Reloading Tips for 40sw
Overview
This is just a quick collection of notes regarding reloading 40sw.
Warning
Some folks take risks, make mistakes, etc. and there is nothing I can do about it. . The data presented here is declared safe, by me, in my firearm only, and I may very well be wrong. You may be reduced to blood, guts and steam by trying these loads in your firearm. You are hereby warned. I am not responsible for what you might do.
Myths
Some people regurgitate the lie that the 40SW is a high pressure cartridge. There is no reason to be that ignorant - the SAAMI specs are freely available.
The 40SW MAP is the same as 9mm - 35K psi. The 10mm is 37.5K psi.
Most of the fear of reloading is due to the horror stories of KABOOMs. Problem with KABOOM stories is that the truth gets lost in the noise of forum chatter.
Facts
The 40SW is a very slightly tapered cartridge that is simple to reload safely. It has been around for 30+ years and is well understood.
The very fast powders (Titegroup, Clays, etc.) are responsible for KABOOMS. You will not find a KABOOM involving Longshot, Bluedot, Power Pistol, AA7, etc. There are two reasons for this:
It is very easy to miss a double charge with Titegroup. Conversely, it is very easy to notice a double charge with Power Pistol.
Bullet setback, with 180gr+ bullets, causes very large pressure increases with the fast powders. Cases do blow out because of it.
I guess there is a 3rd reason too - 1st and 2nd generation Glock 23's and 22's. If you have one of those old "guppy makers" - load light or get an aftermarket barrel.
Slow powders are safer than "economical" powders. And lighter bullets (<180gr) are more forgiving of setback.
To put it bluntly, 4gr of Clays behind a 200gr bullet that does 850fps is far more dangerous than 8.5gr of Longshot behind a 155gr LSWC that is doing 1300+fps.
Fast versus Slow
There are people who want to load a cartridge to the minimum velocity. And there are those who want to squeek out all the performance safely possible. I'm in the latter group.
Going fast is a matter of choosing the right powder, the right bullet, understanding your chamber and your magazine.
Powder
Longshot rules. Power Pistol and Bluedot lack flash deterrents - they'll blind you at night. Longshot rules.
Bullets
A 155gr Lead Semi-WadCutter (lswc) and 180gr round nose flat point can be seated out to 1.16" (SAAMI max is 1.135"). And lead bullets usually give higher velocity with lower pressure.
Chamber
The goal is to load to as long a COL as practical so as to reduce start pressure (MAP in most cases). This has little to do with SAAMI dimensions and more to do with building in safety margin with your loads. The 40sw has been around since 1990, and chamber dimensions are pretty consistent.
The profile of a lswc or truncated cone will usually allow you to load the bullet shoulder into the chamber leade. A round nose profile may not, as the bullet ogive may hit the rifling. So when selecting bullets, consider the bullet profile.
All 40SW chambers will handle a .401" diameter bullet. Most will handle a .402". Usually the quickest cure for leading close to the chamber is a fatter bullet.
Magazine
My M&P magazines will feed with lswc ammo loaded out to 1.17". Most 1911 magazines will handle 1.19".
Data
M&P40 2.0 Compact 4" barrel
Crony Alpha Master chronograph.
Hodgdon Longshot
COL = 1.16" <- very important
Speer Nickel plated once-fired brass
Remington 1 1/2 primers
Missouri Bullet Company Hi Tek coated 155gr lswc, .401"
8.0gr = ~1235fps
8.5gr = ~1310fps
9.2gr = ~1360fps
Brazos 180gr Round nose flat point, Hi Tek coated, .401" diameter.
Hodgdon Longshot
COL = 1.16" <- very important
Speer Nickel plated once-fired brass
Remington 1 1/2 primers
7.0gr = 1061fps average
7.5gr = 1132fps average
Comments
My pistol, an M&P40C with 4" barrel, has the best casehead support I've seen. S&W engineers definitely addressed any potential case blowout issues. I can load to a long COL, to keep MAP down, and achieve some respectable velocities.
Nightmares of Armored Grizzlies
You're young, money is tight, you aren't interested in starting a gun collection, and bear spray isn't comforting. You own one handgun and lets imagine it is a 40sw.
You likely don't reload, nor do you have any relatives who do. You want to carry your pistol to deal with Grizzlies and you're wondering what ammo to use.
In general, you want to maximize penetration, so you want a bullet with a high sectional density (SD) and a non-expanding profile.
Sectional density is bullet weight in grains / 7000 / bullet diameter squared.
.401" diameter bullets common to 40sw:
135gr SD = .120
155gr SD = .138
165gr SD = .147
180gr SD = .160
200gr SD = .178
Some other bullets for comparison
.430" 300gr SD = .232 (44mag)
.356" 147gr SD = .166 (9mm)
And although I don't understand exactly why, Wide Flat Nose (WFN) bullets penetrate better than anything else.
The boutique ammo manufacturers Buffalo Bore, Underwood, and Double Tap all sell a 200gr WFN 40sw load. But their stuff is expensive. A cheaper solition is the 180gr jacketed flat point that you using for practice.
General Woods Load
Black bears, Cougars and Wolves have a body profile (density and size) close to humans. So any ammo designed to stop humans that gives the FBI minimum penetration is a good choice. And since over-penetration isn't an issue out in the woods, you are free to use the cheap practice ammo.