[The Bolt Man]

I have read several articals and from my own experience, found my 9mm shoots most accurately when the brass is .750" in length. The loading manuals show the 9mm case length to be .754" and trim length to be .751".

Someone please tell me why most 9mm brass measures .745" plus or minus .001-.002". New or once fired and resized makes no difference. I don't own a single case trimmer that will make a .745" length case into a .751" one.

It seems the gun industry makes chambers on the large side of the specs so any and all available ammo of that caliber will chamber easily. Then the ammo manufacturers make their ammo to the small or short side of the specs so it too will chamber easily.

What we end up with is a sloppy gun and more sloppy ammo which is not a good combination when accuracy is desired. In the case of the 9mm, 45 ACP and several in between, there is anywhere from .010" to .020" of slop for the cartridge to rattle around in the chamber. For a cartridge that headspaces on the case mouth, we end up with a cartridge that is held in place by the extractor. This is not good for consistent ignition or accuracy.

Who is wrong? The ammo manufacturers the firearms industry or the loading manuals.

It is no wonder many reloaders are disappointed with the accuracy of their ammo, gun or both. With conflicting data and sub standard fitting chambers and ammo, the task of developing accurate ammo in many of the auto loaders is nearly impossible.

I do not have a good answer for why these things are the way they are. Does anyone know of a brand of 9mm brass that is actually manufactured to the listed length of .754". I can use some. Of the more than 5000 rounds of 9mm brass I have, I will be hard pressed to come up with more than 200 rounds at .750". .754" is out of the question. I have seen none over .750". This is based on having sorted over 400 rounds and only 16 were .750" and none longer.

 

[recoil junky]

If the 9mm brass is like 45ACP brass, it shrinks when you shoot it. Might be what you're seeing.

RJ

 

[Jack]

Many years ago, when I was a lot younger and dumber (if that's possible), I measured a couple thousand 9mm cases for length - every brand I could find or scrounge. I never found a single one that measured .754 - everything was shorter.
My thinking was that I would load some 9mm's for accuracy with carefully headspaced cases. .
My conclusion was, after all that, that 9mm's effectively are aligned in the chamber by the extractor, not the case mouth.

 

[broom_jm]

This thread is helping to explain a mystery I'd never quite solved, before. When reloading for 30 Carbine, I've found it critical to keep the case length within +/- .003" or else they won't fire/chamber, since that round really DOES headspace on the mouth. I'd always wondered why I didn't have to trim 9mm cases to the same exacting tolerances...and now I know why.

(I've done very little reloading with straight-walled cases, until recently.)

 

[Marshal Kane]

IME, I've come to the realization that the quest for super accuracy in handgun ammunition is hampered by the method in which the gun is supported while being fired.

Is the gun being fired from a rest e.g. Ransom rest, off the bench from a sandbag, standing and one/two hand hold, etc.? Not to even mention the capability of the shooter.

My point being that you can assemble the most accurate handgun ammunition ever made and still get unsatisfactory groups downrange due to the shooters capability. In general, super accuracy is more attainable with a long arm than a handgun so if your ammunition is grouping about 3" at 50 yards (which is factory specs for match ammunition), you are just about max'd out in your pursuit of accuracy.

My suggestion would be to just shoot using your current 9mm brass and enjoy it. IMO, the 9mm, along with many other handgun ammunition, was never meant to be a "tack driver".

 

[stinky]

OK, I've heard about this, but forgotten almost all of it. You've undoubtably heard about how accurate the .45 acp is, and how inaccurate the 9mm is and that a 9mm cold never shoot w/a .45. (BTW, the same thing is said about the .38 Super vs 9mm)

Enter about the 1990's and S&W comes out w/the PPC9, which is used for PPC shooting and it outshoots a .45. It will hang w/them, if not clearly exceed them in accuracy. Nobody shoots a .45 in PPC now, as the accuracy is the same, but the recoil is a bit dif. My 5" will shoot 2" w/generic white box ammo and my 6", 1"...BTW, that is w/a 10 round mag, at 50 yards, out of a R-rest.

So, IF I REMEMBER RIGHT, what was needed to make the 9mm accurate was to tighten up the chamber dimensions. The 9mm chambers used to be loose (compared to a .45) and that the shell would float in there a bit (exactly like you said in your 4th paragraph) and S&W tightened up the chamber specs...being as there are several folks out there building 9mms that will shoot accurately, the word has spread).

I think that the thinking used to be that 9mms were often carried in a military environment and that the slop was needed in order to make them function/run when dirty. Now...I would submit to you that most, if not all, 9mm development has been done by the europeans, until recently, and that their work hasn't been wrong, as it clearly met, and exceeded their goals.

I submit to you, that all the ammo out there is made to specs...or atleast they attempt to. But, not all the chambers are made to specs. Now, I've heard that nobody makes a .357 chamber to specs, but that is a dif story (I don't know what it headspaces on, shoulder, or case-mouth).

I'm surprised that you say that your gun likes the cases short. I would think that it likes em long...or longer than you can find em at.

BTW, what are you firing them in? The next step would be a match bbl...w/a tighter chamber. My guess is, that a bbl is about the only way to fix your problem.

Star or Federal would be the first place to start to look for long brass as they make the most accurate 9mm ammo...you can take that to the bank (or actually, Atlanta uses Star to make their ammo).

 

[The Bolt Man]

recoil junky,

The brass I measured is new R-P and once fired Win, R-P and FC. With the exception of one box of (100) new R-P where I found (41) casings that measured ,749" to .750" all the other new R-P and once fired casings were around .745".

Jack,

I have never found accuracy to be best when the cartridges are held by the extractor rather than properly headspaced. I like many others have when using lead bullets resorted to adjusting overall length so the cartridge headspaces off the nose of the bullet when possible. This does provide consistent headspace. It may or may not be the best possible accuracy, but what does a person do when the industry only gives us sloppy material to work with.

Marshal Kane,

I feel a person has to understand whatever method used to test loads and gun for accuracy will likely be better than the method used for general shooting. Example: using a Ransom Rest for test a gun and load for accuracy should always out perform the shooter firing off hand standing without any form of rest. Using aids for testing accuracy is a necessary choice so some human error can be eliminated. I think we all understand shooting off hand, the group sizes are going to be larger.

stinky,

I agree with you. The chamber is probably the most important item. A tighter ( minimum dimension) chamber is necessary when best possible accuracy is desired. Also, when you say all ammo is made to spec, we still find that ammo usually has brass that measures only .745" in length and that length is seldom the best for best accuracy because it rarely headspaces on the case mouth as it should.

I didn't say my gun likes short cases. I said my gun shoots most accurately using the .750" length casings.

I shoot a Dan Wesson PM 9 that has a match grade chamber and has been fine tuned and fitted by Keith at Dan Wesson. I also shoot a Rock Island 9mm Tactical, which by the way in one heck of a shooter for an inexpensive gun. Very well fitted and never missed a lick. I couldn't say that about the tightly fitted PM 9. It took over (2500) rounds and about (3000) hand cycles of the slide to work it in so it would cycle without failures. Once worked in it has been a great gun and more accurate than I can be. That said, I am sure if I can come up with some brass that is long enough, I may be able to do even better, at least in the Ransom Rest. Then I will know what the gun is able to do for accuracy.

I also shoot a Star BM 9mm. It is a military style pistol similar to a 1911 in basic design. It isn't a tack driver, just a fun gun to shoot. Like any gun, it can be fooled into shooting better than it was disigned to with standard ammo. Reloading ammo allows us to better fit the ammo to the gun, tricking the gun into shoot more accuratey.

I am still looking for 9mm brass that is consistently .750" or more in length. All the Federal brass I have checked has been in the .745" range.

 

[recoil junky]

Try some Starline brass. That's what I use in my 40S&W and 45ACP. I don't shoot a 9mm so I can't "say" what it'll measure, but the other two are dead (+- .001-2) on for case length until they are fired, then for some mysterious reason they shrink.

RJ

 

[The Bolt Man]

recoil junky,

I called Starline this morning and asked what length they manufactured their 9mm brass to. The answer was .744" to .746". The reason was stated to be that length avoids chambering problems in tight chambers. I suspect most if not all the other manufacturers will be similar. I believe finding 9mm brass much longer than .746" is going to be very difficult.

.745" is the most typical length of hundreds of rounds of new and once fired brass sized in my RCBS steel sizing die. Once fired brass will most often come up a little shorter than unfired brass due to the case being expanded. Resizing helps establish the longest possible case length.

It is normal for 9mm and 45 ACP brass to be shorter after firing. Mostly due to expansion without stretching like a bottle neck rifle case. Most sizing dies do not restore all the new factory dimensions, especially near the base where most dies fail to resize. The result is brass that is shorter than it was before firing. Some testing with 45 ACP indicates continued firing and resizing actually continues to shorten the brass. It is believed this is due to the sizing die working the brass toward the base, causing the brass to flow in that direction. I did conduct this test and it is true, although after twenty firings, I measured an average of only .0006" shorter.

Non lubed carbide sizing dies increase the shortening affect slightly faster than the lube type steel sizing die.

 

[bobthenailer]

IF you want 9mm cases the correct length ? you will have to take the time and take at least a couple hundred cases of the same brand brass ,size it the ck the length. you will probley find less than 30% will be at 0.750 this is what i did for the best accuracy from my 9mms .
With as much 9mm brass thats floating around that shouldnent be hard to come across lots of free brass. I must have sold or given away 3 or 4, 5 gallon buckets full over the years

 

[The Bolt Man]

bobthenailer,

I did sort (1000) each, Remington R-P and Winchester brass. It was cleaned and resized.

I found 14% of the Winchester and 12% of the R-P that were .750" or slightly more in length. I can trim those that are longer.

The vast majority of both brands were .745" to .748" long. Of the entire (2000) rounds only (19) were shorter than .745".

By later afternoon today, I had spoke to persons at Starline, Magtech, Remington and Winchester. They all indicated their 9mm brass is manufactured to a length of .745" plus .002" minus nothing. That accounts for the majority of the brass I have measured to be .745" to .748" in length.

I plan to perform a test using 9mm brass that is .750", .745" in length to see if there is a notable difference in group sizes. The load I will be using will be one known to shoot well in the two guns I will be using. I will try the (19) rounds of brass that is shorter than .745" also, using the same load. The shortest I found was .740" in length.

Since winter isn't over yet, here in Minnesota, there will be some delay. I will get back to this forum as soon as I have something to report.

 

[R*H]

I modified my shell holder to allow the sizer die to size an additional .025" of the case. This, through geometry, lengthens the case an additional .003" or so. I can get 99% of my FC cases to exceed .750" post sizing. The problem is the case mouths are seldom square and while one side of the case might measure .752", the other is usually under .750". if I sort those out, only 33% of my brass ends-up being at least .750" long on the shortest side. I have about 10K of once fired FC cases, and they last about 30-50 reloads, so I have a lifetime supply. But I too wish somebody would make long enough brass. I considered buying some 9x21, but the trimming would be too much.

 

[noylj]

I suspect a conspiracy by the bottleneck cases...

When you find 9mm cases that are 0.750" or longer, hoard them. They will give you the best accuracy.
The .45Auto has the same problem, except that one can use the L-SWC to minimize headspace.
I complained to Starline, but they told me that the cases were within specifications and they were making them to the large side of the specification.
I have NEVER found a straight-wall pistol case that needed to be trimmed, though I have trimmed .38 Special, since they headspace on the rim, to ensure a consistent crimp.

I have also considered trimming some 9x21 brass, but I shoot 9x21. By the way, all the 9x21 brass I have was new Starline and they were all about 1mm short, so then I thought maybe I should buy 9x23 and trim them.
What I sort of wish is that they would supply a 9mm "universal" case so we could trim to the length we want/need.

 

[broom_jm]

I can't seem to locate the picture, but my son used his Hi-Point 995 carbine and open sights to shoot a group from the bench that was just over an inch, at 50 yards. Three of the five shots formed a beautiful clover leaf. I was very happy with both his shooting form and the gun's inherent accuracy. This was done with mixed headstamp brass, 5.0gr of Unique and 124gr FMJ RN bullets. The same ammo cycles well in several handguns, but does not distinguish itself as being particularly accurate in them.

As Marshall explained in post #5, handgun accuracy is more about the shooter than the load. My son's cheap little carbine illustrates that 9mm ammo can be pretty accurate, if the gun has a long sight radius and shooter error can be minimized. Later this season we're going to mount a 2-6X LER scope and see how it will group the same ammo at 100 yards. I'm guessing 3" or better.

 

[R*H]

Handgun accuracy is more about the shooter than the load.

No.

Handgun accuracy is totally about the load. For example, if you take the classic .38 Special 2.7gr of Bullseye under a 148gr HBWC load, accuracy will vary by primer brand and bullet brand. Some loads will be more than 50% more accurate than others, depending on the combination. In the 9mm, for example, accuracy and point of impact will depend on case barand and OAL in addition to the primer and bullet. The same principles apply to rifles and bows and arrows.

 

[broom_jm]

No.

Handgun accuracy is totally about the load. For example, if you take the classic .38 Special 2.7gr of Bullseye under a 148gr HBWC load, accuracy will vary by primer brand and bullet brand. Some loads will be more than 50% more accurate than others, depending on the combination. In the 9mm, for example, accuracy and point of impact will depend on case barand and OAL in addition to the primer and bullet. The same principles apply to rifles and bows and arrows.

Perhaps I didn't express my thoughts very well:

It takes a lot more practice for accurate handgun loads to result in tight groups, because the skill of the person doing the shooting has a great impact on those groups. To be succinct: I can spend an hour or two showing someone how to shoot pretty consistent groups with a scoped rifle, but it takes a lot more practice time to get equally proficient with a handgun. I still contend that most accuracy problems with handguns are caused by the shooter, and NOT the ammunition.

Does you experience differ from mine?

 

[R*H]

I was talking about the handgun alone. Introducing a human shooter firing off-hand makes tight groups more difficult

 

[Marshal Kane]

. . . Introducing a human shooter firing off-hand makes tight groups more difficult

Agree.

There can be several interpretations of accuracy and unless we include a description of what we think accuracy is, we could easily be talking apples and oranges.

If you say accuracy is totally dependent on the load, you are correct if you are only developing a load for one gun and taking steps to eliminate the shooter e.g. Ransom rest. You've succeeded in developing an accurate load.

What some of us consider accuracy to be is the whole picture, load, gun, and shooter. Here, all components have to come together to attain accuracy with the shooter being a big factor in the equation. You are an accurate shooter.

My original point being that one can develop an accurate load off the Ransom rest but add the shooter and accuracy can suffer. IMO, how far one goes to develope an accurate load depends on the shooters' capability and his gun. I load accurate ammunition for my wife, but you'd never know it from the results of her target.

 

[broom_jm]

I'm a lousy shot with a pistol...you could give me the most accurate 9mm ammo in the world and I'll show you a 5" group at 50 feet, every time.

However, give me standard factory loads, or my own run-of-the-mill handloads, and a scoped 9mm carbine to fire them from, and I can shoot groups half that size, at 50 yards.

To my way of thinking, that means pistols are accurate based mostly on the shooter, not the ammunition. To put it another way: Someone who is competent with a pistol will shoot decent groups with most ammo, and tighter groups with great ammo. A novice pistol shooter will shoot horrible groups with both; the greater impact on accuracy being the person pulling the trigger, not the ammo.

I guess it's just a perspective thing. For very good pistol shooters, I'm sure the ammo matters a lot.

 

[R*H]

My original point being that one can develop an accurate load off the Ransom rest but add the shooter and accuracy can suffer.

That is the case with any firearm. My personal goal is to develop target loads that are toward the low end of the power range. I don't like loads with alot of blast and recoil. This in turn makes for a more pleasant shooting experience, with less flinching.

Would you not prefer a mouse fart 1" load to a full-house 3" load, the latter being something you pulled straight from a manual? Don't you think that an accurate load will benefit both a novice and expert alike. The way I see it, no matter how much human error is interjected into the equation, the more accurate load will always be more accurate.