Convert Astra Model 400 (9mm Largo) to 9 x 19mm (Luger/Parabellum)?

[Gun Master]

I own a Astra 400 in very good condition. The search for available 9mm Largo ammo is becoming more and more difficult. Also, supplies are inevitability corrosive, when located. And, as a senior citizen with arthritis, it is taxing to shoot the most powerful blowback pistol ever invented.

The 400 will shoot 9mm Luger, and .38 Super, but accuracy is lacking.
Safety is a concern due to dimensional differences, causing head spacing problems.

Do any of you know of an existing 6" drop in barrel chambered in 9mm Luger that will fit the 400 ? Are there any other reasonable possibilities to convert the 400 to 9 x 19mm ?

Thanks for your input.

 

[kBob]

Don't know who does it or if anyone does these days, but back in the 1960s when this came up folks made up a chamber adaptor of sorts that was just a ring to take up the extra 2.5 mm of length in the chamber. Folks at that time did the same thing to Swedish Brownings to shoot .380ACP in the 9mm Browning Long guns and he same thing to shoot .32 ACP in the French 1935 A and 1935 S that were chamberd for a proprietary 7.65 round that was basically a Pedersen Device cartridge.

Once about '68 or so one of the big parts houses offered a 9x19mm conversion barrel, but whether it was new made or a conversion such as above I do not know.

I must say I enjoyed my limited time with the M21 Astra 400.....until I ran out of ammo.

-kBob

 

[Gun Master]

Thanks kBob for your info on Astra Modelo 1921.

Your last sentence: I hear 'ya!

- Esso

 

[Onmilo]

The breechface on the 400 is not designed for 9mm Parabellum.
Even if you found a drop in barrel reliability will be poor.
I handload using Starline .38 Super plain brass cases and a 9mm +P powder charge under a 124 grain FMJ bullet.
Accuracy does not suffer nor does reliability. HTH

 

[tark]

Onmilo, I must respectfully disagree with your statement about the 400s breechface not being designed for a 9mm. The 9mm Largo and the 9mm Luger have nearly identical rim diameters, with the Luger being .001 larger. A 9mm Luger (parabellum, 9X19, whatever) will fit into a 400s breechface just fine. What WON'T fit, in some early 400s, is a .38 auto, or super. Rim on a Largo is .392, a super runs .405.

My 400 is a later gun, supers fit the breech face just fine. I put a Wolff extra strength spring in it and I used to shoot supers, after pulling the bullet and dropping the charge by 20%.

Then I got a hold of some CCi Largo ammo, with the aluminum case, and got the shock of my life; it was very clear that the Largo ammo was MUCH hotter than my reduced Super load. So I mixed a couple of factory supers in with the Largo ammo. I couldn't tell the difference. Neither could the Chronograph. That Largo ammo was throwing the 124gr bullet at about 1230 FPS. Guess what 124 gr .38 Super ammo is loaded to these days??!! Try 1240.

I shoot my 400 infrequently these days, but I shoot Supers in it when I do, with a warning to all who might do the same;

There was a vast improvement in metallurgy and heat treatment during the inter war years in the last century. The early 400s were not as strong as the ones made in the thirtys. The later ones were marked 9mm&38 on the slide and a super will fit in the breech face without modification.

GET NEW SPRINGS!! Wolff will sell you a new recoil spring for a few bucks. Be safe and get the entire spring kit. The hammer spring is very stiff, and it plays an important role in delaying the movement of the slide until pressures drop to safe levels

If your 400 is an early one, you can remove the rims on a Super with nothing more than a hand drill and a file. This will give you, in effect, a Largo case. Use 9X19 loading data for safe loads. There is no reason to try to convert a 400 to 9X19. Largo cases can easily be made from super ammo and you are ready to go. Load accordingly using super dies and a 9x19 shell holder.

Good shooting.

 

[Onmilo]

TARK.
I understand and agree with what you are saying about early 400s and rim diameter.
My 400 is a late commercial import marked 9mm/.38 and 9mm Luger will not set right against the breech.

Another issue is the length of the magazine in relation to the position of the feed lips.
9mm Luger is a lower powered cartridge than 9mm Largo/Bergmann Bayard or .38 super and the dwell time will cause reliability issues as the 9mm Luger will release from the feed lips before the cartridge is correctly in line with the chamber.

Point I am making is there is no such thing as a drop in solution to firing 9mm Luger in an Astra 400 and that is exactly why the Astra 600 was developed rather than just simply converting the many thousands of available 400s to 9mm Luger.
Can it be done?
Sure. anything is possible with a bit of fiddling.
But there are much easier ways to fiddle.

 

[Capybara]

Sell your 400 and buy a 600. I like shooting mine. Personally, as a reloader, I wouldn't go through all of the hoops in reformatting and adapting loads, if I wanted to shoot 9x19 Parabellum, I would sell the 400 and buy a 600. With some careful selling and shopping you can probably do it for about the same money, perhaps just having to pay a transfer fee if you don't have your FFL03. I see 400s out there all over the place, there is a market and I see a few 600s here and there, in much better condition than mine.

 

[tark]

Onmilo, you are quite right that there is no easy way to convert a 400 to any other caliber. You either shoot with Largo ammo, or converted super ammo loaded to appropriate pressures. The only problem with going to a 600 is the price of a good one. They go for quite a bit more than the 400s and the Nazi marked ones go for outrageous prices.

I love the 400s and 600s Mine will feed anything I stuff in the magazine, including empty cases. It is the only automatic pistol I have ever owned that has yet to malfunction on me. It has never jammed or failed to function perfectly in over ten thousand rounds.

I have an old worn out recoil spring and I use it for light target loads. My pet load is a 148 gr wadcutter and three grains of bullseye. The gun goes "POP" and the empties dribble out the side and the bullets cut neat little round holes in the target, much to everyones astonishment. It is one of my very favorite auto pistols.