Terminal accuracy with a pellet firing pistol Part 2

Terminal accuracy with a pellet firing pistol Part 2 Part 1

The limitations of a rifled barrel blowback action semi-auto

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By Dennis Adler

The Sig Sauer P320 ASP is offered in black or this very pleasing FDE-like monochromatic Coyote Tan finish. The belt fed rotary magazine has a copious 30 round capacity. I managed a total of 50 rounds from one 12 gr. CO2 cartridge before velocity began to drop but the ASP still sent rounds downrange with a solid thwack as they hit the cardboard backer 75 feet away. In terms of weight, balance, trigger design, sights, and operation, the only thing missing from the CO2 model is a slide that locks back on an empty magazine and a few minor operating features found on the centerfire models. The ASP is a decent basic training gun with benefits.

To be fair this is going to be a more challenging test because the same 12 gr. CO2 cartridge that had the solitary purpose of sending a 4.5mm alloy pellet downrange from a revolver now has the dual task of pushing the pellet down a rifled barrel and operating a blowback action slide. The velocity for the test gun, the new Sig Sauer P320, averaged 388 fps with Sig’s own 5.25 gr. cast alloy wadcutter pellets. With that much velocity I expected the gun to do quite well at the 45 foot distance.

Drawing a DAO semi-auto from concealment, even one as large as the P320, is altogether different than drawing a Single Action from a Western holster. I wouldn’t want to go up against an accomplished pistoleer with a Peacemaker, even from this very efficient Galco Quick Slide rig for the Sig Sauer P320.

With a semi auto and a DAO at that, a great deal of the accuracy is going to rely on trigger pull. When it comes down to pulling the DAO trigger on a Sig Sauer P320, standard trigger pull on the centerfire model is factory rated at 5.5 pounds. The trigger on the P320 ASP CO2 model is also remarkably light for a double action only, with an average pull of 6 pounds, 3.5 ounces. It is a strong, straight pull with moderate stacking and a clean break, but requires almost a full release to reset. However, for this particular target shooting test, reset is of little consequence.

From this perspective behind a trio of excellent white dot sights and with a semiautomatic action, the tables are turned and the Sig gains a modest advantage over the rifled barrel Colt Single Action. Even with its shorter internal barrel length the Sig Sauer P320 ASP kept pace with the Peacemaker.

I used the same setup as the Peacemaker test, a large silhouette-sized cardboard backer and a red dot as a point of reference for sighting (I removed the red dot when I photographed the target). What I found interesting first and foremost was the P320 ASP’s POA barely deviated between 10 meters and 15 yards (45 feet) so my aim was almost identical at the greater distance. From 10 meters the P320 had delivered a best 10-round group measuring 1.25 inches, and best 5-shot group measuring 0.75 inches.

Best 10-shot group fired offhand from the 15 yard (45 foot) firing line delivered a best 5-rounds measuring an even 1.0 inches, with two overlapping.

Just to recap before I tell you how the gun did at 45 feet, it has an internal rifled barrel length of 4.68 inches, so it is 2.07 inches shorter than the internal length of the rifled barrel in the Peacemaker. This sounds like a recipe for wider groups. At the extended 45 foot range, the Sig Sauer P320 ASP delivered a best 10 rounds at 2.125 inches and a best 5-rounds measuring 1.0 inches. That’s almost identical to the Peacemaker at 45 feet.

Pushing the pellet-firing, blowback action semi-auto to its limits, the bench rested two-handed hold (same as used with the Peacemaker at 25 yards) kept the DAO pistol on target delivering groups equal to, and for closest group, slightly better than the 7-1/2 inch Colt. The Sig Sauer P320 ASP has proven to be a very good gun despite a few technical shortcomings. POA correction was 12 inches at 25 yards.

The real surprise came at 25 yards shooting from a rested position with the ASP. The pistol’s white dot sights and very consistent, albeit heavier trigger pull kept the gun on point sending 10 rounds downrange with a spread of 6.0 inches but in fairly respectable groups with a closest 5-rounds measuring 3.5 inches. The Peacemaker’s best at 25 yards was 5.2 inches, giving the semi-auto a decisive 1.7 inch advantage for tightest group.

The current long distance champions for 12 gr. CO2-powered, pellet-firing blowback action and Single Action airguns (beyond the nominal distance for their respective designs), the Umarex Colt 7-1/2 inch Peacemaker and Sig Sauer P320 ASP. Two very well thought out pistols; one fiercely rooted in the 19th century, the other barely a year old.

So, a blowback action does not necessarily mean a pellet-firing semi-auto can’t equal the accuracy or performance of a legendary single action like the 7-1/2 inch Peacemaker. Sometimes modern technology is better, if not aesthetically, than at least downrange where it counts.

A Word About Safety

Single Action and semi-auto airguns provide the look, feel and operation of their cartridge-firing counterparts and this is one reason why they have become so popular. Airguns in general all look like guns, these two Western models even more so, and it is important to remember that the vast majority of people can’t tell an airgun from a cartridge gun. Never brandish an airgun in public. Always, and I can never stress this enough, always treat an airgun as you would a cartridge gun. The same manual of operation and safety should always apply.

17 thoughts on “Terminal accuracy with a pellet firing pistol Part 2”

  1. Would have expected higher velocity with the Sig alloy pellets . With 7 trainers, velocity would be in the low 300 range . Pretty anemic . It redeems itself in the accuracy department, but is not terribly powerful.

  2. the website lists velocity at up to 450 with alloy pellets which is overly optimistic to say the least. I suspect the real world velocity you got , was done to allow a full 30 round mag to be fired without having to replace the co2. Personally , I would have gone with a shorter internally belt with 15 rounds at the 450 velocity, I really don’t see what was gained with a 30 rounder , which would have been better for dual co2 fed carbine

    • Just ran another chronograph test with a half depleted CO2 cartridge and the Sig delivered a high of 410 fps and an average velocity for five shots of 394 fps. My posted average velocity of 388 in today’s article stands corrected to 394 fps. With a fresh CO2 the Sig would easily deliver 410 fps to 425 fps, maybe even 450 fps at the beginning.

  3. Could a shorter barrel lead to better accuracy due to the fact that the pellet exits the barrel sooner requiring less follow through with aim and stance?

    • No. A longer barrel will usually provide greater accuracy. In this case it is a combination of velocity and superior sights not barrel length that gave the Sig an edge. If the Peacemaker had the SAA Flattop Target Model sights, for example, they would be more accurate and the Colt would likely out shoot just about any other CO2 pistol in their class.

      • what is truly needed is a target pistol using co2 like the old Crosman 600. Something along the lines of a Ruger Mark IV 5 1/2 bull barrel , a Browning Buckmark, an old Colt Woodsman Match Target or High Standard Citation. The Crosman 600 is sa only , no blowback but the stiff recoil makes it feel like a blowback pistol . W/o blowback to soak up co2 , you could see velocity in the high 400 -over 500 fps with alloy 5.5 gr pellets and low to mid 400s with 7 grainers. The accuracy of a rifled barrel and the higher velocity is a formula for accuracy.

  4. Hi Dennis and the group. Just as I was beginning to think I was learning a bit about air guns and their powder burning siblings, this Sig P320 has me baffled. I thought when you had blow back, it would eject the spent brass and cock the gun for the next shot. As I understand, the powder burning Sig just fires DAO . Is that correct ? It seems like a shame not to have a lighter single action trigger pull. Why did they design this gun that way ? I am sure you covered the reason, but I missed it.
    Good shooting with that heavy trigger pull.
    Have a Great Weekend

    • Harvey, it is a striker fired gun (internal) so no hammer to cock, and as a striker fired pistol the trigger has a harder job, like a DAO revolver, it has to also cock the hammer, or in this case, the striker. Trigger pull is also heavier on modern military pistols as a way to minimize an accidental discharge. The P320 was designed to compete in the U.S. Army trials to replace the Beretta Model 92A1 (M9) and succeeded in becoming the new standard issue U.S. military sidearm this year. The CO2 model has blowback (just like the cartridge model) but there is nothing to eject, the slide moves back to duplicate the action of the centerfire pistols, which do eject a spent shell case when fired.

      • Thank you again Dennis. These answers help me understand the concept behind the replica weapons used for training purposes. I have a Crosman C41 which is DAO and I am able to fire it pretty accurate with it’s heavier trigger pull . At one time when I was just starting in this hobby I bought the non blow back P08 Luger. I had a miserable time with that thing, giving it to a friend . This friend gave it to a mutual friend who also is a avid fire arm shooter and he loves it . This all part of the learning process.

  5. There is a weathered finish Shootist that can be ordered with or without presentation box. The engraved revolver is special order. It is a polished blue as pictured above , with tea stained grips . Initially listed as sold out there are a few remaining . They are hand engraved and labor intensive . Only a few are done per month , due to the engraving coverage . I doubt you will ever see a revolver so extensively engraved for this price again. I ordered one a couple of months ago and was told 9/17 delivery . Now they are listed as 10/17. I spoke to Val and recommended one change re the box for future offerings . A block accepting 12 nickel cartridges. My advice would be to order one and be patient.

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