Large 9mm Barrel?

[Mac Sidewinder]

I have been shooting Berry's 9mm plated bullets and have been pretty satisfied, but I want to see if a properly sized lead bullet would be more accurate (Berry's measure .356). So I slugged the barrel of my Beretta 92FS. I had to do it twice because I couldn't believe the size. It came out to .357. This is the Italian inox version. Is this normal for Berettas? I guess I am going to order .358 sized bullets and see how they do. Penn Bullets have a 125gr round nose that I might try.

Mac

 

[WESHOOT2]

Suggest testing the .357" FIRST.

 

[springer99]

I've found that .357dia. cast bullets are much more accurate in my Beretta M9 than .355 or .356. I use only LSWC or TC designs without any problems. I can't say that I've actually measured my bore, but let group sizes tell me the truth.

FWIW, I've also never found a plated bullet that could match the accuracy of a good cast bullet or, for that matter, a good jacketed one. At a small savings over jacketed and a small premium or cast, plated bullets just aren't worth using AFAIC.

 

[Ozzieman]

I would not go to 358. An over sized bullet will increase pressure and give more variation in velocity effecting accuracy.
The attached photo is a Penn 124 GR in a 9mm case. It’s a standard size (.356) and is very accurate in my Glock 26, Beretta Cougar, Beretta Storm carbine, HK MP5 clone and my old Smith 5906.
Lead bullets with too large diameter will start to strip the lands if there’s too much force put on them.
A agree totally with springer99. I purchased a thousand plated bullets for 44 because the indoor range I use in the winter time no longer allows lead bullets. These were Berry’s, very good bullets but I never got the accuracy out of any of my 44 specials that I could from a lead bullets.
If you’re really looking for accuracy try Penn’s 147 GR. I don’t have any right now but my Storm carbine really liked them and they were very accurate.
Also try calling him. He knows a great deal about reloading and accuracy. He will help you get what you’re trying to achieve.

 

[Jim Watson]

Yes, barrels larger than nominal 9mm .355" are quite common in Berettas and others. This is not normally a problem with jacketed bullets but undersize cast bullets are prone to lead.

The problem is, you might run out of chamber room before you got to a bullet that would fill the grooves. A .358" would shoot fine in your .357" barrel IF and only if the loaded round would chamber freely.

"Bullet pinch" from a cartridge too tight in the chamber to release the bullet is a much greater source of excess pressure than driving the bullet down the barrel. After all, as P.O. Ackley said, by the time an oversize bullet has traveled its own length, it will fit the barrel perfectly.

So don't buy a whole lot of any unusual bullet; see if Penn will send you a small batch to try before you stock up.