223 load work up

[bradhall]

Relatively new to reloading, about 500 rds done in the past year. Trying to workup a new load for 223 with Varget and 69 grain SMK. Shot today with 23.5, 24, 24.5, 25, and 25.3. Best group was with 25 gr at 0.84" at 100 yards. I have a few questions, the more I read the less I understand.

1. Is the lateral string in this group indicative of anything? Shooter, load, rifle etc...?

2. I sat the bullets at the book recommended 2.235". I checked the COAL on the rifle with the hornady gauge and I have a lot of room to go up. Yes I need to use magazines. How should I start to increase COAL? Should I start with the powder charge that worked best, or will that invalidate the results I found at the previous COAL?

[michael1778]

Vary seating depth with the most accurate charge you determined in step one. But, you should definitely check your magazines for max length possible.

Why Varget?

Have you tried a 75-77 grain bullet yet?

What is your barrel twist rate and length?

[bradhall]

1:9 16 inch. Varget just because that's what I could find and seems to do well with heavier bullets. No 77 because of twist rate and had great results with Federal gold medal 69 SMK. Also don't want to go any lower on velocity.

Edited September 13, 2015 by bradhall

[BitchinCamaro]

Once you find your max mag length, back off a few thousandths just to fend off a show-stopper.

Because of differences in meplat and user error, I jammed a mag in the middle of a stage with a 69g nosler hollowpoint loaded to what I thought was mag length.

Now I load to mid-cannelure. I think it's somewhere in the 20 thou range short of mag length, and hugely short of max chamber length in all of my barrels.

Basically for load development I use the cannelure as a reference- top, middle, bottom crimp within the cannelure are my 3 starting COALs and that helps narrow down where I start load development. I can always find a MOA node within 2 or 3 grains, and from there I can tune the charge to tighten down the groups.

There may be a super-sub MOA combination somewhere in there, but with COAL really short of what can be accommodated by the chamber, having 3 gross starting lengths really helps cut down the OCD.

[adamge]

Camaro, how critical is getting the resized cartridge headspace close to your chamber's actual headspace?

[BitchinCamaro]

I am not an expert reloader by any means - the above advice was just based on my own screw-ups. Personally though, I don't think that obsessively matching chamber headspace is practical or even useful for volume shooting using mixed brass. Getting a good match of COAL and charge is "good enough" for multigun, and sub-MOA groups are usually the result.

Others with more experience can chime in, but for ARs I think that there is definitely a point of diminishing returns when it comes to reloading .223 that's mostly going to poke 2 holes in cardboard.