Groove dia for .40 Beretta 96?

[NuJudge]

I have had a 9mm Beretta 92FS for some while, and it's groove diameter is about .358". I just bought a Beretta 96G (it has not yet arrived), and I'm wondering whether it's groove diameter will be similarly huge.

Has anyone measured theirs?

CDD

[GabbyM]

I'm thinking not since the 40 S&W is a SAMI standard cartridge.

I size all my 40 caliber auto to .402” as opposed to the more familiar .401”. after a 40 is broken in with around 2500 rounds you can expect just short of a .0005” wear to achieve that nice polish. This wear will stabilize to slowly wear down over the life of your barrel. Then somewhere between twenty–five thousand and infinity your barrel will be worn to the point you may wish to replace it. Given variable starting dimensions which will seldom be under .4000” you'll be at .4005” to .4010” in short order when final polish is achieved. This all under ideal conditions. So I just run a .402” bullet as standard. So far it's fit in any 40 S&W it's been tried in. I can't imagine that .001” in a combat chamber being a big deal as far as clearance.

European thinking behind making combat arms for the 9x19mm causes me to shake my head in disbelief. But then every 20th home in the USA doesn't have an old blow back operated sub machine gun stashed in the cellar. Add to that the foolishness IMHO of the US Army insisting upon running NATO Ball specification SMG ammo in our M9 pistol. Hence the large bores to drop pressure of Ball ammo down to where it won't trash the pistols. Beretta doesn't make the M9 barrels big because they don't know how to measure. They make them big so they will meet the durability standard of the US Army using NATO Ball ammo. Smith and Wesson pistols offered up back in the 1970's for the test made it using a .3545” bore diameter which yielded a much higher velocity. But then it's so not cool to buy American.... Argh ....!

Lyman makes a couple of nice truncated cone bullets. My favorite in the 40 caliber is the Magma 155 grain SWC which looks like a scaled down 45 caliber H&G #68. The Lyman 175 grain TCFP has a larger meplat than the Magma 180 grain TCFP but at the velocity a 40 S&W lobs a 175 grain bullet meplat won't make much difference. 150 and 155 grain bullets get your velocity up into the realm of temporary cavity wounds and much better straight line penetration through barriers like auto glass. Or hogs chest if that's your target. I like to think of a 40 as a 9mm with 30 grains more lead and larger bore rather than a 45 acp with less lead and smaller bore.

[MtGun44]

SAMMI sets specs, the manufacturers make what they want, and after that they have
tolerances. Some parts exceed even the tolerances.

SAMMI registry of a cartridge will have little to do with the actual dimensions
that the barrel will wind up with, only the "theoretical, intended values". You have
possibly heard about a particular road that is said to be paved with good intentions. . . . . . .

No disagreement with your point about large bores to drop pressures, but the .40 S&W
is actually a pretty high pressure cartridge (witness the large number of blown up
pistols of a certain brand - only in .40 S&W) and there may well be the same sort
of plan for them, on top of whatever manufacturing tolerances there are in the
system - intended or not.

There are lots of documented oversized or undersized barrels out there, IMHO the
only way to have any idea of what you have is to slug YOUR OWN barrel. The last
20 seen maybe in good shape, but that doesn't mean yours will be, too. I've seen
too much variation out there to think any other way would be very useful.

;-)

Bill

[S.R.Custom]

The last couple of Beretta 96s I've had measured between .400 and .401.