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A Tech Force 78T Review

by Randy Mitchell

The new Tech Force 78T arrived at Compasseco, Inc. of Bardstown, KY in late June of 2004. This CO2-powered gun is a bulk fill-only version of Tech Force’s popular TF-78, also known as the QB-78. Steve and Eric Munson asked me to give the 78T a trial test and give my impressions of it.

According to the specs advertised on the Compasseco’s website, the TF-78T weighs in at 6.6 lbs, without the CO2 tank attached. As can be seen in the picture below, the forearm of the stock has been reduced somewhat to accommodate the bulk canister of CO2.

Depending on which size tank you use, the gun’s balance will change. With the 9 oz. tank shown above, the 78T will feel somewhat nose-heavy to those of you who are accustomed to the standard TF-78’s weight distribution. However, when shooting the 78T, I found the extra weight forward assisted me in keeping a steady bead on my target. Depending on your shooting preferences, you may need to experiment with different canisters to achieve the balance you desire.

To remove the rifle action from the stock, follow the standard procedures for disassembling the standard TF-78. First, place the safety in the on position, then punch it out with a screwdriver or other handy item. Then loosen the retaining screw on the bottom of the forearm. Now here’s where the two guns differ. The 78T has an additional two screws in the forearm end, located on the sides, which help secure the bulk attachment to the stock. With a Phillips-head screwdriver, remove the screws (be careful not to lose the lock washers) and the action slips right out of the stock.

To remove the bulk fill attachment from the reservoir, first remove the rear sights. They are located slightly further down the barrel than on the standard TF-78, but still provide excellent target acquisition.

After removing the rear sight, loosen the barrel band screw until the barrel band is sufficiently loose to slide forward. The bulk attachment is attached to a shortened reservoir tube. As can be seen from the pic below, the threads have been removed from the tube, and a bulk attachment substituted for the endcap found on the standard TF-78. The bulk attachment is secured in place with two screws which give adequate rigidity to the unit, quite capable of supporting a full 9 oz. bottle of CO2. The reservoir maintains pressure with the assistance of two o-rings that are set in grooves milled into the neck of the bulk attachment. A side effect of having the shortened reservoir tube is that you can now reach the valve on the inside with a regular screwdriver, rather than having to use a longer tool to reach down a full-length reservoir to loosen the valve assembly. No doubt, this feature will appeal to the many tuners and home-grown modifiers out there who enjoy working with their TF-78’s to extract the most performance possible from this popular little airgun.

After checking out my 78T, I headed to the backyard with my chronograph to do a quick test. The first five shots averaged 617 fps with Crosman’s 14.3 gr. Premieres. This calculates out to roughly 12 ft. lbs. of energy from an unmodified CO2 gun.

One of the advantages of having a bulk-fill setup is that your shot to shot consistency will be more pronounced since you have a much larger source of CO2 to draw from. I sat down in my basement and attached an 88 gram AirSource cartridge marketed by Crosman to the TF-78T. The cartridge can be bought at many discount retailers, and comes packaged two different ways, one with an adapter included in the package, the other with two AirSource cartridges and no adapter. Using the adapter included with the AirSource cartridge, I installed the 88 gram disposable bottle and began shooting.

Using 14.3 gr Crosman Premiere’s in a 72 degree room, I shot rapidly and with no regard for accuracy, simply wanting to test the 78T’s ability to hold consistency. I chronographed every 25th shot, noting that the first shot out of the bottle rang in at 605 fps. That works out to about 11.5 ft lbs of energy from an untuned airgun. I kept an eye on the chronograph and noted that shot 100 was still shooting at 608 fps, for a very nice consistency over the course of many shots. At shot 120, I was still getting 595 fps, at which point the velocity began to drop. Shot 125 clocked at 571 fps, and began dropping rapidly immediately after. By shot 140, the velocity was down to 510 fps.

After removing the AirSource cartridge, I placed the 9 oz. steel tank back on and fired a shot to test how the gun reacted to changing reservoirs. Right back up to 605 fps! Just what the doctor ordered…just switch tanks and keep on shooting!

The TF-78T is priced at $99.95 at the time of this article. What you get is a dedicated bulk-fill gun that will afford many hours of fun shooting without the need to worry about recharging with the smaller 12 gram CO2 cartridges, or the additional cost of buying an aftermarket bulk kit. Happy shooting!

Randy Mitchell
www.adventureinairguns.com

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