View attachment 7099969View attachment 7099970View attachment 7099971Lots of misinformation here. I own both and have shot both extensively for competition. Maybe I can help.
1. Accuracy: The SCAR 20s is more accurate. No question about it. I have shot 2 20s's and 3 Mk11's, 2 ECR/m110's and an EMC. The 20s's consistently out perform the SR-25's.
How accurate are they? With 5 shot groups and factory ammo in each: The SR25's will average sub MOA. They will throw some groups larger and many groups smaller. The SCAR 20's will average 3/4 moa. Once in awhile will throw a group larger than MOA.
Winner: SCAR
2. Long range performance: Both will hit out to 1000. The limitation is 175 FGMM is not consistent enough to hold a tight group. Hand loads: the Scar hovers around 1 moa at 1000, the SR25 1.25-1.5 moa. I have not been able to get the SR25's to shoot as tight with hand loads. The SR25's wont seem to group with any of the low drag bullets ( have tried 175 RDF, 178 ELD, 168 berger hybrids etc), so i'm stuck with 175 SMK's. The SR25 has a long throat. The SCAR has a very short throat which I think leads to it's excellent accuracy. I worked up a load with 178gr ELD's for the scar that shoots lights out. Downside to the SCAR? 1:12 twist causes the BC to become very poor at long range. While the 1:12 stabilizes enough to group well, the wobble increases the profile of the bullet progressively reducing BC as it slows down. Meaning the ballistic calculators are not accurate for the SCAR. Neither of them are great past 800 due to poor ballistic performance. SR25 not being able to group well with low drag bullets, and SCAR twist rate too slow to maintain good stability causing BC to drop.
Winner: TIE
3. Recoil: This depends a lot on configuration weight, muzzle device, and internals. Which one recoils less? The SCAR. By a small with flash hiders and a large margin with suppressor. The SCAR in stock configuration has an unpleasant recoil "Slap" because the aluminum stock transmits the force compared to the 17's polymer stock but is very soft otherwise. Putting a softer buffer completely removes this. MOTOtech makes one or I cut a piece of sorbothane and added it to the stock buffer. The SR25's are smooth shooting for sure. No jump, no slap. They just kick harder.
Winner: SCAR
4. Running suppressed: KAC's are notorious for running reliability. In my experience a KAC with KAC or surefire suppressor will run suppressed or unsuppressed 100%. I have spent a lot of time on my ER with Mk11 suppressor. This combo is very nice shooting. Smooth recoil impulse. Zero shift is minimal. Suppressor is repeatable. some thermal shifting after 15-20 rounds. Over time (2000 rounds) as the mount interface loosened up, the accuracy opened up as well. Replacing the barrel with a matched suppressor returned the accuracy to sub moa. Overall a dated system that works very well when in spec. Fouls the action very fast. After about 250 rounds, the action gets sluggish.
SCAR: I ran a FA762SS suppressor on it. Which is nearly identical except for mount to the 762SV suppressor (waiting on tax stamp). Initial performance was outstanding. I could not believe the accuracy I was getting out of a gas gun with chrome lined barrel. .75 moa out to 700, and 1 moa at 1000. No thermal shifting even after several mags. Even setting on suppressed mode with a low back pressure suppressor, the bolt speed was increased. After about 1000 rounds, the suppressor to mount interface was not as secure. Carbon buildup would cause inconsistent mounting, and my 1st gen FA762SS has coarse teeth not allowing me to lock down the suppressor resulting in thermal shifting. I have not been able to remedy the issue. The 762SV suppressor or a gen II FA762SS suppressor restores the accuracy, but my gen 1 FA762SS has dramatic thermal shifting now. Zero shift with and without can is significant (2-4moa) due to the flimsy receiver.
5. Magazines: SCAR mags suck. SR25 mags are ok.
6. Long term function/reliability/other thoughts: I have 1000 rounds through the SCAR and 2500 through the SR25. The SCAR's construction leaves a bit to be desired. The receiver is flimsy there is significant flex though this does not seem to affect the accuracy. There are a lot of screws that hold the SCAR together. They are constantly coming loose. I have to check every 200 rounds or so. I have blue loctite on all of them. That said the SCAR runs clean and doesn't foul up much at all.
Neither platform is perfect but both of them run well for what they were designed to do. The SCAR seems to edge out the SR25 performance wise, but it has some of its own flaws. I think you would be happy with either one.