.223 Trim Length

[biged85]

Hey all,

 

Just wandering if any of you more experienced folk could advise me. I have used new .223 Lapua brass once, and then neck sized it. The case length is under 1.750 and the cases vary between 1.740 and 1.750. So far my research suggest being within this range is fine but what I can't seem to find out is if I should trim my brass to the shortest length for consistency?

 

Or should I full length resize and see if that stretches the cases a bit?

 

The reason I ask is my hornady brass stretches quite a bit and is full length resized after firing so I trim it down to 1.750 and it is now showing signs that it is more consistent than the lapua. The only reason I full length resized the Hornady is because it was once fired factory ammo from mine and a friends rifle and got mixed together.

 

Any advice is greatly appreciated.

 

My rifle is a Mossberg MVP 5.56/.223 in case that helps.

 

Ed

 

 

 

 

 

 

[ashcroft]

Interesting topic, trim length is usually 1.750 but I can't find any data on minimum safe length.

 

 

Be good to see if 1.740 is considered ok

[snakeman]

My understanding of the drawing is:

 

1.760 = being max overall case length

 

minus the .'030' = being minimum case length

 

Therefore minimum safe case-length would be; 1.730 ..(wouldn't go below this)

 

See link for .223 Sammi case dimensions: http://www.saami.org/PubResources/CC_Drawings/Rifle/223%20Remington.pdf

 

ATB

[biged85]

My understanding of the drawing is:

 

1.760 = being max overall case length

 

minus the .'030' = being minimum case length

 

Therefore minimum safe case-length would be; 1.730 ..(wouldn't go below this)

 

See link for .223 Sammi case dimensions: http://www.saami.org/PubResources/CC_Drawings/Rifle/223%20Remington.pdf

 

ATB

 

 

That does help, guess I will just have to see how I get on. I will be interested to see peoples views on trimming the brass to the shortest one in the batch.

 

Ed

[gbal]

Ed,keep some perspective on this-you don't want brass to be longer than the max (nor under the minimum)....but I would not reduce 'in spec' brass to the shortest case,certainly not if there was only one real shortie....even if there were a few,I'd load them as foulers.....

but even then...do holes on paper actually match onto brass length...ie does it make any practical difference....(given they are within specs).

If they shoot indistinguishably,just check every few loadings-trim any down to max as they stretch....but trim down 99 in spec to the one smallest...no (cull the one-fouler etc).

gbal

[snakeman]

If you have found some cases have shortened to 1.740, some to 1.742 etc etc and everything in-between, I'd just neck-size without trimming because when you full-length again you find they'll be close to 1.750; following neck-sizing, just chamfer inside & outside. Even neck-sizing can slightly put a thou or two back on case length.

 

After the neck size firing it's then I'd full-length size back to spec; then I'd trim only the cases that have stretched beyond the recommended trim length of 1.750 but the cases that are maybe just under spec, I'd leave alone. Your brass will become work-hardended.

 

If you trim all the cases back to 1.740 for 'consistency' you'll have to reconsider your loading... i.e charge weight and bullet weight, due to pressure increase

 

ATB

[biged85]

Thank you all for your advice, I shall do some further loading and see how I get on. Must look after this lapua brass, I want it to to last!

 

ATB

 

 

Ed

[Andrew]

Interesting topic, trim length is usually 1.750 but I can't find any data on minimum safe length.

 

 

Be good to see if 1.740 is considered ok

What the heck is "minimum safe length"??~Andrew