Hornady reloading manuals say max length is 1.760" and trim to length is 1.750".

The vast majority of my cases on hand are measuring between 1.741" and 1.735" with outliers to 1.755" and 1.725".

So, should I discard the entire lot or set a "trim to" length at 25 thou below recommended at 1.735" and hope for the best?
 
I'd run them, no problem. When I was trimming I was aiming for about 1.742", because I'd rather trim lower than "optimal length" so that the case gets more firings before it is "over length".

The only thing case mouth length dimension affects is where on the bullet it touches the case. As long as you are still on the widest part of the bullet, I can't see it being important where exactly that is. I mean, if you move your seating depth back by 0.020", in theory you should trim your neck another 0.020" shorter to maintain the same contact point on the bullet. But no one does that, and no one says you should do that, so evidently it isn't important.

Another reason to trim shorter, is that if I trim at "optimal length" of say 1.750, then what do I do with all the cases that are already shorter than 1.750? Would I rather have an uncontrolled distribution of lengths of 'everything up to and including 1.750' or 'everything controlled at 1.735'? From a consistency and therefore accuracy standpoint, I have a hard time believing the former is preferable.
 
The important thing is that all cases are trimmed to the same length. If that happens to be 0.025" shorter than trim size, so be it. It should not affect your accuracy. Over the life of your cases, they will stretch and eventually come up to the "proper" trim length.
 
It will be good to hear if there is an "optimum" length. I am trying to make up some 9.3x57 cases from 8x57. Can not find the 9.3x57 brass in stock, thankfully - just way too expensive. Very hard to find any standard for what to trim 9.3x57 too - finally found a reference that suggested a length - every single converted case is less than that "trim to" length. Then did a chamber cast - the area in the 9.3x57 chamber cut for the case neck is like .20" plus longer than the case lengths I have now, so not a chance I will be "pinching" the bullets. As well, the same casting showed no way I will ever be putting a bullet into the lands - there is over 1/2" "free bore" (ball seat) in this barrel - more like the bullet rear end will have left the case, before the front end of the "fat" part of the bore-rider cast bullet hits the rifling - so I plan to just load to magazine length and go from there - not even close to a precision .223, but once you know that you have end-ways neck clearance, then diameter with bullet-loaded clearance, then magazine length, the rest might make a difference for you - will enjoy following how you make out. Had read that typically want to have one caliber grab on bullet within neck - not sure if more than that results in some effect on accuracy?
 
The only problem you might have with once fired brass is its spring back after sizing. Meaning this brass might not chamber in your rifle and you might need to size it once with a small base die.

If you have a problem with cases chambering then size them and pause at the top of the ram stroke for 4 or 5 seconds. This reduces the amount of spring back and might save the cost of a small base die.

So again these cases were fired and formed to another chamber and after sizing they want to spring back to their fired diameter. Meaning you may need more sizing effort and force them into submission to fit your chamber.
 
Since the brass is not all from your rifle you will need to do a good full length sizing on them, and you probably find some will have grown a bit when you measure after the FLS. Trim after FLS, not before.
 
jethunter said:
Since the brass is not all from your rifle you will need to do a good full length sizing on them, and you probably find some will have grown a bit when you measure after the FLS. Trim after FLS, not before.
Click to expand...

Agreed. Most of the time brass will seem to have shrank after fire forming. Proper full length resize will often stretch them longer than they were originally.

In my experience with reloading 223 Rem. this was especially true of Winchester brass.
This is likely the result of Winchester being thinner.
I find that Lapua, Lakecity 5.56, Federal brass grow in length too (but not as much as Winchester)
 
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