9mm Minimum Case Length

[Elric]

9mm Minimum Case Length

www.xdtalk.com

noylj

>I'm interested in why you think the longer cases might result in a more accurate cartridge. Another viewpoint might be that the shorter case would let the cartridge go further into the chamber, bringing the bullet closer to the rifling so there is less "jump" for the bullet to engage the rifling.

With a short case, the case is held back by the extractor, but only on that side (so, the case will be held slightly crooked to the bore axis—and it certainly will be when the firing pin hits it)—not exactly the ideal head-space method. Then the firing pin impact can't be as good as having a case head actually against the breech face, so maybe you get a slower/delayed primer burn and powder burn? I don't know.
Why do I *think* the longer cases are more accurate?
Because I have tested them and that is what I found. I load to the longest COL that will feed and chamber, so my bullet distance to the rifle lede is minimum to start with.
So, for my off-the-shelf 9x19 guns and shooting no farther than 50 yards, the things that I found that have improved accuracy in 9x19 are:
•slow powders (slower than Unique but no faster than AA7)
•mid-range to max loads
•115-124gn JHP bullets 0.356-0.357" in diameter
•COL as long as possible
•Cases as long as possible to minimize head space
But please, do your testing to verify a different viewpoint. That is part of the fun of reloading. Just stay safe and let us know.

 

[Jäger]

I (and many others) spent many hours trying to up my 9mm game when 9mms joined the .38 Spl. in PPC when the switch from revolvers to pistols in the police world became overwhelming and PPC followed along. (and more unique matches to shoot in after travelling to a weekend match was never a bad thing).

Sorted brass by head stamp, trimmed the longest cases I could find to the most uniform case length possible within that group of cases, then sorted the trimmed cases by weight, etc. Trimming 9mm didn't seem to make any more difference than trimming .38 Spl. Tried every variant I could think of on cases.

Nothing concerning case length made a significant amount of difference for most guys I shot PPC with.

You would think it would make a significant difference; I wonder what the Bullseye crowd does with their pistol brass as far as reloading?

 

[JustJim]

I've known guys who trim their brass for Model 52s short (like maybe .1" below minimum) to get everything the same length and reduce the powder room. Others trim it long (one guy even used trimmed-back 357 mag brass) to precisely match their chamber. Didn't matter, they both outshot me--I never liked the Smith autos. In the match guns, I think it is more important to have everything the same, for psychological reasons if nothing else.

In my limited PPC-like shooting (1984-ish), I used mixed brass. I'd been shooting 500-1,000 rounds a week DA for years, and was too young/inexperienced to realize better ammo would have helped.

 

[Jäger]

I've known guys who trim their brass for Model 52s short (like maybe .1" below minimum) to get everything the same length and reduce the powder room.

Well, if they ever decide to sell a magazine or two, they should try the price they're looking for on me. It looks like they've become a collector item.

In my limited PPC-like shooting (1984-ish), I used mixed brass. I'd been shooting 500-1,000 rounds a week DA for years, and was too young/inexperienced to realize better ammo would have helped.

Probably not, at least around then. The difference between the ubiquitous Federal Match used back then by those issued it by their departments and those who bought it because the Big Dogs used it at big matches, and good handloads, was small to non-existent.

I still have the targets I shot with my 1500 revolver back then at 50 yards, when I fired 24 Federal Match to compare to 24 rounds at the same distance with my handloads using 231 and Bullseye. The handload I chose grouped pretty much identically to the Federal Match - both would hold the x ring at 50 yards. Still do out of the same 1500 gun.

A better 1500 GUN might have made a difference, ammunition probably not.

When I was really serious, I didn't shoot all that much each week - but I religiously dry fired at home for an hour after getting home from work.

 

[JustJim]

I wanted to learn to shoot DA, so I shot a lot. I remember when I was 16 or so, I "discovered" you could shoot a Smith single action, I think I had forgotten!

I sold my Model 52 a while back, might still have a magazine around. I'll keep you in mind in case I run across it.

 

[Jäger]

Why thank you very much.

 

[Petrol & Powder]

I'm trying to follow this thread and I'm having some difficulty.

So, I'm just going to toss in here:

I have gone to extremes in attempts to squeeze more accuracy out of handgun & ammunition combinations. Some efforts proved more beneficial than others. I can't recall the last time I trimmed handgun brass. I've done it, but it wasn't worth the effort.

In my efforts to squeeze the last little bit of potential accuracy out of a cartridge/gun combination I've sorted brass by headstamp, trimmed casings to uniform length, hand weighed each charge, sorted bullets by weight, played with seating depth, adjusted the amount of crimp, etc.
I've done just about everything short of the occult.

General attention to detail and consistent (but not extreme) loading practices seem to produce ammunition that delivers acceptable accuracy. With handguns, I think the shooter will often be the weak link.

Years ago I was at a range with an acquaintance and we both had new 1911 style pistols chambered in 45 ACP. His was a new "out of the box" Les Baer and mine was a new "out of the box" Kimber. My gun cost about 1/3 what his did at the time. He was a better marksman than me. My Kimber shot every bit as good as his Les Baer. We swapped pistols, no difference. We swapped ammunition, no difference (I was shooting 230 FMJ reloads, he had factory 230 gr FMJ ammo).
I walked away from that with an epiphany. Given decent gear, the shooter is the key.

 

[Winelover]

Who measures 9 mm brass? Or any pistol brass, for that matter. Never did, in close to fifty years of reloading. Trimming

I separate by head stamps, only. Have reloaded 9mm brass 15-20 times, including S&B. Toss, mostly, because the brass balks when inserting it in the shell holder. Damn extractor chews up the rim, after multiple reloads.

 

[CZ93X62]

^^^ THIS! ^^^

 

[Petrol & Powder]

With 9mm, I don't even bother to sort by headstamp anymore, it just isn't worth the effort. I inspect the case before it goes in the press to make sure there isn't a rock or spider web inside the case, but that's about it.

In my quest to find the balance between effort of production and results when shooting; I found a lot of techniques just don't produce significant results.

Techniques that do work (at least for me) include: sizing bullets to fit revolver throats, using a powder that meters well, matching the powder burn rate to the case capacity and using a consistent technique with the progressive press.

It may be possible to squeeze a little more accuracy out of a handgun cartridge with some intense attention to detail. I've done it and improvements are possible, BUT the work isn't worth the payoff. There comes a point, and you reach it pretty quickly, when extra work doesn't decrease the group size enough to justify the extra work.

Spending hours upon hours to assemble handgun ammunition that produces 1.95" groups as opposed to 2.00" groups - isn't worth the time. Producing more ammunition so that you can shoot more, IS worth the time.

NOW, none of this applies to rifle cartridges. Rifle cartridges are a completely different situation. I will spend the effort to make incredibly consistent rifle ammunition.

 

[Winelover]

Agee, up to a point. Some of that thinking changed, I purchased a 9mm carbine.

 

[Walks]

Don't think I've ever measured a 9mm case in my life (66).

 

[Matt]

In my experience measuring and or trimming auto pistol brass has not achieved any noticeable improvement in accuracy . I’ve only tried in years ago in .45 ACP But keeping brass segregated by lot is easy to do and might show some improvement. I’m not a good enough shooter to know the difference and I don’t own a Ransom Rest or other machine rest. I don’t believe that 9mm, .45 ACP, or 10mm headspace in the case mouth in common auto pistols. The case head is held to the breech face by the extractor. In my Ruger 10mm M1911 I can shoot .40 S&W with the same accuracy as 10mm ammunition. Roll crimped .45 ACP (using my Ideal 454423) works very reliably in 1911s for the same reason. They do not work well in a S&W M 1917 using 45ACP brass. That revolver actually head spaces in the case mouth.