I have a .40 S&W Shield with a barrel so short a primer would probably send a bullet all the way out of it.

Right now I'm using only 4.5 grains of Unique behind a 180 grain Xtreme RNFP and that is still enough to snap the slide back pretty briskly.

Just curious to see how light of a charge I can go.

Any risks involved in going down to maybe 4.0 grains of powder, a tenth of a grain at a time, just to see if the slide will still function?

I would only load 10 rounds at each level if possible.

I started reloading in the mid 60's and have never deviated from loads published by bullet/powder manufactures. In military aviation we had a saying "don't tease the animals". I'll place my trust in the engineers working in the ballistics labs.

Rather than a sub-standard (velocity) round, I would try a heavier return spring!

With a short barrel comes a short slide and the reduced mass that absorbs felt recoil.

Ivan

If you want to do that, you'd probably be better off with a faster powder, but there is no danger in going so low (a tenth of a grain reduction at a time) that the pistol barely functions. Bullseye pistol shooters have done that for decades, albeit with faster powders. Having said that, why would you want to do it?

The only risk is having a bullet fail to exit the barrel ... stuck bullet .
Then the RISK ... pulling the trigger again and sending another bullet down the barrel . Things get sketchy here !

How careful and observant are you . No hole in target ...stop and check barrel .

Gary

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Use a proper reloading manual for bullet and powder and just use the lowest recommended combination.

Seeing how low you can go before a squib round or the gun malfunctions?

Brilliant!

There was an article in the NRA magazine (1981ish?) about light loads for 38 Special target shooting. They were well below 1 grain of Bullseye with reliable function and bullet exit (revolver, of course). IIRC velocities were around 200 fps. Might be an interesting article to check out.

Once upon a time, many years ago, just for the heck of it I made up a batch of .44 specials with decreasing charges, just to see how low I could go. Towards the end I could see the bullets going down range. Last one actually stopped with the end of the lead SWC hanging out the end of the muzzle.

I did load some of those loads for shooting in a granary on the farm. 8/10s grain of bullseye with a 148?gr HBWC worked fine. 6/10s and the skirt of one bullet stuck in the end of the bbl(3 inch 36)...so went to the 8/10s load and voila...no problems. The bullets wouldn't go through the corrugated metal walls...the reason for the exercise and still killed rodents. My daughter used a wrist rocket with 000 buck to kill 'em too. Steel balls bounced around too much

Not a .40 cal but..........

With my C9 3.5" 9mm pistol, my slowest ever load was a
124 gr plated FMJ @ 701 fps with IMR 4227 powder.

Good accuracy, however this load was so slow, that I had two stove pipes.

In this short barrel I try to keep the lighter bullets at around 945 fps minimum.

Have fun finding a "Powder Puff" load that is accurate.

It is sort of fun shooting a really slow load, waiting and then hearing it hit a 100 yard metal target.

I am Brilliant and don't you forget it!

Not looking for a squib in only a flipping 2 inch rifled portion of a barrel, but a soft plinking fun load for tin cans in the woods would be...well, FUN!

Most manuals start with a SUGGESTED starting load by the way.

I also have Bullseye on hand, and as I recall my K38 Target .38 Special revolver only required something around 2.5 grains of Bullseye with a 148 grain lead wad cutter bullet for its 6" barrel.

Anyway, until some genus comes up with a .22 conversion unit for these highly popular guns, I still enjoy plinking with a load that won't rattle my dentures every time while still operating the slide.

Yes you can do that, down loading until gun stops functioning. But, load just 2 cartridges at a time. One in the chamber and one in the magazine. After firing one, check to see if the second round has fed properly. Then stop, eject second round and check to make sure first bullet exited the barrel. All knowledge is good and safely (SAFELY!) conducting an experiment is a good thing...

If the gun is functioning you can definitely go lower. How much lower? Nobody can tell you that for your gun.

You’ll start getting sluggish slide performance and failure to ejects if you drop too low. Go even lower and the brass will just stay in the chamber. Eventually you’ll reach the reach a point were the bullet doesn’t make it out but that’ll be lower than 4.0 grains. Worse case scenario with 4.0 grains is that you’ll have to manually extract the brass with risk of smashing the brass in between the slide and barrel.

If you start dropping charges make sure the bullets exit the barrel. Best to use a fresh target so you can see each bullet hole. If uncertain drop the magazine, clear the chamber, verify the gun is unloaded and then check the barrel.

Yes I don't think I'd try anything less than 4.0 gn. Unique, even if I could go lighter.

Just curious, and thank you all for the replies.

LOL

Well if u really want to go slow, shoot that little revolver underwater and see if u can make a load where you can catch the bullet before it hits the bottom of the pool

Thats what I call an experiment!

...as long as the bullet exits 100% of the time. I don't try to go 'minimum' to achieve that, just a lighter load that cycles. It's part of the fun and freedom of reloading, if you use your head.

One of the most accurate 9mm loads I made was a light load for 147 gr bullets.

The 'conventional wisdom' used to be 'light loads of certain powders EXPLODED. That's been proven to be untrue. Explosions happen when you mess something up like put in the wrong powder, charge or fire after a squib round.

__________________
"He was kinda funny lookin'"

I had heard the EXPLOSION theory myself, and that was one concern I had.

Glad to hear that's false.

I think the slide would stop cycling or I'd get a stovepipe long before a bullet might get stuck in a barrel that short, but you can bet I would be carefully insuring that the previous bullet exited the barrel before proceeding.

Like I said though, I wouldn't want to even come close to a possible squib load before calling it quits.

And somebody needs to come up with a .22LR conversion unit, I'd buy one as a trainer for a beginner.

And I'd have a blast plinking around with it too!

That's what I call ridiculous!

...wait a minute...THAT'S IT!

Pop off a round so slow I could run past it downrange and catch it in my teeth!

My friends would be so impressed!

...I really am brilliant you guys.

I like to load light target loads but not too light, just so I know that the bullet WILL exit the barrel if by chance, that I tossed in a light throw of powder....... +/- 1-2 tenths grains.

While testing light loads, I also noticed when I got down to sub-sonic speeds..............
that I could actually hear the slide working, while wearing my head set, which was sort of neat, to hear.

Being outdoors, I always looked for a new bullet hole in the target or a puff of dirt, behind it, before pulling the trigger again.

Puff loads are great in pistols that are broken in but I found out that in a brand new S&W 3", that even medium loads will sometimes not eject or stove pipe, with the new, strong spring. Full factory ammo is needed for best results.

That makes a lot of sense right there, I definitely want to keep it away from the edge of it ending up as a possible squib load.

I also like the idea of my spent reloadable brass not ending up in the next county as well, but that's really become a non-issue with my nifty new brass catcher installed.

Just looking for a lighter plinking load to play with a little out there.

Wait a minute, why would I want to reduce Unique powder charges when I have Bullseye on hand?

Bullseye is a faster powder which builds pressure faster and would probably be a better choice for a reduced load in such a short barrel anyway.

...told you I was Brilliant!

I did that just now, firing one, ejecting the second chambered one, and checking the barrel to make sure the first actually got out of there.

Went from 4.0 Bullseye to 3.5 and the pistol functioned perfectly, locking back the slide when empty.

The spent cases ejected 10-12 feet or so from the Shield .40.

I could probably go even lighter, but I like the safety margin and recoil is quite pleasant so no need to go any further.

ETA: 10/30/20- Just tried 2 rounds of 3.0 Bullseye to see if my .40 Shield would still function, and it did just fine, but obviously with less vigor.

Going to stick with 3.5 Bullseye and feel I have a little reliability insurance.

Feels like a .38 Special in a .357 Magnum, and is really gentle on the gun too.