Madbull Bucking & Barrel Review

Madbull Bucking & Barrel Review

In this review from Fox Airsoft, we test two recent developments from Madbull. The first is the Blue hop bucking; the second is the 6.03 diameter tight bore barrel. They were tested in order, first installing the hop bucking, and then installing the tight bore barrel.

The hop bucking is a thin rubber sheath that covers the rear end of the barrel.  Its primary purpose is to hold the chambered round in place just ahead of the nozzle before firing.  The bucking also applies the backspin, through deformation caused by the nub, to create the hop-up effect on the bb.  Madbull used a softer rubber compound than most OEM buckings which creates a more consistent grip on the bb and helps to prevent wear and weakening of the rubber after many thousands of cycles.  Also, in every hop bucking kit Madbull includes two buckings and two nubs to further extend the life of your purchase.

By their own admission, however, mad bull doesn’t know why their hop buckings are creating such drastic increases in velocity.  According to their website (www.madbullairsoft.com) they feel the three fins on the end of the bucking better channel air down the barrel for increased velocity.  Whatever the reason may be, there are widespread and reliable reports of 20-50 fps increases in velocity by only installing a Madbull bucking.  This test was conducted specifically to determine whether or not those claims are accurate and to quantify exactly what sort of performance gains are to be expected from using this product.

The second component tested was the tight bore barrel.  The idea behind a tight bore barrel is nothing new in the airsoft world, but Madbull advertises improvements that promise both increased accuracy and range. 

A standard OEM airsoft barrel is generally sized around 6.08mm.  Assuming a perfectly spherical 6mm bb, this allows just over .75 square mm extra space between the bb and barrel at any point within the barrel.  Madbull’s choice of a 6.03mm barrel reduces this extra airspace by 62% resulting in more of the air fired directly contacting the bb rather than escaping around it.

The generally accepted view of how a bb travels down the barrel is that as soon as it is fired it bounces its way down the barrel rather than smoothly flying down the center of the barrel.  In this respect, a tight bore is dramatically superior because it gives the bb less room to bounce away from the center axis of the barrel.  This means each shot will be much more consistent with the previous shot resulting in much improved accuracy. 

Of course, a tighter bore also has some disadvantages.  It must be kept much cleaner than a stock OEM barrel.  Care must also be taken before selecting ammo because certain low quality ammo can become jammed in the barrel.  Also certain older bbs, especially some biodegradable brands can swell with age and exposure to the weather.  We recommend only using new, very high quality with any barrel with a 6.04mm bore or less.  The 6.01mm barrels further exacerbate this problem and we will test and present you with the results of that hopefully in the very near future.

Test Procedure

Testing was performed on a brand new completely stock Classic Army CA416 Sportline. Out of the box velocity is in the range of 305-310 fps. After installation of the Madbull bucking, 10 measured shots were fired on semi-auto, followed by approximately 20-50 unmeasured shots on full auto, and finally another 10 measured shots on semi-auto. This procedure is intended to "break in" the new item to see if there is a difference between the performance of a brand new component vs. one that has been lightly used.

Accuracy testing was performed in a similar manner with several initial unmeasured shots to set the hopup, 10 measured shots, an unmeasured full auto burst and another 10 measured shots.  The distance to the target is approximately 30 feet.  The group sizes are calculated by the smallest circle that can be drawn around the 9 most tightly grouped shots (the furthest outlier is ignored).  The circle does not have to include the center of the target so a tightly grouped set of shots to the left of the bulls-eye will score higher than a loosely spaced group centered on the bulls-eye.  This is intended to test repeatability and consistency rather than sight alignment or shooter skill.

Due to time and expense, we will not normally test an item's durability on a long term basis or test it to failure. If, later on, we uncover any durability problems in any of the products we test, we will add those findings to the review at that time.


Data/Results

Velocity measurement with .25g biodegradable Airsoft Elite bb

Stock	Bucking	Bucking	Barrel	Barrel
304.3	311.6	309.8	326.7	326.7
310.7	308.7	310.8	323.2	325.7
308.9	311.0	306.3	323.7	324.6
306.5	307.8	309.7	326.1	323.6
304.5	310.2	309.6	325.1	324.3
307.4	316.7	311.4	325.0	325.1
307.6	311.4	311.2	327.0	329.7
305.4	310.5	313.0	326.1	326.7
306.3	318.9	314.4	326.4	327.8
307.0	311.6	311.1	326.7	326.0

Accuracy Test

Stock	Bucking	Bucking	Barrel	Barrel
5.5 in	5.0 in	5.0 in	4.0 in	4.0 in

 

Based on the data gathered in the above section, the hop bucking added approximately 5-10 fps with a significant increase in accuracy and consistency.  A further gain of about 10-15fps was observed with the tight bore barrel in addition to the bucking yielding a total gain of around 20fps with both components installed.

We saw a significant increase in accuracy at 30 feet, with much tighter groupings than without the upgraded components.  A decrease in average group sizes of about 10% was seen with the bucking alone and a further 20% reduction in average group size was seen with the tight bore barrel and the bucking installed together.  It should be noted that since the gun was fired from the kneeling position rather than securely mounted, a portion of the results depend on the skill of the shooter rather than the accuracy of the components.  The testing was performed this way to get a more “real world” measurement of accuracy that may align more closely with what a player may see in the field. 

From a qualitative standpoint both the bucking and barrel seemed to show a marked improvement in accuracy and consistency.  The gains from the hop bucking were most noticeable at relatively short range and by the reduction of curve off at the limit of range.  The tight bore barrel performance was more noticeable at medium to long ranges where the groups appeared significantly tighter than stock.

Conclusion

Both the Madbull hop bucking and 6.03mm tight bore barrel showed significant improvement in both accuracy and consistency.  Velocity was significantly improved without altering any gearbox components so there is no effect to the mechanical durability of the gun’s internals.  The “curve off” at the limit of range was also reduced resulting in an increased effective range along with the increase in absolute range from the additional 50 fps.

We welcome any and all comments, questions and suggestions at service@foxairsoft.com   If you would like to purchase these products for yourself send us an email at sales@foxairsoft.com or visit www.foxairsoft.com.