9mm Bullet Diameter .355 or .356 ? Help! [Archive] - Glock Talk

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FyreCalG17
08-20-2011, 11:37
Ok, let me start by saying that I'm new to reloading.

I was searching online for bullets and I kept running across different bullet diameters for 9mm.
Rainier - .355
Montana Gold - .355 & .356
Berry's - .356

So I'm wondering, what is the ACTUAL bore diameter of a stock Glock 9mm barrel since it has the polygonal rifling instead of grooves?

Will the Berry's bullets with the larger diameter require more powder to push them at the same velocity as other plated bullets such as Rainier?

DWARREN123
08-20-2011, 11:40
My first thought is to try different diameters to see which ones work best in your firearm. Due to many things some may like .355 while others will work better with .356.
As for powder charge the it should not be much different since the diameter of the bullet (for caliber) is not as important as weight of bullet.
Remember to always start near medium and work from there in reloading.

FyreCalG17
08-20-2011, 11:43
My first thought is to try different diameters to see which ones work best in your firearm. Due to many things some may like .355 while others will work better with .356.
But both diameters SHOULD fit through my barrel?

ron59
08-20-2011, 12:01
jacketed are usually. 355
lead is. 356

guess plated is closer to lead?

DWARREN123
08-20-2011, 13:41
Both diameters should fit, jacketed will be the smaller (usually) .355 and plated may be either while lead can be .356 or .357 in diameter. Some firearms like different sizes so shooting a few thru yours will tell you which is more accurate.

dkf
08-20-2011, 13:45
You can shoot either .355" or .356" bullets thru your Glock. Some jacketed bullets (like the Hornady HAP bullets) are .356" diameter also.

polizei1
08-20-2011, 15:39
I've been using Precision Delta bullets, they are .355".

Meathead9
08-20-2011, 16:05
Here's something else to add to the confusion.

The 9x25 Dillon is a 10mm cartridge necked down to 9mm. I load 9x25 Dillon with .355's, while another GT member uses .356's, and another GT member uses .357's. We've all had success with our handloads, so I'm not sure what's right. I called LWD to ask, and it didn't really seem like they knew for sure. I was told that it "should be" .355, but the only way to know for sure, is to "slug" MY barrel. Each barrel is slightly different, so one may be better suited for .355, and the other for .356.


To answer your questions directly, the Berrys bullets are Plated, and behave much like lead. The data between lead and plated bullets is supposed to be interchangeable, as well as the diameter. Lead and plated bullets are much softer than jacketed, so they are usually .001-.002 overbore. Basically .356 Lead/Plated = .355 FMJ/JHP.

Also, I went to Montana Gold's website and I couldn't find any .356 bullets. I know Zero makes .356's, but they are mainly used for .38 Super.

dbarry
08-20-2011, 16:09
I have used both and cannot tell the difference in my G19

Steve Koski
08-20-2011, 16:54
It doesn't matter.

Ferdinandd
08-20-2011, 16:58
With jacketed slugs, I don't think that .001 will make a difference. Lead bullets, on the other hand need to be be sized to .001 for best performance and to avoid excessive barrel leading.

Steve Koski
08-20-2011, 18:17
A .001 lead bullet would have an outstanding sectional density.

Ferdinandd
08-20-2011, 19:28
Steve, Thank you for pointing out my poorly worded explanation of what I was attempting to convey to the OP. To clarify, .355 to .356 variation on jacketed bullet diameter seems not to affect performance, in my experience. That small difference does seem to matter when using unjacketed projectiles, based on my experience casting and loading for 9mm and .357 Mag.

HAMMERHEAD
08-20-2011, 20:58
Both diameters perform equally for me in a wide variety of 9mms as far a accuracy and speed over the chronograph.
Some good .356" bullets for Glocks are Berry's new 124 grain thick plated, hollow base flat point (HBFP-TP), the Hornady 125 grain HAP and the Rainier 130 grain .38 Super bullet.
I load them all to the same data (data for a 124 grain .355" jacketed hollow point).

argy1182
08-20-2011, 21:03
You can fire either one and be fine. Typically, the softer materials are .356 and the harder materials .355. Both will work fine for anything you're going to do with a Glock barrel.

FyreCalG17
08-21-2011, 01:00
Thanks guys for the advice. I guess lead bullets are larger because they are softer and will conform to the barrel's grooves while jacketed bullets are harder and won't conform as much. Correct?

Anyway, I've been loading Rainier and I'm about to try Berry's. I'm not quite ready to switch to the good stuff yet because as of now I'm just loading to have fun at the range. When I get serious about target loads then I'll start looking for more precision bullets. This should get me started in IDPA as long as I exceed the power floor.

Thanks again for the input

DWARREN123
08-21-2011, 01:59
One of the best bullets I shoot for accuracy in either 40 S&W or 10mm is a 175gr LSWC from SnS Casting. Very accurate to around 25 yards but I have to watch the velocity to keep them from leading, beats any jacketed, plated or othe type lead bullets I have used so far.
Lead sometimes can be very accurate bullets in most firearms.

fredj338
08-21-2011, 13:17
With jacketed slugs, I don't think that .001 will make a difference. Lead bullets, on the other hand need to be be sized to .001 for best performance and to avoid excessive barrel leading.
As you are saying, a MINIMUM of 0.001" larger than groove dia for lead bullets. Many 9mm guys are shooting 0.357" or even 0.358" lead bullets. SInce the Berry's & Ranier are soft lead w/ thin plating, they tend to work better slightly over sized like a lead bullet. I always go 0.356" for plated & pretty much lead too.
Thanks guys for the advice. I guess lead bullets are larger because they are softer and will conform to the barrel's grooves while jacketed bullets are harder and won't conform as much. Correct?
TO prvent leading in the bbl, the bullet needs to seal off the bore form hot gas trying to escape around it, so a slightly larger bullet does this better than a smaller bullet. It's not that the lead is softer but more malleable. A hard cast lead bullet is quite a bit "harder" than a soft swaged plated bullet like Berry's or Ranier.

FyreCalG17
08-22-2011, 12:10
As you are saying, a MINIMUM of 0.001" larger than groove dia for lead bullets. Many 9mm guys are shooting 0.357" or even 0.358" lead bullets. SInce the Berry's & Ranier are soft lead w/ thin plating, they tend to work better slightly over sized like a lead bullet. I always go 0.356" for plated & pretty much lead too.

TO prvent leading in the bbl, the bullet needs to seal off the bore form hot gas trying to escape around it, so a slightly larger bullet does this better than a smaller bullet. It's not that the lead is softer but more malleable. A hard cast lead bullet is quite a bit "harder" than a soft swaged plated bullet like Berry's or Ranier.
I wouldn't mind trying hard cast bullets, but none of the indoor ranges I plan to shoot IDPA allows lead. The outdoor ranges don't care one way or another, but using lead would limit my options.

I guess everyone is afraid of the whole lead vapor - brain damage thing. Go figure

fredj338
08-22-2011, 13:35
I wouldn't mind trying hard cast bullets, but none of the indoor ranges I plan to shoot IDPA allows lead. The outdoor ranges don't care one way or another, but using lead would limit my options.

I guess everyone is afraid of the whole lead vapor - brain damage thing. Go figure

It's just about all I shoot in IDPA is lead, but always outdoors. If shooting indoors, I would go plated ot jacketed. The lead vapor thing is bogus. Lead does NOT vaporize off the bullets being fired, but there are small particulates that "break off" as the bullet leaves the muzzle. That & the lead in the priming compounds of most commercial primers. Add poor range ventilation & you do have an issue. One reason I shun indoor ranges as much as possible, limiting my indoor shooting to 3-4 X a year. I cast & shoot lead bullets almost exclusively, my lead levels are well below nromal. Wash your hands & face after shooting, don't smoke while shooting, avoid indoor ranges, lead bullets are fine.:dunno:

El_Ron1
08-22-2011, 14:12
A .001 lead bullet would have an outstanding sectional density.

Mr. Koski, please limit your posts to items that actually contribute to the thread.

Steve Koski
08-22-2011, 14:41
Damn you Mullah!

gary newport
08-22-2011, 15:05
Mr. Koski, please limit your posts to items that actually contribute to the thread.

This is like GTR used to be in the Good Old Days! :supergrin:

g29guy
08-26-2011, 03:13
I cant speak from experience for the 9mm, but I can for 10mm.
I shoot alot of 10mm/.40 cal hard cast bullets. I have found them to be .401-.403.
I shoot the .401 lead hard cast very accurately out of my aftermarket barrel.

You can do either one of two things. First you can slug your barrel as mentioned earlier(google it if you don't know what it is. also some good videos on youtube). Second, buy small quantities of several sizes and styles of bullets and shoot them and let the results tell you.

Lead reacts different with different loads. If you shoot light target loads then a larger bullet will grab the rifling better. A hot loaded bullet naturally flattens the back of the bullet and seals the bullet around the rifling. This all depends on caliber and bullet weight of course. Also lead and hard cast lead have different alloys that make them react differently due to different hardness.

A glock style barrel also will have different reactions to leading and accuracy.

Let us know what or how your gun shoots best!:cool:

Colorado4Wheel
08-26-2011, 06:49
Nothing smaller then .355 for a real jacketed.
Nothing smaller then .356 (and likely larger) for lead

If your using Jacketed or Plated and it says 9mm your probably going to be fine.

Zombie Steve
08-26-2011, 08:19
Mr. Koski, please limit your posts to items that actually contribute to the thread.

http://i183.photobucket.com/albums/x214/sbecht/ogq4n.jpg

cole
08-26-2011, 11:02
Ok, let me start by saying that I'm new to reloading.

I was searching online for bullets and I kept running across different bullet diameters for 9mm.
Rainier - .355
Montana Gold - .355 & .356
Berry's - .356

So I'm wondering, what is the ACTUAL bore diameter of a stock Glock 9mm barrel since it has the polygonal rifling instead of grooves?

Will the Berry's bullets with the larger diameter require more powder to push them at the same velocity as other plated bullets such as Rainier?

Some people put a lot more thought into these things than I do. I load whatever I can get cheap. Bullet: Whatever (between .355-.356 or .451-.452). Primer: Whatever (mag or standard). Brass: Whatever. It's mostly range fodder after all.

HOWEVER, I only load up to medium velocity/pressure loads which will safely account for variations. I'll make changes only as needed.

When I get a new bullet type, I'll check the specs on it and if it's the same as one I've loaded (I keep detailed records), I'll load 100 to match that load to check 'em, then load the rest. Simple, and has always worked. I only reload 9mm and .45acp now.

FyreCalG17
08-26-2011, 18:48
Nothing smaller then .355 for a real jacketed.
Nothing smaller then .356 (and likely larger) for lead

If your using Jacketed or Plated and it says 9mm your probably going to be fine.
Yeah, you're probably right. Berry's is a reputable company, so I'm not too worried.

FyreCalG17
08-26-2011, 18:53
Some people put a lot more thought into these things than I do. I load whatever I can get cheap. Bullet: Whatever (between .355-.356 or .451-.452). Primer: Whatever (mag or standard). Brass: Whatever. It's mostly range fodder after all.

HOWEVER, I only load up to medium velocity/pressure loads which will safely account for variations. I'll make changes only as needed.
Its not that I've necessarily put a lot of thought into it, its more like being afraid of blowing myself or my gun up. When you're new to something and you don't have a lot of knowledge you tend to be cautious about everything.
I run into burning houses because I know firefighting and the danger signs to look for when inside, so I'm not afraid at all. But reloading???? I don't know much so I'm just a little cautious, probably too much so.
Plus, if I blow myself up, it will be the guys I work with who will respond to treat my wounds. I'd never live that down.