Ataman BP17 PCP bullpup air rifle: Part 2
by Tom Gaylord
Writing as B.B. Pelletier
This report covers:
- Wood stock
- Lothar Walther barrel
- Fill the reservoir
- Velocity test
- The test
- JSB Exact Jumbo
- JSB Exact Monsters
- Shot count
- Why it’s a clip and not a magazine
- Back to JSB Exact Jumbo, shots 22 through 28
- Trigger pull
Today we look at the power/velocity of the Ataman BP17 PCP bullpup air rifle. But before I begin testing, there are several things I need to clarify.
The cocking lever comes to you mounted on the left side of the airgun, but it can be switched to the right by the user. I normally catch those things, but it isn’t mentioned in the manual anywhere. I watched Tyler Patner’s Insyder review that can be seen on the BP-17 product page. If you can watch it I recommend it; it’s excellent! He mentioned switching the cocking lever to the other side of the rifle for lefties. In all other ways except the safety the rifle is ambidextrous, and moving the lever completes it.
This is another design feature the manual doesn’t mention, though it’s in the product description online. Tyler does mention it, and apparently Ataman does this with several of their airguns. All you feel is rubber that I have already told you is very grippy.
Yes, the BP17 has a regulator. It is regulated down to 130 bar, and the fill is 300 bar, so between those pressures are the useful shots. How many we will discover today.
Lothar Walther barrel
Here is a third feature the manual fails to mention — the Lothar Walther barrel. This is as big as the ambi cocking lever, because Lother Walther has a deserved reputation for making great airgun barrels.
Wow! You would think I didn’t do Part 1 with all those things missing. This makes a point that airgun manufacturers need to put more information into their manuals — though I will say this manual is pretty darn good as it is. The LW barrel and wood stock aren’t things that will help you operate the rifle, so perhaps they don’t belong in the book, but the other two things do.
Fill the reservoir
The rifle had 170 bar, according to its onboard gauge, when I started the review. It needs to be filled to 300 bar. I still have the Nomad II air compressor, so I hooked it up in less than a minute and started it. Then I started writing. In less than three full minutes the compressor stopped and the rifle was full! Is that impressive or what? And we know from my test of the compressor that the Nomad II can go wherever your car goes, so you can take it with you on trips. As small and lightweight as the Nomad II is, it’s the perfect companion to this precharged air rifle!
Tyler got superb accuracy from the .22 caliber JSB Exact Jumbo, so that’s the first pellet I tested for velocity. I won’t test the velocity of the JSB Hades pellet because it weighs the same 15.89-grains as the Jumbo Heavy, but when we test accuracy I will surely test it.
The clip holds 7 pellets, so all my testing will be based on 7 shots. First up is the JSB Exact Jumbo.
JSB Exact Jumbo
This pellet gave an average 852 f.p.s. velocity for 7 shots. At that speed this pellet generates 25.62 foot-pounds of energy at the muzzle. So Ataman’s claim of 25 foot-pounds is on the nose. The spread for 7 pellets was 14 f.p.s., ranging from 848 to 862 f.p.s.
Next pellet to be tested was the RWS Superdome. This 14.5-grain domed pellet averaged 871 f.p.s. in the BP17. At that speed it’s generating 24.43 foot-pounds at the muzzle. The spread for Superdomes was 9 f.p.s., ranging from 866 to 875 f.p.s. That’s the regulator at work.
JSB Exact Monsters
I tested the JSB Exact Monster dome next. I did it for 2 important reasons. First, because the BP17 has a rotary clip, the length of the pellets that will fit the gun is constrained to the width of the clip. Any longer and the pellet will stick out on either end and hang up the feed mechanism. Well, these 25.39-grain pellets just fit, so now you know. The second reason for testing with Monsters is that heavier pellets always generate more muzzle energy in pneumatics and gas guns. So this one will test the limit.
Seven Monsters averaged 700 f.p.s. on the nose. Since the “magic number” is 671 f.p.s., we know this pellet produces more than 25.39 foot-pounds at the muzzle. The magic number is the velocity at which the weight of the pellet in grains equals the energy it produces in foot pounds. At 700 f.p.s. the Monster produces 27.63 foot-pounds at the muzzle. That makes the Ataman estimate of energy a bit conservative.
The spread for this super-heavyweight pellet was 5 f.p.s. Yep, that regulator is really working!
After watching Tyler’s video report I knew he had gotten 26 shots before his rifle fell off the reg. With the three 7-shot clips I just fired there were 21 shots on the fill. Why don’t I load 7 more shots of JSB Exact Jumbos into the clip and shoot them so you can see the velocity of each one? I will number them shots 22 through 28. I will also explain why I keep calling this round thing that holds the pellets a clip instead of a magazine. In fact, I’ll do that now.
Why it’s a clip and not a magazine
A clip just holds ammunition. A magazine assists with the feeding of the ammunition. A clip is just a place to store rounds, and, when moved by the rifle, positions them to be loaded or fired or both. A magazine is an entire mechanism. What everyone calls the clip in an M1911A1 pistol is actually a magazine because it contains the spring that pushes the follower up to align the cartridge that is next to be fed. It also moves the slide lock up to lock the slide in the open position after the last round has been fired.
The clip in a TR5 does not lock the firing mechanism. After all the pellets have been fired you can still pull the cocking handle back, cock the rifle and dry-fire it.
When you shoot the BP17, if you cock it and fire it after the 7th shot, it will continue to fire, even though nothing comes out of the gun. If it had a circular magazine, it could stop functioning after the last shot. That is what a magazine does that a clip usually can’t do.
Back to JSB Exact Jumbo, shots 22 through 28
28………….841 fell off the reg?
I would bet that the BR17 under test fell off the reg (the regulator no longer functions because the minimum air pressure in the reservoir was too low) at shot number 28. Yes, its velocity is very close to shot 27 and the others, but looking at the 26 shots Tyler got in his test I think we are now at the end of the useful air supply.
I stopped for lunch and did not resume writing for about 75 minutes, so the rifle has been sitting around all that time. If the reg is the slightest bit slow, I have given it more than enough time to refill the firing valve.
The pressure on the built-in gauge now reads exactly 150 bar. If that gauge is reading correctly and if the regulator is set to spec, the next few shots should be faster than 841 f.p.s. As I write this I have no idea of what we are about to see.
I think it’s clear that I was correct. Shot number 28 was the point at which this test rifle fell off the reg. This rifle is just a smidgeon faster and gets one more shot while it’s on the reg than the rifle Tyler tested. Across the 27 good shots, this rifle varied by a total of 17 f.p.s. That is a fantastic number of good shots. I would use shot 28, as well, so the variance grows to 21 f.p.s. on a fill. That’s 4 full clips.
At the end of these 7 shots the onboard gauge read 120 bar, so there is a large discrepancy in the gauge right at 150 bar. It’s more like 130 bar when the needle reads 150. I refilled the gun from 120 bar with the Nomad II and this time it took 4 minutes 37 seconds, start to finish.
Forget the fact that you don’t have a carbon fiber air tank. Get a Nomad II compressor and go with it.
Tyler’s trigger broke at an average 5.6 ounces and he noted the same thing that I did about the lack of a positive stage two stop on the BP17’s trigger. I knew my trigger was breaking light. It broke at an average 6.1 ounces with no hint of a stage 2 stop. All I can say is keepa your finger offa da trigger until you want the gun to shoot!
The BP17 is not a quiet backyard airgun. It’s louder than a Benjamin 392 (or Sheridan Blue Streak) fired dry on 8 pumps. It’s not ear-splitting, but smaller urban backyards are off limits.
Are aftermarket silencers available? Yes, but they are expensive, plus I am not sure if they go over the line as far as the ATF is concerned.
So far there is much to like and nothing to dislike about the Ataman BP17. I noted that Tyler was able to fit the Aeon 8-32X50 SF scope to the rifle without hanging over the muzzle, so that is the scope I have selected for my accuracy test. It’s short for the power but has superior optics for the price range.