115 grain 9MM - how low is TOO low?

[steelbird]

Working on a reduced 9MM load - got a bunch of 115 grain FMJ bullets, and a stash of Unique. How low would TOO low of a charge be? I don't think pressure spikes from excess space would be too much of a concern in the small case, but I'd like some input from anyone else who may have tried to create some lower powered loads with Unique.

[WIL TERRY]

THIS IS DISCUSSED IN SEVERAL LOADING MANUALS. In most manuals the starting charge with JHP/JSP etc projectiles as as low as you can go and be pretty damned sure you will not stick a bullet in the barrel; NOT 100% but close. Now why do you want to go lower ?? And if you insist, use lead bullets ONLY. Think we are kidding ; just wait till you have to knock out a stuck jacketed bullet from your BBL. OH BOY...is that ever fun !! But you will learn new swear words so not all is lost.

[LE-28]

Are you shooting these in a revolver or semi-auto? In a semi-auto we usually know when we're to low when the slide won't cycle reliably.
In a revolver, see post 2.

[steelbird]

The reason I'm looking for a lower power load with 115's is that I've discovered I shoot my Canik TP-9 better with a slower factory made 147 grain load - more accurate, softer to shoot. I'm just looking to see if I can get a load that is closer to this effect while using 115's. The loads I've seen in the manuals gear the 115 towards the hot side, not the slower one - AFAIK, the 115 was meant to be on the fast hot side, anyway, so a formula for a slower one seems to be hard to find. Of course, I may trade the 115's out, or sell them outright - don't know yet. And as with all things in life, there is what "the book says" and then there is real world experience. That's what I'm trying to find out.

[Sevens]

I spent a good bit of time trying to make 95 and 100 grain bullets (meant for .380) in to light 9mm loads and it was just failure after failure. You can make the 115's far lighter than normal with not a whole lot of fear of sticking a bullet, but not if you want them to run a semi-auto pistol.

MANY folks have experienced that 9mm is more pleasant to shoot with 147 grain slugs, but I've never worked with them.

[caz223]

I found that if you install a reduced power spring you can get lower, but I recommend shooting lead if you want to go low, as there's a reduced chance of sticking one in the barrel. My CZ75b went way lower than any of my other nines, so there's a chance you can get lower than a lot of people think if you have the right gun. Medium/fast powder is also good, as it seals the chamber better, and the low velocities are more consistent. I got 124 LRN so low that it wouldn't knock over steel plates anymore.

[caz223]

As far as marksmanship goes, I find it's not always power level once you get that low (9mm is pretty weak) but finding a bullet your gun likes, and a load that your bullet likes.
For instance, I shoot 124 grain XTP-HP better from a 357SIG, than plated or LRN from a low, low power 9mm load. The load I use is a compressed blue dot load that is way hotter than any factory load I've seen. I just shoot better bullets better.
Try loading up some full power 124XTPs, and see if you do the same.

[g.willikers]

It's possible to make an auto loader shoot just about any cartridge.
But once the gun is modified to do so, it might not shoot anything else worth a hoot.
So, if you want to have a gun dedicated to the load you have in mind, it's probably going to be a one load gun.
Nothing wrong with that, as plenty of competition shooters do just that.

[C7AR15]

Don't bother trying to find the low, low end of a cartridge- no good will come of it.
1. Stuck bullets
2. Single action semi-autos
3. Win 296 powder is dangerous if loaded low
4. Pulling bullets is boring
5. Having a brass rod and hammer in your shooting bag is a drag
6. Bad things can happen with these squib loads. Lookup how Brandon Lee died. (son of Bruce Lee)

Finally -Just load stuff up the way the manufacturers recommend, they have done a lot of research to get their product to market.

[caz223]

My inner schweinhund is forced to respond.
Manufacturers don't want to to even shoot reloads through their guns.
Over the last 20 years, I've stuck exactly 2 bullets in barrels.
1 was a commercially reloaded .38 spl wadcutter out of a .357 magnum.
1 was a full power 10mm that turned out to be a squib due to tumbling media in the flash hole (At 20 degrees F). I immediately switched to ultrasonic cleaning.
I loaded boatloads of LRN 124 in 9mm, they weren't dangerous, done with a little common sense.
It's cool for punching paper, but at some point you'll want to shoot someone else's gun, and your reloads won't cycle the action.

[kilimanjaro]

Just use the minimum published loads for your powder, that's about as light as you want to go. The disadvantages of lighter loads outweigh the advantages by goodly magnitude, including safety. You want to drop the minimum by a half grain, fine, but don't go any lower, it's asking for issues. Your load with Unique is only about 5 grains anyway. Just stick with that.

[Jim Watson]

The usual recommendation for a starting load is 90% of the maximum. That will usually run the gun.
I was not able to get a P225 to function at 88%.

The Lyman starting load for 115 gr 9mm is 4.4 gr Unique = 996 fps
That is very mild and might not function.
Don't load many until you are sure.

[Shotgun Slim]

I start just below the usual starting load and load 20 at a time dropping .2 on the powder charge as I go until the gun won't run in my support hand,which is the first place a load will show a lack of the proper energy. Then I go back up
.2 on the charge and that usually works.Sometimes these light loads are accurate and sometimes not.

[Wreck-n-Crew]

Some good advice here.

For me accuracy is affected on lower power loads. YMMV. Also cycling problems (short-stroke) causing jams/feed issues. Just don't go too low, test from bench for accuracy after 100% cycle and lock it down.

[T. O'Heir]

If it's below minimum, it's too low. Below minimum loads can be as dangerous as above max loads. Causes weird pressures from the powder detonating vs burning.
"...start just below the usual starting load..." Totally unsafe.
Alliant gives 6.3 as the max load for a 115 grain jacketed. Reduce by 10%. That'd be 5.6 for the starting load. If you want light target loads, use a cast bullet.

[caz223]

I took a CCW class many years ago, and during the course, the instructor took out a old smith model 10 heavy barrel .38 spl that had the barrel shot full of bullets, front to back, and then tied up the action. The gun had no obvious external damage, and other than the fact that the bullets would be somewhat difficult to remove, and they tied up the action, the gun was not internally damaged in any way that I could see from the outside under fairly close scrutiny. I've also seen a .45 pistol that was not so lucky. Rifles that stick one in the barrel are potentially lethal to innocent bystanders, so obviously, choose your platform carefully.
With a sturdy gun and some common sense, I believe that shooting low power lead bullets through a 9mm pistol can be done safely with some care.
Would I recommend it to everyone? No, of course not.

I wonder if trail boss would work for this application?
You'd certainly have to get pretty close to a full case, and I bet a 90% full case would make a lead bullet leave the barrel pretty consistently. No chance for detonation. I would load a touch longer than average to avoid compression, though. As mentioned before, you may need to swap your recoil spring for a lighter one. Don't even think about using FMJ bullets. Seriously.
Now, accept the fact that after all that work, you've made a gun that has approximately the power of an old .32, and who knows what the accuracy would look like.

[WESHOOT2]

The conventional 9x19 / 115g any-bullet / Unique load is 5.5g.
You can try a start of 4.8g and see if you maintain function.