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KWA KP45 USP NS2 System Comparison Review

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KWA KP45 / USP — NS2 System




Several years ago Infected Armory reviewed the KWA USP .45 as one of its first reviews. Today we are taking a look at the revised KWA KP45 with the NS2 system that KWA USA has been kind enough to provide us with. Through out this review we will compare it to the original USP that was released several years ago and see how it stacks up. While that review was done in the infancy of Infected Airsoft, and as such was not quiet as methodical or in-depth, we can still draw some clear conclusions as we look at the new KWA KP45.


First Impressions

th_KWA_KP45_NS2_box.jpgKWA's packaging has always been business. Nothing too flashy, just simple clean and functional yet still sharp. The usual items were packed in the box: gun, mag, manual, sticker, bag of bbs, hop up adjustment key, and a vial of silicone oil. I did notice that this time around the gun did not include a tube and rod for loading bbs into the mag. That would suggest that there has been a change in the mag design. One thing to note, is that yet again they include a very heavy weight silicone oil. I would venture to say it's about 80 weight silicone oil. Personally I feel that's way to thick for airsoft use. Either go light weight (10 weight for rotating parts, and valves), or go with a grease for sliding parts such as, well, the slide.


Materials and Construction

Overall the externals, for the most part, look the same on the updated NS2 version as they should. Ridged polymer frame with a metal slide. Serial number located forward of the trigger guard along the underside of the gun. Texturing is the same. The slide is now engraved with the KWA logo and the model number KP45 as well as "cal. 6mm". While not true trademarks, they are at least tastefully done. The safety is still clearly marked in white and red, safe and fire respectively. I did notice that the first generation of this gun had a hammer lock in the mag well (like the actual H&K USP), but this version does not. Not a big deal as the first version didn't come with a key to make the hammer lock worth using (not that any airsofter would bother).


th_KWA_KP45_NS2_profile.jpgMoving onto the slide the first thing we notice is that KWA has switched from having a metal outer barrel to a plastic one. Now if that was the slide I could argue that it was done to reduce weight and increase efficiency, but such is not the case. I do not know why they made the switch, and wish they had not. It's a bummer as the outer barrel that I polished on my previous one really helped set it apart. Also, KWA's website does not show that the barrel now extends about 6mm outside of the slide. The previous version had the front of the slide painted blaze orange (to meet federal requirements), but the barrel – like the real firearm equivalent – did not extend past the slide. The fit of the slide is a bit loose, but no looser than any other airsoft gun. The tolerances in Airsoft are just not as tight as they are with real firearms. At the same time, the slide does rattle a bit if you shake the gun about, and I would expect the tolerances to be a bit tighter than that. KWA's tolerances are amazingly tight on their AEG line, so I would have expected that to translate to their GBB line, but such is not the case.


Moving to the internals of the frame we find that nothing has really changed from outward appearances. The slide on the other hand shows some differences on the inside in comparison to the previous versions. First we have the new spring guide. While it's still a captive 2 spring system, they've changed the design which I hope has increased the strength. On my previous generation 1 USP, I broke 2 spring guides with the only upgrade being a tightbore barrel. I hope this version fares better, but the point at which the previous spring guide broke still uses the same design. The movement of the spring bushing over the spring guide still does not seem as slick as I'd expect it to be even though the spring guide seems to be polished well, and there are no visible burrs on the bushing in front of the spring. The generation 1 shared this problem. With the slide removed from the gun we also note that the rear sight wobbles a bit. Normally this is resolved by tightening the screw that holds the blowback unit in place. Unfortunately this did not solve the problem. There appears to be too much slack between the cut for the rear sight and the sight itself. While it's not enough wiggle to cause you to miss your target within an acceptable engagement distance, guys looking for a show gun or who are meticulous about detail will take note. The slide itself seems to be made of pretty durable metal (most likely aluminum), and should take a beating quite well.


At first glance the mag looks identical to the generation 1 mag. The first version of the generation 1 magazine did not have an o-ring on the fill valve, where this one (and the second version of the first generation) do. The back of the mag also has the fake loaded round count indicators, but as we move around to the front of the mag we see a difference. The previous generation had a different design for the feed lips, and the mag did not used to have a follower with retention. The added retention allows you to pull the follower all the way down and then load the bbs. Personally I don't care for this as it makes it easy to have a gap between bbs. Keeping tension on the bbs as they are loaded prevented this. Of course because of the design of the feed lips you can't use the standard pistol loader adapter, thus the need for the retention on the follower. All that said, the magazine is machined from one solid piece of aluminum, and therefore pretty tough. I did notice however that they are using the same design for the seal at the bottom of the mag. That was flawed in the previous USP as every mag I had developed leaks. While they were easily fixed with some silicone RTV, you shouldn't have to.



Overall the gun with mag and a full 25+1 rounds of .20g bbs and propane weighs in at 865g (approx 1.9 lbs).



The gun holds 25+1 rounds. Great for people who play CQB and primarily use a pistol.


KWA spec sheet shows the fps to be 310+ fps. That is a noticeable improvement over the previous 290-300 fps I had with the previous model.


The safety has a functioning decocker.



Okay, 1100+/- words later we are at the heart of the review, performance. In an effort to be methodical and scientific we arranged for a few tests that would show what this gun could do. Now, any comparisons with the previous generation are going to have to come from my experience and previous review as I do not have the same level of data to go by.


First things first, we load up the mag. Now this again is one of my personal gripes, but you either love it or hate it. The mag follower with retention is difficult to use. If you don't have decently strong finger nails then it's a pain to get a grip on to push the follower to the bottom. The catch for the mag release makes this doubly hard as it pushes your finger away from the follower possibly making you let go of the follower and forcing you to start all over again. The spring also tends to bind a bit in the mag. A very light application of some SuperLube Grease (not oil) to the follower and spring make the movement of the spring and follower much smoother, but does not fix the problem completely.


With the mag loaded with .2g bbs and full of propane we head out to the range to chrono the gun. The mag was gassed up indoors at about 80 degrees Fahrenheit, and left to sit for 15 minutes before testing. Firing was done with a pause between shots to prevent excessive cool down that would affect the data. With an ambient temperature of 91.7 degrees Fahrenheit the gun averaged 333.4 fps over the course of the 25 rounds in the mag. That is well above the spec sheet's 310 fps, and well above the 285-290 that I would get on a warm day out of the previous generation USP. So far so good.


For the next test we wanted to look at cool down over the course of a mag. Now the ambient temperature had risen to 92.7 degrees Fahrenheit. For this test we took five shots rapidly, and then chrono'd the 6th shot. Our results showed the fps readings on the 6th shot of each round to be 333.1, 331.7, 332.5, 332.3 fps. That give us an average of 331.9 fps, and a fluctuation of only 1.4 fps. That's pretty spectacular on a gas gun under rapid fire conditions. The gun showed very little if any negative influence from cool-down.


Next up is the efficiency testing. Whenever I build a gun or buy I gun I test efficiency to see what weight bb is the best to use in that particular gun. FPS, hop system, and barrel length all effect this but in gas blow backs there's even more going on with the reduced efficiency created by the blow back mechanism and slide cycling. All testing was done with the ambient air temp between 91.7-92.7 degrees, and the mag refilled with propane between each swap in bb weight. All measurements were taken with the same Xcortech chronograph which also handled the conversion to Joules for efficiency testing. We tested .20g, .25g, .28g, .30g, .36g, and .40g bbs. Given the consistency of the gun we were felt that 5 shots with each weight bb was a large enough sample from which to draw a conclusion. The LEAST efficient bb turned out to be .20g bbs. The most efficient bbs were actually .40g bbs. This is pretty surprising as at the 350 fps level in AEG's you would find .25 or .28g bbs to be the most efficient. We double checked our findings and continued to get the same readings. My best guess is that with a .40g load it takes longer for the bb to clear the barrel and thus the valve in the blow back unit stays open longer as does the valve on the mag because it takes slightly longer for the slide to start cycling back. Following that theory I would venture to guess that the efficiency would increase to a point as the bb weight went up. The trend showed to hold for the most part. The following averages were recorded: .25g – 1.22joules; .28g – 1.32joules; .30g – 1.34 joules; .36g – 1.35 joules; .40g – 1.41 joules.


So if my theory is correct, the efficiency rated as number of shots per propane fill should be lowest with .40g bbs and highest with .20g bbs. Back to the range and we were not totally surprised, but somewhat intrigued by our finding. We filled the mag with gas completely before each weight was tested, and fired slow controlled shots. With the .20g bbs we were able to fire 64 fully cycled shots before the mag ran out of pressure and was unable to cycle the system. We were astounded when the USP cycled a full 61 rounds of .40g bbs before being unable to cycle further! Three round shy of the .20g bbs, with higher muzzle energy; the only thing left is to test the range.


So far we've been amazed by the fps and efficiency of the KWA KP45 NS2, so what would range and accuracy show us? We hit the range again using .36g Madbull bbs and set up targets at 20, 30, 45 feet. Each shot was taken from a supported position at a 1 inch grid on a target holder. We achieved groupings of 2.14″@20ft, 2.6″@30ft, and 3.64″@45ft. This gun is plenty accurate within typical engagement distances that you would use a pistol. Now comes the obligatory distance testing. Now, keep in mind that this is a pistol with a short barrel length when put in comparison to bolt actions or even most AEG's. If the pistol manages 80 feet of level flight I would consider that superb. We loaded up .20g bbs and headed back out to the range. Our range is measured out to 160feet, and extends as far as 200 (but has no markers after 160 ft). The .20g bbs proved useless for long distance accuracy. The gun's high fps and soft hop rubber make the bbs rise significantly after about 65 feet. For kicks and giggles we tossed in .40g bbs as more of a joke than anything. We quickly found ourselves looking for our jaw somewhere on the ground around our ankles. The bb flew well past the 160 foot mark with very level trajectory… and the hop wasn't even all the way up! Wow. I found myself very impressed. We repeated the test with several other weights and found .30g and higher weights to be optimal, and with time to aim and fire this gun is very formidable at over 150 feet! Amazing. I don't recall the old KWA USP getting anywhere near that distance with level flight and with that weight of bb.




th_KWA_KP45_NS2_springuide.jpgOver the course of the review I found myself reminded of a few things that seem to haunt this gun from the previous generation. First is the slow cycle speed of the slide. The slide itself is pretty heavy, and the compound spring guide hinders the cycling speed even further. The slightly loose rear sight also is a reminder of the generation 1 KWA USP/KP8/KP45. The switch from a metal outer barrel to a plastic one is a bit disappointing as well.


Looking at the performance, this pistol is a dream and very much redemption for the previously mentioned shortcomings. The high velocity (330-340 fps) coupled with a hop unit that has the capability to fling .40g bbs over 160 feet is amazing. The accuracy is excellent, and the efficiency is down right amazing. If you're currently running a generation 1 KWA KP8 and you're considering upgrading to a new pistol… then you're only going to love this one more and more. The new USP is every bit as accurate as the old and even more so at longer ranges. Snipers out there in need of a backup weapon… take note of all this gun has to offer.


If you're not hung up on accurate trademarks and are looking for a solid sidearm or even a primary CQB weapon, then this is an excellent choice. It clearly is as solid as it's predecessor, and even more powerful. In comparison to the previous generation it takes what was a solid GBB pistol and turns it up a notch.


The Numbers

Construction 7/10 — The only dings are really nitpicking. I am disappointed in the switch to a plastic outer barrel and I was hoping to see the whole design of the spring guide revisited. While the end of the spring guide was modified, the weak point in the middle was not changed.

Features 10/10 — It's a GBB, there really aren't too many features to speak of.

Durability 8/10 — Overall the design is great. It really is mostly a copy of the previous design with some slight changes to the spring guide as well as the valve in the blowback chamber.

Performance 10/10 — Accuracy, fps, and range are all above average; with the range being phenomenal.

Value 10/10 At $145 retail price the it's a great balance of performance and durability.

Price — $145 as of 8/18/2010





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my KWA match has the trigger lock holes.


Is it just a hole where the trigger lock is supposed to be, or an actual keyed cylinder that is supposed to be there? Just think it's curious if some have it and some don't. Do you have a pic of it?

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Odd. My old one didn't have a key, and my new one doesnt. Talked with Allizard and he said that they did not put the key or the key cylinder in them as it is a patent held by H&K. Now if you have a KSC or Umarex model that has official trades, then I could see having the key lock.

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