Conversion barrel ?

[jackpinesavages]

Looking through the Lone Wolff conversion barrels I see a lot of these Super 40 barrels, but no load data in my books and very little online data. Any ideas on a direction to go?

 

[mbartel500]

The .40 super is a high pressure bottlenecked cartridge developed by now defunct Triton Ammunition Co. Basically, it's a .45 super case, using a small pistol primer, necked down to shoot .40 bullets at velocities higher than the 10mm can safely go. The idea of only needing to swap barrels, to get a very high performance round, while using your existing .45 acp mags sounded great, on paper. In reality, this is not a round that the average handloader, should mess with. Most pistols that are converted to shoot this round began life as a .45 acp. A low pressure firearm designed to shoot a low pressure cartridge. With the .40 super, you will be working at much higher pressures, bullet velocities, and slide velocities. The margin for safety, is extremely small with this round, as you are working at the utmost limits of gun design, and metallurgy. One small miscalculation, or error in judgement, could be very bad.
Also, the slide velocities from shooting this round are extremely high. Even with a very strong recoil spring, the beating the gun takes is heavy. Also it is tough to get reliable feeding sometimes because the mag lips have to be tweaked for the round. Also, the recoil spring has to be so strong to slow down the slide, and the slide gets slammed back into battery so hard that the top round in the mag will often stovepipe. For my money, I would choose the 10mm over the .40 super. Ever wonder why no gunmakers make a .40 super? At least the 10mm is available in a few factory loads, and there is plenty of reliable load data available. However, if I was to build a .40 super, I would choose a Glock 20 to start. The G20 has a slightly heavier slide than the G21. A high quality conversion barrel with full chamber support is a must. And the Sprinco Cor-Bon recoil reduction system. And some G21 mags. That takes care of the hardware. I would only use Starline brass, and I would only load them 3 times, then chuck em. Any good set of steel dies will do. No carbide dies are available for these bottlenecked cases. So you have to use a case lube. MAKE SURE THOSE ROUNDS ARE CLEAN & DRY before shooting them. Also wipe the chamber with a dry patch before shooting. Sorry this went so long. Hope it wasn't too boring. Bottom line is this.....If the 10mm can't do the job, the .40 super won't either. A 10mm in the hand is worth 2 .40 supers in the bush.

 

[mbartel500]

Oh yea.... I forgot to mention one more thing. The muzzle blast from this bad boy is unreal. Even with $100.00 muffs on, I flinched every time my buddy pulled the trigger. It was the loudest hardest CRACK I have ever heard from a handgun. Without ear protection, there is no doubt in my mind that it would cause permanent hearing damage. As a concealed carry option, it is totally impractical. Too much recoil, WAY too much muzzle blast and flash, and not enough reliability. Did I mention the muzzle blast? Oh yea....

 

[jackpinesavages]

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[mbartel500]

You might have some ignition issues with those small rifle primers. The cup material is much harder than small pistol primers. They are made for the more powerful mainsprings of rifles. In my experience, the Federal SRP are a little softer, and easier to ignite in a pistol. I used the CCI 400s in my Ruger SRH .454 Casull and had misfire problems. When I switched to the Federal SRPs, reliability became 100%. Also the SRPs are about .008 inch higher than the SPPs, so depending on primer pocket depth in those Triton cases, the SRPs might stick up out of the case too far. You'll just have to try them and see. Please, Please check out the Sprinco Recoil system for the G21. I use it in my G21 .45 super. Along with a Jarvis 6" barrel with full chamber support. I have a slew of Texas Ammo 185 gr. 45 supers, that clock out at a measured 1560 fps from that 6" barrel. That's 1000 ft lbs. of muzzle energy, thank you very much.
The Sprinco recoil system uses a full length SS guide rod with a two-stage spring system. The main spring in non-captive and can be changed to whatever rating the shooter wants. I use a 19lb. spring. The stock spring is 17lb. The second spring is very stiff and captive, so that there is no way for the slide to get battered against the slide stop. This two-stage recoil management system is the best I have ever seen, and is well worth the money to protect your pistol from a merciless beating. I have found very little load data for the .40 super that I would consider reliable. Your mileage may vary. Good luck with your G21 .40 super conversion. Please post back here and let me know how it's going. I would be very interested in your results.