Weihrauch’s HW55SF: Part 6
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Rob velocity?
- H&N Finale Match Light
- Sig Match Ballistic Alloy
- Qiang Yuan Olympic
- RWS R10 Match Pistol
- So, what?
- Cocking effort
- Firing cycle
Today we look at the velocity of the HW 55SF target rifle I tuned back in November. If you read Part 4 you’ll see that I just applied Tune in a Tube grease (TIAT) to the mainspring and got great results. Some readers ask me to use TIAT over and over again on different airguns, apparently not convinced that it works as well as it does. But when they break down and try it, they see for themselves. This stuff really works!
But what does it do to the velocity? This is a low-powered spring rifle and we know that thick grease can rob velocity. We have the baseline velocity data I gathered in Part 2 to compare to, so today I will re-test the rifle with the same pellets. Let’s get right to it.
H&N Finale Match Light
First up were H&N Finale Match Light pellets. Before the tune they averaged 613 f.p.s. and had a 31 f.p.s. spread from 594 to 625 f.p.s. This time 10 pellets average 608 f.p.s. and the spread was 17 f.p.s. — from 601 to 618 f.p.s. That’s not much of a decrease, but the spread was almost cut in half — a good start!
Sig Match Ballistic Alloy
Next up were Sig Match Ballistic Alloy pellets. These lightweight lead-free pellets are the speed demons in the 55SF. Before the tune they averaged 811 f.p.s. with a 16 f.p.s. spread that went from 801 to 817 f.p.s. After the tune they average 730 f.p.s. with a 31 f.p.s. spread than goes from 715 to 746 f.p.s. That is a significant change from before — a decrease of 81 f.p.s. and double the velocity spread. I will save the discussion for the end.
Qiang Yuan Olympic
I tested the Qiang Yuan Olympic pellet next. When I tested them before the tuneup they averaged 626 f.p.s. with a 17 f.p.s. spread from 621 to 638 f.p.s. After the lube they averaged 581 f.p.s. with an 8 f.p.s. spread from 576 to 584 f.p.s. The average was 45 f.p.s. slower and the spread was less than half as much as before. Hmmmm?
RWS R10 Match Pistol
The final pellet I tested was the RWS R10 Match Pistol pellet. This was the fastest of the lead pellets in the test before the tune, averaging 624 f.p.s. The spread at that time was 22 f.p.s., from 612 to 634 f.p.s. After the tune this pellet averaged 641 f.p.s. with a 20 f.p.s. spread that went from 629 to 649 f.p.s.
Let’s talk. The first pellet went almost the same speed after the lube as before. The difference was only 5 f.p.s., which is trivial. The velocity spread tightened up considerably though.
Both the Sig Match Ballistic Ally pellet and the Qiang Yuan Olympic pellet shot considerable slower after the lube tune — 81 and 45 f.p.s., respectively. And here is something curious — the Sigs doubled their velocity spread after the tune, while the Chinese pellets’ spread was cut in half! I can’t wait to hear what something thinks is going on there, because I have no idea!
Finally, the RWS R10 Match Pistol pellets were the only pellets that got faster after the tune. They increased by an average of 17 f.p.s. which is small but significant. The velocity spread remained about the same — 20 f.p.s. compared to 22 f.p.s. before the tuneup.
I have a saying I have used several times in this blog. It goes, “Define the universe. Now, give three examples.” It’s a scholastic joke I heard in college. If you think about it, it can’t be done. It’s like an Escher print put into words. I’m saying this because I don’t think this data means as much as some people might try to explain. The rifle is now slower with some pellets and the same or faster with others. So what? As long as it is shooting fast enough to be a reasonable 10-meter target rifle, who cares whether it’s above or below 600 f.p.s.? You can pay $3,000 and get a target rifle that shoots nearly the same as this one.
If we were talking about a hunting rifle the discussion would be different. Then the focus would be in accuracy first, followed closely by power. But a target rifle only has to be accurate and pleasant to shoot, which this one now is. The TIAT has smoothed the shot cycle to near-perfection.
There is one more thing to look at. In Part two I measured the cocking effort and told you it was 18 lbs. for most of the cocking stroke with a spike to 22 lbs. near the end of the stroke. In Part four I showed you what I thought was the problem (the broken flat spring that puts tension on the cocking linkage). This time I measured the effort as 19 lbs. though the stroke, and there was still a spike to 22 lbs. right at the end of the stroke. I’m now quite sure that it is the piston rod cocking the trigger. It came right at the point where the leverage is the greatest, and I doubt any adult will even notice it. I didn’t notice it in Part 4 after I test-fired the rifle several times to see if I’d put it back together correctly. In short, there is no difference in cocking from last time.
On the other hand, this rifle is now a dream to shoot! It is almost dead-calm now, where is had an annoying buzz before. That is always felt the most during the accuracy test, which went well in Part 5.
This tune is great, and the rifle is still in the zone for 10 meter target rifles. I got off lucky this time because new parts were not required. Tune in a Tube, plus a little cleaning were all that was required.