Any danger in going under the starting load?


February 28, 2008, 11:42 AM
Provided the bullet clears the barrel and the action cycles, will there be any problems if I load 9mm with less powder than the "starting load" ?

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February 28, 2008, 11:48 AM
If you're shooting an auto,one 'danger' might be getting one stuck ,not realizing it quickly enough,and pulling the triggger again.Not good.

You cold also get a much dirtier pistol because of the powder not burning efficiently,posiibly tieing the gun up.

If you are doing it for economies sake,the savings will be miniscule in a small caliber cartrdige anyway.

If doing it for less recoil,starting loads are generally pretty wimpy as-is.

February 28, 2008, 11:55 AM
I'm doing it mostly out of safety since I'm a rookie. I want a decent pressure margin if I happen to seat too deeply, etc.

February 28, 2008, 11:58 AM
Start out at the minimum charge for the powder that you use and you will be fine.

February 28, 2008, 12:10 PM
I want a decent pressure margin if I happen to seat too deeply, etc.Nothing you can do, within reason, will make a dangerous load out of a starting load listed in a reloading manual.

Seating depth will not increase pressure to a dangerous level with a listed starting load as long as the completed round still looks something like a loaded round.
That's why they are called starting loads.

You can create a much more dangerous situation by going below a starting load. (stuck bullets, squib loads, etc.)

Reloading isn't rocket science!
You have to really be trying in order to blow something up with listed & tested load data!


February 28, 2008, 12:42 PM
yep, stuck/squib, poor cycling. Everybody and their lawyer's brother has gone over the starting loads in manuals. That's why it's a starting load. Start with it.
good luck, be safe and have fun.

February 28, 2008, 12:43 PM
If you go lower than the starting load with some ball powders you can create what I've seen called as Secondary Explosion Effect. This creates excessive pressure with less powder. Ballisticians are not sure why this happens. It may be that the powder (lying horizontal in the case) is ignited all at once by the primer making the pressure skyrocket.

February 28, 2008, 04:02 PM
Those powders that create SEE (kaboom) with low charges are all VERY SLOW rifle powders. With fast-burning pistol powders you are not going to see this, even with pistol powders in full sized rifle cases (some of us use fast powders for cast bullets in military cartridges).

So, unless you are using TINY amounts of a very slow RIFLE powder in your 9mm, that's not really an issue. In rifle reloading, you want to be VERY careful about reduced loads. Anything for 9mm out of a loading manual would be safe to load even further down, EXCEPT for bullets getting stuck in the barrel. Start with starting loads and you will be perfectly fine.

February 28, 2008, 05:19 PM

There are those who believe there is not even such a thing as a SEE or detonation possible.

My pet theory is what happens is very close to, or in fact is, a bore obstruction.

IE: The reduced charge of slow rifle powder ignites, but doesn't build pressure fast enough to keep the bullet moving when it hits the rifling.

SO it stops, and in the meantime, pressure continues to build up faster in the chamber then the stuck bullet can get out of the way again.

The fact is, there is not enough energy available in a reduced charge of slow rifle powder to blow up a rifle if the bullet gets out of the barrel when it should.

But regardless what the true cause is, it just doesn't happen in pistols, only over-bore Magnum rifles using very slow powder.


February 28, 2008, 06:20 PM
You can get either one of two outcomes. One Squib load. Two a kaboom, if the powder has too much room in the case it can burn to fast and cause a dangerous pressure spike leading to the loss of a pistol rifle and some part of you.

just start out at the minium load in the book and take your time.

February 28, 2008, 08:43 PM
Do you own a caliper? If you have one, you shouldn't have to worry about seating too deep. If you don't have one, you should get one. YMMV

February 28, 2008, 09:45 PM
So, to sum up the responses:

For a newbie,

1. Stick with the starting load as your minimum load; do not go below; and

2. Buy a caliper if you don't have one, to make sure you have a good LOA.

Good advice.

Jim H.

February 28, 2008, 09:46 PM

Steve C
February 29, 2008, 12:45 AM
will there be any problems if I load 9mm with less powder than the "starting load" ?

There's "less" and then there's "a lot less". The 9mm is a high pressure round from a small capacity case to begin with and loading it down to say .380 pressures would still put the bullet out the muzzle without any real danger (other than to something in front of it) but you'd likely turn your semi auto into a single shot requiring the slide to be operated manually as the load may not cycle the action. The point of impact would likely be quite different than the point of aim used for standard ammo.

The start load is usually a 10% reduction from the max load. If I wanted a reduced load for some reason I'd limit them to no less than 25% below maximum. I'd also stick to the faster powders like W231, Red Dot, Bullseye, AA#2, Tightgroup, etc. If you drop the pressure too low on medium and slow burn rate powders you will see more powder residue, smoke and incomplete burned powder in the bore.

Like with any load development its a good idea to work it "down" in this case. Load ammo with progressively less charge weights, shoot them and stop at the load you get the results you desire or bullets become stuck or other problems manifest.

February 29, 2008, 05:25 AM
My favorite 9mm load is 5.5gr power pistol, with 115gr fmj(1100fps). No problems cycling any of my 9mms. I believe 6.0 is the start load. Very slow powders are the ones to watch out for(Win 296). Dont back off too far from the start load, but a .5 grain wont stick a bullet.

February 29, 2008, 07:57 PM
Seat your pistol (or rifle) bullets at or near the crimping groove and you will be fine, no need to be concerned with calipers accurate to a thousant of an inch.

We were loading safe and effective ammo LONG before such calipers became common tools.

Jumping Frog
February 29, 2008, 08:04 PM
The Lee MODERN RELOADING Second Edition ( has a section on reduced loads. It states one reason to reduce loads below the starting charge is if you are using softer lead bullets and want to avoid leading. He says one can go as low as 20% below maximum charge for slow powders, ranging up to 50% below maximum charge for fast powders.

March 1, 2008, 06:41 PM
The detonation issue is very controversial but I can tell you that surprisingly close underloads can give you squibs. The first one presents no's the second shot that could blow up your gun and injure you/bystanders. Don't do it.

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