40 S&W Powder weighing error - Can I shoot this load?

W

wondering121

Inactive
I attempted my first loading of 40 S&W but screwed up my powder weight and did not realize it until I had loaded 50 rounds.

I was using the minimum load in Hornady's 5th edition which is 6.2 grains of Power Pistol to push a 155 grain bullet to 950 fps. I used Acme coated lead RN bullets.

I'm using an RCBS beam scale and brainfarted and set it to 5.2 grains instead of my intended 6.2. I just received a 10th edition of the Hornady manual the day I loaded this and found that the new minimum load is listed as 5.8 grains of Power Pistol for 1000 fps for a 155 grain bullet. Both minimum loads have the same COAL of 1.125", but slightly different speeds.

I'm concerned that if I pull these bullets taht the coated ACME bullet may not be re-usable.

I'm at 1 grain below the old (circa 2000) minimum load and about 0.6 grains below the new minimum load that is set at 50 fps faster than the old load.

As best as your experience can tell will this load be okay to fire through a Glock G27 or should I just pull these and try to re-use the components?
 
They will go bang, and in a G27 will certainly exit the barrel---but I suspect that
they will not operate the action. Try a few before you start pulling them down.
Even your 6.2 load might have problems with the G27----load a few and try them
before you load a bunch.
 
The Hornady data is for a jacketed bullet. Your bullets will be softer and produce a lower start pressure. You want to use cast bullet data, and Lyman's says their closest cast bullet (150-grain RN) starts with 6.3 grains of PP and stops at just 7 grains to avoid leading. With your undercharge, as BillM said, you will get the bullets out (Power Pistol ignites relatively easily), but you will probably not cycle the gun. You will probably find the burn at that low pressure is dirty, leaving a lot of unburned powder particles in the bore, and if they blow around enough, you may even need to perform a full disassembly and detail cleaning. But they won't damage anything. You will just likely be using these loads for single-shot practice working on your trigger control. There are worse things a shooter can spend time and bullets on.
 
Thanks for the feedback guys. I think I will pull one of the bullets and load it properly to see if I can re-use the Acme bullet. If I can then I will re-load the entire set. Otherwise I may just use it for single shot trigger control practice.

Thanks guys!
 
Unclenick stole my thunder. Heh, like that never happens. I do want to put in some detail though . . .

I have a lot of experience with Power Pistol. It is without doubt, my second-favorite propellant.

As Unclenick said, Power Pistol ignites easily. Furthermore, it's highly energetic. And in this instance, both bode well for you. These characteristics are why I like Power Pistol so much. Its common "wheelhouse" purpose is to make high-velocity semi-auto ammo. What isn't often mentioned is how well it "turns down." Power Pistol de-tunes well. I've loaded consistent, clean running, excellent ammo with it on the low end of the charge weight data.

Now, your situation is a bit extreme than what I'm talking about; but my point is that they may not perform as bad as mentioned. If you came back and told us that they cycled the action, I would only be slightly surprised.

Either way, the best news is that your situation doesn't warrant pulling the bullets. Pulling bullets is unfun. (Taper-crimped semi-autos aren't nearly as bad as hard roll-crimped light weight revolver rounds, btw :p )

What works for me is when I decide on a load, I jot down the data on a sticky-note and bring it down to the load bench at the time of loading. It's prominently displayed in front of me the entire time I'm loading (along with the canister of propellant - label facing toward me). This process has kept me from making load errors a time or two.
 
Nick,

Thanks for the extra information. I actually followed that process of researching loads and writing down the ones I want to try/ having my reloading manual open on my bench, however I set my beam scale up wrong and didn't catch it until after I had finished the load. I have an RCBS beam scale that came with my kit and it has the 1/10 grain adjustments to the right of the pivot and I set it at 0.2 instead of 1.2...Luckily I set it up for a different load immediately afterwards and caught my mistake.
 
Nick may be correct that my warning about being dirty is excessive. I'm used to running this powder in 45 Auto where the pressure drop from a proportionally lower-than-peak load would produce about 2/3 of the pressure you will get doing it in the 40. Nick has mentioned before that Power Pistol looks like a thick-cut version of the current formulation of Bullseye, and indeed, it could be pretty close to exactly that, as the two powders share the same MSDS along with several other Alliant powders, including Unique, Sport Pistol, and BE-86. When Alliant changed Unique's formulation to burn more cleanly, they apparently had in mind to move Bullseye to a version of the new formulation and to be adding the other powders into the group. (The pre-change Bullseye and Unique flakes looked different, and this is another reminder of why you shouldn't rely on appearance to identify powders.)

When I get QuickLOAD to match the maximum numbers for the .40 S&W, it thinks your reduced load will run about 10,000 psi and give you about 700 fps from your barrel length and will push out about 40% of the powder unburned or still burning. That should make for a nifty fireball in low light.
 
40 S&W Powder weighing error - Can I shoot this load?

When I first started reloading I had Win 231 in 40SW and we went significantly under the min load and the rounds barely got out of the barrel... literally saw them fly 6-7 ft away and fall. Thankful that I had no squibs in that outing. If you go shoot these, Id do two things.
1) shoot one at a time making sure barrel is clear, see the impact, and verify safe / light thru barrel. It may work fine as a light load, or they could get stuck.
2) take several loads to try, it’s better to plan to disassemble a few rounds that are too light to keep shooting safely than to get there and have to go home after the first 4 shots because you’re worried the next one won’t clear the barrel. I was super conservative and had 3 variations of load below minimum and none of them were viable to even keep shooting a loaded magazine instead of one at a time (minimums are starting load for a reason).

* to Unclenicks point about fireball and low load with I burnt powder... yep I saw that with the Win231 under loads, it was a smoky sparkler.


Andrew - Lancaster, CA
NRA Life Member, CRPA member, Calguns.net contributor, CGF / SAF / FPC / CCRKBA / GOA / NAGR / NRA-ILA contributor, USCCA member - Support your defenders!
 
I just loaded a bunch 3,000 rounds of 40 S&W. The OAL seems to be on the short side. I'm out to 1.180. Seems odd that a .055 difference in OAL
 
Don P said:
I just loaded a bunch 3,000 rounds of 40 S&W. The OAL seems to be on the short side. I'm out to 1.180. Seems odd that a .055 difference in OAL
Click to expand...


Hi Don, you’re loaded long. If that works reliably for your gun that’s ok, but it’s longer than SAAMI spec and may not function in all guns. 40SW maximum COAL is 1.135”. OPs 1.125” is reasonable, that is the same I use for all bullet weights so I have let seating depth vary while weight changes to maintain COAL.


Andrew - Lancaster, CA
NRA Life Member, CRPA member, Calguns.net contributor, CGF / SAF / FPC / CCRKBA / GOA / NAGR / NRA-ILA contributor, USCCA member - Support your defenders!
 
Yep I gust looked at that. They work in my 2011 with a Barsto barrel. Again learn something new today
 
You must log in or register to reply here.
Back
Top