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We are in the process to modify our APS ASR107 M4 URX Raptor into a science fiction CQB airsoft rifle. In order to create the scifi look we wanted, we need a shorter barrel than the stock 275mm stainless steel barrel. In our Barrel Length and Red Dot Sight Accuracy Test, we found that barrel length difference in CQB situation has virtually zero effect. However, in our Reduce Inner Barrel Flex with a Mock Silencer accuracy and precision test, we found that inner barrel movement and flex makes a big deal. So we definitely want to stick to a hard stainless steel barrel.
Evike placed the Angel Custom G1 Stainless Steel 6.01mm AEG Inner Barrel (110mm) on sale at half the original cost, we figure it's a great opportunity to build the scifi gun we wanted and test out this super tightbore at the same time. In this article, we will review this 6.01mm tightbore barrel (model ANGEL-601-110), install it in our airsoft gun, and provide accuracy/precision tests against the stock 6.04mm stainless steel inner barrel.
At 110mm, this barrel is the shortest on the market. When the package has arrived, I could not resist being surprised by how small the shipping tube (see below) is. The shipping tube has Angel Custom brand on a label. The other label says 110mm.
Pulling either red end cap allows the tightbore inner barrel to slip out of the shipping tube. Compared to the stock stainless barrel in the APS guns I have, the Angel Custom barrel is much more shinny. This barrel is meant for a pistol, but the specs says it will work for an AEG. Maybe that's why it how two hop-up slots cut into the sides (see poto below).
Two rubber dampers are inserted into the two ends of the tightbore barrel (see photo below). They keep the barrel in the center of the shipping tube and prevent damage to the barrel. The hop-up nub hole has a slightly different cut than what we've seen in the past; not sure what purpose it serves.
We aligned the tightbore barrel on our measurement pad (see photo below). It measures exactly 110mm.
The real question is how does this extremely short Angel Custom tightbore barrel compare to bigger and longer barrels? Let's find out. The application will be hand-held indoor CQB scenario, not gun-on-the-vise shooting competition. The rest of this article will focus on the test.
We downloaded the following free target from Evike's web site. This target has inches markings. But Evike provided a raster (JPG) image, not a vector file. Therefore, when we printed the image on our laser printer, the target wasn't to scale. However, the 7" mark was almost exactly 7 centimeters on our print out. Therefore, it provides a good relative measurement.
This target worked so well in our previous tests, we plan to keep using this target for our future tests as well.
For this test, we used an APS ASR107 M4 URX Raptor. The stock inner barrel in the URX Raptor is a 6.04mm stainless steel tightbore that is 275mm in length. We will see if the 6.01mm Angel Custom stainless steel tightbore makes a difference or not. APS ASR107 M4 URX Raptor Review
We will use the Barska Red Dot Scope on the URX Raptor upper receiver (see photo below) for this test. The Barska Red Dot Scope has been zero in at over 30 feet in an outdoor environment. Barska 30mm Red Dot Scope Review
The stock hop-up unit has been adjusted to be accurate and precise out to over 30 feet in an outdoor environment. It has a stock plastic H-hop spacer. We will test the 275mm inner barrel first, because it's already installed into the hop-up unit (shown in the photo above). Then we will swap the 275mm inner barrel with the 110mm inner barrel--using the same hop-up setting--to see if it makes any difference. The following photo shows the 110mm inner barrel installed in the metal hop-up during our test.
The shorter 110mm inner barrel will only utilize about half of the outer barrel length. Many Internet folks has claimed that extended mock silencer will have negative effect on the performance of an inner barrel, if the inner barrel fails to meet the length of the mock silencer. We will test that theory through the extra long outer barrel.
In fact, we will add one addition test by installing a Shark Flash Hider to see if it impacts the short barrel accuracy and precision.
We used Evike Professional Grade 6MM Airsoft BB (0.20 g) in this test. 0.2 grams is the most common weight BB's. In an indoor controlled environment, BB weight should make very little difference in the outcome of this test (but sounds like a good test for another day).
The controlled environment is a dim garage to eliminate external atmosphere factors. The target trap is located 20 feet from the shooter. The shooter will hand-hold the shots to simulate real combat situation versus using a gun vise. 10-rounds will be fired into the target trap in semi-automatic mode. The shooter is free to take as much time as possible (within reason) to make accurate shots. Aim is performed with a single eye open (in order to reduce error) with the red dot directly on the center of the target (no manual adjustment of the shot is allowed). The red dot brightness is set to 1 in order to keep the MOA as small as possible, but highly visible this dim environment.
In the first test, we used the stock APS ASR107 M4 URX Raptor airsoft to create a baseline. The baseline (see result below) showed a fairly tight 3cm x 5cm grouping. In the next test, we see if the short barrel is any better.
In the second test, we installed the 110mm Angel Custom 6.01mm tightbore inner barrel into the hop-up unit. We adjusted the hop-up setting to be very close to the original setting. However, we overdid it slightly, therefore, the shots all landed in the upper quadrant. As you can see from the result below that the grouping is 4cm x 4cm.
The third test was actually a mistake. I had forgotten to add the shark flash hider. So the configuration of the gun is exactly the same as the second test. Nevertheless, it's shown below for comparison. The grouping is roughly 4cm x 4cm; same as the second test. Therefore, you can see that we were consistent and hadn't goofed the result.
In the last test, we added the shark flash hider. We wanted to see if adding flash hiders, mock silencers, or using extra long outer barrels make any difference. The result is show below. The grouping is still roughly 4cm x 4cm.
I took the APS ASR107 M4 URX Raptor AEG to an local indoor CQB field tonight with the short 110mm Angel Custom inner barrel and the shark flash hider. The gun chronoed at 266 FPS with 0.2g BB's. It was extremely accurate with the Barska Red Dot Scope zeroed to over 30 feet. Photo below showed the AEG I took to the field.
The gun was extremely loud, due to the extremely short barrel. The loud bang was nerve-wrecking to my own teammates, whom were able to hear it even in the staging area. One teammate said it sounded like gas blow-back. I hoped it was as nerve-wreck to the other team as it was to my own team.
The shortened APS ASR107 M4 URX Raptor performed practically the same as my APS ASR106 Mini Patriot M4, which had a 175mm barrel and an Ultimate Arms Gear Tactical 4 Reticle Sight JH400. However, it was much louder.