Posts Tagged ‘Tech Force 4-12x40AO rifle scope’
by Tom Gaylord, a.k.a. B.B. Pelletier
Today, we’ll look at the firing behavior and velocity of the Tech Force M12. You readers had mixed feelings about this rifle. Some of you liked the look of the gun and the fact that the trigger is nice, though it’s only single-stage. Others were put off by the lack of open sights. Once again, for anyone who missed it, the Tech Force M12 is made for Air Venturi (who owns the Tech Force name) by Mendoza. It is not a model Mendoza makes under any other name, so if you want one, you have to get an M12.
I’m testing the combo with the 4-12x40AO Tech Force rifle scope. The scope comes into play in the next report, when I look at the rifle’s accuracy. Now, we’ll look at its performance over the chronograph. The first pellet I shot was the one I think may shoot best in the rifle — the venerable Crosman Premier 7.9-grain dome.
The first several shots from the rifle detonated, which means they were accompanied by a loud bang. Some people call that dieseling, but it’s more than that. Dieseling means that the piston causes the oil in the compression chamber to ignite when the gun fires. All spring guns in this power class diesel with every shot — even the ones that have been tuned. You don’t usually notice it because there’s so little oil to act as fuel for each shot that the gun neither makes a bang nor does it smoke. Only when there’s too much oil does the gun smoke with every shot, and only when there’s even more oil does it detonate. Detonation usually goes away after one to several shots, so you just keep shooting until the gun becomes quieter.
The M12 only detonated on the first 4 shots with Premier lites. The first shot went 1012 f.p.s., which is well over the advertised velocity of 750 f.p.s. for lead pellets. It was the detonation that caused the higher velocity, because shot No. 2 went 932 f.p.s., even though the rifle was still detonating.
After 7 shots, the rifle had stabilized, and the velocity had dropped to the 800 f.p.s. mark, which is what we expect it to do with this pellet. The average velocity was 797 f.p.s., and the spread ranged from 792 to 800 f.p.s. That’s a tight 8 foot-second range that tells me the Premier lite will probably be a good pellet for the accuracy test. At the average velocity, this pellet generates 11.15 foot-pounds of muzzle energy.
The next pellet I tested was the RWS Hobby — an all-lead pellet that weighs 7 grains. I use Hobbys or other RWS pellets of equivalent weight to test spring guns for power, so we can have a standard reference.
Hobbys averaged 848 f.p.s. in the M12, but their performance was not stable. They ranged from 829 to 877 f.p.s. While I did not hear any definite detonations while shooting Hobbys, there was a lot of smoke with each shot, so the rifle is still burning off oil. It’s good to get that out of the way now before the accuracy test, where it would disturb the shots. At the average velocity, Hobbys produced 11.18 foot-pounds of energy at the muzzle.
The next pellet I tested was the 10.3-grain JSB Exact dome. I felt that a heavier pellet might help stabilize the rifle in the early stages of its break-in. This pellet averaged 716 f.p.s.; but like the Hobbys, it wasn’t too stable. The spread went from 699 to 746 f.p.s. At the average velocity, this pellet generated 11.73 foot-pounds — the highest power noted in this test.
And the last pellet tested was the lead-free RWS HyperMAX pointed pellet that weighs 5.2 grains. These averaged 961 f.p.s. in the test rifle if I throw out the first shot that registered 919 f.p.s. The spread of the average string ranged from 948 to 970 f.p.s., so once more it wasn’t too stable. At the average velocity, this pellet produced 10.67 foot-pounds of muzzle energy.
The M12 has surprised me thus far. Why? Because it’s a Mendoza, a company that I know can make some wonderful air rifles. But they often add too much oil during assembly. The M12 is not like that. Yes, it does have a little too much oil, but the same can be said of a new Weihrauch these days. And Air Venturi had them eliminate the oil hole they put on all their rifles, so there’s no encouragement to continue over-oiling the gun.
It seems well-behaved. The oil takes care of itself during the break-in period, so it’s of no consequence. The trigger is still very nice, though I can now feel it moving through the single stage. But there’s still no creep and it still releases crisply. The trigger breaks at 2 lbs., 15 oz. fairly consistently.
The firing behavior is accompanied by a slow shudder, not by high-speed vibration, so this rifle will probably be pleasant to shoot. The trigger is good enough to do good work on target, and I think the rest remains to be discovered.