9mm bullet diameters

[njl]

I just thought to measure the diameter of my various 9mm bullets at the base with my digital caliper. The results were a little surprising:

MG 124gr

CMJ 0.354"

JHP 0.3535"

PD 124gr

FMJ 0.354" - 0.3545"

JHP 0.3545"

X-Treme 147gr 0.355"

BBI 130gr 0.3555" - 0.357"

Speer 147gr GDHP 0.354" - 0.355"

Random 9mm 115gr bullet I pulled from what I assume was factory round picked up at the range (may have been PMC) some time ago was 0.3535".

The BBI's generally won't gauge in my Dillon 9mm gauge, but they've chambered and functioned just fine in a Glock 17.

So, what diameter should 9mm bullets be?

Edited January 20, 2011 by njl

[mds131s]

.354 is what 9mm converts to in inches. There could be some slight variations due to manufacturing tolerances but .357 seems to be a larger than acceptable variation to me.

[al503]

Slug your bbl. Use the same calipers and measure the diameter of the slug and use a bullet anywhere from that size up to .001" larger and call it good. You could probably go up to .002" larger, though without issue.

My 9mm bbls slug out to .355" and I use jacketed zeros that measure .3555" to .356" When I shoot moly, I start at .001" over.

[G-ManBart]

SAAMI specs call for a .354" bullet. The rifling specs are lands at .347" and grooves at .355". Since all of those bullets are larger than the lands, and not much bigger than the grooves, they should work fine. Schuemann did some testing and found that the best accuracy was often with the bullet being .002" larger than the lands. R,

[superdude]

SAAMI specs call for a .354" bullet. The rifling specs are lands at .347" and grooves at .355". Since all of those bullets are larger than the lands, and not much bigger than the grooves, they should work fine. Schuemann did some testing and found that the best accuracy was often with the bullet being .002" larger than the lands. R,

my reading of the SAAMI specs (ANSI/SAAMI Z299.3-1993) for the 9mm Luger (page 21) indicate a bullet diameter of .3555 and a barrel bore diameter of .346 and groove diameter of .355.

G-ManBart, can you direct me to your source with the other dimensions? thanks,

[noylj]

Just to repeat history, In the '70s it was quite common to use 0.357" jacketed and 0.358" lead bullets in 9x19. There were few 0.355" jacketed bullets available.

Never had any pressure issues.

Also, back then, almost every military 9x19 had groove diameters of 0.356 to 0.361".

A jacketed bullet can be smaller than groove diameter and still be accurate, but, in all cases with my guns, the best accuracy is with groove diameter or slightly larger jacketed bullets. Lead bullets must be 0.001" or more larger than groove diameter to be accurate and not lead.

I don't know about SAAMI, but I use jacketed bullets that are 0.355-0.356" now that the "correct" bullets are available.

I also find that most of my guns prefer 0.357-0.358" lead bullet (except for one Browning HP that has groove diameter of 0.3595").

My P08s and P38s NEED the larger bullets.

Each reloader needs to find what works in their gun. There is no universal rule for what is best.

[flack jacket]

G-man and noylj nailed it.

Shoot the bullet with best results.

I tried .357 diam 158 RNL in my 9mm... Tumble at 3 feet. I'm not using those anymore.

[TMC]

My steel gun has a Comander length Schueman AET in 9x19 and it will only shoot .357 bullets well, .355's and .356's don't group.

I have shot .358 lead/plated bullets in all my 9x19 guns (Glocks, Para's, S_I's) with no issues.

I think its partially gun specific, use what works best in your gun.

I spoke with Will Schuemann some years ago and he said he shoots jacketed .357's in his guns. He said gas cutting (gas leaking past the bullet) will do more barrel damage than larger bullets going down the bore.

[njl]

By that logic, assuming things don't vary from batch to batch (which they certainly could), I should probably stick with PD for 124gr JHP and X-Treme for my non-JHP loads.

[rhyrlik]

I have seen 9mm bullets as large as .356"

I have seen 9mm barrels as large as .358"

Interestingly, shooting a .354" bullet through a .358" produces accuracy similar to shooting a .355" bullet through a .355" barrel. For some reason, bore diameter does not affect accuracy as much as reloading voodoo.

I have a Sig P210 with a .357" barrel. It hates 124gr bullets (2" groups at 15 yards). A few weeks ago I tried 4.1grs of N320 under a 124gr Hornady FMJ and 125gr Sierra FMJ. The bullets are slightly different, with the Hornady having a slightly slenderer nose. The Hornady shot under 1" while the Sierra shot 2". This is from a bench rest. This is voodoo. there is no rhyme or reason to it.

I even went as far as having a swaging die made to bump-up the bullet diameter to .357" which made no difference in accuracy. For the record, my 147gr loads shoot around half-inch at 15 yards (.355" bullets ina .357" barrel).

I would not worry about it.

[Bob DuBois]

I've shot .355 through .357 in my Trojan, it seems to like the heavier bullets. My S@W 67 and Single action like the 147 lead .355 bullets I use in the Trojan, go figure.

[jbrown13]

I just measured the 3 variations of 9mm MG bullets I have on hand and got different numbers. I used a vernier micrometer to do the measuring as I'm not comfortable using a caliper for accurate 3 or 4 decimal place measurements.

115 CMJ = 0.3552"

115 JHP = 0.3555"

124 JHP = 0.3550"

So, I guess there are variations batch to batch.

[George]

So, what diameter should 9mm bullets be?

Generally speaking, jacketed "should" be .355" and lead "should" be .356" for 9x19. I say "should" here because small variations will always be found.

I have pushed .356 jacketed and .357 lead fairly fast down various 9x19 barrels to no ill effect.

As mentioned, small variances across bullet brands and bbl's are to be expected. When the bullet obdurates from the pressure behind it, even a slightly small one will fill the bore and seal properly. A slightly large one will just not obdurate as much and pressures will be a little higher, not a problem if you are not running max loads.

[Havis]

I have a sig P365 with a bullet lodged halfway down the barrel. It is solidly in the barrel and I can't get it out.  I was using Winchester 9MM Luger 115 Grain full metal jacket. When I check the box of shells, they all seem to be about .355 diameter and will not go in the front of the barrel so I am thinking the barrel must be around .354. I have some Hornady hollow point shells that are about .352 so they fit easily up to the casing. What would cause the bullet to be so tightly lodged in the barrel if they are supposed to be .001 to .002 larger than the barrel?

[Miranda]

you have posted three questions?

to get bullet out... press, tap, hammer, heat.

I have a thick washer that just fits the barrel.   it was made to slug/size the barrel.

 

to chase why the bullet is lodged in there...

lack of powder is most likely.

 

or two bullets are in there... copper jacketed bullets should be about the size of the barrel,

your measure of slug and copper jacketed bullet the same.

lead plated or painted should be a thou (.001) bigger and hardened lead between a thou and 2 thou bigger.

 

and you are in for a treat.

read carefully.

 

miranda