Back From The Gunsmith

Ok, here is the full post that the sneak peak promised. All of my guns are back from the gunsmith; all but one of them had a picatinny rail and optics installed. The last one was the antique Diana 27, it was in for a re-seal, re-lubrication, sight alignment, and cleanup. All of the pistols are sporting new Cerakote, which unfortunately means that the model number and logo for these pistols is no more (see below.) Also, you might notice that the Diana pistols don't have the right-handed grip; I ordered the left-handed grips for both pistols, and swapped out the right sides, thus giving both of these Diana pistols ambidextrous grips.

The Hatsan 25 Supercharger (.22 caliber,) and two Diana P5 Magnums (.177 caliber.)



The Hatsan Model 25 Supercharger with Tru Glo red dot scope.

Close-up of the Hatsan, to show the custom Picatinny rail. The logo is gone.

My Diana P5 with its new Tru Glo red dot scope.

My son's Diana P5 with its new (used) BSA red dot scope.
He is 7 now; he will inherit this gun when he turns 16.

Close-up of my P5  to show the custom Picatinny rail. As with the
Hatsan, the Diana logo on top of the gun has been covered by Cerakote.

Close-up of my son's P5  to show the custom Picatinny rail. As with the
Hatsan, the Diana logo on top of the gun has been covered by Cerakote.

My antique 1934-era Diana Model 27, all cleaned up and ready to roll.

I went a little picture happy with the Diana 27. There's no reason for this close-up
view, other than the fact that I love looking at this gun.

A thing of beauty is a joy forever.



My local gunsmith, Benny; the guy who made it all possible.

Well, that's all for now; when I return, I will be shooting these guns, posting data and target photos as I go. Until then, may all of your pellets fly true!

Discoveries, Hobbies, and a 3-Inch Metal Post

Ok, this last Friday, I went back to the range; I went after work, so I was only able to catch about an hour and a half of the remaining daylight. But it proved to be sufficient.

I shot up a bunch of yellow targets that I won't bother to post here today; all I was doing with those is trying to fine-tune my shot placement, and also trying to test out my newly-arrived RWS Hobby 11.9 grain pellets. At first glance, using the bench rest, the Hobby pellets don't seem to strike as true as the Benjamin Discoveries; they're close, but I have noticed that I get more fliers with the Hobbies for some reason. I will have to experiment with them some more before I can realistically say that the Discoveries truly perform better; but that is what my gut is telling me that the probable outcome will be.

I did, however, get the chance to pass the Hobbies over the Chrony; they're averaging 520 fps, about 20 fps faster than the Discoveries. I expected a wider variance than that, considering that there is a 2.4 grain difference between the two pellets.

I also had the chance to do some free-handed shooting; at a distance of 10 meters, from a seated position, elbows OFF the table, holding the pistol like a carbine (right hand around the grip, left hand supporting the lower body of the gun) and close to my face and chest, with my shoulders "shrugged." Here are the results of that, which, if you compare them to the bench rest results of the previous posts, prove once and for all that the gun shoots better than I do.

10 of each; Discoveries on top, Hobbies on bottom.

Results with Benjamin Discoveries.

Results with RWS Hobbies.

As you can see, even with the one flier, the Discoveries resulted in a 3.5" group at 10 meters. Using the same hold, same position, etc., resulted in a 5" grouping with the Hobbies. Plus, the Hobbies seem to have a lower POI; I will gladly admit that some of that is possibly my fault, but these targets were shot one after the other, in the space of maybe 10 minutes max. I was not fatigued when I started, nor was I fatigued when I finished. There was plenty of daylight for both targets. And I had the benefit of the red dot on all 20 shots. I can't imagine that the inconsistency of the Hobbies is entirely my fault, when I did so well with the Discoveries. The only thing I can think of is this: If my shooting technique has some consistent fault to it, i.e., if there is something I do every time that affects the POI, then the Discoveries are less affected by it than are the Hobbies.

Another thing that I did while at the range was to re-visit my old friend, the metal post, which sits on the 100 yard line of the rifle range. The post is typically shot with .30-06s and .270s; as you can tell from the enormous holes that have been shot through it. If the post could talk, I am sure that it would have been happy that the only thing I shot it with was a few pellets. (That's airgun humor, in case you missed it.)

The post is actually only 3 inches wide, not 4 as previously reported.

During my session with the post, I never actually hit the cans on top; but I did manage to hit the post. The light faded before I could figure out how many "imaginary mil dots" to adjust upwards by.

The good news is that I videoed the session (or at least, most of it; my iPhone died before I could return to the Hobbies for a second chance) and that I have figured out how to embed videos into my blog, so you can see it instantly, without having to follow a link. Here is the video:

I hope you enjoyed reading this post as much as I enjoyed creating it. Until next time, may all your pellets fly true and hit with authority!

Some Interesting Data

I noticed, while playing around with the calculators on Airguns of Arizona, that there is an advantage to middle weight pellets vs. heavy pellets.

Look at this:

9.3 grain RWS Supermag pellets (.177 caliber)
Ballistic Co-efficient = 0.012
Average muzzle velocity in the Diana P5 Magnum: 450 fps (4.18 FPE)


8.2 grain RWS Meisterkugeln pellets (.177 caliber)
Ballistic Co-efficient = 0.010
Average muzzle velocity in the Diana P5 Magnum: 507 fps (4.68 FPE)


Not only do the lighter pellets provide slightly more power at the muzzle, they retain it better initially as well:


Supermag retained velocity at 10 yards = 406 fps (3.4 FPE)

Supermag retained velocity at 20 yards = 365 fps (2.75 FPE)

Supermag retained velocity at 30 yards = 329 fps (2.24 FPE)



Meisterkugeln retained velocity at 10 yards = 447 fps (3.64 FPE)

Meisterkugeln retained velocity at 20 yards = 395 fps (2.84 FPE)

Meisterkugeln retained velocity at 30 yards = 349 fps (2.22 FPE)


At shorter ranges, the medium weight pellet performs better, but starting at 30 yards (which is long range for a pistol like the P5) the heavy pellet starts to edge out the medium weight pellet. That's because FPE (Foot Pounds of Energy delivered) is a delicate balance between velocity and mass; once the pellets are traveling at roughly the same speed (329 fps vs. 349 fps), the mass of the heavier pellet is going to enable it to deliver a harder punch. The heavy pellet is traveling 20 fps slower at 30 yards, but still hitting harder.

However, at shorter ranges, the medium weight pellet's advantage is that its lighter weight helps it to retain more velocity.

CONCLUSION: Under 30 yards, the medium weight pellet packs more of a punch. At 30 yards plus, the heavy pellet has the edge.

I just thought I would make a note of this. I love examining data like this. It really helps one gain a better understanding of the physics involved in this enjoyable sport.

Shooting At Cans

Distance: 10 M, using bench rest.
Weather: sunny & clear.
Airgun used: Diana P5 Magnum.
Pellet used: Diana Meisterkugeln Pro-Line, 8.2 grain.

First Shot, In Through The Bottom

First Shot, Out Through The Top

Second Shot, In Through The Bottom

Second Shot, Out Through The Top, Through SAME HOLE!

Third Shot, Change-Up: In Through The Top, Just Under Tab

Third Shot, Big Dent In Bottom, No Exit

Deformed Pellet From Third Shot (Closeup)

Diana P5 Magnum Second Range Test

Well, I went to the range yesterday, and here are the targets and results. I was going to shoot 25 of each pellet, but when I got to the Hyper Max pellets, they were shooting such tight groups that I had to shoot a lot more of them in order to see the true range of variability. (I ended up shooting 40 Hyper Max pellets.) I think you can see by these pictures that the Hyper Max is the true champion when it comes to accuracy; 58% of the Hyper Max pellets went through the same, quarter-sized hole. Only 40% of the Crosman pellets hit the same mark. Both targets were shot standing, at a distance of 7 yards (21 feet) with open sights, using a police-style, 2-handed grip.

25 shots with Crosman SSP 4.0 grain pellets @ 7 yards, police-style 2-handed stance.

About 10 of the 25 shots hit this quarter-sized area.

The red area is 3 inches in diameter.

40 shots with RWS Hyper Max 5.2 grain pellets @ 7 yards, police-style 2-handed stance.

Again, the red area is 3 inches in diameter.

About 23 of the 40 shots went through this quarter-sized hole.

I also chronographed these two pellet types. Here are the results. The first Hyper Max result was due to dieseling, I believe. I cleaned the barrel with an alcohol swab, then put a drop of silicone lubricant on the breech seal just before shooting the chronograph test.

Hyper Max 5.2 Grain: 718, 683, 663, 650, 639, 658, 644, 659, 656, 649

Average: 661.9 (662 fps)

Taking off the first 2 results: Average: 652.25 (652 fps)

Foot Pounds of Energy (FPE): 4.91 [Let's round this up to 5.0, since our last result was 5.17]

Crosman SSP 4.0 Grain: 787, 792, 789, 784, 782, 775, 785, 785, 785, 786

Average: 785 fps

Foot Pounds of Energy (FPE): 5.47 [Let's round this up to 5.5, just to be fair to the Crosman pellet.]

As you can see, while Hyper Max gives superior accuracy, the Crosman SSPs deliver more velocity and power.

785 vs. 652 = Over 130 fps faster!

5.5 vs. 5.0 = 10% more energy delivered.

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EDITORIAL NOTE: (This comment was added 03-19-2014, more than 2 years after the original post, by an older and wiser Scientific Airgunner!) The super-light-weight pellets (less than 5 grains in weight) should not be used, because they put additional and unwanted stress on the gun's mainspring; thus, despite the fact that SSPs deliver slightly more velocity and power, Hyper Max pellets are a better choice, because they aren't hard on your gun. However, I wouldn't shoot anything under 7 grains nowadays, because retained energy at the point of impact suffers greatly in lighter pellets. Look at the following post for details:  

http://thescientificairgunner.blogspot.com/2013/09/some-interesting-data.html

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You may have noticed the "flyer" at the bottom of the Hyper Max target, this is not an error of the gun, it is human error. I was at the gun range on a very busy day, and there were large caliber pistols going off all around me, and at times, that made it hard to concentrate. That particular shot came after a cease-fire had ended, and I kind of jumped when all the shooting commenced again.

Well folks, that's all for now. I hope to make the next post about my new Crosman Titan GP rifle. I have toyed around with it a little, but I haven't taken it to the range for any serious target work (yet!)

Pellet Data Chart For The Diana P5 Magnum

Data for Diana P5 Magnum

The other day, it occurred to me that it would be a good idea to have the data that I posted on other websites posted here as well, in case the other websites happen to either go away, change web hosts, or lose their data to an unexpected crash. So here it is, complete with bar chart. Each pellet (listed by brand and weight) was chronographed ten times, and then the average of those results was used to calculate FPE (Foot Pounds of Energy.)

Cabela's Ultra Mag (10.56 Grain) = 417, 410, 394, 408, 402, 416, 414, 418, 411, 421

(avg = 411.1) @ 411 fps = 4.11 FPE

Gamo Rocket (9.6 Grain) = 451, 450, 451, 457, 453, 454, 440, 434, 472, 445

(avg = 450.7) @ 450 fps = 4.32 FPE

RWS Meisterkugeln Pro Line (8.2 Grain) = 504, 504, 510, 505, 498, 512, 516, 510, 512, 499

(avg = 507) @ 507 fps = 4.68 FPE

Gamo Tomahawk (7.8 Grain) = 531, 506, 526, 533, 525, 509, 503, 537, 527, 524

(avg = 522.1) @ 522 fps = 4.72 FPE

RWS Hypermax (5.2 Grain) = 671, 667, 664, 673, 669, 668, 663, 670, 675, 675

(avg = 669.5) @ 669 fps = 5.17 FPE

I find it interesting that the FPE was greatest in the lighter pellets. It would seem that although mass plays a large factor in the hitting power of a projectile, velocity can have a pronounced effect as well.

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EDITORIAL NOTE: (This comment was added 03-20-2014, more than 2 years after the original post, by an older and wiser Scientific Airgunner!) The Hyper Max pellets WILL get you close to the 700 FPS that is promised on the box, and they weigh JUST ENOUGH that they aren't hard on your gun. (Pellets that weigh 4.9 grains or less will place additional stress and "wear & tear" on your spring; pellets that weigh 5.0 grains or more won't. That's why RWS makes their "light pellet" heavier than most other manufacturers.) However, I wouldn't shoot anything under 7 grains nowadays, because retained energy at the point of impact suffers greatly in lighter pellets. Look at the following post for details:  

http://thescientificairgunner.blogspot.com/2013/09/some-interesting-data.html

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Initial Review Of The RWS Diana P5 Magnum (RWS Model 5G Magnum)

Hello, and welcome to my blog. This blog is about the scientific method: I gather data on the performance of various airguns, and analyze it. Then I do it again and again. Each time, I compare the new data to all of the previously gathered data, to see if there are any noticeable trends, similarities, or differences. I also use data gathered from other sources (i.e., other reviews posted on other blogs) so as to provide the reader with a "second opinion," from an unbiased, unrelated party. All data from secondary sources will be properly credited and linked.

EDITORIAL NOTE: (03-21-2014) I have revised this post somewhat, deleting links that are no longer active, and making the occasional comment as well. Revisions will appear just like this, in light red text.

The first review that will appear here is my review of the Diana P5 Magnum Pistol (RWS Model 5G Magnum.) The second part is in parenthesis, because the box that the pistol came in was marked "RWS 5G Magnum," but the top action of the pistol clearly cites the model number as the "RWS Diana P5 Magnum." I am a librarian by profession; when cataloging books, a librarian goes by two main sources when looking for the proper title of a book: the title page, and the title page verso. ("Title Page Verso" simply means "the back of the title page.") What the dust jacket or book cover says is irrelevant (and often quite different from the official title!)

The RWS Diana P5 Magnum Pistol, with cocking extender attachment.

Thus, using the same principle, what is stamped on the gun supersedes whatever the box says. But since many people refer to it as the 5G rather than the P5, I chose to include the box citation in parenthesis, to indicate that it is an unofficial designation for the P5.

On other forums, I go by the handle HCAirgunner. The HC stands for "Hard Core," in reference to the extensive research that I perform on each gun before I purchase it, and to the rigorous testing that I put the gun through afterwards.

Here is the Pyramyd Air blog post about the P5 Magnum pistol:

http://www.pyramydair.com/blog/2005/11/diana-p5-magnum-air-pistol-from-rws.html

as well as this re-printed article:

http://www.pyramydair.com/article/Fast_and_accurate_Testing_the_RWS_Diana_5G_Magnum_P5_pistol_March_2009/58

It should be noted that the P5 is a discontinued model, having been replaced by the LP8.

You can see a review of the LP8 (also by Pyramyd Air) by following this link:

http://www.pyramydair.com/blog/2009/09/rws-model-lp8-magnum-part-3.html


I believe (but am not 100% certain) that the following reasons led to the discontinuation of the P5:

1) There was a safety recall of the P5 in April of 2008. Details are here. EDITORIAL NOTE: (03-21-2014) One of the P5 pistols I originally bought was part of this recall; Umarex fixed it quick at no cost, and I haven't had a problem since.

2) The gun had no scope rail, forcing those who would want to add one to modify the gun with machine tools.      EDITORIAL NOTE: (03-21-2014) I have now done the same to my P5 pistols. Look here.

3) The safety mechanism was awkward, and non-ergonomic for some people to operate. (Personally, I found the safety mechanism quite user friendly and easy to operate, but I seem to be in the minority.)

4) The grip that came standard with the pistol was a right-handed groove type, which made the pistol cumbersome and difficult to use for left-handed shooters. (Personally, I agree; I think that such grips ought to be sold as optional equipment, and that ambidextrous grips should come standard.) EDITORIAL NOTE: (03-21-2014) I have solved this problem by ordering the left handed grips, and then swapping out the right sides, which creates an ambidextrous grip, making the gun considerably more comfortable to shoot.

5) Some people found it hard to cock, and worried about breaking the fiber optic sights on the muzzle break. (Me too, but I solved the problem by buying the cocking extender from Umarex. Now, cocking the pistol is fast and easy, and I no longer run the risk of fouling the sights.)

6) Most people believe that the 700 fps claim is unattainable. If you have already read my posts elsewhere on this blog, then you know that the gun does approach 700 fps (averaging about 669 fps with the RWS HyperMax 5.2 grain pellets.)

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EDITORIAL NOTE: (03-21-2014) The Hyper Max pellets WILL get you close to the 700 FPS that is promised on the box, and they weigh JUST ENOUGH that they aren't hard on your gun. (Pellets that weigh 4.9 grains or less will place additional stress and "wear & tear" on your spring; pellets that weigh 5.0 grains or more won't. That's why RWS makes their "light pellet" heavier than most other manufacturers.) However, I wouldn't shoot anything under 7 grains nowadays, because retained energy at the point of impact suffers greatly in lighter pellets. Look at the following post for details:  

http://thescientificairgunner.blogspot.com/2013/09/some-interesting-data.html

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As for accuracy, the P5 performed well at the shooting range (the masthead picture for this blog is a picture of the P5's initial groupings,) however, I still have work to do in this area, because I believe that A) my P5 isn't sighted in perfectly yet, and B) I am not the world's best marksman by any stretch of the imagination. The next time I visit the shooting range, I intend to shoot a lot of targets, and the results, of course, will be posted here.

That's all for now. I hope you enjoyed reading my initial assessment of the Diana P5.