first impressions: new bighorn, new Vortex gen2 4.5-27 and new TBAC 5"

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taliv

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I had a new competition rifle build by Wade Stuteville which is pretty much an exact duplicate of my previous rifle (which will become a practice rifle), except I'm using the new bighorn action with the integral recoil lug. I also wanted to try the shorter Thunderbeast can (5" instead of 9") to save both a little weight and length. I got those a month or so ago and I've been waiting to shoot them until my new glass arrived, which just came this Monday. Since it's only Wednesday, I've only made 3 range trips with it so far and did break in (took 2 rounds), and zeroed (way too many rounds) and a box drill.

So here are a couple pics and first impressions, keeping in mind I have about 42 rounds on the gun.

bighorn2.jpg
bighorn2a.jpg

Vortex Razor HD gen II 4.5-27x56 with EBR-2C reticle
-It's heavy, but also short.

-The glass is fantastic. No distortion that I've seen so far. I tried to take some 'through the scope' pics of the vortex test chart, but between my crappy iphone, the sun and the .jpg compression algorithm the little lines on the target were completely whited out. My eyesight is pretty bad, so I was really only able to read the 3rd 'vortex' down on the right side. I could see the others but couldn't tell what they were.

-The knobs are very stiff. I expect they will break in a bit. (I hope)

-The clicks are very crisp. I like them.

-The parallax so far is better than any scope I've owned, including my S&B. The image is crisp and parallax free at the same setting (inexplicably not the case on some of my other scopes) and so far, that spot lines up with the markings on the turret. (rarely the case with my other scopes, especially S&B) But at the same time, it also seems sensitive to it.

-Spinning the diopter has that super high quality feel that an optic should have before it gets gritty from sand and all the crap that happens when you use them. But I haven't figured out what's going on with it yet. The reticle seems fairly clear over most of the diopter range, so I can't really tell if I have it set right or if it doesn't matter.

-I put the scope all the way forward in my spuhr mount, and the mount all the way forward on the rail, and I still had to hold my head back a little uncomfortably on the stock to get the right picture. Today I went to the hardware store and bought extra long screws and stuck additional spacers in the stock. (shown in 2nd pic)

-I like the illumination control a lot. and the illumination in the reticle is the way it should be

-The reticle is usable, but I sure hope they offer more choices in the future. On the positive side, it is labeled, is an appropriate thickness and isn't obnoxiously busy like the Horus, while still offering hold points for wind and elevation. The hold points aren't as nice as the MSR, but they're better than the H2CMR.

-I really like the way you zero the knobs, which is sometimes an engineering feat with zero stops and locking turrets. it is kind of like the USO EREK knob but not exactly. Essentially, you dial the knob to zero, then spin the cap off and turn a brass screw with a flathead screwdriver until it's zeroed. The upside is it is basically continuous, not discrete clicks, so you can put your zero EXACTLY where the bullet hits, instead of being stuck with the impact between 0 and .1 mil and having to remember to hold just a little high or low. The downside is nitpicky, but the markings you use for zeroing don't match the bullet adjustment at all. (they seem to be 2x what is written a .4 adjustment moved me .8 on paper, and when i needed .2 right, 2 marks moved me .4 right, and 1 mark moved me the .2 back to center). So where I used to be able to zero a scope with 1 round, adjust then shoot one to confirm and slip the knobs to zero, with the new vortex, I'm guessing, adjusting, guessing, adjusting, etc. but it's worth it to eventually get it exactly where you want it.

-also nitpicky, but it takes 3 tools to zero the knobs. a coin, an allen wrench and a narrow flat blade screwdriver. somewhat surprisingly, their solution was to invent a combo tool and include it in the box that does all 3. problem solved, i guess.

-looking forward to getting my cat tail / switchview lever soon. that will be very nice.

-as expected, the box test went pretty well. I'm going to say it tracks ok :)
I shot the bottom dot labeled 0 eight times, dialing up 1 mil after each shot. Then I dialed back to zero and shot the black dot on the bottom right 5 times (in order ABCDE), adding 4 mil left, then 4 mil up then, 4 mil right, then 4 mil down (which put me back at zero on the knobs. The cows were icing me on the 2mil dot. I think the box may be some sloppy shooting on my part, but it does seem to be leaning a bit left.
vortexbox.jpg



The Thunderbeast PSS
-shorter
-weighs less
-jury is still out on sound reduction, but so far it's right on the border of being uncomfortable to me, the shooter. so I swapped back to the 9" today to zero and shoot the box drill. i may use the 5" in matches where i'll be wearing earpro anyway, or use it on a SBR AR15 blackout. I like lightweight, but I like my hearing more.

Bighorn TL2 short action
-super slick and smooth (slicker than surgeon, imho)
-lots of updates since my old bighorn, too many to list here
-I think Wade's put together a pretty accurate rifle here. I haven't done any load development or anything and am out of practice. That last shot "E" is the only one that's more than 1/4" from the center, which isn't bad for 12 rounds.
 
Looks like it comes with a resolution chart. We use those for microfilm...the real things can be pretty expensive.
 
Very nice setup; looks like it performs alright too. ;)

.260 AI? I recall reading that's your preferred caliber to date, unless that was someone else...
 
Yep 260ai. Good memory bobson!

Hoofan actually vortex put a stack of them on a prize table last year with the stickers hats and patches. I picked it up there. I was hoping it would come with another. This one is actually adhesive backed but I used a stapler since I only have one and didn't want to waste it.
If anyone knows what the numbers mean please clue me in. (particularly the minus 1 and 2. )
 
Well in micrographics you obtain the resolution by finding the smallest set of lines which you can distinctly see are all separate lines, and do not seem to blend together. Then using the reduction ratio you can calculate the line pairs per millimeter.

Looks like the chart there is based on the USAF 1951 Chart
http://en.wikipedia.org/wiki/1951_USAF_resolution_test_chart

The USAF 1951 resolution test target consists of a pattern of 3 bar targets. Often found covering a range of 0.25 to 228 cycles/mm. Each group consists of six elements. The group is designated by a group number (-2, -1, 0, 1, 2, etc.) which is the power to which 2 should be raised to obtain the spatial frequency of the first element (e.g., group -2 is 0.25 line pairs per millimeter). Each element is the 6th root of 2 smaller than the preceding element in the group (e.g. element 1 is 2^0, element 2 is 2^(-1/6), element 3 is 2(-1/3), etc.). By reading off the group and element number of the first element which cannot be resolved, the limiting resolution may be determined by inspection.

Looks like 1951 USAF goes by the largest group you can't make out, instead of the smallest you can. (Microfilm resolution uses an ISO 3334 NBS 1010a/ ISO #2 target).

Obviously distance will matter, and it seems that the distance to the target should correspond to the focal length of the optic(I am finding a bunch of different numbers via google...)
 
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wow, very interesting! thanks hoofan!!

what's the focal length on a variable power optic with adjustable parallax/focus?
 
I guess a scope would actually have multiple focal lengths, for the ocular and the objective lense. Apparently the magnification level is the focal length of the Objective divided by the focal length of the ocular lens. Most of the stuff I am finding via google is talking about camera lenses with only a single focal length...and a single magnification.

Doing some more searching it seems that the distance can be factored into the equation to determine resolution

http://www.cloudynights.com/topic/36040-binocular-resolution-testing-wusaf-charts/#entry467142

http://fmgpublications.ipaperus.com/FMGPublications/GUNS/GUNS1209/?Page=29

http://www.thefreelibrary.com/Can+you+see+it?+Resolving+power+matters.-a0241516863

seems the forumula is

Angular resolution in arcseconds= 8,121 / (D x LPM)

where D is the distance from the target in inches and LPM is the line pairs/mm value taken from the chart
 
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seems the forumula is

Angular resolution in arcseconds= 8,121 / (D x LPM)

where D is the distance from the target in inches and LPM is the line pairs/mm value taken from the chart

ahhhhhh the light goes on! and suddenly the LP/MM value used to describe night vision makes more sense. thx again!


yep its an atlas
 
couple more pictures of both rifles together. old bighorn and new bighorn. the USO 5-25x is on the old bighorn. barrels are same length, just camera perspective that makes the one in front look longer.


bighorns1.jpg
bighorns2.jpg

it's still shooting pretty good up close. 6 rounds in the 3.5" head of the target below from 520 yards looks pretty good. But I haven't hit much past 1000. the round outside the group low left shot from past 1000, but i was aiming at the body haha. and the rest weren't even close.
8-15-520y2.jpg
 
Guess you found what you like in a stock. Who makes it?

it's still shooting pretty good up close. 6 rounds in the 3.5" head of the target below from 520 yards looks pretty good. But I haven't hit much past 1000. the round outside the group low left shot from past 1000, but i was aiming at the body haha. and the rest weren't even close.
Is there some sort of rifle voodoo to attribute this to? I mean in regards to the shots being "off" at further ranges with it being a brand new rifle.
 
http://kmwlrs.com/



dunno, i haven't figured it out yet. but it's prob because i don't know my velocity on the new bbl yet and am just guessing at my dope :) and where i'm shooting it's really hard to see misses
 
I see :p

The Sentinel is a nice stock. I'm not expert, ofc, but integrated DBM seems like an awesome feature.
 
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Doesn't seem right to me that the Vortex moa adjustments are incorrect? Is this typical of their quality? I really wanted to get a Vortex scope next.
 
you mean when adjusting with the screwdriver? those aren't really a big deal. and they are covered by the caps so you don't use them when shooting. definitely wouldn't keep me from buying another one. heck, i may even be using them wrong or something.
The marks you use when shooting are spot on.
 
My question is this, if you knew based on the estimated range to target you wanted to raise your POA by 8 MOA by counting clicks on the scope, would you have to move what the scope calls "4" because you said it moves double what it is marked as? That seems to be what you wrote in the OP.
 
oh no, not at all. besides the fact that it's in mils :)
i was talking about the marks you use to zero it. when shooting, the knobs have very clean "clicks" and they track just fine.
when zeroing, you take the knob cover off, you can see some additional marks underneath it used for zeroing. you undo the set screws and turn with a flat blade screwdriver to move the zero. you dont' feel any clicks at all; you can turn it smoothly any distance you want.

i'd take some more pics of the knob but it's raining.
 
taliv, what's the skinny on bolt fluting? It looks like your newer rifle has shallow flutes, while your older one doesn't have any at all.

In regards to advantages, I'm guessing it's mostly for aesthetics, but is that the whole story? I can't imagine you'd see more than 3-4 ounces of weight reduction even from the deepest bolt fluting.

As far as disadvantages, I've heard of bolt fluting allowing for crud get into the action. Is that a legitimate concern? Are there any other potential detriments?
 
honestly, no opinion on it. the new bighorn has it; the old one doesn't. i didn't specifically ask for it
 
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