Diana model AR8: Part 2

by Tom Gaylord
Writing as B.B. Pelletier

Diana AR-8
Diana AR8 N-TEC air rifle.

Part 1

  • Cocking effort
  • Slanted breech
  • H&N Baracuda Match
  • Air Arms domes
  • RWS Superdomes
  • Baracuda Match retest
  • Trigger pull
  • Recoil and vibration
  • Evaluation so far

Today we learn how powerful the .22-caliber Diana AR8 Professional Success air rifle is. This will also give those who wonder about the rifle a good idea of what it’s like.

Cocking effort

I’ll begin with the cocking effort, because on this rifle it is really hard! I registered 54 lbs. on my bathroom scale. That makes it a two-hand job for me. I can do it with one, but just barely and not for many shots. Because it has a gas spring, the max effort starts almost at the beginning of the stroke.

Slanted breech

A reader was curious whether the AR8 has a slanted breech block like most Diana rifles. The answer is yes, the breech does slant. Let me show you what that does to loading.

Diana AR-8 slanted breech
When the breech slants, a portion of the pellet skirt will stick out like this.

When the breech slants, part of the pellet skirt will stick out.When that happens…

Diana AR-8 bent pellet
When the breech is closed, the part of the skirt that sticks out gets bent like this.

H&N Baracuda Match

I knew from the few times I had shot before that the rifle was detonating, so I selected the heaviest pellet first. That was an H&N Baracuda Match pellet. I happened to select one with a 5.51mm head, but they all weigh pretty much the same — about 21.14 grains. Remember the “magic” number? That’s the velocity at which the weight of the pellet in grains equals the muzzle energy in foot pounds. That number is 671 f.p.s. I expected faster from this rifle, so let’s see what it did.

Shots 1-3 registered 764, 678 and 564 f.p.s., respectively. That’s not right. Fortunately I have a lot of experience with these mega-blaster gas spring guns and I knew what it was. I was holding the muzzle too close to the start screen of the chronograph. The muzzle blast of air is so sharp that it actually “fools” the screens. I backed up another 6 inches and the next shot went out at 923 f.p.s. That was more like it. So I counted 10 shots from that point.

The rifle averaged 904 f.p.s. with a low of 844 and a high of 929 f.p.s. That is a spread of 85 f.p.s. and is diagnostic of detonations. You can hear them sometimes, but even when you can’t they are still there. There is nothing to do for it but keep on shooting.

Air Arms domes

Next up were some Air Arms 16-grain dome pellets. In a powerful rifle like the AR8, these qualify as medium-weight pellets. They averaged 857 f.p.s., which is much slower than the heavier Baracuda Match, but what it means is the rifle is starting to simply diesel and not detonate. The spread went from a low of 812 to a high of 902 f.p.s. which is a 90 f.p.s. difference. So, there is still some detonating happening. In my experience it sometimes takes many shots before this goes away and the rifle calms down. Look for the average to be slower when that happens.

RWS Superdomes

The last pellet I tried was the RWS Superdome that acts like a lightweight pellet in a rifle this powerful. These 14.5-grain pellets averaged 915 f.p.s. and this time the spread was just 33 f.p.s., from a low of 896 to 929 f.p.s. That tells us the gun is settling down. If we were to shoot the Baracuda match pellets again, we could expect to see a lower average at this point. Let’s do that and see.

Baracuda Match retest

Since I was tiring from the cocking effort, I only shot 5 Baracuda Match. The average was 721 f.p.s. with a 38 f.p.s. spread. It went from a low of 706 f.p.s. to a high of 744 f.p.s. That’s definitely slower than before, and it illustrates the fact that the gun was detonating before. It has probably stopped doing that now.

At this point the rifle is generating 24.4 foot-pounds with this pellet. The Superdome is lighter and should produce more energy in a springer and the average of 915 f.p.s. is good for 26.96 foot pounds. I didn’t show the enrgy for the earlier shot strings because I believe they are artifically high from the detonations.

Trigger pull

The trigger pull on the AR8 is shockingly light. I measured just 15 ounces when stage two broke, and there was no creep. This is the lightest sporting trigger I’ve ever measured on a gun straight from the box!

Recoil and vibration

The AR8 has almost no vibration. The recoil, however, is heavy. My trigger finger was pounded by the triggerguard as the rifle moved in recoil every time it fired. This is something to consider.

Evaluation so far

Lightest sporting trigger I ever felt. Feels like a home tuner gone too far.

The rifle has a lot of power. It’s clearly a magnum spring gun.

The recoil is heavy. It will make you take notice.

Cocking is a chore. This is no plinker, that’s for sure. It is an all-out hunter. Fortunately you can leave the rifle cocked for hours, because compressed air never takes a set.

The AR8 is a large powerful air rifle. Let’s see if I can mount a scope and successfully sight her in fo the accuracy test that’s next.

29 thoughts on “Diana model AR8: Part 2

  1. B.B.
    On my 340 N-Tec the cocking when i got it was well over 70 lbs. This was on cocking, on closing the cocked barrel the effort was about 60 lbs. I needed to loosen the barrel pivot bolt substantially, maybe you need to do the same?

    -Y



    • 45Bravo,

      My Diana 46 has a slanted breech and is an under lever, not a break barrel. Most of the time if you load the pellet straight you can get it in far enough without too much effort, but a pellet pen with a seater would be the easiest and most consistent way to load any break barrel. Crunching the skirt has been known to be detrimental to the accuracy of the shot. 😉





      • Hi B.B.

        I have had people show me their rifles and report that they had adjusted it to a “hair trigger” – which makes what little hair I have left stand on end!

        I check these rifles by having the owner hold the rifle pointed in a safe direction while a tap the butt with a rubber mallet. I start with a light tap and increase the speed up to a reasonable level. If it passes, all is ok. If not I strongly suggest that the owner correct the adjustment.

        Had a couple of triggers that were “tuned” with a file and I needed to make replacement parts to make the rifle safe.

        Hank


      • The Huber anti-friction ball trigger installed on my Mosin Nagant required a drop test as part of the installation. I had a gunsmith do it for me, and I did not get the particulars beyond the fact that he was dropping the butt onto a rubber mat from some height. But as a firearm, this could be done safely with a dry fire which you couldn’t for an airgun.

        Matt61


  2. Years ago I suffered a traumatic brain injury (TBI). This injury has affected and limited many activities in my life that I had previously taken for granted. But, this lead me back to air gun shooting, an activity my “new” brain seemed to tolerate well. Or at least I thought so until I began shooting a Gamo .177 Whisper Fusion.

    With peep sight and a trigger replacement, this rifle was uncanny accurate; but after each shooting session I felt like I had suffered another “mini” concussion. Finally I came to understand this gas piston powered rifle had a jolt upon firing like no other I had ever shot and this jolt was jarring to my brain. Eventually and sadly I had to sell the rifle, which brings me back to today’s blog. Reading BB’s description of shooting the rifle AR8, I can almost feel the recoil impacts in my brain. Anyone who suffers from TBI or migraines or any other brain related trauma issues, should think twice before purchasing a gas piston powered air rifle. Thank you BB for this review and pointing out the violence of a magnum power plant rifle.



    • Sorry to hear about this condition. I once asked a doctor a related question. I believe that hearing results partly from vibrations through your face as well as input from the ear. So, I was wondering if spring guns could cause hearing problems from contact with the stock that circumvented hearing protection. The doctor who was a shooter of firearms suggested placing a large foam pad on the stock. (I ended up not bothering, and I’ve been okay.) Perhaps you could try a similar solution, but the safest course would be to not use the gun.

      Matt61


    • TEH,

      If you do not require much power, you would be a candidate for a nice rebuilt Feinwerkbau (FWB) 300s or 150. If you do need the power your magnum Gamo provided, you should look into the Diana / RWS 54 Air King. Well-made, accurate, excellent trigger, powerful, and almost no felt recoil.

      Michael


      • Michael,

        That is exactly what I have done. I now own three FX PCP’s, 2 Marauders and several lower powered versions of other rifles. Thank you for the suggestions though. Very much appreciated.

        Tom


  3. B.B.

    This may be a good rifle for testing rings/mounts to see if they can hold a scope on a nasty rifle .
    Might not be a good idea to use your favorite scope on this one . You got a cheap junk scope laying around that you can afford to destroy ????

    twotalon


  4. BB, I am Soham from India & I am 18. I have been reading your blog for 2 years and have finally caught up. I have a question regarding direct sear locking triggers. Can their pull weight be reduced without comprising safety? My current guns have 2.5 kg trigger pull ( sorry I have hard time calculating pounds & Oz’s). Two years back I bought a gun that I did not know had the piston sear angle to almost 75 degree instead of 90 resulting in a misfire that nearly cost me my Left index finger. After that have learnt to disassemble springer s and built a spring compressor thanks to your blog( in the 13 part R1 tuning series) but can’t find any info on google about reducing weight of direct sear locking triggers.


    • Riki,

      Welcome to the blog.

      You identified one of the problems with direct-sear triggers. If the mating angle isn’t correct, the sear can slip and fire the gun. The other big problem is when the contact area becomes too small. ghen it can be shaken or jarred loose, and the gun fires.

      Two point five kilos is close to 5.5 lbs, and that makes a heavy trigger pull. The way to lower the pull is to lubricate the trigger correctly. If the sear/trigger angle is correct and if no “polishing” has been done to either part, a moly-based grease is good. If you don’t know about those things, I would stick to lithium grease.

      Also oil the pivot pins the trigger parts rotate on. And, if possible, remove as much slack as you can from the trigger parts. They should pivot on their pins, not rock side-to-side from outside forces.

      B.B.



    • 6.5,

      I would be shocked if there was. These rifles are built from common parts. Having two different spring tubes would be a killer in a production cycle. I haven’t seen different port sizes in any other spring-piston rifles, except the Whiscombe which has transfer port limiters.

      B.B.


  5. So after 400-500 shots through my new Beeman P17 I got tired of practicing my Handgun technique. I eventually went to 2 hand hold and that did make an improvement in my groups, but honestly my hands shake way more than they should and I wasn’t doing justice to the incredible accuracy of this gun. I also have poor vision which made it hard to even recognize the target when I was focusing on the front sight. Honestly, it just wasn’t fun, and that’s what it’s all about for me.

    So I mounted my 6 ounce green laser on it

    https://s15.postimg.org/wq9xb5gcb/20161103_144910_1.jpg

    oh my gosh !!!!!!!!!!!!!!!!!!!!!!!!!!!!

    this is so fun. I’m using a submachine gun hold, left hand under the barrel and up against my ribcage. This is an extremely accurate gun, I can’t imagine how small the groups would be if got some new glasses. 😉 😉 😉

    And best of all, when I fire, the pellet picks up a reflection of the laser and it looks like I’m firing laser beams at the target, just like the movies. LOL 🙂 🙂 🙂 🙂 🙂


    • 6.5,

      I have a 92FS Beretta pellet pistol with a laser sight on it. Love it! Try a small piece of cheap scotch tape on the target. (3/4″ X 3/4″) Makes it light up like a Christmas tree! The cheap stuff, (not) the no glare,…. the glossy/shiny type.

      Glad you are having fun!


  6. I had a Diana 38 that clipped pellets in the same way and I resorted to deep seating them. Another cracking idea from the company that brought you power sapping dogleg transfer ports and inbuilt barrel droop
    This rifle sounds like a pig. I have little time for gas pistons. Their lauded advantages evaporate like mist under critical inspection and these new owners have immediately tried to join the US velocity race without looking at their product which suggests the dollar is ruling the design in quite the wrong way.
    The absurd name was coined by the firearm manufacturer btw. The centre fire rifle has an identical stock.


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