Do i need to use a stronger spring to use these loads listed at 1440fps out of a 5 in test barrel for my 3in 3913?

No. Do not change the spring to use the Cor-Bon ammo. You may want to replace the spring every few thousand rounds, but do not use a heavier spring. A heavier spring causes other issues. Possible over running of the next round up in the magazine resulting in a failure to feed because the magazine spring does not push the next round up in time be in place when the pick-up rail comes forward at accelerated speed. In addition, while you may save a little bashing going backwards, you will bash it going forward. S&W knew what they were doing with springs, and they knew LE agencies were using +P+. Do not change from the factory spring.

This is NOT correct.

+P+ ammo might be used in todays modern machine guns......

But the German machine gun of WWll used their Euro made ammo that was close to our +P ,as we know it, to work the action. I believe it is known today as the NATO round.

I don't believe the S&W manual gives a green light to +P+ ammo............mainly due to it not being a regulated Pressure among the companies that load it.

+P ammo has pressures that are followed by the ammo makers.

I do not know what type of 9mm pistols you are talking about, but I have never met a 9mm pistol that would not safely shoot +P+.

Too much of a round for too little of a gun, there are plenty more controllable rounds out there. JMO.

There is no SAAMI spec for +P+ so S&W will not condone its use for that reason. For the most part they are safe to use, always monitor for extreme pressure signs in your particular firearm. Some boutique +P+ loads will pierce primers in certain guns.

The following statement is from the S&W Owner's manual for this particular pistol:

“Plus-P-Plus” (+P+) ammunition must not be used in Smith & Wesson firearms. This marking on the ammunition designates that it exceeds established industry standards, but the designation does not represent defined pressure limits and, therefore, such ammunition may vary significantly as to the pressures generated and could be DANGEROUS."

frankpior,

Where did you get +P+ CORBON? Does it say +P+ on the label?

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Captain

Good post, Mike.


OP, Corbon 9mm is +p & not +p+!!!! Put on your bifocals, Dad.

You youngsters have to cut us old guys a little slack, every now and then.............

with out short eye sight and sometimes short re-call memory...... a bo-bo is going to happen every now and then.

I Messed up last week when I typed in xtp by mistake on the Hornady 90gr load............. but they only make ONE 90gr load..... figured no big deal.

you right the +p+ are winchester loads. All the same is the Smith & Wesson M&P 9L Race Gun a stronger fire arm. The chronograph data was in an article about installing a C-more sight system.

So why do some people think they need a 115gr +P+ load ?

Is it that much better than the standard +P rounds?

In a single word: YES

No, you do not need a heavier spring.

Remember, stronger springs carry certain disadvantages. The slide is now running forward faster than intended by the designers, which could cause failures to feed if the next round does not get topside by the time the pick up rail races forward during cycling.

In addition, while you may save some battering as the slide goes backward to eject, you have battering as it comes forward. S&W is well aware that LE customers use this ammo, which is no worse than 9mm NATO. I would leave the stock spring and simply replace it a little more often with another stock spring. This is the procedure I have followed ever since 9mm +P+ ammo was introduced and I have never had a problem.

Yes. 9mm +P+ almost turns the 9mm into a low end .357 Magnum. It makes the 9mm every bit as good as the old Treasury Load which the feds (except the FBI) used in the 70s so they could say they were not using the politically unpopular "Magnum."

The Treasury Load is still available now from Winchester, except they now load the exact same ballistics into a .357 Magnum case and it is sold in their White Box line. It is the 110 grain JHP, catalog number Q4204. Its ballistics are 110 grain JHP at 1295 ft/sec.

The 9mm +P+ 127 grain JHP Winchester, on the other hand, runs along at 1250 ft/sec., while the 115 grain +P+ has a muzzle velocity of 1335 ft/sec. The .357 Mag has a bullet diameter of .357 (same as the 38 Special) and the 9mm is .355 inch, making them, for all practical purposes the same diameter. The 9mm +P+ equals the .357 SIG in ballistics, yet holds more rounds in most pistols because the SIG round has a fatter .40 caliber case necked to 9mm.

Thus, the 9mm is a low end Magnum in a smaller, flatter package, holding up to 3 times as many cartridges as a revolver in a duty size pistol and up to 2 times as many in a pocket pistol.

As a size comparison, the Glock 19, which holds 15 rounds, takes up the same real estate as a 2 1/2 inch K frame, and the Glock 26, holding 10 rounds, takes up the same space as a 2 inch J frame. While the revolver is certainly more elegant, the practical choice these days is a semi-auto in 9mm or bigger.

I'm going to have to be contrary here and state that +P+ 9mm frequently isn't better than +P and can actually be far worse for you. I'm not referring to pressures and warranty here either, but it's really dependent upon exactly what loads you're comparing, under what conditions and from exactly which pistol.

Cor-Bon +P 9mm with the 115 gr Sierra bullet has been reliably chrono'd at/over 1300 fps from service pistols. I've got no clue what Cor-Bon sticks in those cartridges, but their loads do produce the velocities claimed. The bullet tends to act much like a Nosler Partition bullet in use, with the nose blowing away, creating secondary wound tracks while the base continues on it's merry way. It's been one of my favorite loads since it performed in truly spectacular fashion. This is essentially one of the loads Shawn mentions that performs much like a .357, but isn't +P+.

On the other hand, I've clocked +P loads that barely matched the claimed velocities of their standard pressure versions. Also, +P+ versions that came nowhere near their claimed velocities and may not have matched the velocity specs for the equivilent +P load by the same manufacturer.

Finally, we get into the area of bullet performance. Bullet design today is much, much better than it was in the days when +P and +P+ ammunition was developed. Frankly, given modern design, you really don't need hyper velocities to get bullets to perform well. More to the point, when you drive bullets beyond their design envelope, they over expand or shred and limit penetration. This is something seen in a certain legendary +P+ load when dealing with folks .....larger than average as well as in ballistic media testing.

Frankly, I'd quit worrying about having maximum devastation and concentrate on shot placement. Every "failure" I've been provided complete data on has shown a failure to hit vital systems and structures.

BTW: The Speer Gold Dot 124 gr +P load has racked up an excellent track record.

Guys, the +P+ designation was a solution to problems that existed over 40 years ago. Changes in the political landscape and advances in bullet design and powders have produced similar results at much lower velocities and pressures since then, and with little, if any, political drama.

The major reasons the designation still exists is tradition and possible remaining terminology in police ammunition bid requests. [The phrase of many years of tradition unaffected by progress comes to mind.] Most of us wouldn't choose to drive 1968 vehicles, there's little reason to use 1968 spec ammunition either. Particularly when it could eliminate warranty protection.

There are excellent points here. I agree that bullet technology has come a long way. So has powder technology. It is now possible, for example, to get .45 ACP velocities from the .45 GAP case. The technology developed during the quest to make "short magnums" in rifles has carried over to pistol ammunition.

The new Winchester PDX1 round in 9mm is only a +P and I have reason to believe it performs well. The Speer Gold Dot 124 grain +P is another that seems to have a great track record.

Oddly enough, a round that has had, since its introduction, a dismal track record has been dropping suspects like flies the last few years. Winchester has apparently applied its newest powder and bullet technology to its 147 grain JHP loads. St. Louis Metropolitan Police, for one, has finally found a load that equals its old revolver load, the so-called FBI, Chicago or St. Louis load, which is the 158 grain +P LHP 38 Special load. I am not exactly sure what Winchester did, but some tweaks to the projectiles and powder has turned the 147 grain JHP into a true performer.

One of the issues I always had with the 9mm was that it was slightly more difficult for non-LE people to get a supply of the really good stuff, which always was the +P+.

The +P+ loads have excellent track records, especially, the Federal 9BPLE and the Winchester 127 grain JHP Ranger load. That said, however, there are several options available to non-LE people that will perform admirably.

Thus, I believe Mr. Moore made some very valuable points in his post.

Some of the most thorough and official studies on SD loads that I've read are at least 20 years old. Now their validity must be discounted. What could kill you 20+ years ago can still kill you today, but now a more efficient job is done with modern bullets and powders so there is less need for super velocities (and super recoil)

The Win. 124 gr. +p clocks exactly the same as their 127 gr. +p+. I have chronographed both side by side. Same velocities, circa. 1,250 fps in a G19. That said, their old 115 gr. +p+ load using the old "cup & core" style JHP averages 1,365 fps in the same gun. Obviously, something happens dramatically when 9mm velocities are increased. The .357 Mag. & .357 SIG are testimony to the fact that velocity works as well. A person either believes it or they don't. Without excess velocity the latter two are basically a .38 Special dependent on soft lead for expansion.

I have seen nothing on St. Louis PD having great success with the 147 gr. Source? They were using the generic White Box 147 gr. JHP which is worthless in that it almost never expands. In 2008 they were screaming to switch to .40 S&W from their Beretta 92's.

St. Louis police want more pistol firepower