SCAR 17 CQC....why or why not?

[MadAngler1]

Interesting stuff. On a side note, who has played around with the gas jets? I have a 17s and a 16s, both using AAC cans. I havent had any issues, but I keep seeing to cut down on wear and tear to replace the jet...

You only need a different gas jet if you plan on chopping down the barrel. The factory gas jet is meant for thr 16" barrel suppressed and unsuppressed. Some people think otherwise, but from what I have gathered (including from FN reps), it is not the case.

One other thing, I think a 1:10 twist barrel is what was meant rather than 1:8. Who makes a 7.62 nato barrel in 1:8 twist? Not just for a scar, but for any 7.62 nato rifle?

I would love to see FN update the SCAR and provide more options and parts such as 1:10 twist barrels with larger shoulders for muzzle devices meant for suppressed use, a sturdier stock, etc.

[Defaultmp3]

One other thing, I think a 1:10 twist barrel is what was meant rather than 1:8. Who makes a 7.62 nato barrel in 1:8 twist? Not just for a scar, but for any 7.62 nato rifle?

The CSASS (H&K G28E) will feature a 1:8 twist rate. It has been noted that the faster twist rate works quite well in shorter .308 barrels, and that previous fears about excessive twist rates has not been borne out.

With the newest research on external ballistics, we know that if a 1/8 or faster twist is used, the Mk316 175 SMK fired from a 16" barrel will not have transonic stability issues until well after 1000 yds.

[Sensei]

Interesting stuff. On a side note, who has played around with the gas jets? I have a 17s and a 16s, both using AAC cans. I havent had any issues, but I keep seeing to cut down on wear and tear to replace the jet...

Marvin Pitts probably knows more about the SCAR gas port sizes for various barrel lengths than anyone else working on the platform. That is part of the reason why I would send my rifle only to him for a barrel chop.

[Tspeis]

You only need a different gas jet if you plan on chopping down the barrel. The factory gas jet is meant for thr 16" barrel suppressed and unsuppressed. Some people think otherwise, but from what I have gathered (including from FN reps), it is not the case.

One other thing, I think a 1:10 twist barrel is what was meant rather than 1:8. Who makes a 7.62 nato barrel in 1:8 twist? Not just for a scar, but for any 7.62 nato rifle?

I would love to see FN update the SCAR and provide more options and parts such as 1:10 twist barrels with larger shoulders for muzzle devices meant for suppressed use, a sturdier stock, etc.

No, I meant 1:8". Todd Hodnett has been preaching fast twists for years. He's shot 12" Surgeon 308 bolt guns (8 twist) to a mile with no issues. USG / LE testing only further validated his observations.

Not saying a 12" gun is ideal for that, but it's been done. You'd be surprised how far you can stretch short guns with fast twists and high BC transonic stable bullets. If you get a chance, check out Hornady's website and look at the list of ELD bullets and their listed BC's. You'll see they increase significantly when shot from fast twists. The 180 gr 7mm is listed at .816 G1 from 1:7.5" twists above 2,500 fps.

Something like the Warner Flatlines will basically turn a 16" 308 into a 20"+ 6.5 Creedmoor in terms of drop and wind deflection at ELR. Terminal performance closer than 300 would likely suck due to their solid monolithic construction, but it shows the art of what's possible at long range with new bullets. Another very reputable company well known for transonic stable bullets has plans for a high BC solid copper 308 bullet that can provide good terminal performance as well.

Of somewhat relevance to put the twist thing into perspective, the currently popular 6.5mm calibers have trajectory advantages over 308 past 600 meters. Per Doc Roberts, inside 300 meters, 308 typically has better terminal performance than 260 Remington / 6.5 Creedmoor and inside 600, flight characteristics are very similar. However, with the right load and twist rate, I can make my 308 mimic 6.5 performance beyond 600 meters. With a good brake like the KAC MAMS, I can also get recoil down below that of a comparable 6.5 large framed setup. So I can have my cake and eat it too.

If sticking with 1:12", I think the OP should pass on the 13" barrel for now.


Tspeis

[MadAngler1]

Well this is what I love about this website. Thanks for the info. It sure would be nice if HK offered a civilian version of the G28 with an adjustable gas block for suppressed use.

[lj_1187]

Thanks for the very informative posts.

So if I am planning on running the 1:12 twist stock barrel cut to 14" or so, shooting m80 ball, 155/168gr TAP pills suppressed, I will be disappointed in the terminal performance past 300m?

[themonk]

Thanks for the very informative posts.

So if I am planning on running the 1:12 twist stock barrel cut to 14" or so, shooting m80 ball, 155/168gr TAP pills suppressed, I will be disappointed in the terminal performance past 300m?

Personally I would stay at 16" and put the money in a KDG MREX rail to cut the gap between the rail and the can down. Its a different gun with an MREX on it.

[Sensei]

Thanks for the very informative posts.

So if I am planning on running the 1:12 twist stock barrel cut to 14" or so, shooting m80 ball, 155/168gr TAP pills suppressed, I will be disappointed in the terminal performance past 300m?

There seems to be some debate as to the velocity loss in this platform when going below 13 inches. I posted my results for the 168 grain TAP from a 20" barrel last week here:

https://www.m4carbine.net/showthread...-FGMM-190-FSMK

I plan on chronoing some loads through my 16" MDR and SCAR within a couple of weeks and will post the data for your review.

[RHINOWSO]

It depends what you want the rifle to do.

Fun rifle or just shooting targets <400m? SBR that mofo.

Want to keep stretching the shots beyond that? Keep it 16"

Mine is a 13" cut by Marvin Pitts with an MREX and it's great. With a 2.5-10x24 NF it's a slaying machine.

[RHINOWSO]

It depends on the round. Mk 319 Mod0 supposedly has good terminal performance down to 2000 fps which is about 200 yards assuming 2600 fps and a BC of 0.277. H

IME MK319 out of my SCAR 17 13" is just a hair below 2700 FPS - I use 2690 in my calculator. I'll have to look at all my photos to find the chrono pics I took of a 10 shot spread last year.