400 Cor-Bon is running

reflex264

Handloader
Jun 13, 2007
325
320
To start from the beginning I had one of my hair brain ideas to use modern technology to make the 400 relevant. The problem with the 400 was it wouldn't match a 10mm once bullets weight exceeds 155 grains. The 10mm operates at higher pressure. The 400 has higher case capacity but SAAMI pressure maxes out at 29,000 psi. It was designed to get 10mm power out of 1911 guns with a simple drop in barrel.
It was designed around 135 grain and 150 grain bullets. There were several companies that made 400 barrels for Glocks. I absolutely lucked into one of the best. Accu-Match built Glock barrels with a comp specifically for the 400. The bore is absolutely mirror-like.

My plan which was inspired by the 10mm load I used last year to kill a big doe. The 120 grain Cutting Edge Bullets traveled at 1439 fps. wrecked the insides of a big doe. My thought was the weight would work well with the 400 but the length of the bullet would intrude into powder capacity. I contacted Cutting Edge to see if they had any data. They had worked out data using load map. After comparing case volume with the known 10mm loads I realized that with the pressures and powder capacity with the bullet seated it needed a powder that would be slightly compressed to keep the bullets from setting back. Accurate #7 had the second highest projected velocity and was bulky compared to power pistol. Since Starline Brass changed to the small rifle primer pocket on 400 brass you have two options. Small rifle primers or small pistol magnum.

I opted for the small pistol magnum. I have had great results with the Federal small pistol magnum in .357 magnums. I decided to use it with the #7. Using the starting load of 14 grains of #7 in Starline brass the only thing left to do was load it. I sized the brass and then carefully flared the case mouth. With the short neck and reported bullet set back issues I kept adjusting the die until the bullet would start in the case and quit. As it turned out the crimp groove is perfectly located for the overall length to be correct. I adjusted the seating die so that it would crimp the brass in the groove and followed up with a Lee factory crimp die. With the case mouth firmly in the groove, setback would be nearly impossible.

I was able to get it sighted in and shot 2 groups from a solid rest that were both right at 1 inch. The load was very mild to shoot and the cases dropped in a neat pile about 18” to my right. My thought was it was too cold but shooting was great. The chronograph would tell the tale. It would have to wait till the weekend to find out. I grabbed a handful of cartridges and the chronograph and headed to the range. The load averages 1526 fps with an extreme spread of 5.39. The high was 1529 fps. Nearly 100 fps faster than the 10mm and recoils like a 9mm. If the 120 grain weight seems light to you remember this bullet is about the same lengths as the 200 grain XTP. It acts all outside of its weight. The only thing left to do is hunt with it.
 

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