DarkLordOfOptics
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BTC-50 Picatinny Mount wrap-up
October 03, 2022
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I talked a few days ago why I am so fond of the relatively inexpensive and not very high end BTC-50 clip-on from Burris. A big reason for the fondness is the mount. The original post is here.

I took a couple more pictures to better illustrate what I mean.

First of all, here is the bottom of the mount. Burris strategically placed the recoil lug all the way toward the back, so that you could have the clip-on as far forward on the upper receiver as humanly possible:

Note also that Burris' QD mount is quite robust. I do not think I have ever seen this arrangement with a stack of leaf springs with QD mounts before, but I have a couple of version of it and they do work well. While I am sort of on the record that I generally prefer normal non-QD mounts, on a clip-on that gets moved around a lot, having a QD lever is quite nice.

Here is a picture of the BTC-50 with the Burris RT-3 prismatic. Ignore the slight height mismatch. The mount came with two spacers and I think the shorter one would be better with RT-3, but I nee dto doule check. Either way, th emismatch does not really get in the way much at all. I've used that way simply because I was too lay to look for the other spacer.

Note that with the diminutive RT-3 3x prismatic, there is enough space on the top rail for a back-up iron sight (only there for illustration), RT-3 prismatic and BTC-50 clip-on. There is still enough rail space in front of the clip-on mount to potentially add an offset red dot sight if I am so inclined. The FOV of the RT-3 matches horiontal FOV of the cip-on nearly perfectly.

The rifle I am showing this on is my old 6.5Grendel that I really like for hog hunting. It is just a great general purpose rifle and I have had it for a long time. It has an old Lancer handgard on it where the aluminum handguard mounting (the thing right on the front of the receiver) is attached with permanent loctite. In order to swap it out for a more modern handguard, I would have to heat it up significantly. I am not hugely motivted to do it, simply because I have a lot of other rifles and because sometimes it is best to not try to improve what is not broken. This is the same rifle I shot that hog with last year:

That time I used SAI 1-6x24 LPVO with a Leica clip-on attached to the objective. While it worked well, I generally prefer to mount the clip-on on its own base when I can. However, since this handguard does not have a top rail, my options are limited.

Here is the same rifle, this time with a much larger prismatic: Elcan Specter OS 4x. Because of how the Elcan mount is designed (external adjustments), it takes a lot of space on the rail. Still, I have enough space to mount the BTC-50 in front of it. In this case, there is no rail space left for anything else, but I have a piggybacked RDS on the Elcan, That takes care of the redundancy issues and there are good reasons to use piggy-backed sights with Ecan Specter sights.

I left the RT-3 on a different upper in the picture to give a scale for the size comparison. These new micro prismatics are remarkably compact. RT-3 is essentially have the ength of the 4x Elcan. Now, you can't compare them optically, but the money and the size, I am really impressed with RT-3, PA's SLx Micro 3x and Vortex' Gen2 3x Spitfire. I suspect that Burris and Vortex are made by the same OEM, while PA is made in a different factory, but I am not sure. It really does not matter. They are essentially the same size, however, and FOV is very close (Burris is slightly wider) so they would all match the BTC-50 clip-on very well.

The FOV of the higher magnification Elcan is a little narrower. BTC-50 has a 400x300 image sensor, so instead of seeing 400 pixels horizontally, you are seeing 300. That's pretty workable. In terms of mounting height, they are matched nearly perfectly at right around 1.5" above the top rail.

Now that I think about it, I have a Mepro X4 here somewhere that has wider FOV than the Elcan. Perhaps I should try it as well. It is essentially a copy of the 4x ACOG with a different mounting system. It might be an even better match than the Elcan.

For the time being, I will probably keep the BTC-50 on the Grendel in front of one of the prismatics. I need to take this gun to Texas and see if it brings me luck again.

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Burris XTR PS Wrap-Up

The first Burris XTR PS scope I got my hands on landed here in the beginning of March.
That means I have been messing with this design for a bit under four months. That does not quite qualify as a long term test by my standards, but it is a fair amount of time and quite a few rounds shot, mostly 5.56 and 308.
I have both of the models of XTR PS and both work well.
https://alnk.to/3U3cZEC

For matches and such, I would lean toward the 5.5-30x56 version, but for general purpose use, the smaller 3.3-18x50 model does have an edge. You can shoot a match with it, take it hunting in the mountains or slap a thermal clip-on in front to go shoot some pigs. While not light weight, it is a very flexible design owing to moderate size and mid-pack magnification range.

As I said in the video, I think XTR PS is a meaningful step forward in simplifying how we shoot at distance.

I will provide occasional updates as I continue using the scope.

00:26:02
5x Prismatic Wrap-up

This is not the end of my commentary on 5x prismatics, but it is a wrap for an unintentionally very long term project I had. I spent an unhealthy amount of time evaluating these four prismatic riflescopes:
Element Immersive 5x30 https://alnk.to/gzXEPUr
Swampfox Sabre 5x36 https://alnk.to/aAPTubq
Vortex Spitfire Gen2 5x https://alnk.to/3co4hVD
Primary Arms SLx 5x https://alnk.to/2jOhnT7

Two are large prism designs. Two are small prism designs.

The order in which I list them above corresponds to the image quality, from best to worst, although there isn't a ton of difference between SLx and Spitfire Gen2. Purely on the merits of resolution, Sabre is comparable to them as well, but much wider FOV and forgiving eyebox does put it a step above in terms of performance (at the expense of about a pound of weight). Element Immersive 5x30 is a different beast optically and it should be at a higher price at which it sells. It resolves better, has higher contrast and widest FOV of the bunch. Side-focus adds ...

00:16:40
Blast From The Past: Millett ZoomDot RDS

I dug this thing up purely by accident. It has been a long time since I used it for anything, but I am thinking I should, especially as I work on a magnifier video.

MIllet's ZoomDot was a unique red dot sight that had auto brightness and variable dot size from 1MOA to 10MOA.

Early ones, like mine, were made in the US. Millett had some aspirations of selling these to the US military.

I do not think they got very far, then the company was bought by Bushnell and essentially shut down after a little bit. At some point, the manufacturing for the ZoomDot moved to China and it was not really the same.

00:05:44
Independence Day, 2025

Publishing a "Happy Independence Day!" a day after independence day is probably bad form. It is also bad for posting affiliate links. Everybody and their grandmother is having discounts and I am not posting any links. To be honest, I do not particularly like posting general links and I simply did not have time to dig through everything and come with specific product links.
Still, if you plan to be buying something from one of the retailers I have an affiliate account with, I would appreciate it if you were to start with one of my links listed in the FAQ: https://darklordofoptics.locals.com/faq

I started writing the more substantive part of this post yesterday, but got sidetracked with thinking about the origin of the ideas that make America and ran out of time. I was only able to get back to it now. I suppose, better late than never.

We live in the world that, as far as the details go, is dramatically different from the world of the founders of the United States.

For the majority of this ...

July 04, 2025

This is a good deal:

https://alnk.to/c0a5bf9

Hi Ilya,

For many years I have been looking for a new spotting scope that has an FFP mil reticle for accurately calling corrections.  I have the angled version Kowa TSN-883 with 20-60 eyepiece that is great except it doesn’t have a reticle so the correction calls are not as precise or as fast as they could/should be. An ideal reticle would have a crosshair or L with a grid off of center but a simple crosshair, L or a tree would be sufficient.

I really like dual focus (can settle for single focus) that uses the small knobs that rotate very easily/smoothly so the scope can be focused on a v-bag while staying on target when it's impractical or a hassle to use a tripod. 

I also like an angled eye piece because it’s easier to establish a comfortable position in many situations as compared to straight eyepiece where you need to be directly behind the scope.  

I haven’t found anything with these attributes with max magnification and glass quality at least “good enough” for clear ...

A morning with a chronograph

When I tell people that I am using Hornady's factory ammo for matches, I get occasionally surprised looks.  Occasionally.  Most of the time, I get fairly condescending looks from handloaders who would not let a factory round pollute the chambers of their precision rifles if their lives depended on it.

To be fair, if I had the time, I might be reloading as well.  I might be able to do better than modern factory ammo, but the truth is that I am not a quarter MOA shooter, so a lot of that would be lost on me.  The UKD matches I fidn most interesting can be done by a competent shooter with a 1MOA gun.  I am working on that first part.  I reload when I have to, but if I can get factory ammo that's not outrageously expensive and that shoots well, I will go with that every time.

I looked around and realized that I have about 600 rounds of Hornady 147gr 6.5CM factory ammo from two lots.  400 rounds from one that I will use during the match later this month.  The remainder I will likely use up practicing prior to that.

I woke up early and snuck out to the range while my family was still asleep earlier today.

I set up in the 100 yard tunnel we have.  I took my four shots to zero with the lot I plan to use for the match.  Then I fired a six shot ~0.7MOA group.  That's accurate enough for my purposes.

Here are the chronograph results:

It is slow, but accurate and consistent.

Then I shot a five round group of Hornady 147gr ammo from the other lot.

Both of those lots are not too shabby for factory ammo.  POI was within 0.2mrad between the two lots, all laterally.  

 

I had some other ammo on hand, so I fired two five shot groups with Berger 144gr hybrid target ammo and Sako TRG 136gr.

Here is what I got for five rounds of Berger:

That's not a ton of statistics, but it is a data point.  The group was ~1.1MOA

 

Here the data for the Sako TRG 136gr ammo:

This ammo showed some mild pressure signs, but not too significant.  

Again, this is not a ton of data, but Hornady is looking pretty decent here.

I'll repeat the zero retention and consistency tests a couple more times between now and June 18th when we head to Wyoming.

I might pick up a couple more boxes of Hornady 147gr from a different lot to get some more data.

More to come.

 

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First PRS Match is behind me
High Noon at Del Norte

My first PRS match is officially behind me.  It was, I think an officially sanctioned regional PRS match at the shooting range called Del Norte about an hour from me (just east of Rio Rancho).
As I discussed previously, rather than using the rifle I originally prepared for it, I ended up having to change gears at the last moment and slapping a 5-25x56 Tangent on my daughter's 6ARC MiniFIx.  A lightweight 16" Proof barreled 6ARC is not an ideal set up for PRS competition, but, in the grand scheme of things, the rifle did hot hold me back at all.  I had a couple of weights that fit the Q-cert handguard, so I slapped them on there as well, which got the rifle to right around 12lbs.  The balance point was almost where I want it, but not quite.  In all other ways, this was a very handy rifle to shoot.  I am actually thinking of getting a couple more weights that I can stack on it (Sawtooth weights are stackable), so that I can shoot some future local matches with it.  It shoots Hornady's Black 105gr ammo very well (it also shoots 108gr ELD-M and 103gr ELD-X well, but I had a larger supply of Hornady Black ammo on hand).

It chrono'ed pretty consistently for factory ammo.  Here are the measurements for a 20 shot group.

If I were to take out the fastest shot, SD drops down to 8fps.  

In terms of wind performance, it is a 5mph rifle, so slightly better than the 308 ammo I was going to use originally, but not as good as the 6.5CM that was my intended match rifle for this year (we make plans, but then life happens).

I do have to admit that I really enjoyed shooting the match with the MiniFix.  So much so, that I am seriously thinking of building another one for myself, since this rifle is technically my daughter's.

The closest shot we had was a bit over a couple of hundred yards.  The furthest was around 1150.  That was a bit challenging for the 16" barreled 6ARC, especially since the terrain there is tricky and wind is doing strange things.  Morning was relatively quiet wind-wise, but then the wind becamse gusty with changing directions.

It was a one day match with about 30 shooters (six squads) and ten stages.  The 17 year old kid who won the match was in my squad with his dad.  Apparently he is on the US team, so it should not be surrpising that he won.  He was very good.

Overall level of the shooters in the match was quite good.  I really was not sure what to expect.  Somewhat paradoxically, the only matches that I have shot in so far are the much larger two day NRL Hunter matches.  In those, I am just out of the bottom third in terms of skill level.  In this match, it was pretty much in the same spot, I think.  

The terrain was a little bit like Cameo, I think (I have been there, but not shot there), with some angle changes and sufficient vegetation to make getting on target occasionally troublesome. 

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Getting back on the horse, little by little

My original plan was to do a livestream on Thursday of this week, but I think I'll push it out to next week.  A few days at home is doing wonders for my recovery, but my voice is still not quite there.  I do not think any of you are looking to listen to me cough for two hours straight.

Also, I am going to try to shoot that local PRS match this coming Saturday, so doign a livestream next week after the match is likely to be more productive.  It is my first one, so I fully expect that I will screw it all up.  It should be a good learning experience.  I do not have a dedicated PRS rifle and I am not looking to set one up jsut yet.  If I like it, I'll put something together, but as far as competition goes, my focus is really on UKD matches like NRL Hunter, Competition Dynamics, etc.  My 6.5CM is not back yet, so I'll just shoot it with my 308 FIx.  It is not ideal, but it will do just fine for my purposes.  I am in no danger of winning anything either way and this will stress my ability to read wind.  A secondary purpse here is that I am not 100% certain what rifle I will take on a mule deer hunt with later this year, but it will be either something new to test or this 308.  Now that I think about it, the 308 is going with me regardless either as a primary rifle or as backup.  The rifle shoots, so if I miss, I know it is on me.

For the match, I have Burris XTR PS 5.5-30x56 scope on the 308 Fix.  I think the way they did the heads up display in these is a meaningful improvement over conventional riflescopes.

https://alnk.to/d3EjPHC or https://alnk.to/8iVRlGN

Optically, I think XTR Pro is a little better, but the EO integration in the XTR PS is, I think, in advantage.

In parallel, I am looking at the replacement AAC ammo (they replaced the faulty ammo and I have chrono results on it) and testing the optics of the 40mm scopes in parallel.

 

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