Tagged: 9mm largo Star Super
April 9, 2018 at 10:26 pm #50033
Years ago I picked up a Star Modelo Super chambered in 9mm Largo.
Take down is really easy, just remove the magazine, throw a lever on the right side and slide the two parts apart.
The Star Super is very similar to 1911, except the barrel has a lug on the bottom to handle locking and unlocking instead of a link.
The 9mm Largo is basically a longer 9mm Luger, and dimensionally is almost the same as the 38 Super except the 9mm Largo is a rimless case vs the 38 Super’s semi-rimmed case. The brass case is .900″ long and the factory loaded length is 1.300″. I had a sealed can of surplus Sante Barbara Ammo for it, but it went up in flames with my shop a few years ago. The factory ammo has a brass case, but is berdan primed, so I ordered up a sack of Starline brass to use instead. I pulled a bullet on the old ammo and the flake powder inside was still dry and looked to be in good condition. So I pulled down a dozen more and measured each powder charge. Most were 6.1 grains, but there were a few 6.0 and one 6.2.
I primed a bunch of the new Starline cases with Win small pistol primers, charged each case with 6.1 grains of powder and seated the factory 128grain FMJ bullet to 1.300″ and applied a taper crimp.
I’m going to shoot the “reloads” to get a baseline as to velocity and accuracy. When I first bought the pistol around 1995-ish I chronographed some factory ammo and I seem to remember that it was only about 50fps slower than 38 Super. Some sources list the 9mm Largo as being a low pressure round, but that is probably because the Astra M400, that is also chamberd for the 9mm Largo, has a weaker action. Some of the Star Supers were offered in 9mm Luger which has a max pressure of around 35,000 psi, so it would seem that the guns chambered in 9mm Largo should be able to handle the same pressure. I had read that some of the Star Supers could chamber and fire the 38 Super. I referenced Quickload and it shows the 38 Super having a max pressure of around 33,000 psi. I tried the plunk test with a round of 38 Super in the Largo’s barrel and the semi-rim got hung up on the hood of the barrel. So I broke out some needle files and cut a small step in the hood for the 38 Super’s semi-rim to rest on.
I put it all back together and dry cycled a few rounds. The Feed lips of the magazine needed tweaked open just slightly, after that everything cycled perfectly.
So armed with a box of each ammo and a chronograph I made my way to the range. If my memory serves me, it seemed that the Super ammo was only about 50fps faster than the Largo. I tried some 9mm Luger ammo in it also and it fed and fired fine. I tried some 380acp and it would chamber and fire just fine, but didn’t have enough power to cycle the slide.
I have since ordered and installed a Wolff extra power recoil spring with the thought of running some heavier loads through it.
April 10, 2018 at 1:10 pm #50042HarterParticipant
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Is this the 9×21 largo ?
A number of yr ago I had a bunch of 357 cases with split mouths . I cut them back to x23 I think , and loaded them as the accordingly they were actually quite accurate in both a carbine and revolver ……..then I remembered that they would also drop into 38 Special and bad things could happen . So I burned it all off and resorted to 38 short class data should I ever load them again .
While it’s probably a not worth it hassle I believe the whole 9mm clan 17-25 (9mm Win mag ?) share the 223 rim so you know if you have a bucket full of split necks and cabin fever or the doldrums and a 35 cal neck reamer ……. 🙂 Don’t see me being that bored any time soon either .
April 10, 2018 at 3:26 pm #50043
I think the case length is the same as 9×23. The 9mm Largo case is .900″
April 10, 2018 at 4:29 pm #50044
Well, I set up the chronograph today and shot the “reloads”, some 38 Super and something abit heavier…
The factory reloads with the 127gn FMJ clocked at 1134fps and really didn’t make a group worth even taking a picture of, but did have some high and some low.
The 38 Super with 130gn FMJ clocked at 1161fps and had verticle stringing from point of aim to about 6″ low at 25yds.
I had some of the 358-190 Ranch Dogs cast and wondered if what it really needed was a fatter bullet. So I powdercoated some, and used quickload to come up with a starting point for BlueDot.
I loaded 6.0 grains which gave 963fps at 101% load density, 6.4 grains which gave 1002fps at 108% load density and 6.8 grains that gave 1048fps at 114% load density. None of the loads had flat primers and the spent cases didn’t go very far. But none of the targets were anything to be proud of.
So I crimped on some gaschecks and went back to the 6.0 grain load. This time it gave 949fps and a target that looked like a good starting point.
I’ve got two big problems. First is the large verticle dispersion of all ammo shot in it. Second is it is shooting very low. I was aiming at a target on top of this one. So I’m thinking a taller rear sight for starters, then try some different powders and velocities?
April 14, 2018 at 8:14 am #50106
I loaded up some lubed with Carnauba Blue and shot the 6.4 gns of Bluedot. I spent a few getting the rear sight tweaked ,but they looked a lot better. I have an adjustable rear sight on order. I just hope that the dovetail will be close enough to the same size.
My Father in law took a spill and hit his head, so we’re in Kentucky for a few days.
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