Put together this “SPRish” build…quick rundown…
BCM VLTOR upper with a 18in. 1/8 twist,rifle length gas system
VLTOR VC1 flash hider
C3 defense lower
Magpul UBR and MOE grip
Larue SPR mount and a Luep. 2.5 -8 Mid-range scope, TMR reticle
Troy irons and a VLTOR/Tango down bipod
I have shot 69 grn match kings and it has shot well out to 400 yds. The only thing ,why did BCM use a 1/8 twist?Why not the 1/7?I am wanting to run some 77 grn fodder thrugh it at some point to see what it will do. Does anybody have a 1/8 barrel, how does the heavier bullets perform?Now for the gun porn…
Trigger?
Very nice:)
I have the same upper, and I can assure you that the 1/8 twist is more than adequate for the 77gr bullets. Nothing to worry about.
righteous build. what fcg did you use?
I have had two uppers with 1/8 barrels and they shoot 77GR just fine.
The fun part is testing a bunch of different loads to see what shoots best, and then make sure you stock up on that load (hopefully all from the same lot).
If you haven’t already keep a log book if nothing else to track rounds fired, dope, and what ammo you are shooting. Then get a free program like On Target which you can scan targets, then check to see what type of groups you got. I have a file folder system on my computer of scanned targets that way I don’t have a pile of used targets sitting around. Allows quick and easy references. You can create a folder of that date, scan the images, calculate them in On Target, and even throw in a quick word document in the folder with notes and such.
My first AR15 was a DCM model with a 1:8 twist for High Power matches and I shot 80 grain Sierra Match Kings out to 600 yards with no problems.
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Cool, thanks for the info guys…Running a standard trigger right now, but will upgrade at some point.
Dave, Nice rig! My winter project is an 18" SPR. I ordered one go the rifle gas 18" polygon barrels from Black Hole. I’ve read a lot of good data on its performance. It’s a 1 in 8 as well. I have a buddy in town that is a master reloader. We are going to work up the perfect load for this barrel, using a 77 gr. HPBT.
I found a couple of loads I’m going to try out on another forum in the 75 gr.
- 75 gr. BTHP with 22.0 gr of H335
- 75 gr BTHP with 22.3 gr of H335
I’m going to load a box of each and see how they print.
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