Drozd BB machine gun – bulk fill! – Part 3

B.B. Pelletier

Part 1
Part 2

Let’s finish the Drozd velocity testing we began on Friday. Remember, the ambient temperature during shooting was 61 degrees F.

Performance with 4.4mm lead balls
The average was 458 f.p.s., with a spread from 444 to 474. A 4.4mm lead ball weighs 7.6 grains, so the muzzle energy for the average is 3.54 foot-pounds. The extreme velocity spread with this ball, which is larger than a steel BB, is quite large. I believe there is still a lot of gas blowing by the ball in the bore. Why the smaller steel BB has less velocity variation might be because it isn’t engraving the rifling, so it encounters no resistance, while the 4.4mm lead ball does.

Performance with 4.5mm lead balls
This was the big eye-opener! The 4.5mm Beeman Perfect Round balls are a true .177 bore size, and I suspect that the bore of the Drozd barrel, being rifled, is .177, too. There is no rationale for rifling a BB bore, only a pellet or lead ball bore. The only rationale for using a rifled barrel in a gun meant only to shoot steel BBs is because you have easy access to rifled barrels. It’s just easier to use what you have than to add another manufacturing process to make smooth bores. And, we know IZH makes several models of .177 pellet guns. That is another reason why I believe 4.5mm lead balls are correct for this gun But let’s look at the performance.

These balls weigh 8 grains even. They averaged 473 f.p.s., with a spread from 464 to 481. That’s FASTER than the smaller, lighter 4.4mm balls, with a tighter velocity spread, too. The muzzle energy comes out to 3.98 foot-pounds, making 4.5mm balls the most efficient ammo for this gun. I believe they get this efficiency from a tight bore fit that seals the gases behind the ball.

I have read a couple of comments regarding hunting with the Drozd. With the low energy it delivers, I cannot recommend the gun for hunting beyond very small critters like mice and moles. I understand that the semiautomatic capability helps in a hunting situation, but it is not sporting to have to shoot an animal several times to get results.

Other considerations
All the velocity tests were done while firing in the semiautomatic mode. Because the Drozd is powered by CO2, the velocity drops as it is fired repeatedly. I waited for about 15 seconds between shots to let the gun warm up after each shot. Even on a very hot day, the velocity will still drop with repeated shots. The hotter the day, the faster the recovery.

The chief reason people have said to not use lead balls is they tend to jam when fired in the burst mode (3-round or 6-round bursts). One reader said 3-round bursts were okay but 6-round bursts produced jams. I will test for this in the future. In the past when I did accuracy testing, all my firing was semiautomatic, because that is the only way to get reasonable accuracy from a select-fire gun. I will therefore do all accuracy testing in the semiautomatic mode.

After that, however, I will test this gun in the burst-fire mode in an attempt to see if it will jam. I will try all the cyclic rates and both burst modes to see if it will jam. We’re going to really wring out this gun for you in the weeks ahead. I hope you enjoy the reports.

19 thoughts on “Drozd BB machine gun – bulk fill! – Part 3

  1. B.B. This is unrelated to your Drozd review but I have read that the foam in gun cases isn’t good for guns. If true, why do the majority of dealers ship airguns in beautifully quilted, formed cases (nationally and foreign)? I have 27 airguns resting neatly in foam-lined cases and they seem fine. Your opinion would be appreciated, as always. Thanx.

  2. hi bb
    im the kid who asked you about the benjamin sheridan 392. i do believe i will be buying it in the nea future. i know you have talked about the importance of using pellgunoil for proper maintnence but i was wondering if there is anything elts i should know or do to keep this rifle in tip top shape. (pump, barrel, trigger)thanx and i apreciate your info

  3. I take a slight issue with the idea that “There is no rationale for rifling a BB bore, only a pellet or lead ball bore. The only rationale for using a rifled barrel in a gun meant only to shoot steel BBs is because you have easy access to rifled barrels.”
    If the ball has engaged in the rifling and is spining axially it is no longer free to spin on any other axis. Balls fired from a smoothbore may and often do spin sideways and take up a curved trajectory, especially if they slightly undersize in the bore and can “roll” within it. If oversize, the ball will be swaged into a slightly non-spherical shape and can then “tumble” in flight.
    This however is all theory – yould need two barrels identical except for the rifling, one with twisted rifling and the other with straight rifling, to check this out. Perhaps this has already been done? Has anyone heard of such an experiment?

    David, New Zealand.

  4. Lots of people suggesting blog topics so I thought I’d put my two cents worth in. How about a little biographical info, B.B. You have quite a following, but I think few of us even know what you look like. How about a couple posts on your personal history, how you got into shooting, etc. You have mentioned some facts as asides while discussing airgun topics, some army and childhood stories, but I for one would love a few posts just about you yourself, an overview perhaps. I would also love to get a rundown of what your own collection consists of, if that’s even possible. Just something to think about!

  5. David,

    There is no way for a steel BB to “take the rifling.” Steel cannot be engraved by rifling at the low pressure and velocity of an airguns.

    That’s why I said what I said.

    This has been tested inadvertently. Steel ball bearing have been shot in .177 rifled bores. They don’t move! They cannot be engraved by the rifling, regardless of how shallow it is.

    Before someone points out that many military bullets have a mild steel outer shell, let me point out that there is a world of difference between the 1,500-2,000 psi operating pressure of a spring air rifle and the 45,000 psi of a firearm cartridge.


  6. Turtle,

    I was not aware of this invention. It’s very impressive.

    Of course the multi-pump has been done many times before, but the valve looks new to me. And the efficiency it gets is really amazing!

    Thanks for sending that link.


  7. You’ve shown me much here, and elsewhere. glad you enjoyed it…I think it may become a trend. only firing off the top of a charge and pumpimg only to maintain Max and consistancy…outside the box and just so obvious.

  8. bb,im gonna get a new air rifle around christmas or so and i need your advice,i need a hunting break barrel .22 caliber with a lot of power.300$ or less and it will be used at no more than 55yds.i was thinking of a xisco b-30. thanks 4 any advice.PS what do you think of the rws350

  9. Xisico B30,

    I have no experience with this airgun, so I really cannot say. The RWS Diana 350 Magnum is a great spring air rifle, but it reguires a lot of technique to shoot accurately, as all breakbarrels do.

    Whatever you get, shoot it a lot and hold it as lightly as you can.


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