Scar 20 not grouping at all. - Page 1

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[ARCHIVED THREAD] - Scar 20 not grouping at all.

Posted: 10/28/2019 11:57:07 AM EDT

Took my SCAR 20 out for the first time yesterday. Im not very impressed. Range varied from only 100 to 300 yards. Shooting 150 Austrian surplus, 147gr MEN, and 168 gr Hornady Amax. My 17 loves all of these and shoots them fairly well with it liking the MEN the best. Sitting on top of the 20 is my Steiner 5x25 military in a Geissele S&B mount. Now one detail about this mount is I got it in their blemished sale due to some machine chatter on one of the radii I believe. Honestly the best group of the day off a bench was 2 inches at best and everything else was worse. Anyone have any suggestions? Im thinking about trying a Spuhr mount as the Steiner is a hefty scope. That being said I didnt see my zero being lost, more just like it would not group.

Posted: 10/28/2019 12:09:33 PM EDT

[#1]

Thoughts:

1. I would want to test more types of ammo. I’d not worry a thing until it doesn’t print FGMM 168’s or 175’s well. If those don’t shoot, those shoot well out of pretty much anything, and I’d think there’s an issue with the setup.

2. Your rifle is brand new. Does it have any gunk in the barrel? Also, sometimes, though usually with stainless moreso than CL, the barrel just needs breaking in.

3. Is your barrel nice and tight? There are times SCARs come with loose barrels. Uninstalling, standing it vertical, and hitting it with a torque wrench would be a good step.

I don’t have a 20 but I have a 17. The 17 shoots pretty darn good.

Posted: 10/28/2019 9:29:09 PM EDT

[#2]

First thing I'd try would be to re-torque the barrel assembly to the receiver.

Posted: 10/28/2019 10:13:58 PM EDT

[#3]

I have the 20 and yes- try 168 FGMM. Mine shoots them 1/2 moa as well as Remington 168 match.

Posted: 10/29/2019 6:57:01 PM EDT

[#4]

Quote History

Quoted:
First thing I'd try would be to re-torque the barrel assembly to the receiver.

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This is interesting...I have both a 17 and 20, what is the torque specification for the barrel nuts? I may double check mine before heading out to the range next time.

Posted: 10/30/2019 3:27:21 PM EDT

[#5]

Quote History

Quoted:
First thing I'd try would be to re-torque the barrel assembly to the receiver.

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This, someone posted the same problem
he realized factory didn’t correctly torque the barrel

Posted: 10/30/2019 3:44:53 PM EDT

[#6]

Quote History

Quoted:
This, someone posted the same problem
he realized factory didn’t correctly torque the barrel

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
First thing I'd try would be to re-torque the barrel assembly to the receiver.

This, someone posted the same problem
he realized factory didn’t correctly torque the barrel

This is how a lot of these quick change barrels are. You have to make sure both the barrel extension and receiver are clean and free of debris, and that the barrel is torqued in properly. Also, it usually seems to help a ton if you stand the rifle up during the install instead of laying flat. My MWS is the same way. If it’s loose, dirty, or sloppily installed groups will be several times what they’d otherwise be. It may not be OPs problem, but it may be someone else’s problem that reads this.

Posted: 10/30/2019 10:39:04 PM EDT

[#7]

Quote History

Quoted:

This is interesting...I have both a 17 and 20, what is the torque specification for the barrel nuts? I may double check mine before heading out to the range next time.

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62 inch/lbs

Posted: 10/31/2019 11:55:15 PM EDT

[#8]

Crappy picture, but there's a tightening sequence as well (17 shown).

Attached File

Posted: 11/1/2019 1:07:20 AM EDT

[#9]

take your time - don't break those screws. I have heard horror stories of them breaking and no spares

curious: what scope is on the 17?
hate to suggest the obvious: parallax?

Posted: 11/1/2019 5:34:24 AM EDT

[#10]

Quote History

Quoted:
take your time - don't break those screws. I have heard horror stories of them breaking and no spares

curious: what scope is on the 17?
hate to suggest the obvious: parallax?

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Scope was a burris xtr 2 1-8 but in the process of getting something else.
Parallax is gtg

Posted: 11/1/2019 9:32:01 AM EDT

[#11]

- Clean barrel thoroughly
- Check torque values on all optic mount points (I would suggest using blue locktite on these)
- Check torque value on barrel mount screws (...if you own a 20s, and not a torque driver = fail)

As others have suggested, I'll utilize other ammo types, including factory match ammo, and allow for some break-in period on that barrel. I realize it's a CHF, CL barrel but there may still be some microscopic imperfections that are throwing your rounds.

and

You're fundamentals. Without these in check, you'll never put rounds on target

Posted: 11/1/2019 2:49:00 PM EDT

[#12]

Quote History

Quoted:
- Clean barrel thoroughly
- Check torque values on all optic mount points (I would suggest using blue locktite on these)
- Check torque value on barrel mount screws (...if you own a 20s, and not a torque driver = fail)

As others have suggested, I'll utilize other ammo types, including factory match ammo, and allow for some break-in period on that barrel. I realize it's a CHF, CL barrel but there may still be some microscopic imperfections that are throwing your rounds.

and

You're fundamentals. Without these in check, you'll never put rounds on target

View Quote

Shooting a semi, especially a .308, and especially a piston, is very demanding on fundamentals. I consider myself a proficient rifle shooter, and once I got into large frames it took me a good couple hundred rounds to figure out the demands of a .308 semi. Like a little Glock 43, they’ll definitely keep your fundamentals solid if nothing else. They’re demanding to shoot well, and they’ll let you know if something in your shooting needs work.

Posted: 12/15/2019 8:34:16 PM EDT

[#13]

use match ammo

Posted: 12/19/2019 1:01:54 AM EDT

[#14]

are these chrome lined? More than once I have had chrome lined barrels shoot funky when brand spanking new. Usually settle down by 100 rounds at most.

Posted: 12/19/2019 7:38:06 PM EDT

[#15]

Quote History

Quoted:
are these chrome lined? More than once I have had chrome lined barrels shoot funky when brand spanking new. Usually settle down by 100 rounds at most.

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Yes they are CL

Posted: 12/21/2019 5:37:17 PM EDT

[#16]

First... your scope may be broken. SCAR 17 and 20S can damage a less well built optic. Before you do a bunch of work on your rifle, look there.

Second.. with a quality mount and a robust optic, use good ammo.

Sighting in mine today with a NF ATACR 5x25, testing 155 grain Sierra and Scenar bullets with RL15 powder, my SCAR was shooting into .5 MOA for 5 shots from a hot barrel. Its a very capable rifle, but your Burris might not be up to it.

Posted: 1/2/2020 3:26:29 PM EDT

[#17]

Its been awhile since ive gotten back to this. I havent resorted to retorquing anything yet but did switch scopes. Steiner military 5-25, seems to help with groups but it is still over an inch with black hills, 175 and 168gr and also my handloads. Im wondering if the scope mount is up to it. Im using a geissele schmidt and bender mount but wondering if a spuhr would be in order? Before I do that ill try torquing the barrel this weekend and see where we are at.

Posted: 1/2/2020 11:28:40 PM EDT

[#18]

Quote History

Quoted:
Its been awhile since ive gotten back to this. I havent resorted to retorquing anything yet but did switch scopes. Steiner military 5-25, seems to help with groups but it is still over an inch with black hills, 175 and 168gr and also my handloads. Im wondering if the scope mount is up to it. Im using a geissele schmidt and bender mount but wondering if a spuhr would be in order? Before I do that ill try torquing the barrel this weekend and see where we are at.https://www.AR15.Com/media/mediaFiles/455200/20191024_230053-1217651.jpg

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You really should check the torque on the screws just to eliminate that as a source of potential problems. If you are wanting to maximize your accuracy you will want to do it at some point and might as well do it now. After I had an issue with my first SCAR it’s one of the first things I have done with the rest of mine. It shouldn’t be something you have to check but once you get past that it’s just an easy and relatively inexpensive thing to take care of. The Harbor Freight inch pound torque wrenches are cheap and are surprisingly good.

https://www.harborfreight.com/hand-tools/sockets-ratchets/torque-wrenches/14-in-drive-click-type-torque-wrench-63881.html

Posted: 1/3/2020 11:43:47 AM EDT

[#19]

I’d definitely retorque. Your equipment is almost surely fine, and you’d just be throwing hundreds of dollars at it instead of 30 seconds with a torque wrench. Also, it was new, right? Continue breaking in the barrel, and clean/refoul it.

Posted: 1/25/2020 4:00:54 PM EDT

[#20]

So its been awhile but still having problems. Retirqued everything correctly, checked scope mount torque as well. Shot hand loads and 168-175 gr black hills out of it. Me and a buddy are both getting groups of 1-2 inches at best out of it. We are both decent shooters as well. Wondering if I should call FN to send it back. My 17 has always done more than I could ask for.

Posted: 1/26/2020 6:57:29 PM EDT

[#21]

Quote History

Quoted:
So its been awhile but still having problems. Retirqued everything correctly, checked scope mount torque as well. Shot hand loads and 168-175 gr black hills out of it. Me and a buddy are both getting groups of 1-2 inches at best out of it. We are both decent shooters as well. Wondering if I should call FN to send it back. My 17 has always done more than I could ask for.

View Quote

I’d still rather see this tested with FGMM 168’s, but I wouldn’t be happy with your results, and I’d probably be calling FN. the problem is that while your results aren’t satisfactory, I worry that they’re not bad enough for them to be too worried about it either. Hopefully that’s wrong.

Posted: 1/26/2020 9:06:27 PM EDT

[#22]

Try 150 gr.
Handloaded 150 SGK (in faster barrels) that are just as accurate as the 168 SMK. Mr SCAR17 has not tasted 175, but Barnes 130 is 0.5 MOA @ 100
You said that you shot 1-300. I prefer to work up groups at 200 vs 100 - sometimes the boat-tails may not stabilize until further out....
May have to go custom and OCW that puppy

Posted: 1/26/2020 11:24:08 PM EDT

[#23]

If you haven't already look at your crown and/or muzzle device. That's about all I got.

Posted: 1/27/2020 12:01:57 AM EDT

[#24]

Clean barrel

Retorque barrel screws

Buy a few boxes of FGMM

Shoot....if still not shooting well...

Remove muzzle device and check crown. Mine was so fucked up it’s not funny.

Crown good?

Remove optic from mount and mount from rifle. Remount to torque and try again.

Shoot...still won’t group...off to FN it goes. Don’t send it with a suppressor mount or they’ll accuse you of shooting it suppressed, void your warranty, and charge you just to look at it. FN customer service is worse than that of HK in the 90’s...

Posted: 1/27/2020 11:01:18 PM EDT

[#25]

Mount a different scope with a different mount if possible and rule out that possibility?

[ARCHIVED THREAD] - Scar 20 not grouping at all.

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