brass trimming

[survivalshop]

What do you trim your .223 brass to ? I just loaded up some 62 gr. Barns TSX bullets & made some of them to case length spec's of 1.760" & some trimmed to trim length spec of 1.750 " from my older Lyman 45 th edition hand book & the trimmed loads out shined the case length spec ones , big time on the target & grouping .

All charges were weighed on my new Pact electronic scale & all were compared with like charges .All were same name brass & close to same weights , as I always choose , all had Remington Bench rest primers , all same COL.

Rifle -AR ,24 "  ultra match HB., 5.56 chamber, S/S .

Results of Chronograph.

23.5 grs. WC 846 ( trimmed to 1.750")

Avg. vol. -2994 fps

ES ------- 10 fps.

SD ------- 5  fps.

23.5 grs. WC 846 ( trimmed to 1.760" if needed )

Avg. vol. -3000 fps.

ES --------18 fps.

SD--------- 9 fps.

24 grs. WC 846  ( trimmed to 1.750" )

Avg. vol. -3020 fps

ES ------- 5 fps.

SD ------- 2 fps.

24 grs. WC 846 ( trimmed to 1.760' if needed )

Avg. fps --3044  fps.

ES -------- 47 fps.

SD -------- 20 fps.

All the trimmed to 1.750" printed one hole groups @ 100yrds & the ones that are at case length specs of 1.760 " were spread out a little , still good groups but the 1.750 " were real good .

It may be that this chamber likes the one case length better than the other , but now I have to test in other calibers & barrel lengths , because in all my years of reloading , I have never done a test like this . I have always trimmed to the trim to length spec's from this manual .

Any one else trim as I do ?

[MikedaddyH]

I am doing a little over 900 rounds of LC brass with military crimps. Sorted the brass per height of 1.760" and less ,then inside and outside champher those cases. All cases over 1.760" get trimmed to 1.750" then champhered. The military crimps are a real PITA, been using the RCBS tool but can only do one tray of 50 at a time.

[Tripledeuce]

    Its possible, with your rifle ,that the 1.760 cases  are starting to run into the "end" of the chamber.

    Just a possibility, rember.

    Respectfully

    Terry

[survivalshop]

    Its possible, with your rifle ,that the 1.760 cases  are starting to run into the "end" of the chamber.

    Just a possibility, rember.

    Respectfully

    Terry

Ya , I thought of that , but 1.760" is the 5.56/.223 case length , as far as I can see ,in every one of my reloading manuals.

When I tested them , I staggered the loads so I know it was not jut me shooting better ( <laughs>) fat chance. I have never  trimmed any case , no matter what cal. to the factory case length , I have always used the trim to length # in this manual .

I just find it strange there would be a difference . Even stranger that I tested it at all . As said, I will have to try different calibers & bbl. lengths ,just because I'm curious .

Also this barrel is 1-10 twist & 24 " long , Barns instructions for the 62 gr. bullet said they are for a 1-9 twist & under . Maybe barrel length make a difference in bullet selection as much as twist rate does.

[survivalshop]

I just noticed the New 8 th edition of Hornadys loading manual ( I just got it , first new one in over twenty some years ) has trim to length measurements in it & the only other manual that gives that , is my old Lyman , that I spoke of . The Speer, Sierra & older Hornady manuals do not. 

This is good ,because I use a lot of Hornady's bullets & surprising.

[Dane Armory]

Ok guys I brought this thread back. I processed 450 cases of 223 brass this weekend. (out of 1600+)

 

My question is ... What is TOO short ??

I have around 40 pieces between 1.740" and 1.749"

Should I just toss them in with the 300Blk brass or used the ones up to a certain lenght ??

[planeflyer21]

Just found this subject a couple of months ago on sniper's hide...I think, in reference to .308 brass.

 

Find the SAAMI minimum length or the shortest stuff in your batches, and trim to that.

 

Jon

[392heminut]

I've loaded some that were 1.735 with no problems.

[survivalshop]

I think when you get to a point that the case doesn't support the bullet at your specified COL , the case length may matter , maybe not . It may also have a neck tension problem with some bullets with the case too short , so to speak .

I have found its more important to have them as close to the same length as possible & also with in a weight range for case volume . Pressure is important in keeping everything consistent from one loaded round to the other.

It's probably the same as with COL & I'm sure different bullet types & brands will act differently, depending on case trimmed or not trimmed length.

I know when I first started loading .223/5.56 , I didn't have a trimmer & they seemed to work , but at that time I was not loading for precision , just blasting away. now after all these years , I am more of a refined reloader ,not that I don't reload blasting ammo ,I'm just more picky about how I do it.

You may also run into chamber pressure problems with an over or under length case. Basically , if they are close ,it won't matter much , as long as they go bang safely .

[planeflyer21]

http://www.saami.org/specifications_and_information/publications/download/206.pdf

 

Page 41

 

.223 Remington

 

Case length 1.760" -0.020"

 

That means you're good down to 1.740"...just trim it all the same length.

 

The thread I mentioned before was on .308 Winchester (page 66).  A person had many that were 2.005" and was worried.  Another person spoke up how nobody ever talks about minimum cartridge length recommended by SAAMI, which with the .308 is 1.995" (a -0.020" tolerance from 2.015").

 

It is a good practice to have all your brass trimmed to the same length, for uniformity of the seated bullet giving the same COL cartridge after cartridge.

 

I load handgun brass at the lowest loads that cycle the semi-autos.  9mmx19 and .45acp brass varies 0.020" easily from case to case, brand to brand.  But you aren't dealing with 60,000psi chamber pressures either.

 

Some people at one of the ranges I use picke up any and all .223/5.56 brass and stuff it all, no trimming, with the cheapest primers they can find (think of that thread on the Korean tool shed).  They alternate between rounds that never fire to completely blown primers.

 

I don't shoot their stuff.

 

Jon

[Dane Armory]

So 1.745" should be a min/min length. Any thing shorter gets turned into 300blk,

[planeflyer21]

SAAMI says you can go that extra 0.005"...if you really need to.

 

Of course, if you have an operational .300 BLK do it.

 

Jon

[Dane Armory]

I got another Lee trim setup last week a finished 700 cases yesterday. They are being trimmed to 1.753" to 1.755".

[Dane Armory]

I finished trimming , champhering and priming 1720 223/556 brass cases. Mainly LC , PMC , Fed , RP and Win. There were over 1000 military crimps I did with a rcbs tool.

Used fed 205 , cci 41 , cci br4 , cci magnum srp and win srp.

Now I can start the fun stuff.

[Dane Armory]

Got a new Lee trimmer/cutter for 10mm piston cartridge and trimmed 59 peices today. It took 25 for it to break in , had to redo the first 20+ because they were .003" to long.

I / O chamfering and primed up the cases

[Justintoxicated]

I hate picking up federal 223 lately cause it's always short 1.740 or less I have tons of it and it just sits there.  Of course I trimmed as the last step after swaging like 1000 cases loI.  I always trim to 1.750 even if the brass does not really need trimming it gets chucked in the trimmer, cause it's easier to just process than measure then process.  This gives a more uniform crimp.

Edited May 28, 2013 by Justintoxicated

[survivalshop]

I like the case lengths as close as possible to each other , just for the crimp,if the bullet has a grove for it, Even if I'm using a taper crimp die.

 

Now I wonder if a case at the shortest posable length would make a difference with Chronograph results . Compared to , say one trimmed to the 1.750" spec., I guess I have to find out.