It varies by a number of factors. It can be totally negligible, or it can make up for an inch or so of barrel, which may or may not be significant.Quote:
Originally Posted by Wake27
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It varies by a number of factors. It can be totally negligible, or it can make up for an inch or so of barrel, which may or may not be significant.Quote:
Originally Posted by Wake27
Like the person above said, a number of factors can result in a suppressor adding a noticeable amount of velocity to a rifle (if any). In this case, I was basing it on the fact that Strikefirst was reporting a 208 fps increase in average velocity going from 12.5" to 13.9". That's a bigger difference in velocities between those two barrel lengths than I have ever seen, so I was wondering if the suppressor he was using on the 13.9 was possibly contributing to some of that increase in velocity.Quote:
Originally Posted by Wake27
Triarc published some velocity data on their barrels a while back that showed around a 100 fps increase in average velocity going from 12.5 to 13.9, so 200+ fps would be a really nice increase in velocity if its due to the barrel length alone.
Ofcourse go to the range to chronograph and zero 7 ARs and the stupid magnetospeed 3 wouldn't read the bayonet. Atleast I got them zeroed but I still need to chrono. Got a sporter magneto that still works so just have to use that till I get the V3 sorted out. Not sure it is the cord as I tried a spare cord and still would not read the bayonet. May have to send it in to see if they can sort it out.
Finally got to the range
11.5" Expo Heavy barrel with Banish 223 suppressor
55 TAP reload 2700
55 FMJ reload 2570
75 Hornady reload 2270
12.5 BCM cutdown Gov mid w/YHM T3
55 Tap 2833
55 FMJ 2678
75 Horn 2457
13.4" BCM cutdown mid ELW w/YHM T3
55 TAP 2810
55FMJ 2767
75 Horn 2477
14.5 BCM ELW mid w/YHM old TurboK
55 Tap 2904
55 FMJ 2773
75 Horn 2500
16 Green mountain mid unsurpressed new barrel
55 Tap 2929
55 fmj 2824
75 Horn 2511
18 WOA 3 gun interm gas w/YHM Turbok
55 Tap 3100
55 fmj 2960
75 Horn 2643
My TAP load is a 55 vmax with 24.7 Benchmark
My 55 Hornady FMJ is 25 XBR for matches
75 Hornady is over 24 varget or 26 CFE 223.
Thats much more in line with expected results.Quote:
Originally Posted by joedirt199
Looks like 12.5 is kind of a sweet spot for the heavier projectiles.
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My 12.5 is my oldest barrel brand new being 18 and 16 with only a few sighters rounds through.
Velocity loss/gain per inch of change steepens under 12.5. It is moderate between 12.5 and 16, and fairly flat 16- 24 or so. As we look at medium length barrels like 13.5 or 14.5, an inch in either direction makes very little or no difference, but down in the 10.3 region, an inch can be a big change in noise, flash, trajectory/ballistics, reliability, and silencer wear. In the opposite extreme, there is almost no difference between an 18 and 20 barrel, in practical terms. As in, you really need a chrono to see the difference.Quote:
Originally Posted by mig1nc
Handling difference between a 12.5 and 10.3 is nil.
In my view of general purpose rifles, which is merely my opinion, the sweet spots are:
11.5-14.5 for silencers (Mk18/M4 role),
12.5-18 for A2 flash hiders(M4/M16 role),
16-20 for light support weapons (M27/M38 roles).
I'm very fond of the 12.5-13.9" with a K-can.Quote:
Originally Posted by 1168
I very much regret selling my 12" but I'm loving my 13.7".
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I thought I had a spare gas block to assemble the 13.5, but I dont. While we wait on that:
81*F
12.5 Hodge/Velos
Federal XM855
2819 fps
39 es
13.6 sd
12.5 BCM Kino/Turbo K
XM855
2825 fps
69 es
20.3 sd
12.5 Criterion Core/.264 MG7k
XM855
2824 fps
31 es
9.5 sd
69gr Norma .223
2620 fps
38 es
11.1 sd