View Full Version : Has anyone here had a SCAR17 ruin your optic?
After a few months of deliberation over 7.62 platforms, I went ahead and ordered a SCAR17. I've been reading about how the rifle breaks optics, but it all seems like second-hand info (hearsay). Has this actually happened to anyone here? How long did it take? What type of optic are you using? Are there certain brands that don't have an issue on the 17?
I've seen a document from Crane that the SCARs weren't to be user with certain optics but I can't find it again.
No issues. I've had a Leupold illuminated Vari-X III with German #4 reticle mounted in a Larue LT104 since day one with zero issues. It's been run through a couple of carbine courses (though I did limited firing at one of them as the AI) and has around 3K rounds through it total.
Stephen
No issues. That said I've been using an H1 (well, actually an R1) so I wouldn't expect any. It's been through a couple classes/clinics, but probably only about 1000-1100 rounds total.
Doc. Holiday
10-18-12, 13:30
They were probably running crap plastic like Bushnell and BSA...Hell maybe even a Tasco...
Yeah, I doubt a quality optic from Aimpoint or Trijicon will give you any issues.
QuietShootr
10-18-12, 13:55
They eat EoThingys like popcorn.
I have had an ACOG on one for two years, and fired around 5k rounds through it with no trouble.
What exactly does the SCAR do to these optics?
QuietShootr
10-18-12, 14:17
They won't hurt an ACOG, but they're hard on electronics.
They won't hurt an ACOG, but they're hard on electronics.
Does a SCAR cause more problems than other similar .308 rifles? What is it about the SCAR that's rough on electronics.
I ask because I am heading to a Costa 7.62 Heavy class in FL next month as was thinking about an Aimpoint or Eotech with magnifier.
They won't hurt an ACOG, but they're hard on electronics.
I've read that as well, but I haven't seen any first hand accounts of it happening. Have you broken any electronics or optics on a SCAR? Do you have a link to reports of someone who has?
Not trying to be a dick about it, I just want to chase this down and find someone who has had it happen.
Failure2Stop
10-18-12, 17:26
The issue definitely exists in military guns, and not with BS optics. I have yet to see a report from the non-Mil side. I have no idea why.
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From what I understand the EOTech XPS/EXPS is the only series the military deemed able to handle it regularly.
My groups opened up more than enough to notice and (over time and 1,900 rounds) I saw a 1 MOA change in the elevation setting with my standard surplus load. (Zero Stop went from -1.5 to -2.5 MOA.)
I switched out the LT-104 to a ADM Delta mount and those issues appear to have been no BS fixed. Optic is a NF with no indications of any problems - now at 2,400+ rounds on the SCAR 17.
Failure2Stop
10-18-12, 17:43
From what I understand the EOTech XPS/EXPS is the only series the military deemed able to handle it regularly.
I assume you mean within the EoTech line, because if you don't, I highly disagree.
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Magic_Salad0892
10-18-12, 18:23
The issue definitely exists in military guns, and not with BS optics. I have yet to see a report from the non-Mil side. I have no idea why.
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Maybe it's because of full-auto usage?
Maybe it's because of full-auto usage?
I would guess that most civilian shooters can't afford to dump large enough amounts of 7.62 to see any meaningful trends emerge. Military shooters have unlimited ammunition and the benefit of full auto.
LtNovakUSA
10-18-12, 18:54
I have a little over 3k through mine now, with a T1 in larue mount. So far so good, despite the rail slots being a little dinged up. This is despite pushing it up and keeping the lever tight.
I have a little over 3k through mine now, with a T1 in larue mount. So far so good, despite the rail slots being a little dinged up. This is despite pushing it up and keeping the lever tight.
I wonder if a strip or three of Teflon tape would help take up the slack on the rail slots.
They eat EoThingys like popcorn.
Seen too many EoTechs fail on 556 cal ARs to blame those failures on the SCAR.
I think the suspicion is is that the SCAR's heavy* bolt carrier is knocking stuff loose inside the failing optics.
H
*1lb, 2oz.
QuietShootr
10-18-12, 19:06
I've read that as well, but I haven't seen any first hand accounts of it happening. Have you broken any electronics or optics on a SCAR? Do you have a link to reports of someone who has?
Not trying to be a dick about it, I just want to chase this down and find someone who has had it happen.
I have broken a PAQ-4C and two Surefire incan bulbs so far. The Aimpoints and ACOGs seem pretty impervious on mine and the others I've seen and have first hand experience with.
John Hearne
10-18-12, 20:29
Michael Bane mentioned it on his weekly podcast, probably 18-24 months ago.
QuietShootr
10-18-12, 20:55
Howdy John :-)
The issue definitely exists in military guns, and not with BS optics. I have yet to see a report from the non-Mil side. I have no idea why.
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You have to heard of one:D. A buddy of mine wanted me to test his counter sniper. The Counter Sniper did not like it.
During a recent conversation with a SME from these boards, I was told the SCAR has a more pronounced recoil impulse due to its piston operating system, which was said to be the reason behind optics getting beat up.
Tspeis
Lightweight rifle, heavy bolt, 7.62x51 = heavy recoil impulse imparted to anything attached to the receiver.
Quite believable/possible.
You have to heard of one:D. A buddy of mine wanted me to test his counter sniper. The Counter Sniper did not like it.
Counter Sniper posts here too? LOL I first heard of these on SH. Such trash rofl. :D
Counter Sniper posts here too? LOL I first heard of these on SH. Such trash rofl. :D
Ya well they fit a spot in the market. Not what I want to spend money on though.
You might want to read all of the post from Sean M in the link provided.
http://pistol-forum.com/showthread.php?5683-308-Semi-Auto-Rifle
Not a 17s, but my 16s caused a Surefire M600a head to fail.
Alaskapopo
10-20-12, 00:21
The issue definitely exists in military guns, and not with BS optics. I have yet to see a report from the non-Mil side. I have no idea why.
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Civilian guns have a muzzle brake which reduced the recoil forces on the gun quite a bit. I bet that is at least part of the reason.
Pat
Civilian guns have a muzzle brake which reduced the recoil forces on the gun quite a bit. I bet that is at least part of the reason.
Pat
Although it should be noted that muzzle brakes and supressors do not necessarily reduce the impact on optics. There's a lot of talk about this on the night vision forums. Anything above 6.8SPC is capable of damaging NVD's not designed to be rifle mounted. Adding a suppressor or a brake in their opinion doesn't help because the racoil impulse largely happens before the gases reach the brake. Actually brake just adds a second impulse to the opposite direction right after the actual recoil impulse.
I'm not sure if it is entirely so, and/or does it have any connotations to the daylight optics world. Image intensifiers are a bit different breed because the components are so tightly packed together and any contact between these leads to instant damage making it different from your rifle scope in the way it reacts to recoil. But I thought I'd share this bit of information.
Actually, some of the recoil force occurres from the reaction to the bullet accelerating down the barrel. However, the majority of the recoil is from the gas from the burning powder as it escapes from the bore. You're throwing a measurable weight of gas forward that has a respectable velocity. And since E=1/2M*V^2...
H
Failure2Stop
10-20-12, 07:47
Civilian guns have a muzzle brake which reduced the recoil forces on the gun quite a bit. I bet that is at least part of the reason.
Pat
I actually misspoke about my not hearing about civilian 17s breaking optics.
I have indeed heard of three instances. None were second-hand info, and all were from people that I trust. One was with the aforementioned "not highly rated" optic. One was with an EoTech, but the issues might have been linked to the optic.
The likely culprit is the impact of the piston on the bolt carrier. In a piston gun that's quite a smack.
59_Gretsch
10-20-12, 10:36
Were the rumors you've heard about red dot (electronic) optics only or did they include scopes? I'd think that scopes wouldn't have the same issues.
steyrman13
10-20-12, 10:49
More of a question than comment. Wouldn't a bolt gun put more recoil force on an optic than a semi-auto because the BCG actually absorbs some of the impact as it disengages and moves back? I would think any optic that could witstand a bolt gun could withstand a gas or piston operated
I wonder if it has more to do with the bolt carrier slamming forward. I remember Mini-14 owners saying that the rifle was hard on scopes because of the operating rod slamming into the gas block. That scopes were designed to take the rearward recoil, but not the forward recoil.
I don't own a SCAR17, but I do have a SCAR16. When the bolt carrier slams forward during firing, my muzzle goes down. Instead of the up & to the right that I get with an AR, the scar with a Battle Comp goes slightly down.
Does anyone thing an S&B Short-Dot would be okay on a 17s? That is what I was thinking about mounting on mine since it's sitting unused.
Alaskapopo
10-20-12, 14:11
I am running a Nightforce 2.5-10 and a Aimpoint R1 on my SCAR with no issues yet.
Pat
Magic_Salad0892
10-20-12, 18:52
I'd think that any scope rated for use on a .50 caliber weapon should be okay.
QuietShootr
10-20-12, 19:44
Does anyone thing an S&B Short-Dot would be okay on a 17s? That is what I was thinking about mounting on mine since it's sitting unused.
I think it would be fine.
ruedger455@yahoo.com
10-20-12, 20:06
Yea .308 will eat up eotechs they can't handle the recoil.
QuickStrike
10-21-12, 02:24
Crap, they eat up surefire lights too???
Is there a particular model of surefire light that is especially tough?
Im seriously rethinking about using one with a tape switch now.
pentosinjunkie
10-21-12, 03:49
Acquaintance of mine at my LGS had his SCAR17 toss a Surefire Scout off of a Haley mount. Specifics of install unknown, but I don't think he monkey****ed the mount/M600 install.
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In terms of physics, a muzzle break will only reduce the effect of secondary recoil (gases leaving the muzzle after the bullet), thus reducing muzzle climb. A suppressor can reduce the recoil energy, and alter the primary recoil (momentum of the gun/bullet system) by adding mass, even if it at the same time slightly increases the velocity of the projectile.
The recoil energy does not change because of different operating systems, ie bolt gun vs AR or piston vs DI. In terms of the former, recoil will be perceived as softer in the assault rifle as the recoil energy is spread out over time compared to the bolt gun. The recoil energy of the system is still the same. In regards to the latter, the recoil energy will be the same, but a piston system usually exhibits faster acceleration of the reciprocating parts, thus the recoil will be perceived as more snappy. *
*When I say that recoil energy will remain the same, it is implied that all factors; cartridge/projectile characteristics and weapon characteristics, are identical.
When it comes to the impact of the piston against the bolt carrier, and how heavy that impact is, it will depend on the design. On my 416, there is maybe 1mm of movement before the oprod engages with the carrier. How much movement is there on the SCAR 17?
If the accessories are mounted to the rail properly, ie forward tension while mounting it, the rearward recoil should not affect the items, as they should not be able to move. However, the forward force of the bolt going back to battery can affect them. As I understand it, the bolt carrier is quite heavy?
SCAR 16S bolt weighs 59g, the bolt carrier is 516g (1lb 2oz for Americans)
I can measure the gas piston free motion before it impacts the bolt carrier when I get home from work.
H
A few points from Gordo over on LF about the issue:
-The mass of he SCAR bolt has long been a point of discussion within the community. I have repeatedly talked to FN and Crane folks about this in that this is a well known contributer to the recorded high abrupt peaks in recoil impulse that have contributed to ancillary item breakage from SOPMOD Block II MDNS suite.
-Conversely, the AR series bolt assembly has a much more manageable bolt mass in the system that gives the residual benefit of a) manageable recoil/controllability in rapid shot sequences and b) more receptive/consistent recoil impulse for ancillary items
I'll try to answer this from the perspective of knowing the recoil impulse tests intimately - I don't want to say more on that.
-On the SCAR, the accelerometers showed a lesser overall impulse with a longer peak, but a harsher peak and more abrupt curve in the peak at cartridge ignition. This resulted in a higher curve on the scale even with a lesser time at high peak.
-That sharp peak is considerably more significant than originally thought
-Although the M4 showed a higher (slightly)recoil impulse, the impulse was steady and evenly distributed throughout the pressure curve resulting in a more acceptable pulse
-All of the SOPMOD Block II items were durabalized to be placed on a number of weapons platforms - M4, M240's/MK48, M249/MK46 (5.56mm, 7.62mm in some cases even .50 cal). All of those systems showed more consistent M4 type recoil impulse curves to peak. None of the MDNS suite had issues with those platforms.
DISCLAIMER - This is just theoretical/opinion from my very non-scientific observation - only applying my experience nothing more. If you look at the comb of the SCAR stock, you'll see that there is a slight (albeit very small) deviation in the comb angle to the shoulder seat. This drops the weapons fulcrum to accept the momentum from a straight back lineal movement through the point of recoil acceptance at the shoulder. What I mean is that where the stock sits on the shoulder there is a linear difference from where the recoil naturally is traveling (Newton rears his ugly head) to where the impulse actually ends up in the form of where the stock sits on the shoulder. I think - ONLY OPINION - that this difference has something to due with the peak being high at cartridge ignition.
-On the other hand, the M4's stock assembly is straight back to the shoulder. therefore although the impulse may be slightly higher, it doesn't have a detrimental affect because the pulse is more naturally accepted by the fulcrum point (the shoulder) and therefore more evenly/consistently distributed.
JUST MY VERY UNEDUCATED, "LAYMENTISTIC" OPINION
Doc. Holiday
10-22-12, 09:15
Were the rumors you've heard about red dot (electronic) optics only or did they include scopes? I'd think that scopes wouldn't have the same issues.
If you have a good high quality scope, you should be ok.
FlyingHunter
10-22-12, 20:28
SCAR 17 with ADM mount holding a Leupold VX-6. No problems. I've run it pretty solid thru several three gun matches, well over 500 rounds total so far...so good. My friends that also run the SCAR 17's have seen no problems with an assortment of optics.
SomeOtherGuy
10-23-12, 16:35
A 6lb bolt-action hunting rifle in a heavy caliber has a lot more true recoil than the SCAR or most other semiauto .308s, yet decent hunting scopes (like a Leupold VX-3) seem to survive them. Speculation only here - but if the SCAR is breaking optics more often than other rifles, I expect it would be a combination of:
1) Forward "recoil" pulse - that 18oz carrier slamming a cartridge home pushes the whole gun forward when it hits. Any OK scope can handle rearward recoil, but many scopes are not made to handle any significant forward jolt. Simple spring-piston airguns will often break scopes because of the forward impulse. I would hazard a guess that some quality scopes are made to be just as durable against forward jolts as rearward, and others probably are not.
2) Vibration from full auto or rapid fire - If the next shot is triggered before the gun has completely settled down from the last one, the second and subsequent impulses may cause vibration that is different in character from what you get from single shots, and that could start making things vibrate in a way that electronics don't like. The heavy carrier going forward would probably magnify this compared to something with less reciprocating mass.
Just guesses, but didn't see them listed above.
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