I had my first opportunity closely examine and take my brothers SCAR apart this weekend, without the benefit of a manual or previous experience. Not as simple as an AK but wasn’t bad. I fired this rifle around Christmas and I liked it quite a bit but I hadn’t had a chance to really look at it good since. I have been debating selling off a couple of my 6920s and getting a SCAR, especially once the SCAR 17 is released. I am not as enthusiastic about it now after a thorough investigation. Let me know what you guys think.
My Observations:
Rev M Pmags hand to be forced in and no way could they drop free. FN makes M-16’s why not make magazine well the same dims?
Rear of receiver is not positively attached. It is held on by the stock, which is in turn held on by slots machined in the receiver and mated to slots on the stock. Is it possible to hit the stock hard enough on top to keep drive the lower down and keep the hammer from hitting the firing pin? (My brother wouldn’t let me do it to his:() Looks like with enough field stripping the stock engagement would wear to the point it would be loose. I would have thought there would have been a pin or something to hold the back of the lower in place.
Why does the piston hit the op-rod at the bottom? Why not hit it in the center. And it is very small, maybe 1/8” of an inch, I would have thought it would have been bigger.
Why are there holes in the receiver where the piston impinges on the op-rod? Looks like a really good entry point for crap that could keep the piston from hitting the op-rod. Is this something related to the OTB capability?
I was expecting a revolutionary change but the bolt is basically a slightly modified M16 FOW bolt. Yes it has 6 lugs instead of 7 and they are bigger and radiused and so is the extractor but it is all basically the same mechanism. The cam pin is a lot smaller and so is the firing pin. So it “should”, in theory, be less likely to fail at the cam pin slot or break a bolt lug. The firing pin retaining pin has an O-ring on it that was already starting to disintegrate with only 50 or so rounds on it. I was really expecting to see a completely new bolt design, this kind of calls into question all the testing that has shown the SCAR to be significantly less prone to malfunctions than the M-4. If the lockup, extraction and ejection are basically the same, barring part failure, what makes the SCAR perform better? Random luck?
The front sight is very difficult to deploy from the locked down position. It requires an odd, squeeze and push down on a very small pad while pulling backward motion. It is difficult to do on the living room floor much less after firing several hundred rounds under stress. I don’t have any experience with folding front sights so maybe this is normal, if so, I think I would like to keep the fixed front.
The gas block looks like it is cast or MIM. It has ejector pin marks and quite a bit of porosity in it. :eek: With that much visible porosity I would have been concerned about voids but surely they are checking for that. (A cast iron brake rotor would have been returned to the foundry for that)
There are a lot of lube points, the carrier runs down full length rails within the receiver and there are wear marks at the front and back of the carrier. Where there are raised centering nubs. I guess that will definitely preculde and carrier tilt but I would have thought that less contact would be better. However, since it is extruded aluminum you have full length everything if you don’t hog it out.
The left hand charging handle made it very easy to do one handed manipulations/bolt lock back.
The sight picture is great with the circle on circle and the small aperature seems to be the perfect diameter for me.
With the stock folded you can’t drop the magazine unless you use your off hand to push the left hand mag release.
With the stock extended it was 1.5 to 2 inches longer than a 6920 with the stock fully extended. Of course the Colt has a 4 position stock and the SCAR has a 6 position.
The safety was too small and difficult to flip off, and very annoy to get back on, needs to be much longer.
the rear of the lower is positively attached. the tang at the rear of the lower fits through the rear aluminum ‘block’ which is bolted to the rear of the upper, and retains the stock in place. the only way for the stock to be driven down is to hit it hard enough to shear the tang off. the stock can’t move down, and neither can the lower with the tang intact.
Some of my pmags work and other don’t. They all work after modification. Another issue for some SCAR owners it that the bolt won’t release by pulling the charging handle to the rear on a loaded pmag. The pmag is easily modified to work properly. All metal mags I’ve tried (large number) work properly.
Mine has performed properly for over 6000 (not a lot, but a decent number) rounds through 1 course and multiple 3 gun matches and training.
I trust FNH, they’ve been building firearms for a while now and the SCAR seems to be holding up. Time will tell. Do you really believe your idea is better than their version, if so I’d apply for a job there.
Same as 3
The extractor is an advancement. Why change other parts that are known to work well. Placing it in the large carrier changes things quite a bit too. The piston system on the SCAR is quite a bit different in the sense that the rod is part of the carrier and is built more sturdy/simple than others. As far as the random luck comment, that was off base - they’ve been doing this a while and why would you assume random luck. How about this answer - only time will tell.
Leave it up
Same as 3
Same as 3
Some like the reciprocating CH, others don’t. I like it. It’s there because it was requested to be that way. It also runs well on the right side.
I’ve found the sights to be very user friendly.
True. Although I have only folded the stock for putting the SCAR on a pack and hiking back into the river for hunting coyotes. Other than that I pull the stock out for use.
OK
I find the safety very user friendly and very quick/manageable. The portion of the safety on the ejection port side is smaller.
Nothing wrong with your opinions and I’m just giving mine for those that might still be interested. Nothing wrong with your choice to keep your Colts and not get the SCAR. Sounds like you don’t care for the SCAR and I’d never spend that much on something that I felt like writing the things you wrote about it.
The reason I originally became interested in the SCAR is because an old friend of mine who just retired was using one on a two way range. He told me I should try to get one if possible (before we could get them). He had nothing but praise for the SCAR. That (of course) doesn’t imply that everyone should get one, just my reason for getting my SCAR.
This paragraph confuses me. I have never handled the SCAR, but reliability is tied to more than the design of the bolt. Say, for instance, the gas system? The recoil system?
The extractor is an advancement. Why change other parts that are known to work well. Placing it in the large carrier changes things quite a bit too. The piston system on the SCAR is quite a bit different in the sense that the rod is part of the carrier and is built more sturdy/simple than others. As far as the random luck comment, that was off base - they’ve been doing this a while and why would you assume random luck. How about this answer - only time will tell.
[QUOTE]
I was just surprised that it really doesn’t seem that much different from the M16 FOW design.
I don’t think it is off base to ask the question if the SCAR feeds out of the same magazine, holds the case the same way, extracts it the same way and then ejects it out the same way, what makes it perform significantly better in the only publically available test data. Most of the changes seem to me to be affecting durability rather than operating system performance.
I honestly was expecting to find something done significantly different, especially since there is always so many complaints about the M16 FOW and “jamming”.
I am not a gun designer but I have alot of experience with setting up and troubleshooting very complicated machines/processes. Usually if a machine has similar operating parts/principles, it will usually have the same types of problems regardless of manufacturer.
Maybe the increased reciprocating mass of the carrier combined with the piston keeping more of the lubrication on the operating parts improves it significantly.
Interesting discussion.
By the way, this rifle would release the bolt both ways.
Oh, I have no doubt there is more to it, but I found it very odd that the most basic functions of the weapon, feeding/extracting/ejecting are not any different than a M-4 which suprised me.
To me it is the key component. Any rifle should feed and fire and eject rounds manually, the gas/recoil system is a method doing it automatically. So to me it is the heart of the system, the primary means of functioning.
It just seems odd to me that something so similar would result in such dissimilar results without some other influence.
Maybe its just my very limited experience. The only rifles that I have experience with are AR’s, AKs, and M1As. All 3 of them have completely different means of feeding/extracting/ejecting.
I am just posting my observations hoping someone else with more experience would argue with me.
it’s thicker than 1/8", especially at the base. it’s also about 1/4" wide. in order to shear it, you’d need a vertical downward hit directly on top of the stock right above the tang behind the rear sight. a hit anywhere else at any other angle, and it’s going to be a bending load and will be taken up by the aluminum rails the stock slides onto, the stock pivot, the stock latch and the stock itself. the stock will probably fail at the weakest point - the pivot/latch before the tang shears.
Yeah but what if a MRAP or HMMWV runs it over? Just think, an A1 runs a SCAR over, something might break. What a pile of crap…:rolleyes: Or what if you wanted to hammer in some 36" concrete forming stakes with the SCAR stock? I guess your shit out of luck…
Many rifles use similar systems with sometimes dissimilar results. Ak47 variants? Galils? K2s that are hybrids of AR15s, Ak47s? By the way, the ACR bolt is based on the AR18, not the AR15. As is the bolt system that is used in SA80s, G36s, XM8s, and the SCAR to name a few.
Yes it has 6 lugs instead of 7 and they are bigger and radiused and so is the extractor but it is all basically the same mechanism. The cam pin is a lot smaller and so is the firing pin. So it “should”, in theory, be less likely to fail at the cam pin slot or break a bolt lug. The firing pin retaining pin has an O-ring on it that was already starting to disintegrate with only 50 or so rounds on it. I was really expecting to see a completely new bolt design, this kind of calls into question all the testing that has shown the SCAR to be significantly less prone to malfunctions than the M-4. If the lockup, extraction and ejection are basically the same, barring part failure, what makes the SCAR perform better? 
