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bullet diameter for 9mm

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#1 mgcchkn


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Posted 09 November 2007 - 09:04 PM

I'm still trying to decided on the right bullet for my application (9mm Major). Should I be looking at 355 or 356 diameter for 9mm? If they are interchangeable, what's the point in making 2 different diameters?

I don't want to get the wrong size. :) Thanks.

#2 syme71


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Posted 09 November 2007 - 09:48 PM

would assume it all depends on your barrel.

#3 get2now


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Posted 09 November 2007 - 10:11 PM

Typically 9mm FMJ's are .355 and lead are .356.


#4 G-ManBart


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Posted 09 November 2007 - 10:34 PM

I'm still trying to decided on the right bullet for my application (9mm Major). Should I be looking at 355 or 356 diameter for 9mm? If they are interchangeable, what's the point in making 2 different diameters?

I don't want to get the wrong size. :) Thanks.

The traditional size was .355 for 9mm. The traditional size of .38 Super was .356, but now a lot of companies seem to be cutting their Super and Supercomp barrels at .355. Some guns will shoot either size just fine and others will have a preference for one over the other.

The bullet companies are making the in both sizes so that you can tailor the load to the gun/barrel.

The interesting thing is that some people will claim more wear if you shoot a jacketed .356 bullet in a .355 barrel and others say the opposite, that it wears less because it allows a better seal between the bullet and barrel so you get less flame/gas past the bullet and flame cutting. I'd say go with whatever your barrel maker suggests unless there's an accuracy problem that can be solved by switching bullet diameter.

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#5 mike deguire

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Posted 18 November 2007 - 06:54 PM

Typically 9mm FMJ's are .355 and lead are .356.


When I was shooting .38Super in a Schuemann Hybricomp (4 port), I sent an e-mail to Wil Schuemann. He favored the .356 size bullets. You should send an e-mail to Wil on this.
I'm now shooting 9mm Major using .356 bullets (OAL 1.175) with 8.0 Silohouette. Very happy with the load and ecstatic with the SVI IMM. As with all loads, start lower and work up. My load makes 1330 using the Zero .356 125 grn JHP. As I've seen in other references to Silohouette, very low SD.


#6 Kingman


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Posted 18 November 2007 - 07:39 PM

what has been said is true.

Originally super was .356 and 9mm was .355

having two different sizes of barrel cutters costs more money. So a lot of companies have gone to just one bore size. I shoot all .355 and have for about 6 years even with supers.
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#7 ipscbob


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Posted 18 November 2007 - 08:57 PM

I have shot Montana Gold .355s in my 38supers for 4 years with excellent results. Try some different bullets and loads and pick the one you prefer.

#8 rhyrlik


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Posted 19 November 2007 - 10:02 AM

9mm bullets range from .354" to .356"

9mm barrels range from .354" to .356"

The nice thing about lead, it will swage down or obturate under pressure. This means a .356" bullet will easily swage down to .354" in the barrel. A .354" bullet will bump-up to .356" in that barrel (we're talking soft-core jacketed bullets.)

Paractically, it does not matter and I have a Sig P210 that proves it.

#9 Fozzy357


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Posted 28 July 2008 - 02:18 PM

I had a hard time getting the precision I needed in my Pardini GT9-6 until I loaded a .357 143 grain copper plated bullet over 3,5 grains of VV 340. Average velocity is 918fps.
Now all is well :D

#10 smallshot13


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Posted 08 May 2009 - 12:00 PM

9mm bullets range from .354" to .356"

9mm barrels range from .354" to .356"

The nice thing about lead, it will swage down or obturate under pressure. This means a .356" bullet will easily swage down to .354" in the barrel. A .354" bullet will bump-up to .356" in that barrel (we're talking soft-core jacketed bullets.)

Paractically, it does not matter and I have a Sig P210 that proves it.

I just purchased Remington 124grn JHP that measure .354. I checked factory rounds and they measure 0.355, so I know I don't believe it is measuring error. I have not loaded them yet, but I am very concerned that they are undersized and may not perform well, or worse. Has anyone ever noticed this before? These are in Remington packages of 100, but marked packaged by Black Hills in the bottom corner of the package. :unsure:

#11 Gregory_k


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Posted 11 May 2009 - 01:19 PM

.356 125zero fmj, it is all I can get my paws on.

#12 norbs007


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Posted 11 May 2009 - 01:25 PM

Same MG .355 124gr. JHP for my 38 Supercomp and 9mm Major blasters.
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#13 Jaxshooter


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Posted 11 May 2009 - 07:12 PM

There is good information on this subject on the Scheuman Barrel website.
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#14 1bigshooter


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Posted 07 July 2009 - 10:19 AM

Recently came across some .356 bullets, have always loaded .355 for 9mm. Looking forward to trying them thanks to the great feedback from this forum.

Just wanted to say thanks for all the good info folks!!

#15 Graham Smith

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Posted 07 July 2009 - 10:43 AM

Hornady makes a bullet called a HAP (Hornady Action Pistol). It's a JHP specifically engineered for shooting sports rather than defense. While it's listed as being a 9mm bullet it is a .356 diameter, Hornady says it was primarily designed for .38 Super but is now also being sold for 9 x 19 open. When I asked them why not 9mm minor they said it did not work well at the lower velocities. That was about 2 years ago.

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Edited by Graham Smith, 07 July 2009 - 10:43 AM.

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#16 GrumpyOne


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Posted 08 July 2009 - 06:23 PM

I emailed STI the following questions, hope this helps:
Question #1:I recently acquired a used STI Trubor in 38 super. Since I intend to reload for this round, I have a few questions pertaining to it.
1.What size projectile (bullet) would be best suited for this barrel? I have heard conflicting reports from websites (some say .355, some say .356, while others even say .357).

2.What type bullet would be best suited for this weapon to make major in?

3.Is it possible to add a recoil master to the Trubor, and if so, can it be lightened so that factory ammo may be used in it?

Answer:The bullet size you need to use .355 either FMJ or HP 121 to 125 GR. and with an OAL of 1.235/ 1.245 I recommend using a light RCM for everything and do not modify it. --------------------------- DC

Question #2:Why use the .355 (9mm) bullet when the 38 super is actually .356? Too much pressure with the .356?

Answer:The .355 bullet is what we recommend our barrel bore is .355 but you could get away with .3565 or .356 but not .357

Question #3:Can the 9 x 23 operate in the 38 super trubor?
Is this an actual quote from your website? Iíve looked, but canít find it. Bear in mind, the message was from 2006.
Q. Why does my new TruBor not cycle properly?
A. As you know, STI guns are fit very precisely. Because most purchasers of this model intend to use it in IPSC competition, shooting major, we factory test them with approximately 170 power factor ammunition. Seldom does factory ammunition meet this criteria, and frequently match hand loads do not either. We recommend that hand loaded ammunition at about 175 power factor be used during a ďbreak inĒ period. This may take 100 Ė 500 rounds. Many purchasers have simply used 9x23 factory ammunition during this period. From: http//stiguns.com/faq.html

Answer:Its true that you can use 9x23 in a 38 super barrel but I recommend doing it only in a pinch and if you have to do this you will need to check extractor tension because the 9x23 rim around 12 thousands smaller than a 38 super rim. ------------------------------- DC

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Posted 08 July 2009 - 07:17 PM

use a .355" diameter bullet.

#18 Godzilla


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Posted 08 July 2009 - 08:28 PM

Ok here is the scoop!

The spec for a 9mm luger calls for a .355" diameter bullet and a .355" diameter bore. As we know the 9mm luger was not made for long distance accuracy.

Browning designed the 1911 around the 38 Super and then the 45 ACP. He called for a .357/.356" diameter bullet with a .355" diameter bore for the 38 super and a .452/.451" bullet with a .450" bore for the 45 ACP. The bullet needs to be oversized to properly seat into the rifling and not get into the bore misaligned which will lead to tumbling at some degree. The only portion of the bullet that can expand in firing sequence is the bearing surface or the flat part of the bullet. So this will lead to the assumption that a hollow point or flat nose bullet will have better accuracy than a round nose bullet of the same weight which is correct to all of our findings.

So the question, what is best for a 9mm 1911, .355" or .356"? We need to separate 9mm Luger and 9mm Major which in the forums are not always differentiated and may cause more confusion among the newer shooters.

The confusion lies in the fact that the 9mm Major is a wildcat cartridge and does not have a SAAMI spec so most people look to the 9mm Luger for info(.355"). Without a SAAMI spec to go by, most of us pick and choose which specifications to pull certain information from, I believe the 9mm Major is closer to the 38 Super Spec than the 9mm Luger. So.....355" bullets will work but they will be under performing at certain distances. Any undersize bullet will have accuracy issues so if you buy .355" bullets and they have a +/-.001" tolerance (normal for most bullets except the HAPs) quite a few bullets by statistical sampling will be undersize. Those flyers that you have, maybe due to your random undersized bullets (except for Bart's case, he jerking the trigger :)). I used .356" diameter bullets in my 9mm Major, so if I have an undersized bullet due to tolerances hopefully it will be around .355" instead of .354" which is not good. We recommend .356" or .357" diameter bullets for 38 Super, Super Comp and 9mm major.

So for a 40 S&W which has a .400" bore and a .400" bullet your best accuracy will come from a 200 gr bullet verse a 180 or 165 due to the larger bearing surface. Enough said.

I have heard that plated bullets will not shoot out of a Schuemann AET barrel and this is not factual. Plated bullets will not normally be as symmetrical as a bullet manufactured by other methods. Plating can build up on one side of a bullet at a little faster deposition rate than the other side. If the batch of bullets (they are plated in a batch) are not as good as another batch, the high point of the plating can be easily taken off by any rifling or free bore entry. It is a quality control issue of the bullets not the AET barrel. If fact the AET's lands are straight rifling for the 1st inch or so which will help correct the bullet's entry into the bore and its flight if the high points are sheared off. Plated are cheaper but with anything in life they have their place and tradeoffs.

Other notes of interest for the 9mm Major while I am at it.

For a normal 9mm luger - Every .010" too deep that a bullet is seated will raise the pressure by approximately 10,000 psi due to the small case volume. If you retain the same OAL for 9mm Major and increase the powder charge the pressure will grow exponentially. That is bad if you are wondering.

Different cases can change the pressure in your 9mm Major load by as much as 4,000 psi so try to work with the same brass.

Load as long as possible and use a larger bullet (.124 gr or larger) to reduce the pressure, this will allow you to load around 1.185" OAL length. Avoid the smaller 115 and 121 unless you have the proper experience.

If you notice swelling in the bottom of a case you have a problem that needs immediate attention. The radius in the beginning of a AET Barrel allows for a more reliable feeding bullet and should never contact the brass (ie the radius is not the issue, the brass in a 9mm case is many times thicker in this area). If this is happening it is an indication that something is causing over pressure. Itís like a engine light in your car blinking no oil. Proceed with caution.

Let me know if you have any other questions that I can answer.


Edited by browndog, 08 July 2009 - 08:35 PM.

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#19 al503


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Posted 08 July 2009 - 08:51 PM

Slug your bbl. Slugged my new limited gun (9mm) and it came out to exactly .355". Get some bullets and measure them with the same set of calipers. I'm using .3555" to .356" bullets.

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