Diana 75
The Diana 75.

Part 1
Part 2
Part 3
Part 4

History of airguns

This report covers:

  • Introduction
  • The test
  • RWS R10 Match Pistol
  • H&N Finale Match Light
  • Qiang Yuan Match
  • Discussion
  • Velocity
  • Summary

Today BB wrings all the accuracy he can from the Diana 75/Beeman 400 target air rifle. This one will be good!

Introduction

Yes, this blog was published by accident on Saturday, and no, I didn’t write another one for today. I worked on Michael’s rifle.

Last week I wrote about follow-through and I said sometimes these reports help me as much as anyone. Today is such a day. 

Just to remind you, I am planning a shootoff between this Diana 75 and my FWB 300S, which I believe to be the most accurate 10-meter target air rifle I own. Before doing that, I wanted to find the most accurate pellet(s) for this rifle. I already know the best ones for the FWB.

This is the third time I have tested this rifle for accuracy. I also have a surprise test for you after the accuracy test, but let’s stick to one thing at a time.

The test

I shot the rifle off a sandbag rest with the rifle rested directly on the bag. I shot 5-shot groups to try more pellets and also to not tire too quickly.

I wore my regular glasses that seem to work well with the target sights. And I followed-through on every shot, starting with the fourth shot on the first target. I had forgotten about  that report until then, but the smoothness of the shot cycle reminded me to keep my eyes on the target longer after the shot.

RWS R10 Match Pistol

The first pellet tested is the RWS R10 Match Pistol pellet that has demonstrated good accuracy to this point. The best to date has been five pellets in 0.162-inches between centers at 10 meters. Today, with follow-through, that was bettered.

Today five R10 Match Pistol pellets went into 0.108-inches between centers at 10 meters.  That is a gold dollar group!

R10 Pistol group
RWS R10 Match Pistol pellets are very accurate in this rifle. Five went into 0.108-inches at 10 meters.

RWS R10 Match Heavy

I wanted to try some heavier pellets in this rifle, so next up were five RWS R10 Match Heavy pellets. They surprised me by going into a 0.134-inch group at 10 meters. That’s another gold dollar group!

R10 Heavy group
Five RWS R10 Match heavy pellets made a 0.134-inch group at 10 meters.

Find a Hawke Scope

H&N Finale Match Light

Ooops! Since H&N Finale Match Light pellets have turned in the best 10-meter groups in the past (0.14-inches between centers) with this rifle, I expected them to do well today. But something happened. They gave me the largest group of the test, at 0.225-inches between centers.

I don’t know what happened because the sight picture looked good every time. And the follow-through was spot on. Obviously something went wrong with this group and I am at a loss to explain it. I can’t blame the rifle and after you see the entire test you’ll understand why, but something happened to open that group.

Finale Light group
Five H&N Finale Match Light pellets made this 0.225-inch group at 10 meters. Yes, I see the torn paper, but I measured across the round holes only.

Qiang Yuan Match

The last pellet I tested was the 8.2-grain Qiang Yuan Match pellet. When I saw the group they made I was surprised. It appeared smaller than the first group that was made by the R10 Match Pistol pellets. When I measured it after shooting I found it measured 0.112-inches, which is slightly larger than the first group. 

Chinese Match group 1
Five Qiang Yuan Match pellets went into 0.112-inches at 10 meters. It’s the second-smallest group of the test.

Because I thought the Qiang Yuan Match pellets were best I shot a second group with them, just to see if the first group was a fluke. Apparently it wasn’t because the second time around 5 went into 0.189-inches at 10 meters.

Chinese Match group 2
The second group of Qiang Yuan Match pellets is larger, but not by much. At 0.189-inchaes between centers it still merits a trime for comparison.

Discussion

Well, I believe I am finally wringing out much of the accuracy this Diana 75 has to offer. In five targets there are three gold dollars (groups smaller than 0.15-inches between centers) and one trime (group smaller than 0.20-inches between centers) used for comparison. Only one dime was used for group comparison today.

And wait, there is more! This is the special test I mentioned at the beginning. If you remember last time I retested the velocity of the rifle after the accuracy test. In Part 2 the rifle shot RWS R10 Match Pistol pellets at an average 534 f.p.s. After Part 4 when 60 more shots had been fired that average had increased to 545 f.p.s. I retested it today because some readers thought the rifle might still be breaking in after the reseal Dave Slade did.

I shot a total of 27 shots today. The first two were just to wake up the powerplant, and then the five, 5-shot groups. Before this velocity test I shot the rifle an additional 20 times, bringing the total since the last velocity test up to 47 shots.

Velocity

With ten RWS R10 Match Pistol pellets the velocity averaged 501 f.p.s. That is a decrease of 44 f.p.s. from the average seen in the last test and also proof that there is something amiss in the powerplant. Before I pit this rifle against the FWB I will have it resealed.

Summary

Today’s test was a good one because it demonstrated to me and I hope to you as well the importance of the basics. Specifically I refer to follow-through.

I was also alerted to the state of tune on this rifle. Something is definitely off and needs to be corrected before I put it up against the FWB.