Gunwerks G7 BR2 Rangefinder Review

[jmden]

i dont understand all the beam width talk and frankly dont even care to.

Beam divergence is a key factor in rangefinder performance. Your Swarovski has a round shape beam with a larger beam divergence (wider angle so it gets bigger [the beam width, that is] the further away from you it gets. A wide, round beam and cause problems quickly, especially on flat ground as the bottom of the beam could be ranging at 500 yds and the top at, say 800 yds with your target likely somewhere in the middle and good hits on the target tough to get.

I think many folks like a small beam (narrow angle so the beam doesn't get so big way out there so you can be more confident the beam is on your target and not a bunch of other stuff) that is retangular with the horizontal dimension longer than the vertical dimension--more in line with the shape of the body of an big game animal minus the legs and head. But small beam divergence (narrower beam than wider) is, I think, a good thing in most instances.

http://www.swarovskioptik.us/upload/media/media/26/2008_06_03_LG_TD_2008_266x1951[1162].pdf

Beam divergence on the Swarovski Laser Guide is 2 milradians and the beam shape is round as I understand it from several past conversations here.

 

[jmden]

Mr. Aaron Davidson-

What is the beam width divergence of the Gunwerks G7 BR2?

Lots of discerning customers won't spend $1600 without knowing this specification.

Thank you.

gseven - G7 BR2

2 x 4 milradians. So, bigger than the Swarovski Laser Guide, which is round shape and 2 milradians. Not sure which dimenion is horizontal/vertical on the G7. Pretty big divergence, but I'm not sure how often these guys plan on shooting much beyond 1K. This has been one of my main concerns with this unit. Perhaps the near/far targeting mode can help with this, but I just don't see when a large beam divergence is ever going to be a good thing. Until I can afford the new Swarovski bino/rangefinder combo, I'm sticking with the smaller divergence and rectangular shape beam that Leica has.

http://www.6mmbr.com/rangefinders.html

Good article that discusses beam divergence/shape issues a bit showing what happens with this, although a bit out of date. Note the 2.5 milradian width x .5 milradian height of the Leica beam and the issues later on with the large beam divergence of the Swarovski Laser guide.

http://www.eurooptic.com/PDF/Swarovski-EL-Range-Training-Document.pdf

Page 6 of this Swarovski Training Document for the EL Range shows a beam divergence of 1.5 milradians by .5 milradians. Now that is pretty doggone good beam divergence and shape.

Not sure what the Vectronix units are doing...

 

[Shawn Carlock]

I asked them about beam div when they send me the G7 and I read the specs. They talked of the programing in the RF to be able to detect beam strength from the multiple pulses given off by one firing of the unit. It then gives you the strongest feed back range, this is usually the most verticle target (side of the animal). Signals with less strength are culled in favor of the strongest signal. It is my understanding that the large beam div was made on purpose to accomodate this target strength technology. I was somewaht skeptical but what they told me made sense. I may have not made my testing clear because the large beam div was a concern to me as well. I ranged probably a hundred targets from rock faces to stumps on a nearly flat ridge top (going down the ridge). Out to 1400 yards there was never more than a yard or 2 difference between the G7 and the Vectronix. This really suprised me as I thought the results would be much different. Now at longer distances say 1700-2000 yards there were some diferences in range but this is not the operating zone of the G7 nor was it ever intended to be. Out to any distance the G7 will give you a balistic solution it stayed right with my Vetronix. I used it all hunting season in the locations I thought the shooting was going to be under 1400 yards. Now I don't have quick access to rolling sage flats so was not able to test there but I tested in locations that would have given a Swaro or Leica fits due to the flat nature of the terrain. My opinion is still the same if you are a 3 digit shooter or even out to 1200-1300 yards the G7 has a serious speed advantage and I could not see where my Vertonix/Recon/Kestrel/ ACI setup had even a single advantage over the G7. I won't be getting rid of my other setup anytime in the future but I have left it at home in favor of the G7 quite a few times.

 

[jmden]

I asked them about beam div when they send me the G7 and I read the specs. They talked of the programing in the RF to be able to detect beam strength from the multiple pulses given off by one firing of the unit. It then gives you the strongest feed back range, this is usually the most verticle target (side of the animal). Signals with less strength are culled in favor of the strongest signal. It is my understanding that the large beam div was made on purpose to accomodate this target strength technology. I was somewaht skeptical but what they told me made sense. I may have not made my testing clear because the large beam div was a concern to me as well. I ranged probably a hundred targets from rock faces to stumps on a nearly flat ridge top (going down the ridge). Out to 1400 yards there was never more than a yard or 2 difference between the G7 and the Vectronix. This really suprised me as I thought the results would be much different. Now at longer distances say 1700-2000 yards there were some diferences in range but this is not the operating zone of the G7 nor was it ever intended to be. Out to any distance the G7 will give you a balistic solution it stayed right with my Vetronix. I used it all hunting season in the locations I thought the shooting was going to be under 1400 yards. Now I don't have quick access to rolling sage flats so was not able to test there but I tested in locations that would have given a Swaro or Leica fits due to the flat nature of the terrain. My opinion is still the same if you are a 3 digit shooter or even out to 1200-1300 yards the G7 has a serious speed advantage and I could not see where my Vertonix/Recon/Kestrel/ ACI setup had even a single advantage over the G7. I won't be getting rid of my other setup anytime in the future but I have left it at home in favor of the G7 quite a few times.

Thanks, Shawn. That insight is valuable.

 

[Autorotate]

gseven - G7 BR2

2 x 4 milradians.

Thanks for the link...that must've just been posted...as I checked the website prior to making the post.

 

[dstewart51]

It would be a huge plus if the ballistics calc would work in milliradian.

 

[yobuck]

Of course lighting conditions and other factors affect the rangefinders ability to give a reading, we've all seen that with all of them. But their ability to give us a number is not what I was referring to at all. Their ability to give an accurate number on flat ground when the landscape or vegetation is more reflective than the target is what this is about.[/QUOTE]

well that may be true, especially for those who do primarily hunt fairly flat terrain.
i will say this in defence of my swarovski.
over the last 2 years ive made two five day trips to montana for prairie dogs.
the terrain was fairly flat where i hunted and had typical prairie dog surroundings.
i didnt attempt any readings beyond about 650 yds. the sun was bright enough that i came back with a burn. i cant remember a single incident where my unit didnt give satisfactory results. as the distance increases however the realibility of the unit decreases. on some days i cant get a reading on any target regardless of size. it could be a rock as big as your car. nothing comes up. ive tried everything including a tripod. when it works it works well.
but on certain days it wont work at all on targets over about 800 yds.
ive compared its accuracy with my barr&stroud and wild. the comparisons are close enough for me and usually within a few yards at a 1000 yd range im a member of.
so again, you guys debate the technical stuff. all i want is a unit that shows distance and shows up
for work every day. i can handle the rest.

i would like someone to respond to my earlier question about registration.
i am very serious about aquiring a new rangefinder. but the idea of registering it dosent sit well.
do the vectronix and or this unit require registration?

 

[Scot E]

It would be a huge plus if the ballistics calc would work in milliradian.

Agreed!

 

[Too Much Fun]

I've been waiting for feedback on the G7 BR2 RF...should have known it would turn into a "chevy vs ford, not to leave out the dodge" Well, now that the testosterone levels have finally come back into "range", the information gathered and shared has been informative as well as impressive! Thank you Shawn, for the extensive research and WELL written article. Some good points shared by ALL!

Is this device a battery eating beast...??

Mark

 

[bigngreen]

How is it holding up in sub zero weather with all the electronics on board? The whole system I've been using has done well in my hunting conditions except for the Dell PDA which has to live in my shirt pocket. The G7 would be a little big for a shirt pocket

 

[Shawn Carlock]

Battery life has been really good, however I have not had a chance to really run it out in sub zero weather.

 

[Too Much Fun]

Battery life has been really good, however I have not had a chance to really run it out in sub zero weather.

Sounds like a great product.

 

[SBruce]

It is my understanding that the large beam div was made on purpose to accomodate this target strength technology. I was somewaht skeptical but what they told me made sense. I may have not made my testing clear because the large beam div was a concern to me as well. I ranged probably a hundred targets from rock faces to stumps on a nearly flat ridge top (going down the ridge). Out to 1400 yards there was never more than a yard or 2 difference between the G7 and the Vectronix. This really suprised me as I thought the results would be much different. Out to any distance the G7 will give you a balistic solution it stayed right with my Vetronix. I used it all hunting season in the locations I thought the shooting was going to be under 1400 yards. Now I don't have quick access to rolling sage flats so was not able to test there but I tested in locations that would have given a Swaro or Leica fits due to the flat nature of the terrain. My opinion is still the same if you are a 3 digit shooter or even out to 1200-1300 yards the G7 has a serious speed advantage and I could not see where my Vertonix/Recon/Kestrel/ ACI setup had even a single advantage over the G7. I won't be getting rid of my other setup anytime in the future but I have left it at home in favor of the G7 quite a few times.

Thanks for that feedback Shawn. That's positive info. I am glad you had the concern too.

You mention the most vertical target should give stronger readings, so I would like to run this by you: One of the tests that I've done gives rangefinders a real fit. Both my Leica 1600 and 1200, and a friends Swarovski and Vectronix PLRF10 failed this test, only the distance they began failing at was greater with the Vectronix. The Leica and Swaro failed at 500 yds or less, the Vectronix failed at 800 yds but was closer to being accurate, it was kinda splitting the difference and only giving a 10 yd error.

Here's the situation, I have a 12" diameter AR-500 plate hanging 20 yds directly in front of a small clay cutbank. The cutbank is a few feet tall and is probably about 15 yds wide. All these rangefinders will read the cutbank and not the plate, the plate is very very close to being perfectly perpendicular to the line of sight, and the cutbank is really not all that vertical, a person could walk up it. The only way I can get them to read the plate instead of the bank, is to hang a reflective tractor triangle on the plate. We know that a 20 yd error at 780-820 yds is over 5" of vertical even with the big 338's and 300 grn bullets. And I don't see any reason it couldn't just as easily become a 50 yd error in the right circumstance.

This is a test I'd like to see the G7's performance on. The country I live in and hunt in is relatively flat, but is full of these little cut banks and rock outcrops and sagebrush patches and of course the game that inhabits this country is usually not as big as these natural features are. Some places here the deer can stand up in the Sage and all we can see is their neck and head. Do you have any thoughts on this that you'd care to share?

Again, thanks for the review. I am really interested in this units performance in country that is relatively flat, and if the unit will give priority to readings from the center of the reticle rather than the most reflective or bigest things inside the whole beam. I can see how the beam divergence wouldn't be nearly as big an issue.

 

[AaronSkipDavidson]

First of all, I would like to thank Shawn for a very accurate portrait of the G7 BR2 product.

I've always been interested in the beam divergence debate. Frankly, I find the arbitrary concept of smaller is better very similar to the bigger is better argument in the cartridge selection debate. The intended application must be considered, and an understanding of the underlying science. I've always loved the comparison of the terminal velocity comparison of a 30-378 wby with a 165 Barnes TSX vs the 7mm Rem Mag and a 168 Berger VLD.

To have a discussion about the merits of beam divergence without discussion signal processing technology or FCC Class one requirements is fruitless.

SBruce's function test is a good idea. If there is no standard to judge by, test it. I'm happy to put one up, I doesn't do me any good to do it and report it. I'm not certain it passes, but from my experience with the measurement mode (Nearest in this case), I have high expectations.

I think a brief understanding of signal processing options is covered in the article at 6mmbr:

Laser RangeFinders

Look at the information about pulsing systems and target priority. The G7 works because the beam is bigger and you can remain on target even without a rock steady rest. The bigger beam allows more power output while staying class one eye-safe. The most other RFs send out a burst on firing, the G7 will continuously sample and add signals to detect targets for up to 5 seconds. Target priority is the key to difficult shot situations. We see it, detect it, and the measurement mode allows us to select which one you are after.

For example, if we selected N for nearest mode (one button press to switch between measurement modes) we would return the hanging target, not the hillside behind. If it did identify multiple viable targets, an indicator shows it, and the different ranges are shown. You will have the information available that you need to make the shot.

The device uses a 905nm laser diode. The expensive models achieve better ranging performance because they use a 1550nm diode which is more expensive and is not limited on power output to remain eye safe.

Bottom line, this device was configured to work with nearly any scope turret or reticle system (sorry Mrad guys) and give a sophisticated ballistic solution with a single button press. Very precise and very easy to use.

The ballistic calculations match the G7 program calculations available here on this forum or at our site gseven - Home Learn to use the Trajectory Validation feature and the G7 drag model standard (if necessary) to fit field performance data. If you like the calcs online, the RF matches exactly. By the way you can use your G7 ballistic coefficient in the RF if you prefer.