by B.B. Pelletier

Before we begin, there are 3 new articles up, and they’re about accuracy. The September podcast is also live.

Part 1
Part 2


The big Browning is powerful, but hard to cock.

Today, I’ll do a second velocity test of the Browning 800 Mag. In the first velocity test, done in Part 2 of this report, the velocities I recorded were considerably slower than those other shooters had seen. I was met with a large outcry to shim the breech seal and test again. That work, coupled with my extremely busy schedule (I’m in New York, filming more episodes of American Airgunner right now) made me put this project on the back burner until now.

The first thing I did was remove the breech seal, which in the Browning is not an o-ring but a formed seal, much like Weihrauch rifles have. You can see in the photo that it’s much deeper than an o-ring, so of course the groove it fits into is also much deeper. I was fortunate to still have a couple steel shims Vince had sent me for the Diana 27 breech seal project, so all I had to do was drop one in the channel and reinstall the breech seal.


The breech seal is a formed seal–not an o-ring. The thin steel washer I slipped under the seal raised it up just a bit.

To keep things the same, I tested each pellet from the first velocity test in the same order as last time. You may not recall that in the first test I actually tested the gun twice, because the numbers started decreasing after some testing had been done. The dieseling was diminishing significantly, so I had to retest the first pellets to see what velocities they really produced.

Gamo Match
Gamo Match pellets produced an average velocity of 450 f.p.s., with a spread from 412 to 469. In this test, they averaged 651 f.p.s., with a spread from 644 to 656. That’s an increase of 201 feet per second, which is a dramatic change. Note, also that the velocity spread dropped from 57 f.p.s. to just 12. So, the higher breech seal stabilizes the powerplant.

RWS Basic
RWS Basic pellets are lightweight, at just 7 grains weight. They averaged 455 f.p.s. in test one, with a spread from 434 to 471. In this test, the average increased to 665 f.p.s., and the spread was from 654 to 681. Again, the velocity jumped 210 f.p.s. and the total spread for 10 shots dropped slightly from 34 f.p.s. to 31.

Gamo Raptor
This is where the test got squirrelly. Some Raptors fit extremely tight and others fit loose. So they vary in size by a large margin.In the first test, Gamo Raptor pellets averaged 456 f.p.s. with a spread from 347 to 510 f.p.s. I knew something was wrong just from those numbers. In this test, the average was 723 f.p.s. and the spread went from 668 to 770. So, the velocity jumped up by 267 f.p.s. and the huge spread of 163 f.p.s. dropped slightly to 102 f.p.s. Once again, we see that Gamo Raptors are not meant for the Browning 800 Mag pistol.

700 f.p.s. air pistol?
One reader asked me if this would have been the first pistol I ever saw top 700 f.p.s., if the breech seal had been working correctly in the first test. I said I wasn’t sure, but here’s the deal with that. If the Pittsburgh Steelers had not won the 2009 Super Bowl, the Arizona Cardinals would have. You can always play “What if?” games, and it doesn’t matter. What matters is what actually happens. Yes, the Browning 800 Mag is a legitimate 700 f.p.s. air pistol, when shooting non-lead pellets.

800 f.p.s. air pistol?
Someone also asked me to test the pistol with Crosman Silver Eagle hollowpoints, which are the undisputed velocity champs of the lead-free set. These pellets fit the breech much better than the Raptors, though some did fit pretty tight. They were not tested in the first test, so all we have is the results of this test. The average was 846 f.p.s. and the spread ranged from 823 f.p.s , to 869 f.p.s. That’s a spread of 46 f.p.s. You can’t get these 4.8-grain pellets anymore, but they do show the pistol is capable of velocities over 800 f.ps. That’s not just dramatic–it’s phenomenal! And it shows clearly that the Browning is more powerful than the RWS LP8

The LP8 averaged 755 f.p.s. with Silver Eagle hollowpoints. The 800 Mag was 91 f.p.s. faster! So, that breech seal that I shimmed made one heck of a huge difference in performance.

Cocking effort
Toward the end of this velocity test, I checked the cocking effort, again. In the first test, it measured 47 lbs. on my bathroom scale. This time it measures 45 lbs. It’s wearing in, but no big dropoff as some people had hoped.

Next, we’ll look at accuracy, which matters even more than velocity.