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| The .177 caliber
BRNO TAU-200 CO2 rifle
is a great entry level
10 meter style target rifle. With a scope mounted it makes a sweet little
tack-driver for close distance plinking at small targets. The TAU kind of
resembles a mini-sniper rifle, with a scope mounted and sights removed. Very
nice! A short time ago I bought a "used" TAU-200 CO2 rifle just because it seemed like something I might want to tinker with for a while. The first thing that had to be done was a complete disassembly. The gun was sitting unused for over a year and I wanted to give it a thorough cleaning, inspection and lubing. Okay......I wanted to see what made it work. The TAU-200 rifle has a few similarities to the TAU-7 pistol. Both guns use the same powerlet piecer caps, bulk adapter end cap, bulk fill transfer bottle, valve stem and valve seal. The all metal construction and wooden stock are nice to see these days. My rifle is the adult version but a junior version is also available, with a shorter stock. The stock on my rifle has a short pull length of 13.5" and it can be adjusted to 14.0" with the two spacers installed. When a scope is mounted the two comb spacers are removed and can be used to increase the pull length another 1/2". I seem to like the 14" length for my shooting. The TAU-200 has a deeply recessed muzzle. The actual crown on my example is 6 7/8" down the barrel and the total barrel length is 23 1/4". From the outside of the barrel you can't tell it's recessed until you look at the huge 1/2" hole in the end. The actual rifled section of the barrel would be 16 3/8" long. The recessed muzzle really seems to dampen the report. A low sounding thunk is about all that happens. Reduced lock time is usually the reason for the shorter rifled section and the use of a longer barrel with recess allows a long sight radius. Here are some stats on the TAU-200 Adult version: Barrel Length ---------------------------- 23.25" Rifled Section --------------------------- 16.375" Barrel Diameter ------------------------ .706" Receiver Grooves ---------------------- 5" long CO2 Pressure Tube Length--------- 9.75" Total Weight ------------------------------ 8 pounds 11oz Weight --------------------------------------- 6 pounds 14.8oz (without sights) Weight --------------------------------------- 8lb 5.2oz (5040 mount, 3-9X Sportsman scope 72-0039) Rear Sight --------------------------------- 4.8oz Front Sight Assembly----------------- 1 pound 7.4oz Front Sight Aperture Size --------- .582" hole Trigger is 5-way adjustable and can be set to two stage or single. The beech stock is adjustable for comb height and pull length using the four spacers provided. The butt plate on the TAU rifle is adjustable for vertical position. The metal front sight is mounted on an 8.75" long removable sleeve which functions as a muzzle weight. The sleeve is heavy and all one piece but could be cut into 3 sections and set screws installed. This would allow weight to be varied. I don't know why the factory doesn't do this simple task. The rear target sight is made of both metal and thick, tough synthetic. It looks like the stuff that synthetic wheels/cams on some compound bows are made of. The adjustment parts and knobs of the sight are all metal. It seems pretty durable. The TAU-200 comes with 3 metal rear aperature sizes and several front sight insert sizes. Dry firing is a simple task with this gun. A short bolt movement of maybe 1/2" cocks the trigger for this feature. A complete bolt movement allows for firing a pellet. A cocked gun can also be de-cocked using the dry fire feature. The receiver on the TAU-200 is a bolt action style, all metal of course. Grooves run along the top surface of the receiver and allow the mounting of the target sight provided or a scope. The rear section of the barrel is also grooved for use of a notch type rear sight. Disassembly of the TAU-200 is a simple task. The trigger mechanism is fastened to one of the side plates so things don't fall apart when the other plate is removed. This gun seems user friendly and home maintenance is possible with no specialized tools needed. The 10 meter testing for my TAU-200 showed decent potential. For all testing I used an unaltered rifle which was clamped into a Black & Decker Workmate for stability. Velocity is variable on this air rifle but I chose to set the adjustment screw flush with the receiver tube and leave it there. Different velocities may produce different accuracy results. This testing was done at 64F degrees.  (fps)
JSB Match (4.49/7.3gr) ------------- 555, 554, 554, 556, 553 AVE= 554fps JSB Exact (4.50/8.44gr) ------------ 537, 538, 542, 538, 540 AVE= 539fps Crosman Premier (7.9gr) --------- 512, 517, 520, 518, 519 AVE= 517fps H&N Finale Match (4.50/7.7gr) - 543, 543, 538, 538, 539 ----------AVE= 540fps 
(5 shots ctc @10m)JSB Match ---------------------------- .132, .077, .200, .128, .190 AVE= .145" JSB Exact ----------------------------- .215, .153, .221, .215, .139 AVE= .189" Crosman Premier ----------------- .214, .212, .234, .125, .166 --------- AVE= .190" H&N Finale Match ---------------- .184, .167, .210, .183, .173 ----------AVE= .183" The unaltered rifle was then tested for temperature sensitivity, after sitting in a warmer area for a couple of hours. Thermometer reading indicated a temp of 72F degrees. The following velocities were then recorded: (fps)
JSB Match (4.49/7.3gr) ------------------ 565, 565, 567, 564, 560 AVE= 564 JSB Exact (4.50/8.44gr) ----------------- 541, 540, 540, 541, 541 AVE= 541 Crosman Premier (7.9gr) ----------------512, 512, 522, 513, 519 AVE= 516 H&N Finale Match (4.50/7.7gr) ------- 541, 541, 541, 539, 544 ........AVE= 541 The slightly higher velocity for the JSB Match pellet was questionable so I waited 10 minutes and tested two pellets again at 72F. The results are as follows: (fps)
'JSB Match (4.49/7.3gr) ---------------- 564, 561, 566, 560, 560 AVE= 562 H&N Finale Match (4.50/7.7gr) ----- 546, 542, 541, 544, 546 ..........AVE= 544 Velocities for the second 72F test are pretty much the same as the first at this temperature. A shot series of 20 pellets would be a more usable figure for this type of test. Overall the TAU-200 velocity doesn't seem to increase any great amount when temps change from 64F to 72F degrees. A velocity increase of 10fps is very small and POI would not be effected. Some accurate airguns will vary in velocity by 10fps within a shot string. This is nothing to be concerned about. Velocity strings with the TAU-200 seem to be tighter than 10fps between highest and lowest. Other tests with a 10 shot string showed this same consistency in velocities. My next experiment involved replacing the factory hammer spring with a shortened 16# Colt 1911 recoil spring. I used about 1/2 the spring and bent the ends a little flatter so it sits better inside the receiver. The new spring was cut about two coils longer than the factory TAU hammer spring. The diameter is slightly smaller but it works fine. During the velocity testing I did some shooting in two locations in my house so slight temperature changes could be involved in the test. This testing was done in early spring time and my basement was getting a bit cool because the furnace doesn't cycle on anymore do to the warmer outdoor weather. Basements are always a bit cooler where I live. The screw that holds the hammer spring in the gun also allows pre-load tension to be applied and adjusted as desired. About 10 turns of the screw are possible for adjustment. The new modified hammer spring was installed for further testing. Ambient temperature was 63F. The following velocities were recorded: (fps)
JSB Match (7.3gr) ------------------- 589, 589, 588, 590, 584 Ave= 588fps JSB Exact (8.48gr) ------------------ 575, 574, 571, 575, 573 Ave= 574fps Crosman Premier (7.9gr) -------- 565, 567, 567, 563, 565 ......... Ave= 565fps Crosman Premier (10.5gr) ------ 520, 526, 522, 523, 525 .......... Ave= 523fps The odd thing about using the new hammer spring is that tension adjustments had no effect on velocity. I tried turning the screw inwards and outwards throughout the 10 turns with no effect on velocity. Maybe the 1911 recoil spring is consistent throughout compression while the factory TAU spring varies in tension. This is only my guess. Next, the TAU-200 (with moded spring) was warmed up in an area with a temperature of 70F degrees, according to the theromostat. Velocities recorded at this temp are listed below. The heavy hammer spring results are listed first and the factory spring results (warm temp) are in brackets. (fps)
JSB Match (7.3gr) ------------------- 605, 606, 603, 605, 604 Ave= 605fps (vs 564) JSB Exact (8.48gr) ------------------ 592, 589, 593, 592, 587 Ave= 591fps (vs 541) Crosman Premier (7.9gr) -------- 586, 587, 583, 582, 585 .. .. ...Ave= 585fps (vs 516) H&N Match (7.7gr) ------------------ 597, 599, 595, 598, 599 Ave= 598fps (vs 541) Crosman Premier (10.5gr) ------ 540, 539, 534, 539, 536 ----------Ave= 539fps At the warmer ambient temperature the velocity adjuster still had no effect on velocity readings. With the factory hammer spring the tension adjuster did effect velocity Originally I was hoping for 600-625fps with CPLs and I think I should hit this velocity when shooting outdoors in 75-80 degree weather. Currently, at room temp I am getting exactly 6ftlbs with the CPLs. For some strange reason the heavier JSB Exact are producing 6.9ftlbs. I think the smaller head diameter may be the reason but I will have to check the actual pellet weights on a reloading scale to be sure. Accuracy with the heavier hammer spring is close to the factory spring accuracy with some pellets and different with others. The heavy hammer spring results are listed first and the factory hammer spring results are in brackets.
(5 shots ctc @10m) Crosman Premier Lt --- .202, .141, .129 ---- - AVE= .157" (vs .190") Crosman Premier Lt --- .192, .221, .219, .161, .209 --- --AVE= .200" Crosman Premier Lt --- .191, .226, .206 ------ AVE= .208" JSB Exact ------------------- .211, .274, .180 AVE= .222" (vs .189") JSB Exact ------------------- .202, .135, .203 AVE= .180" JSB Match (4.49) --------- .204, .259, .236, .257, .179 -- AVE= .227" (vs .145") H&N Match ----------------- .125, .147, .229, .190, .222 AVE= .183" (vs .183") *** I then did some 30 yard shooting from a rest with the heavier hammer spring using CPLs. With a slight breeze I managed .7", .75", .75", .8" for 5 shot groups. I think I should get .6"ctc on a calm day. The factory spring should be about the same accuracy but trajectory wouldn't be as flat and any breeze would have more effect on POI. The average 10m group size with the H&N Match was the same with the 16# spring as it was with the factory spring. The JSB Match definitely liked the factory hammer spring better. The domed pellets (exact/cpl) were tested on more than one occation so multiple tests are shown. All 11 groups (with heavy spring) with the CPLs average to .191" and all 6 groups with the Exact average to .201". Only .01" difference. More tests may keep this the same or change it slightly. I think the two pellets are very close in accuracy out of my rifle. Different days show preference to either one. Of course, 30 yard comparisons will be more fun. I encountered a slight problem with using the heavier hammer spring (Colt 1911 spring). After a few hundred pellets the hammer rod linkage bent towards the trigger in a bow shape. This is typical with the light metal used on the factory rod. Some guys make a new rod from a short length of heavier spring wire so bending will not happen. I found a length of spring wire that measured .107" and it worked fine after I thinned the end a bit to fit into the hole in the hammer. It's not an extremely difficult task and the new rod will not bend. I ended up straightening the factory hammer rod and re-installed it along with the factory hammer spring and all is working 100% again. I will likely keep the factory spring installed since most of my shooting is at 10 meters and with factory parts I get over 100 shots from a bulk fill. With the more powerful parts I tested two bulk fills and got 48 and 54 shots. In CO2 form the TAU-200 is a simple gun to operate. Bulk CO2 is cheap and 12 gram powerlets can also be used. MAC-1 makes a PCP conversion kit for this rifle that turns it into a entry level FT gun. Check Mac-1 web site for further details (www.mac1airgun.com). Later, Todd Cooper . .......................................Click on this line to open Other airgun articles By Todd Cooper .. |
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