Replica Air Guns

ASG STI Duty One CO2 Blowback Steel BB gun

(10 reviews)4.5
In Stock
$ 145.97

Total: $145.97

Type: BB air pistol
Manufacturer: ASG
Model:  ASG STI Duty One 1911 Blowback
Materials: Metal slide and polymer frame
Weight: 1.8 pounds
Barrel: Metal non-rifled
Propulsion: CO2 x 1
Action: Semi auto blowback, single action
Ammunition Type: 4.5mm BBs
Ammunition Capacity: 20 round magazine
FPS: 383

Trigger Pull: The trigger pull on the ASG STI Duty One 1911 is nice and light due to its true blowback operation that cocks the hammer back with each shot taken. The pull is rather long but nothing really happens until you get right to the end and then there is just a slight bit of pressure and a quick release.

Accuracy: I shot the STI Duty One 1911 air gun at a target from 20 feet away in a free standing position, and it performed well getting a 1.5 to 2 inch grouping right in the center of the target. The rear sight is adjustable for windage which is always nice to have just in case you are shooting a bit to the left or right. For me there was no need to adjust the sights. My Chrony testing with an eight shot averaged result was 373 fps - very decent for a blowback pistol!

Build Quality: ASG did an awesome job designing and making the STI Duty One 1911 Blowback BB gun. They didn't really compromise on anything other than the polymer frame! With that said all that important parts like the Slide, Slide Catch, Safety, Mag Release, Hammer, Barrel and Magazine are all metal. The fit and finish as with all the ASG air guns is excellent!

Realism: The ASG STI Duty One 1911 Blowback is a really close replica to the real steel STI 1911. The only real giveaway is the trigger design as a true 1911 trigger is not your typical lever type. Even with the different type of trigger the STI Duty One is a very good replica complete with all the STI licensing and trademarks.


  • Realistic true blowback action.
  • Adjustable rear sight for windage.
  • True single action blowback gun.
  • Excellent quality control. Very well made, fit and finish is excellent
  • Good power, accuracy, and CO2 efficiency for a blowback gun.
  • Metal dropout magazine.
  • Good STI Replica.
  • Extremely enjoyable gun to shoot!


  • Trigger is not true to the real 1911 style.
  • Has a polymer frame, not metal.
  • I found the CO2 kind of hard to get out.

Comments: I am quickly realizing that ASG is a company that makes not only some really nice air pistols, but also ones with excellent quality control and design. The STI Duty One 1911 Blowback CO2 BB gun is no exception to this and I found it a blast to shoot because it felt great in the hand, shot hard and on target, performed flawlessly and I was able to get a lot of shots from a CO2 even with the blowback and high fps for a blowback shooter. If you're a 1911 fan or you simply like full size guns that mean business, then take a look at the ASG STI Duty One 1911 Blowback CO2 BB pistol. If I had to pick one BB shooter to take out for a day of plinking, this would probably be the one!

Barrel Size:4.55 Inch
Caliber:4.5 mm (.177 cal)
FPS:350 to 400
Ammo Type:Steel BB
Power Source:Co2
Rail Type:Weaver
Trigger Action:Double
Body Type:1911
Blowback Action:Blowback
Rear Sight:Fixed
Front Sight:Blade
Barrel Length:11.6 cm (4.55 inch)

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Oct 22, 2017


Initially, when I first purchased the BB gun it worked quite nicely and had a crisp recoil action. I only used it between 4-6 times before I got carried away with other things and stopped using it for about a month and a half to two months. Once I tried using it again the first two magazines would shoot but not as well as before and the third magazine wouldn’t shoot properly before it would shoot 4-5 magazines without a problem. Unfortunately, you cannot directly contact ASG as a customer. I’m very displeased with this ASG product.
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Oct 07, 2017

Nice gun but...

Great gun but with some cons. First what I like. Great feel in the hand. Shoots hard strong blowback. Really well made with a great design but one notable exception. Now the negatives. As mentioned on other reviews, the c02 really is hard to remove. It took a lot of jiggling fiddling and swearing to get it out. I finally slid a thin blade behind the bottom of the c02 and gently pried it out. Another issue I had was found when I pulled back the slide I found paint missing. That being said the fit and finish other than this is great. The gun definitely shoots a little low but I'm am going to fart around with the sites. Overall I really like this gun and I recommend it .
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Feb 21, 2017

Great Value

Good all a round quality as usual with ASG products. It did take some time for it to break in and function well though. After 6 months and 4000+ rounds it functions smooth and as flawlessly as can be expected. I found that for me the elevation with the sights was low. However with the barrel extension GPASG17644 the issue was corrected and consistency was improved noticeably. Chrony speed without barrel extension 370 fps +/- 10 fps and with barrel extension 425 fps +/- 10 fps consistently. I found that the crosman copperheads tend to double feed frequently but haven't had any problems with other brands. Just as others have mentioned, some Co2 cartridges can been a nightmare to get out........use a magnet and problem solved. Overall a great product at an unbeatable price as far blowbacks go.
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Oct 21, 2016

Excellent value

I've had my Duty 1 for a while now and have to say it's one of the best values out there. It's hard hitting for a blowback and looks very realistic. If you own this pistol or are considering buying it, do yourself a favour and get the ASG barrel extension too, it looks wicked cool and at a guess I'd say it adds around 40fps to the muzzle velocity. Only a couple of negatives. The ejection port isn't cut out, it doesn't seem to be field strippable and you may have to grind down that high front sight a bit to get the best accuracy
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Aug 31, 2015
Certified buyer


I am more than pleased with this purchase..although first impressions were mixed. The initial look, and feel of the product is amazing....great weight, and feel in the hand. First co2 leaked a fair amount, but somewhat expected until seal is seated properly. As in the video review I also experienced the slide locking back mid magazine, but after a little more lubrication, and break in the gun works flawlessly. No white warning all over the gun which makes it look more realistic. Co2 usage very good considering the strong blowback, and after much great, and still tight. Great addition to any collection...only problem is what to order next!!
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Jul 16, 2015

Blowback BB Pistol With Major Issue

I bought this because of the excellent reputation of ASG and because of its features:1 - Full Blow Back2 - Accurate look to the real thing3 - Fully functional controls 4 - Reasonable price point for all of the above features -And, I find that it has an even stronger blow back action than I anticipated and is even a little bit louder than I thought it would be (both good things!).Unfortunately I found a major issue with it when I went to replace the Co2 powerlet - even though I had been warned that it would be difficult - it proved to be impossible for me to remove it without doing damage to the grip. YMMV - as all Duty Ones may not have this issue - but be warned!Recommended with a caveat.
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Jul 15, 2015


i like the bb gun. its perfect for me. its jawsome!!!!
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Jan 27, 2015

A simply GREAT piece, if you'll pardon the pun !!!

The ASG STI DUTY ONE 1911, well where do I start, the great accuracy, amazing construction, superbly accurate, very fun too shoot, and put simply a great looking semi auto pistol, as a huge 1911 fan I am very discriminating, and the DUTY ONE not only met my expectations but greatly exceeded them, if you're looking for a sturdy well made 1911 semi auto bb shooter then this gun is for you, a very efficient, fun to shoot very affordable pistol, get one while you can, to put it simply, it's worth adding to your collection, get one while you can, thanks again, you know your business. Jim -Edmonton
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Dec 23, 2014


Asg makes a beautiful gun! Very pleased with this replica. Out of the box it is a work of art in my opinion. I could see that it had been well oiled. Very nice metal stick mag which is easy to load. It needed a little lube. Loaded up using Daisy bbs and Daisy Co2 since that is what I had on hand. Gun surprised me with its load report and fairly hard blowback. Was misfiring at times and the slide was sticking back before the clip was empty. Was not too impressed with that but thought maybe it needed to be fired a bit to loosen things up?? In any case I ran low on bbs so I went to the closest store and bought some Crosman Copperhead bbs since that is all they had. Loaded up and problem solved.Shoots hard and cycles flawlessly especially with a new Co2. Pros- very well made-good quality, quality metal stick mag which is easy to load, co2 loading and unloading works well for me, nicely finished and no white warning signs on the right side of the gun,serial # on right side, comes in a box with an allen key to adjust the rear sight elevation. Cons- because of NOT being all metal such as say the Colt Commander it is a bit lighter feeling which slightly detracts from the realism in the hand. It would have been better to have had a functioning grip safety but I understand with the design of the grip and the Co2 being in the back of the grip this was not possible. Conclusion: the cons are minor and not a deal breaker for me. It is such a beautiful piece. If the internal workings are built as well as the outside this gun should last and function well for a long time. Recommendation:if you like Co2 pistols in any of the 1911 versions I think you would be pleased with this one. As well if you have access to the recommended Co2 and bbs you will likely have the best performance. Satisfaction-OFF THE CHARTS!!! Fun factor-OUT OF THIS WORLD!!! A bit of advice for people new to Co2 Gunning- use pellgun oil often and sparingly on your Co2 seals and moving parts. Keep it clean and store it dry and safe and you will get the best service and pleasure from your gun. Happy shooting! Dennis-Saskatchewan.
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Nov 05, 2014

a must have

a must ALL 1911 replicasI was not disappointed when I received my duty one after watching the review...this gun feels awesome in hand...handles well and has a nice blowback feel and isn't too shabby in anti the accuracy depth either...A must have for your collection in my opinion and isn't overpriced! Great value!
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ASG STI Duty One 1911 Blowback CO2 BB Gun Review

ASG STI Duty One 1911 Blowback CO2 BB Gun Review

(1273 raters) 356235 views - 5/22/2011 9:08:24 PM - ASG STI Duty One 1911 Blowback CO2 BB Gun Review.

-CO2 Powered
-4.5mm Steel BB
-20 Round Metal Magazine
-STI Duty One 1911 Replica
-Semi Auto - Single Action
-Blowback Action
-383 FPS
-Purchased from

This video is a walkthrough review of the ASG STI Duty One 1911 Blowback CO2 BB Pistol. I show off the gun close up from all angles and point out the metal and polymer components and the excellent quality and features this airgun offers . I also show you a target that I did an 8 shot accuracy test from 20 feet out in a free standing position along with the results of my Chronograph 8 shot test. - very impressive!

This is a very realistic and fun full sized air gun to shoot, it offers just about everything you can ask from a replica airgun including, true blowback action, nice high fps, decent CO2 usage, accuracy and excellent quality. If I had to pick one gun to take out for a day of plinking, this would probably be the one!

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