Trimming necked cartridges

[five.five-six]

I have done a bunch of .223 and some .308 but now I am on to .300WM and that brass is expensive so I do not want to mess it up

Do you trim the cases before or after sizeing?


I have done a few and it seems they grow 3-5 thousandths in the sizeing die.

[Apex360]

I trim after sizing.

[scotty99]

Size then trim. Don't forget to deburr after trimming.

[koehn,jim]

I size than trim,also de-bur and clean the primer pocket.

[five.five-six]

ok, so

size → trim → deburr → clean pocket → uniform flash hole


Is that right?

[CABrainerd]

ok, so

size → trim → deburr → clean pocket → uniform flash hole


Is that right?

Correct.

The 300WM is is an especially high pressure cartridge, it's one of those that might benefit from annealing.. I haven't done it myself, maybe someone else can chime in? It might prolong the case life since there is so much stretch and hardening in the neck when re sizing..

You only need to uniform the flash hole the first reload on surplus/NATO brass IMO.. You can do it on commercial brass if your a stickler for detail, but they usually come relatively good to go out of the box and I haven't noticed any accuracy difference or reliability advantage in doing so..

[five.five-six]

Can I anneal with a common propane torch?

[Bill Steele]

No need to trim unless you full length resize. It is the process of resizing that causes the growth in case length. You can neck size if you are shooting a bolt gun and it will help with case life and you won't have to trim.

Annealing will help with your neck tension. You can anneal with a propane torch. I use a deep socket (appropriate size so case fits) as a holder and chuck it up in a cordless drill. I use 10 seconds in the flame as my nominal time, some thicker headstamps need a little more, thinner a little less but usually within a second or two. When they come out of the flame I drop them in a stainless tray to cool. Not the ideal way to anneal large amounts of brass if your are making blasting rounds for pretend army stuff, but fine for bench shooting and hunting applications.

[CABrainerd]

Can I anneal with a common propane torch?

Yes. From what I've been told, heat till' purple but not glowing 2/3 down the case up. Do a little research because there's a fine line between just right and too much. I don't load any rifle rounds except 5.56 and 7.62 which don't require it, but I know guys shooting the hotter rounds that stretch more swear by this step to prevent separation of the neck.
-Chris

Looks like Bill beat me to the punch.. ^^ =P

[five.five-six]

I am ranging targets at 6-700 yards, this is not "blasting ammo"

[Bill Steele]

I am ranging targets at 6-700 yards, this is not "blasting ammo"

My point is for 50 or so at a time, the propane torch and socket in a drill motor approach works fine, for more than that, it gets pretty tedious and an automated approach will definitely look better.

Annealing will improve your neck tension consistency, which tends to help with your groups and SD's.

[Whiterabbit]

700 yards? blasting ammo is fine for that. Unless my standards for blasting ammo are higher than yours, but I don't wanna imagine how lax you'd be loading compared to me! I can load pretty darn lax and seems to shoot 700 OK.

Anyways, size then trim. You wouldn't want to trim the the edge of spec then size it and be too long again.

But you already knew that.

you can also stand brass in a tin of water for annealing. where the brass is in water will never go over 212F.

[popeye4]

If you really want to get crazy with annealing: http://www.giraudtool.com/annealer1.htm

[five.five-six]

700 yards is not exactly point blank, you have almost a full seccond of time in flight.

[mark501w]

Size, trim ,deburr, prep pockets. I don't anneal for fear of affecting the hardness of the base of case. Belted magnums head space on the belt & base of case. I believe that factory tolerences are a lot looser on the shoulder to base demensions , this allows the shoulder to be blown forward changeing the volume leading to problems setting your powder load max. After fire forming, put a small amount of lube on the neck & shoulder so you can see it,back off die so it sizes neck & just kisses the shoulder, check for functioning in your weapon. Since you are prepping pocket you might weigh cases & bullets take a average culling out the highs & lows.