Needing load and seating depth advice

[91publicsafety]

So recently I purchased 500 laser cast 155g. 40 s&w Round nose semi-wad cutter boolits only to realize that I have no reliable load data on them.
I use Unique powder and CCI primers. Several of my load books have load data for lead boolits but none really have data that is for 155g or they may have a load but it is with a different powder or it fails to denote if the boolit used is a flat nose, hollow point, or what have you.
Then I find a fairly reliable load but it's for a fmj and I can't seem to find a consistent OAL listing for my particular round.

Any ideas guys?

Much appreciated

[MtGun44]

OAL is of interest for only two reasons. First, to locate the base of the boolit when the test
rounds were fired so you can know if your combustion chamber and their combustion chamber
are about the same. If you are putting the base of YOUR boolit much deeper than the base
of the boolit in the book data example that you are using, then your ammo will have higher
pressure so you need to know to make a small correction downward from the book load.

The second issue is you set your OAL (or LOA) to fit in the magazine and be able to chamber
properly. Dismount the barrel and use it to set the LOA so that you do not have the boolit
jamming into the rifling and preventing the slide from closing all the way. Then you set the
taper crimp (prefereably a separate die) to ensure that the round will chamber fully, too.

As far as book data for jacketed with a different shape, don't sweat it. Find a jacketed load
that is a similar weight and use that data with cast - it will be fine. OF COURSE your are
going to use the STARTING load and slowly work up, right?

Sweating the LOA (OAL) like it is some magical number is just spinning your wheels. It is
just a moderately useful piece of the puzzle - the most important use is to make sure you
are not burning the recommended quantity of powder in a much smaller than recommended
volume under the boolit.

Bill

[91publicsafety]

Thank you Bill,

So essentially as long as when I have the boolit seated and crimped and it fits flush in my chamber my OAL is good to go?

[Cadillo]

Thank you Bill,

So essentially as long as when I have the boolit seated and crimped and it fits flush in my chamber my OAL is good to go?

I assume that your .40 S&W is a semiauto. If that is the case your first OAL issue is finding a measurement that will feed reliably. Start by measuring the OAL of a factory or handloaded round that has proven to feed reliably in your gun, and try that OAL with your handload.

At this point we are talking about feeding, which can also be complicated if your load lacks sufficient pressure to achieve proper slide velocity, but OAL will be the first item to adjust, assuming that you are using a safe powder charge. If the cartridge is too long, it won't fow properly through the magazine, as the bullet nose will drag. If it is too short, it will jam against the top of the chamber, ramp or chamber mouth rather than go into battery.

Always remember that the deeper you seat a bullet, the more pressure you generate, and the .40 S&W is a high pressure round. Determine your best OAL with a moderate charge prior to working up the charge scale.

The first time I load a new bullet in a semiauto, I will often load enough of them in unprimed and uncharged cases to fill the magazine, and will cycle them manually through the gun a few times to test the viability of the OAL. While not proof positive, it is a good indicater that the OAL your looking at will work with that gun, magazine, and bullet.

[mpmarty]

The shape of the boolit nose has no effect on interior ballistics in a pistol.

[runfiverun]

and,,,, i'm sorry on your recent purchase.

[91publicsafety]

The first time I load a new bullet in a semiauto, I will often load enough of them in unprimed and uncharged cases to fill the magazine, and will cycle them manually through the gun a few times to test the viability of the OAL. While not proof positive, it is a good indicater that the OAL your looking at will work with that gun, magazine, and bullet.

thats a really good idea; thank you i'll give it a try. That and comparing it with factory ammo is a good idea too.[smilie=w:

[MtGun44]

For a semiauto, you have to meet the requirements of the magazine, the requirements of the
chamber and throat, and the requirements for feeding up the ramp, and finally, the power
requirements to cycle the gun. Not extremely difficult, but a good bit more involved than with
a revolver. Most of these are dimensional requirements, such as proper taper crimp to make
sure the case will seat fully, and proper LOA to make sure you are not jamming the boolit
into the throat. Dropping a dummy round into the chamber of the dismounted barrel should
have it fall in freely. If it takes more than about 1 lb of fingertip pressure to fully seat, then
there is a dimensional issue, either needs more TC or shorter LOA.

The dummy ammo hand feeding testing is worthwhile. I find that if I take a factory round
and set up a dummy/sample round right beside it and line them up exactly so I can compare
the new boolit to the factory one, that if I get the "front corner" of the boolit adjusted to fall on
the contour of a round nosed factory round, I have the best results with feeding.

Start low, and only load a few rounds of each increasing powder charge to get the power set
to eject and cycle reliably. Look where the cases land. If they are dribbling out of the port
or jamming by not getting fully ejected, you need more powder. Setting the powder level so
you get consistent ejection of 3 to 6 ft should be about right for plinking ammo if the gun is
reliable at that power level. Some guns require pretty hot ammo to function reliably, and the
only way to know is to try it.

Bill