.223 Case trimming

Greyhunter

Greyhunter

New member
I'm reloading .223 for my AR's and I enjoy most of the process, except case trimming of course. I was just in my war room looking at the 1,000+ cases that need trimmed and its almost depressing. So if you have the time I'd like some education in this department.

I believe max case length for .223 is 1.760" and trim to length is 1.750". I know that years ago I reloaded alot of cases w/o trimming (didnt even own a caliper then) and I have a buddy that said he has never trimmed a .223 case. When I load for accuracy I now trim every case, but I have skipped this when loading cheap FMJ blasting/SHTF ammo.

So what is your proceedure? Do you trim every case or just those over a certain length? And how many firings do you get before you have to trim that case again?

At what point does excessive case length become a problem, and what problem does it create? Can they actually stretch enough not to fit in a 5.56 or Wylde chamber?

How much does varying case length affect accuracy? I loaded some Rem 55gr FMJ's into LC brass w/o trimming and got 2.5"-3" groups. The same rifle and same powder/primer combo (this time trimmed Winchester cases) produced .5" groups on the same day with 60gr Vmax. I dont know whether to attribute that difference to the trimming or the bullets. Those LC cases vary from 1.755" to 1.780" on the upper end.

I've been using the Lee hand trimmer and cordless drill method. I'm wondering if I would find a Gracie type trimmer to be worth the money...
 
I dont crimp any of my .223 rounds. Maybe I should on those FMJ's since they have a cannalure? They were the cheapest bullets I could find and I didnt expect much from them, but wow, did those loads suck. Tried several powder charges, same result.
 
No, you don't need to crimp, I was just wondering if that was causing the problem, because if you DO crimp, you need to have all the cases the same length or you get neck tension problems, or bulged shoulders.

here's what I do:

I size the cases and set the trimmer up to trim .010 shorter than the trim length (1.740) and run everything.
Once in a while I'll check one to make sure it hasn't grown past 1.760. Mostly I've found they never get there before I've lost them or the primer pocket wore out or the neck split.
I've never had a problem doing it that way, but I'm only loading for semi-autos and using small-base dies, so my ammo rattles around in the chamber a bit anyway. I can't seat to the lands and still feed out of the mag., so I don't feel I'm losing anything by sacrificing the .010 of neck.
Somebody will most likely come on here and tell you I'm crazy to not follow the trim length recommendation, but that's the way I do it. /ubbthreads/images/graemlins/confused1.gif
 
Well I wont have to worry about anyone calling me crazy because the Lee trimmer wont let me adjust the trimmed length. It just does what it does. After playing around with the calipers I see that I'm not terribly consistent with this setup, as even my trimmed cases will still sometimes vary .005". I'm probably getting sloppy while trying to watch TV at the same time and sometimes it unscrews from the handle just a bit not allowing it to trim fully if you dont catch it. Despite this I still seem to get very acceptable groups with quality bullets.

I suppose I should set up some test batches and purposly not trim 2 out of 5 or so and see if they cause fliers in the group. But there I go experimenting and blowing the $ savings, lol.

This is what I love and hate about rifles. Accuracy is fun but it drives you bonkers at the same time. For now I'm wondering what the worst case senario is for shooting excessive length cases and I suppose trying to justify some laziness. Thanks for the opinions.
 
Chuck up your Lee trimmer in a drill press. You can really turn out a bunch in a short time. Don't even bother to use the shell holder, just bottom it out on the drill press table.
 
Quote:
For now I'm wondering what the worst case senario is for shooting excessive length cases



Well, if they get longer than the chamber, the case gets "crimped" by the free-bore and your pressure goes way up. From the reamer specs., however, that length needs to exceed 1.772 for that to happen.

.223 Reamer Specs
 
Last edited:
Problems:

If your cases exceed chamber length you will get pressure spikes which could be dangerous. All chamber lengths will vary to some degree. The gage mentioned below will tell you what YOUR max length is.

The Sinclair Chamber Length Gauges are designed so the handloader can determine the true length of his rifle's chamber when measuring from the bolt face to the end of the chamber's neck. This measurement will tell you how much excess case length your chamber may have over published trim lengths in reloading handbooks.

The Sinclair Gauges are inserted into a fired, unprimed shortened case and then chambered into your rifle. The insert pushes back into the case when it contacts the end of your chamber. You then extract the case and measure the overall length. The gauge is made of 12L14 soft steel so it will not damage your chamber. Step-by-step instructions accompany each gauge. The gauges can be used over and over again. The gage costs about 6 or 7 bucks.

Accuracy:

The reason so many people go bonkers in case prep is for better accuracy potential. Trimming cases to the same length is one of them including: flash hole deburring, primer pocket uniforming, neck wall thickness, weigh sorting, etc. If you are concerned about accuracy I would at least trim to same length for consistent neck tension.

Just my opinion.
 
The max length where you are suppose to start trimming is a sammi spec. Most factory gun makers order their reamers to cut the the neck portion deeper than sammi just in case a reloader doesn't trim as often as they should. This spec was developed by lawyers. Like one of the above posters says, you will cause pressure spikes if the mouth of the case gets jammed against the end of the chamber. Your friend that never trims his 223 brass is just lucky with a very long neck cut chamber. I don't recommend pushing your luck. You could have a gunsmith cerrosafe mold the chamber. But do you really want to push your luck.

There are some good options out there. You can get a trimmer that is powered by a electric drill. Forster makes an attachment for their trimmer. RCBS makes a power trimmer I believe. There are two manufacturers that make powered trimmers that are real fast. Do a search in this forum for power trimmers and you should find some of these options. Others have adapted the RCBS case prep center with the lee trimmer. This allows you to trim, deburr at the same time. There are some utube links listed in this forum where guys have made little movies about this.

I didn't save any of these links because I already have a fast method for triming. It isn't cheap, but I start with a dillon 650 press. I punch the primer out on station 1. I trim with dillon's trim die on station three. Lastly I expand the neck with the lyman M die on station 5. My brass comes out resized and trimmed in one easy step. The only problem with this method is dillon only makes trim dies for the most popular of calibers.
 
Greyhunter, I use two Lyman trimmers. One is set for my .223s and one for my .204s..

CaseTrimmers.jpg


Both have been converted to allow me to use a cordless screw driver for power...

I will put the trimming operation right in to my normal case prep routine...Everything gets either Full Length or Neck sized (depending on its intended firearm), trimmed, chamfered & deburred, and them primed... Lots of times, I won't charge and seat until I'm ready to go to the range..

If, when I get to the trimming stage, the trimmers are preset and if it removes no metal, good... If it does, it saves me having to measure each one..

I don't crimp any of mine, normally, and a while ago I missed charging 9 of 50 and the neck tension was high enough that even though the primers ingnited, I didn't have any bullets stuck in the barrel...
 
This was the first thing I thought about when I got my Case Prep station. I just need to find a machine shop that can center the .223 cutter,tap the threads, and start trimming. Thanks for the Videos Bob. /ubbthreads/images/graemlins/grinning-smiley-003.gif
 
Necessity of trimming is sort of dependent on what you are doing. I trim all my competition cases to the same length every fifth or so firing. This is not because I need to, but I want everything as consistent as I can get it with competition rounds.

My pdog cases, OTOH, will get an initial trim, as much because it makes me feel good as anything else, and rarely ever get trimmed again....here's why.

Sinclair sells chamber length gauges (plugs, if you will, that insert into one of your fired cases that's had the neck trimmed down to .1" or so. This allows you to precisely measure the exact length of your chamber, so you'll know how long your cases can grow before trimming becomes a real necessity.

Most chambers, even custom ones, are cut considerably longer in this area than SAAMI "Max Case Length". YMMV, but I've found that to be true with all the chambers I've checked.

For instance, the .223 Rem has a published max case length of 1.760", with a trim to length of 1.750". My two .223 Rem chambers actually measure 1.782" and 1.777". My 6mm Rem has a published max case length of 2.233", and my actual chamber is 2.270".

Chances are, I'll never trim a case for any of these rifles because I have to.

The chamber gauges run around 7 bucks each (caliber specific), and if you hate trimming large volumes of pdog cases as badly as I do, they are the best reloading gizmo money you'll ever spend.

Mike
 
After measuring and noting that my chamber length was just over 1.772, I use the max length for the trim length. Since I only have one 223, and I only neck size cases fired in my chamber, I easily get by with the longer necks. The neck on a 223 Rem is short as it is, and a little more working length can only help with bullet grip. I try not to trim till after they have been fired in my chamber and either FL or neck sized. This is more important when your going to neck size. Case length is not very critical as long as it is .005 under the chamber length and your not crimping. I don't crimp any .223 rounds for my AR since I have not found it is needed or really desirable. This is just what works best for me, and may not be best in your rifles with your equipment and methods.
 
Back
Top