Minimum case lengths on S&W 40 Cal


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HK SD9 Tactical
September 7, 2011, 12:36 PM
I bought a bunch of once fired (1000) Winchester range brass for re-loading for practice rounds. I may use some of the brass for carry rounds. During the cleaning and de-bulging process (using a Redding G-Rx push through die), I noticed that when I measured for case length many of the cases were below the published minimim case length of .840 (.850 max - .010 trim). Some cases were down to .832 in. I know that straight walled cases actually shrink after being fired and thus the "I don't ever trim pistol cases thing" that I read so much about.

Now I know that you want to keep a minimum of .400 seating (one caliber seating minimum). If I can maintain the minimum of .400 seating and stay within the published COAL, or the SAAMI COAL, or the COAL that I derive from my barrel, with there be a problem using this shortened brass?

I use a Lee FCD so the variances in the short case length is not an issue at this time.

Are there other things that I should be looking at using these short cases?

Firearm: H&K USPC .40 S&W FFDO (Fed Flight Deck Officer model - just means it has the LEO heavy trigger and Tru Dot night sights)
Powder: Ramshot Zip (faster) at 5.1 min to 5.7 max or Ramshot Silhouette (slower) at 6.2 min to 6.9 max (thinking more silhouette due to more powder in case) or Ramshot True Blue (slowest) at 6.3 min to 8.1 max (fullest case capacity). These are published loads for a 165gr JHP from Ramhot.
Projectile: 165gr Ranier Ballistics JHP (will use a 155gr Hornady XTP for carry and adjust accordingly)
Primer: Remington 5 1/2 SPP
COAL 1.124/1.135/1.135 or there abouts.....

I'll be loading these on a Hornady LnL AP with attached case and bullet feeder.

Cases were deprimed and cleaned using SS media. Cases were de-bulged as indicated.

Stn 1: Resize
Stn 1.5: Prime
Stn 2: Charge and bell
Stn 3: Bullet feed
Stn 4: Seat
Stn 5: Lee FCD and size check

I know about the powder check and plan to do so visually. Although I do have a RCBS Lock Out die, unless I do the seat and crimp in one station, I can not use it if I use the bullet feed die so I will visually check each case for charge.

TIA

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rcmodel
September 7, 2011, 01:14 PM
You may have to resize them before you can measure them.
The .40 case has a slight .001" taper, so I don't know if the Redding push-through bulge buster will return them to normal length or not.
They expand and get shorter when fired.
They get smaller around and longer when resized again.

BTW: My Lyman & Hornady books says .850" max, .845" trim length.

At any rate, I would not be concerned about it as long as the firing pin can reach the primer.

I have never measured or trimmed a straight-wall pistol case in 50 years of loading them.
Normal case length variation has no noticeable effect on a taper crimp when done in a standard auto pistol seating die.

Case length is only critical with a revolver caliber roll-crimp die.

I do "chamber check" them after loading by dropping them in a pistol barrel or case guage.
Never found one that was too long, or too short so far.

rc

Steve Koski
September 7, 2011, 04:13 PM
I've reloaded about 100k of .40 S&W and have never trimmed one. I think I stopped measuring them on day 2. Length doesn't matter in straight walled pistol cases. Load 'em up and shoot 'em.

HK SD9 Tactical
September 7, 2011, 07:00 PM
Thanks. I did not think that it mattered in straight wall cases.

243winxb
September 7, 2011, 11:42 PM
.840" SAAMI minimum. I would guess not a problem with an inertia firing pin, if the firearm has one? http://www.saami.org/PubResources/CC_Drawings/Pistol/40%20SandW.pdf

Steve Koski
September 8, 2011, 03:10 AM
The round functionally headspaces on the extractor anyway. Which is why you can fire a 9mm in your .40. Or a .40 in a 10mm, or a .45 GAP in a .45 ACP. (I'm not recommending this, just sayin'.)

Koski

PO2Hammer
September 8, 2011, 09:46 PM
I agree with Koski on this, chances are you're headspacing on the extractor. I've shot a few .40s in my 10mms over the years, no problems, measured my .40 barrels and compared them to the brass length, and I think I'm headspacing on the extractor there too.
Keep your COAL to spec's so that you are not deep seating your bullets, adjust your crimp die for you brass length and go.
The one caliber seating depth is a general rule of thumb, never let it override the COAL in the data you're using.

Keep in mind the the Redding G-Rx only returns the diameter back to normal all the way down, it doesn't re-thicken the brass that has been thinned when it bulged. Once that metal stretches and thins, it's never going to be the same.

I never try for max loads in the .40 with once fired brass. If you're going to load SD loads, I would recommend new brass.

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