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Discussion Starter #1 (Edited)
Has anybody done a 14.5" barrel with a permanently attached flash hider? Seems like a good middle ground to save a little OAL without giving up too much in performance.

I use my SCAR 17 for hog hunting in a few different states. I just purchased a SWR Specwar 762 can which is awesome (still in NFA jail), but now I would like to shorten the barrel a little bit. I don't want to go all the way down to 13" as I don't want to lose that much velocity (and gain that much noise), and I would like to avoid having to file paperwork every time I leave the state for a hunt.

I ran across this velocity vs. barrel length data on another forum, but was curious if anybody here had tested their SCAR with the 14.5" length.



150 gr HPBT Win 748 loaded to a chamber pressure of 56.4K PSI WARM load 45 gr NOT a starting load. I chose 748 as the powder as it is most like NATO powder.

26" = 2918 FPS MP= 6.6K PSI ––99.6 % powder burnt -2836 ft/lbs
24" = 2873 FPS MP= 7.4K PSI ––––––––––––––––––––––––––––2750 ft/lbs
22" = 2823 FPS MP= 8.2K PSI ––––––––––––––––––––––––––––2655 ft/lbs
20" = 2766 FPS MP= 9.2K PSI ––98.7 % powder burnt -2548 ft/lbs
18" = 2700 FPS MP= 10.5K PSI ––––––––––––––––––––––––––––2428 ft/lbs
16" = 2623 FPS MP= 12.0K PSI -97% powder burnt ––––2291 ft/lbs
14" = 2531 FPS MP= 14.0K PSI ––––––––––––––––––––––––––2133 ft/lbs
12" = 2417 FPS MP= 16.7K PSI -94% powder burnt ––1946 ft/lbs
10" = 2273 FPS MP= 20.5K PSI ––––––––––––––––––––––––––1721 ft/lbs
8.0"= 2080 FPS MP= 26.0K PSI -87% powder burnt. -1441 ft/lbs
6.0"= 1800 FPS MP= 34.1K PSI -79.4% powder burnt -1080 ft lbs
 

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I like a shorter barrel as well on the SCAR 17s, i've asked here before with no avail. People usually leave the gun alone because the parts for SCAR are very pricey and tinker with the gun will decreasing the potential resale value.
 

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Here is another photo with a friends AAC SDN-6. I have shot plate steel out at 600+ yards without issues. I love having a shorter OAL. I have my 16 also cut, but I have a friend who does the work for free so it can be pricey because you are just trimming off 1.5".

image.jpg
 

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Discussion Starter #6 (Edited)
I do. Had mine cut right away.
Looks great! Have you had a chance to chrono it to see what sort of muzzle velocity you are getting? Is it noticeably louder?

For the guys who have cut their barrel, who do you recommend to do the work? My biggest concern of course is maintaining the excellent accuracy my 17 already has.

Here is my 17 with the SWR Specwar 762 attached, I think dropping from 16" to 14.5" would be just right.
 

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Discussion Starter #7
I took the above data and plotted it in a graph. As you can see what most everybody already knew, the velocity does not change linearly with barrel length. I fit a 4th order polynomial to it, which looks to match the data really well. You can use that formula to calculate the velocity at any incremental barrel length between 6" and 26". X=barrel lenth (input), Y=velocity (ouput).

It looks like a 14.5" barrel would be at 2559 ft/sec, a total drop of 65ft/sec from 16" (2624ft/sec), which means it was losing 43 ft/sec per inch in this length range. Obviously this data will change depending on the specific barrel, powder, and bullet, but I think this gives us a good idea of what behavior to expect. I'm currently shooting reloads with Hornady 150 grain Interlock bullets and H335, so my numbers may not be too far off of this.

 

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Discussion Starter #9
A 17 with a barrel <16" will make the BOOlets bounce off the target.

Just ask around, it'll be like shooting a AK.

;)
Funny!

If I remember right you had your barrel cut down. Can you recommended a trusted place to ensure there aren't any problems with the chrome lining and accuracy/longevity?
 

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Never chronoed it. I wasn't really worried about the FPS loss. I have shot plates at 800 yards without issues with is good enough for me. Like I said I had a gunsmith friend that did it on the cuff so yeah it would be a pain if you had to pay. I just like the way it looks with it cut down. That is why I had it done.
 

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Discussion Starter #13
So now that I have my Specwar I'm again thinking about having this done. Any new reports from guys who have had theirs cut? My biggest concern is maintaining good accuracy.

Approximately how much does Marvin charge to cut, thread, and pin a barrel?
 

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For 1.5 inches... sounds like a pain in the a**.
Agreed. Doesn't seem worth the expense for the minor gain in size... nor the pain in messing with the gas screw size.

I got to mount my Specwar 762 on my stock SCAR 17S yesterday (brought the gun in to test fit while I was filing the Form4 on paper) and I was fine with both the look and the balance with the stock configuration.
 

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Discussion Starter #15
I understand not everybody sees the value in it. But if you compare going with the factory 13" barrel for $1100 plus a tax stamp for $200, and then a six months wait, then spending ~$250-300 total w/out a tax stamp to go with a 14.5" pinned barrel is actually much better bang for your buck if you just want to make your SCAR a bit more compact.

So I was hoping to hear more from people who had actually had their barrel cut and how it is holding up over time in terms of accuracy performance.

My biggest hangup with the SBR route is the need to inform big brother every time you travel out of state. I travel out of state for hunting trips all the time and I like taking my SCAR 17. "Most" forms are supposed to be approved in 1-2 months but considering how the .gov works these days I'm just not sure that is a hassle I want to sign up for. If not for the travel approval stuff I would have already submitted my SBR forms and would have the factory 13" barrel on order.
 

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Honestly I wish I would have pinned a QD FH on my barrel rather than pay the $200 for the stamp. Right now I am trying to decide if I should buy a barrel for $1100 or have mine cut. Due to budget I am thinking of just having mine cut to 13"
 

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I understand not everybody sees the value in it. But if you compare going with the factory 13" barrel for $1100 plus a tax stamp for $200, and then a six months wait, then spending ~$250-300 total w/out a tax stamp to go with a 14.5" pinned barrel is actually much better bang for your buck if you just want to make your SCAR a bit more compact.

So I was hoping to hear more from people who had actually had their barrel cut and how it is holding up over time in terms of accuracy performance.

My biggest hangup with the SBR route is the need to inform big brother every time you travel out of state. I travel out of state for hunting trips all the time and I like taking my SCAR 17. "Most" forms are supposed to be approved in 1-2 months but considering how the .gov works these days I'm just not sure that is a hassle I want to sign up for. If not for the travel approval stuff I would have already submitted my SBR forms and would have the factory 13" barrel on order.
That's only if you travel with the SBR barrel. If you swap it out for the 16", you can go about your business without issues.

And a bit more on velocity follows. Look closer at the drop. If the thought of taking a shot at 700m in a 10mph FV crosswind is entertained, the 20ft of drop alone is gonna stretch the limit of most glass without a reticle such as the Tremor2, and the dude behind the glass better know his equipment very well.

-SS

RangeDropDropWindageWindageVelocityMachEnergyTimeLeadLead
(m)(in)(MOA)(in)(MOA)(ft/s)(none)(ft•lbs)(s)(in)(MOA)
0-3.5***0.0***2558.22.2672179.40.0000.0***
100-0.0-0.01.31.12295.52.0351754.70.1350.00.0
200-4.4-1.95.32.32048.41.8161397.20.2870.00.0
300-18.8-5.512.73.71817.91.6111100.50.4570.00.0
400-45.9-10.024.05.21601.81.420854.40.6490.00.0
500-89.2-15.639.87.01410.01.250662.00.8680.00.0
600-153.5-22.360.98.91249.01.107519.51.1150.00.0
700-244.5-30.587.110.91125.60.998421.91.3930.00.0
 

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If only......CA resident here :(
I am in california as well, you can cut your barrel to 14.5 as long as you pin n weld the muzzle device to kake it a 16 inch barrel. It will still meet 30 inch oal. In cali you have to block the stock from folding anyway so its not like it makes it too short for that cuz a scar 17 folded is 28.5 inches long so you are short as it is.
 

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So I was hoping to hear more from people who had actually had their barrel cut and how it is holding up over time in terms of accuracy performance.
There's a pic over on Arfcom in the Scar pic thread of a 17 with a 14.5" barrel that was pinned. You can try asking the user there.
 
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