November 2017

Big-Bore Autos: Two More 10mms and One 357 Magnum

Of the Colt and Smith & Wesson 10mms, the former proves the 1911 platform is well suited to the cartridge. The Coonan offers a hard-hitting revolver chambering in a 1911 platform.

Big-Bore Autos: Two More 10mms and One 357 Magnum

When we added up the scores, we found that the Colt Delta Elite was the top big bore, with the used S&W Model 1076 10mm and Coonan Classic tied for a very close second place.

Other than the 45 ACP, a big-bore automatic means a pistol chambered in 10mm Auto or a less-common caliber. In the recent past, we have tested a few new 10mm pistols and found we liked what they offered. For this test we went to Colt, one of the original manufacturers of the 10mm in the 1911 platform, and acquired one of the company’s new Delta Elite pistols. We also went back in time to the early 1990s when the FBI determined they were under-gunned and opted for the 10mm round. We found a used Smith & Wesson Model 1076, which is similar to the FBI Contract Gun, and shot it side by side with the Colt. Then we added a Coonan, which has been around for a number of years, with its claim to fame being a 1911-style platform chambered in magnum revolver calibers. We acquired one of the latest models, the Classic 1911 chambered in 357 Magnum, to pit against the two 10mms from Colt and S&W.

Bottom line is, these are expensive pistols with expensive ammo appetites, but that wouldn’t stop us from owning any of these three tested pistols. Any of these pistols are well suited for short-range hunting and personal defense. These pistols are all full-size models with heavy steel receivers, and that is a good thing when firing hot 357 Magnum and 10mm loads. In addition to their weight, another similarity were locked breech actions, where a lug or pair of lugs on the barrel locked into grooves cut on the inside of the slide, similar to a 1911 set up. They also had single-stack magazines and fixed three-dot sights. The triggers on the Coonan and Colt were exceptional. The S&W was heavy, but it still kept pace with the newer pistols.

We tested for accuracy using a rest at 25 yards and found these pistols were well matched in accuracy. Accuracy averaged about 2 inches for five-shot groups. We also practiced double taps at targets set at 10 yards. During that round, we found the 10mm pistols were easier to control than the 357 Magnum pistol.

For ammunition, we used SIG Sauer V-Crown 180-grain jacketed hollow-point bullets and SIG Sauer full-metal-jacket 180-grain bullets. We also used Armscor USA rounds loaded with 180-grain FMJs. The Armscor clocked about 100 fps less than the SIG ammo. We’ve noticed that SIG is loading 10mm ammo hotter. Many factory loads in 10mm are light and do not bring out the true potential of the 10mm round. The 357 Magnum rounds consisted of SIG Sauer V-Crown 125-grain JHPs, Aguila 158-grain semi-jacketed hollow points, and Winchester PDX1 Defender 125-grain JHPs. We had issues with the Winchester ammo in the Coonan, which we will get into below. Here are details about how each gun performed.

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