As I reported last week I was trying to make some very light loads in .40 S&W for new shooters. I made up 200 rounds with the 180 grain Rainier FP over 3.9 grains of Bullseye with an OAL of 1.131”. On Christmas day, while at Brother Doug’s place I shot some over the chronograph. This load yielded a mean velocity of 825 fps (standard deviation of 9.6 fps) for a Power Factor of 148.5. The expected result was 800 fps for a PF of 144. Not too far off from the actual. I would have preferred it be on the low side instead of the high side but still, not bad.
My typical handloads run about 940 fps for a PF of 169 or so. 180 grain factory loads run about 1000 to 1025 fps for PFs of 180 to 185. Hence these new loads are have about 80% of the momentum of a factory load and a little under 90% that of my usual handloads. This is better but I would like to do better still.
While in Idaho this weekend I bought a pound of Clays from Alan B. I loaded up 100 rounds of the 180 grain Rainier FP over 3.0 grains of Clays. I ran them over the chronograph today. Remember that the reloading manual said to expect:
180 grain bullet over 3.0 grains Hodgdon Clays => 727 fps with 131 PF
The result was 728.11 fps (standard deviation of 8.8 fps) for a PF of 131.06. Wow! That was freaky close compared to the expected result.
That gives me a load with about 78% of the momentum of my typical handloads and a little over 70% that of a factory load. And get this, it’s right at the same momentum as a typical 147 grain 9mm round but with a muzzle velocity that is about 100 fps less. That is even less velocity than a typical 230 grain .45 ACP. With such a low muzzle velocity it is much more of a push than a “snap” on the recoil. It’s a very comfortable load to shoot.
Thank you Mike B. and Alan B. for the Clays powder. That made a big difference.
I was thinking ahead to how to make a self-defense load with similar recoil properties and found that Speer makes a bullet they call Gold Dot Short Barrel for good self-defense characteristics with lower velocities. This sounds like just the ticket for Cherie. We have another range trip planned for the end of next month to do some more training and test out the new loads.
Sounds like a good suppressor load.
You are right! It does–assuming you have a .40 with a suppressor.
Fun little project, I’d never considered the .40 for low recoil loads.
Quite a few competitive shooters use low power .40 for steel and other pursuits where making major isn’t an issue. If you want the ultimate, shoot a Glock 20 with a conversion .40 barrel for a Lone Wolf 6 inch slide. That big frame Glock just soaks up recoil, even with hot 10mm loads and low powered 40 loads it feels like a pussycat!
Since felt recoil is a function of cartridge pressure and bullet weight, you lower recoil by lowering pressure, as you have done with your 3-grain loads. You can lower ir more by dropping down to a 135-gr bullet. The powder peeps say to pay attention to minima, else you stick a bullet in the bore. Try a slower, bulkier powder like HS6 and you will get low and slow without the risk. With the Bullseye and Clays, you are increasing squib-risk due to low powder volume: less than a third of the available. In a light load, HS6 is going to take up 60% of the available volume.
Defense: if recoil is an issue, use Glasers or similar frangibles. Or put together a Hong Kong load with a reversed 170 LFN and shoot it at 800 fps out of a Charter Arms Pitbull. The semis probably will not autoload a wadcutter. I love my Pitbull. I can get close to 400 #/’ with it. Only issue, it is SLOW to reload, no speedloaders for FortyShorty.
Felt recoil doesn’t directly relate to “cartridge pressure”. The pressure at the time the bullet escapes the barrel affects the velocity of the gases as they escape. This velocity multiplied by the mass of the gases (mass times velocity equals momentum) contributes to the total momentum leaving the gun. Hence a fast burning powder will generally result in less felt recoil than the same mass of a slow burning powder.
The other contribution to felt recoil is the momentum of the bullet. Adding the momentum of the gases and the momentum of the bullet at exit give the total momentum leaving the gun. Since momentum is conserved the gun (and shooter) “absorb” an equal and opposite momentum in the other direction.
By having low pressure at bullet exit time and a low powder mass (the mass of the gas is equal to the mass of the powder) the contribution to the recoil by the powder is reduced compared to a slow burning charge of greater mass.
If you look at my numbers from the previous post on this topic you will see the contribution to the momentum by the bullet for published loads of 135 grain versus 180 bullets is essentially the same. And by going to a 135 grain bullet you end up with a higher velocity bullet. This means the recoil of the gun is more “snappy” than with a slower bullet.
The risk of a squib is a concern. But the powder volume of Clays appears to be about half of the case so it appears to be fairly bulky. I’ll measure it the next time I reload. Thanks for the pointing this out.
Frangibles are better suited for small varmints. They don’t penetrate deep enough to reliably stop a heavily muscled (or fat) two legged predator. I’m more comfortable with a bullet explicitly designed for self defense at relatively low velocities.
I measured the volume of the available case consumed by Clays. It is 48%. I don’t know what this means in terms of risk of squib load. Can anyone help me out here?
Hopefully the reloading manual listed their test parameters(primer manufacturer, barrel length, etc). If so, did your setup match theirs pretty closely?
I don’t think I’ve ever gotten a result that close to what the manual listed, but I’m almost never using the same gear.
I’ve never come that close before either. And I have never used the same components or gear either.
In this case I used the same primer, WSP, as Hodgdon listed, but nothing else. Their bullet was a Hornady XTP, mine the Rainier FP. Their barrel was 4.0″, mine was 5.0″. Their cartridge OAL was 1.125″, mine was 1.131″.