by B.B. Pelletier
Photos and test results by Earl “Mac” McDonald
I had fully planned on testing the velocity of the HW 55 CM for you today, because so many of you indicated an interest in the gun in Part 1. In preparation for that report, I test-fired the rifle against both my HW55 SF and my Walther Olympia LGV, and the results were not what I expected. First, I discovered that the stock screws on the 55 CM were loose. Wouldn’t you know that when I tightened them, the gun vibrated less than before? But the firing cycle still felt a little harsh, so I then fired both the 55 SF and the LGV alongside the 55 CM for a comparison.
As things turned out, the 55 SF recoils about the same as the 55 CM (now that the stock screws are tight), but the SF buzzes a lot more than I remembered. Instead of shooting what I’d remembered as a “perfect” rifle (the SF), I discovered that I probably need to do something about the powerplant in that rifle, as well.
Then, I shot the LGV. It recoils a lot less than the 55 CM, but you would expect that from a rifle that’s several pounds heavier. However, the LGV also buzzes just a little, so it isn’t the sweetie that I remember, either. It’s not enough to do anything about, but it’s still not the perfectly smooth rifle that I remembered it being. Apparently, the tune that Beeman did on the CM was a good one, and that put me in a quandary about what to do next.
Here’s what I’ve decided. I will definitely test the velocity of the CM as it is now, but then I plan to open the gun and look inside. I expect to find a synthetic piston seal now that I know Beeman rebuilt the rifle. I’ll apply some black tar to the mainspring to soften the firing impulse. Of course, the rifle will be tested once it’s buttoned up again. You’ll have a positive before and after velocity test, plus we’ll all learn if the mainspring inside is an upgraded one or not and if the piston seal is synthetic.
That’s a lot of work, though, and I’m not prepared to do it for today’s report. But Mac just finished testing a Diana model 60 target rifle, so I’m starting that report today.
Mac owns a Hy-Score model 810, which translates to the Diana model 60 recoilless breakbarrel spring-piston target rifle. Diana made several breakbarrel target rifles on what is known as the Giss contra-recoilling piston system that cancels all recoil. I will cover how the Giss system works in the next report, but our Russian blog reader, duskwight, knows all too well how it works, as he’s designing something similar for himself.
Besides the model 60, they made models 65 and 66, both of which have a barrel locking lever to hold the barrel positively shut when firing. The model 60 is the only one of the three that doesn’t have that latch. The model was made from 1963 to 1982, and Mac’s was produced in February 1967.
The Diana model 60, which is a Hy-Score model 810 in this case, is a breakbarrel target rifle from the 1960s and ’70s.
Can a breakbarrel rifle be accurate?
You know, whenever that question is asked, the Diana Model 60 is the rifle I use to answer it. Since the sights are not both (front and rear) mounted to the barrel, the breech joint does come into play! I won’t string you along on this question. Yes, a breakbarrel air rifle can be just as accurate as a fixed barrel air rifle, and Mac will prove it to you in Part 3 of this report.
The Diana 60 uses just a single ball-bearing detent to close and lock the breech in position. It’s the same design that many of their sporting spring rifles of the same era use. Apparently, it works quite well. How well? You’ll have to wait to see.
Description of the rifle
The model 60 is heavy, at about 9.5 lbs. It’s all wood and metal. The only plastic to speak of are the trigger and triggerguard. The rifle spans 43.5 inches, of which 18 inches make up the barrel. The Hy-Score version of the rifle came with a steel barrel jacket for added weight. The length of pull is 13.5 inches, which Mac finds perfect.
The bluing is deep and flawless — what would be found on airguns costing over a thousand dollars these days. The wood stock is checkered with hand-cut diamonds. Of course, the gun was made in the days when human labor was still affordable, so that isn’t such a surprise.
Generous checkering on the flat bottom of the forearm.
All checkering is hand-cut.
The depth of the stock makes it possible for the cocking lever to be one piece and still have a short cocking slot. This would reduce vibration if there was any, but Mac assures me there isn’t. He says it’s difficult to tell when the gun has fired, because it’s so smooth.
The cocking link is one piece, but the depth of the stock allows the cocking slot to be short. This adds to the stability of the rifle.
Mac is very taken with the obvious quality of this rifle. He scrutinized the smallest details, and though I won’t show you all of them, perhaps just one will give you the sense he is trying to convey in his report. The pivot bolt is locked down by a screw that intersects the larger bolt head on its periphery. Many rifles have this, including the Slavia 631 and even the Diana sporting rifles, but few of them have a total of 11 cutouts for the locking screw to intersect with!
It’s a small detail, but Mac feels it conveys the overall quality of the airgun. The barrel pivot bolt head has 11 cutouts on the periphery for the locking screw!
Mac can’t stop talking about the trigger on this rifle, and you must remember that he owns 7 FWB 300 rifles to compare it with. He says it is so delightful that he doesn’t want to adjust it, though it allows for plenty of owner adjustment.
Since the Hy-Score 810 was sold by Air Rifle Headquarters (the original one) back in the ’60s and ’70s, I have a catalog description of it from contemporary times. The next report will have a little more history from this material.