SIGforum.com Main Page Mason's Rifle Room A case for the general-purpose carbine, and challenging the sighting paradigm.
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If you are interested in what works for a variety of target presentations, under stressful conditions, I recommend you go too a good regional or national level 3 gun match and put your theories to the test. If it will gain a fraction of a second, a top competitor will be doing it. | |||
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This is not necessarily about gaining fractions of seconds; it's about versatility across a broad spectrum of circumstances with one rifle. I haven't been to a match; there aren't any within a practical distance, and committing days at a time (or even just one entire day) to travel to and participate in such a thing isn't in the cards for me. I can only assume that night matches are not common, so would a top competitor at a regional or national match have to consider performance of night optics? Are silencers common at these matches? Are SBRs common? Perhaps not, considering the legalities of competitors travelling with NFA items. I imagine that the majority of competitors rigs are 16", lightweight, wearing an LVPO, perhaps with a piggyback or offset MRDS, though an acquaintance who does compete says that he just point shoots the near targets. I suppose it all depends on the "class" you're competing in, perhaps? Each class likely has a different ideal setup, and competitors cater their gear to give them advantages in each class. This thread is about the potential of a rifle "system" that can be effective across multiple "classes", without breaking into "long range" (hence the 400m limit). Like I said, I can only guess as to what the matches are like. Please set me straight, if I am way off base. I know a lot of contemporary fighting rifle theory is influenced by competitive shooting, and I know these matches have a lot more to offer than a square range. I do my best to create circumstances for myself, and those I shoot with, that are more diverse than square range beep speed drills. As an example, only a couple days ago, a friend and I spent some time in the woods, setting up what you might call a "lane". The shooter is travelling and is presented with a pop-up target at about 25M; he engages and turns back the way he came, following the lane cadre to the next shooting point. The next point has a terrain feature and large tree trunk that can provide cover/support, while the shooter scans a relatively small sector for a six inch red plate at about 75M; that sucker isn't easy to find. After locating that target, and hitting it, the shooter will need to hit it again, to prove he's got it dialed in. The cadre will then guide him to the final shooting position, where he'll scan a sector for a 10" red plate at about 100M; once he finds it, he'll engage it to the same standard as the first. This is an example of circumstances I create, to test myself and my equipment. Not quite as elaborate as a curated match, but a bit more diverse than the typical square range session. On the topic of optics, and back to the core discussion: the 25M pop-up mentioned above is something I'll shoot on 6x, because that's where I leave my scope, in a "patrolling" context. Leaving it on max magnification enables the shooter to observe his surroundings effectively, quickly. The way I see it, so long as I lack a MRDS, I am engaging a "surprise" near target by point shooting, or point shooting as I get into the glass, ending up with a proper sight picture for the last shot or two. I am rotating to 1x in a moment that grants me the time to do so, when the circumstances change quickly into a CQB scenario, that I think will carry on for a while. My sighting system switch happens when/if the mission has a prolonged CQB situation ahead, that I have a moment to prepare for; the switch also happens before dark. So, as we consider the MRDS, I think it'd be potentially advantageous for the surprise near engagement; performance would likely be the same, in the quick shift to a somewhat prolonged CQB scenario; and not as good as a more refined choice, for the situation that grants us the ability to swap to the other CQB-dedicated system. The truly challenging circumstance is one that has a constant back-and-forth between engagements inside 25M, and engagements at further distances. I imagine this circumstance is potentially somewhat unique; I can only speculate. | |||
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I performed a quick test this morning, of the return-to-zero (RTZ) performance of the ADM Recon, with the Leupold 6HD Patrol. BLUF: I observed a potential 1MOA vertical shift in POI, after removing and re-installing the mount/optic. Test procedure was: I fired a five shot group from 100M, using M193, from the prone position, resting on a backpack, with a rear bag. Result was a 3.5" group, with a potential flier at 12 o'clock; group size after discounting the flier was 2.75", which is fairly representative of what I've see out of this gun previously. I removed the optic and put it in my pocket, while I walked to and from the target, marking that first group. I re-attached the optic and fired another group, which measured 2.25", which is representative of what I know to be the systems typical performance in these conditions. If what I felt was a high flier, in that first group, is included, all ten shots fall into that 3.5" diameter dictated by the first group. If we do discount that flier, the majority of the shots from the second group are above the top shot of the first group, and the relative centers of each group are 1" apart, with the second group directly above the first. I will perform further testing, to see if a vertical bouncing back and forth is all that is experienced, or if that 1" is gonna poke out to the right or left too. That would indeed begin to be a problem, especially past 100M. This could likely be summed up in "know your system". Regardless of your approach, testing the system (you included), learning it, and knowing it, will help you win the day. I may try tightening my levers slightly, to see if that has a positive effect, but not before I do the same on/off test described above at least once more. I have my levers at a tension that makes it quite easy to remove/install, because my system relies on that functionality; they might could do with a tightening, at the expense of a bit more effort in removing the optic; especially if better RTZ is a result. It seems a better mount overall might be advisable, if I pursue this effort further, and do expose consequential shifts with the ADM. Bobro seems universally lauded for RTZ, as does Spuhr. I think I'd gravitate toward Bobro first. Consequentiality of the shift is relative to your use-case. Like I said earlier in the thread, I have shot a decent five-shot group on a torso-sized plate at 500M after optic on/off before. That is damn good, and likely good enough for a lot of different applications. The 1MOA shift wouldn't put me off a man at 500M, regardless of shift direction, depending on the inherent dispersion of my weapon. Even with my 2.5MOA(ish) rifle used in the above test, I might only miss at the extreme edge of the maximum dispersion. In a more precision application, however, we see the negative effects. Given my pursuit of a medium range precision capability, as outlined in another thread, I may do well to look into a better mount, if I am to apply my sighting system switching theory to that rifle. More to follow. EDIT: My daughter was actually patient enough to allow me to shoot another cycle of the RTZ test. Long story short, it seemed to exhibit a less-than-MOA shift to the right, after re-mounting. Pretty good. It seems, with my setup, I should expect a .75-1MOA shift in any direction. Certainly unacceptable in a precision application, but of little consequence in most cases. I will tighten the levers a bit, and try it again. Here is an article I found, which compares some QD mounts' RTZ performance. ADM isn't top dog, but all of them, other than the Burris, are quite minimal. I think I am comfortable with continuing my optic switching method. I have yet to test my Larue, which holds the Eotech; that article implies I shouldn't have an issue, but I will see for myself anyway. https://www.recoilweb.com/guid...pe-mounts-57239.html Did another off/on again today, after tightening the levers one increment, and re-zeroing. I did some better shooting, which may have served to make the drift more measurable. My first group was 1"; second group was 2", and about 1.25" high and left of the first. So, the 1MOA(ish) change in POI seems to be the case, with this setup.This message has been edited. Last edited by: KSGM, | |||
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A 12.5-14.5” barreled carbine with lpvo, offset or piggyback red dot, laser for nvg capabilities, and white light is just about the most versatile “do all” carbines. The offset height off of the bore on the piggybacked red dot is a detractor to some. An Aimpoint T1/T2 or better yet ACRO P2 in an Arisaka offset mount is great. You roll the rifle to place the red dot in the vertical, shoot it just like you would any other red dot. If you use the 1.93 height offset, you can use it for passive nods shooting too. I don’t know anyone who uses a rifle in harm’s way that would trust the RTZ of any optic mount without confirming it on paper. --------------------------------------------- "AND YEA THOUGH THE HINDUS SPEAK OF KARMA, I IMPLORE YOU...GIVE HER A BREAK, LORD". - Clark W. Griswald | |||
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I shot two more off/on groups; this time from 300M. Unfortunately, my shooting is highly compromised by stupid animals, as the 300M position has me out in a pasture, where there's plenty of opportunities for animals between me and the target. I have to come partly out of the glass between every shot, to make sure no dummies are going to strut in front of the next shot. So, the groups aren't as good, and the measurement in POI differences isn't as precise. The shift still seemed to be about 1MOA; this time to the right. 6/10 shots hit the 18" steel, behind the paper, with the rest missing just beneath it. Is the 1MOA shift acceptable? That depends on what your goals are. Is it repeatable(dependable)? Yes. Is it predictable? No; it'll go one way or another, in a 1MOA radius, relative to the original zero POI. Can it be less, with a better mount? It seems like it can, and I intend to find out, when I can swing a Bobro. A Micro T2 has been on the want list for a while, and, when I get one, I'll try a piggyback setup. What makes or breaks that, for me, will be NVG performance. I already know the Eotech has better light transmission, and an overall NVG-friendlier interface. I'd be willing to make those two sacrifices, if the piggyback is doable with passive. I don't know that I care for the offset approach; the tall dot doesn't bother me. My hang-up with the GP carbine is night vision performance. For the best NV performance, you need an Eotech. One could certainly just have a LAM, and call it done, but I like to prioritize passive aiming, as I have seen situations where it provides advantages over lasers/illuminators with regularity. I do trust the RTZ of a quality mount; even more, since these tests. I know what this one's capable of, and I know there are even better ones. So long as the mount doesn't get damaged, it'll be good-to-go. As Voshterkoff lamented: it would be quite cool if someone made a lightweight fixed 6x or 8x scope, with which you could pair a Micro or Acro. An ACOG is stinkin' light and compact, but 4x isn't enough for me, and the higher magnification ACOGs get heavy quick. Leupold also makes a nice fixed 4.5x (still not enough), which would end up only just heavier than an ACOG, once matched with a mount. Until I can prove or disprove the piggyback night vision performance, I am sticking with a sleek LVPO in the daylight hours, and an Eotech in the dark, on the same gun, with QD mounts. Added 6/5: Ultimately the ADM doesn't RTZ well enough for me. I don't have a problem with continuing it's use, in the switching system that I have been employing, but I am going to prioritize the acquisition and evaluation of something better. I hope to be able to emplpy the same system with my impending medium range precision GP project, and something like the ADM certainly isn't good enough for that.This message has been edited. Last edited by: KSGM, | |||
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Bolt Thrower |
I’m not sure why the 6x ACOG is such a pig. One thing to look for would be GDI (based name) brand mounts. Back in the day they were always considered to have the best return to zero. I’m only seeing a few red dot mounts left around, as it looks like they went out of business. | |||
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| Sigless in Indiana  |
How many shots are you using to establish your group and verify zero? Is your rifle capable of sub moa accuracy? Zero shift could get lost pretty easily inside the statistical noise of normal dispersion. Bryan Litz with Applied Ballistics has some pretty good articles about this. Many people use the smallest group that they have ever shot as the metric for how capable their rifle is. When in reality they should use a statistical average for mean group size and understand that statistically there are going to be outliers above and below that number. Also 3 shot groups are not a sufficient sample size for evaluating a load and a rifle. In reality it takes multiple 10 rd groups to truly establish a baseline. ETA: Sorry I somehow glossed over the methodology that you included about how you were conducting the test. I recommend that you bump up the round count in your testing protocol to ensure that you aren't finding zero shift that is actually within the normal dispersion of your rifle. Do you have access to any ammo better than M193? That stuff is 2-2.5 moa out of my best barrels. | |||
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| Sigless in Indiana |
Article from Byran Litz:
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In these optic off/on comparisons, I have been shooting five-shot groups. The rifle is not particularly accurate. As I mentioned above, it seems the average for the rifle is around 2.25"; that 1" group was exceptional. I have never shot ten-round groups with any rifle I own, as I don't have (or haven't taken the time to create) a platform with which to truly hold the rifle stable; nor do I have any triggers installed, which would make such accuracy evaluation truly meaningful. The overwhelming majority of my shooting is impromptu. It sucks, because I am always trying to learn or evaluate some aspect of the rifle, equipment, or myself, but I never have the time to make the conditions truly favorable and scientific. The circumstances nullify almost all of what I do, but I do it anyway, and I share it here; I always seem to learn something from it, and/or the members here, as a result, so I'll keep on keepin' on. I appreciate everyone's feedback. It all helps with the depth and breadth of the consideration of the topic. | |||
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| Sigless in Indiana |
I think you are muddling your results by discounting data. Did you feel yourself pull that shot or was it just outside of the group when you walked up to the target? | |||
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| Sigless in Indiana |
If you aren't shooting these tests from heavy bags or at the very least a solid bipod and a good rear bag, the data is going to be questionable. Any kind of load development or accuracy testing needs to done from a very stable platform. | |||
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Yes; this. I have historically struggled with first shot anomalies, and thought that particular shot may have been a victim of that phenomenon. I am not one to make excuses, which is why I said that could potentially be read either way. I need to create a quick-deploying stable shooting system. You're absolutely right about the stability issue. It's on me to get it done. | |||
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| Freethinker |
You’ve identified the critical factor. I have a very heavy and stable portable shooting bench that I can recommend without hesitation (despite my usual hesitation to make recommendations), but they have gotten very expensive, and probably beyond what most people want to spend. There are, however, others available and many would be much better than what I understand your situation to be. As one comment, though, I would avoid any setup that makes the seat a fixed attachment to the bench. I see no benefit to such a bench, and believe it probably just compromises stability. There are many options for things to sit on, and I actually have a “drum throne” that works very well. Ultimately, though, it’s sort of like buying a quality scope for long range precision shooting that costs more than the rifle. You probably already know it, but to state what may not be obvious to everyone, at some point in our progressions the accessories really are just as important as what our primary focus is on. ► 6.4/93.6 “I regret that I am to now die in the belief, that the useless sacrifice of themselves by the generation of 1776, to acquire self-government and happiness to their country, is to be thrown away by the unwise and unworthy passions of their sons, and that my only consolation is to be, that I live not to weep over it.” — Thomas Jefferson | |||
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Sigforum K9 handler |
Yesterday, I removed the optic off of my Saint to splash a little paint on it. I wasn’t digging the brown and tan combo, so I sprayed a little green here and there to my satisfaction. No paint was placed on the bearing surfaces of the rifle or Vortex Huey. When I checked zero with XM193 at 50, the group had moved 2 inches right and a little under an inch up from where it shot on Thursday. A sample of one, but relevant to this conversation. The Saint has rapidly become my favorite in that cost range FSP rifle. | |||
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I forgot to add to my earlier post, I am a big fan of Larue QD mounts. I've not done as extensive of testing as the OP, but even with a higher quality mount, I always retest zero with the specific ammo in my magazines. There usually is some adjustment to get re-zero however small each time you re-attach a QD mount. I have had bad luck with ADM mounts and don't recommend them. -edit I went back and looked at what LT120 30mm mounts go for on Larue's website. 399 seems insane to me for what it is. I think I got mine for less than half that new some time ago.This message has been edited. Last edited by: HKAngusKL, | |||
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Yikes. Thank you for sharing that, jones. A 4MOA shift is a big deal in any circumstance, at any range. I saw a bodycam clip yesterday, actually, that was a damn fine example of the HR circumstance you mentioned previously. An officer took the classic hostage shot with his Aimpoint Micro-equipped short carbine down a hallway. It was hard to judge the distance, but I'd say it was potentially 25Y. Amazing performance under amazing pressure; I think it was in Milwaukee. It was a circumstance where that 1/4" mystery shift likely wouldn't have been acceptable. Though, the LEO on the tac team has infrastructure that exempts him from the context presented in the OP. He's got an armory and/or vehicle base of operations from which he can quickly pick from two or three rifles or uppers equipped for different circumstances. The optic switch concept doesn't apply to him. They certainly don't seem to be capable of true RTZ; I intend to invest in better, when the wallet allows. When it comes to Larue: I have historically been a fan, and have a few of his mounts; one is responsible for the Eotech. I was curious about the lever rubbing directly on the receiver, and did some research that confirmed the suspicion. There are more than a couple folks out there that reported tolerances changing, as the receiver was worn by the levers. Could this be mitigated by adjusting to minimum required tension and regular surface lubrication? Probably, but that's another maintenance factor. This is why I went with the ADM, for my Leupold; though that route is proving less-than-adequate in the RTZ department.This message has been edited. Last edited by: KSGM, | |||
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| Sigless in Indiana |
The people who report Larue mounts damaging their rails are from people who adjust the mounts so tightly that it gouges the rail. There are specific instructions including with the Larue mounts that if followed will prevent this from happening. Really no different than people who over torque standard optics mounts and strip out the screws. If you don't follow manufacturer instructions any mount can fail if you damage it or the rail during installation. | |||
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| Sigless in Indiana |
Yeah. Larue prices went bonkers a few months ago. I regret not buying more spare Stealth barrels before the price hike. I think their barrels were undervalued at $250. But now they are approaching cut rifled barrel prices. | |||
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| Freethinker |
Although not the subject of this thread, can you provide a link? I search for things, but results are spotty. ► 6.4/93.6 “I regret that I am to now die in the belief, that the useless sacrifice of themselves by the generation of 1776, to acquire self-government and happiness to their country, is to be thrown away by the unwise and unworthy passions of their sons, and that my only consolation is to be, that I live not to weep over it.” — Thomas Jefferson | |||
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| Freethinker |
Thank you. The channel appears to have some useful stuff. As you say, judging distances from bodycam footage is difficult. The cameras have wide angle lenses to capture as much of the area in front of the officer as possible, but that distorts the image and makes things appear to be much farther away than they are. ► 6.4/93.6 “I regret that I am to now die in the belief, that the useless sacrifice of themselves by the generation of 1776, to acquire self-government and happiness to their country, is to be thrown away by the unwise and unworthy passions of their sons, and that my only consolation is to be, that I live not to weep over it.” — Thomas Jefferson | |||
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SIGforum.com Main Page Mason's Rifle Room A case for the general-purpose carbine, and challenging the sighting paradigm.
Main Page Mason's Rifle Room A case for the general-purpose carbine, and challenging the sighting paradigm.© SIGforum 2024