First build. Thought I'd try a "3 gun" rifle.

Dan Haught · Dec 12, 2014

Ok I thought this would be a cool project and maybe I could get to some 3 gun matches in 2015 instead of shooting USPSA all year. Never messed with a rifle like this before so hopefully the results will be good. Maybe I'll get some range time tomorrow. Anyway, thought I'd share.

Build:
Seekins forged lower. (Overpaid for during scramble of 2013)
Vltor MUR upper.
Rainier arms NiB NM Bolt and carrier.
Rifle buffer and Ace Skeleton stock.
Mega Arms 18" 5.56 SPR barrel with rifle length gas.
SLR adjustable gas block.
Surefire Pro Comp.
BCM KMR 15" handguard.
HDII with JM reticle and ADM mount.

Rifle weighs 6lb 14oz unloaded without optic and 9lb with optic.

jtischauser · Dec 12, 2014

Nice!

charger arms · Dec 12, 2014

Awesome looking blasters!

Dan Haught · Dec 13, 2014

Went to the range with it today to tune the gas and get it on paper. Not enough time to really try to dial it in or get a feel for shooting it off hand but managed to heat it up a little and at least get it working and hitting at 50y. I took my 4 1/2 year old son to the range for the first time too which was fun but a little distracting.

Having never built a rifle completely out of parts I'm not sure what to expect as far as a break in goes. Right now it doesn't seem terribly accurate except with 77 gr. Atlanta Arms match ammo which it actually shot really well. Pretty much all the 55 grain stuff I put through it was pretty bad and even the 69gr. winchester match that is sub MOA out of my LWRC SPR didn't seem to shoot that well. Though the 55gr. stuff shoots terrible out of the LWRC too. I will get more time later this week and shoot it solo and try to see what it's actually capable of.

I hate to even post this picture but to show that the 77 gr. ammo actually seemed to shoot well despite the one pulled shot to the left that I saw happen so no surprise flyer. The other four shots looked to be about 3/8" group or so which makes me think it would at least shoot that stuff sub 1" at 100 yards.

The recovered brass was a little beat up which surprised me. The case mouth on each one is smashed in and a little and deformed. There is quite a bit of brass marking on the deflector which makes me think it is getting spun out of the ejection port hard and hitting the mouth on the deflector. The brass was ejecting directly to the 3 o'clock and landing about 4-5 feet away.

Wall · Dec 13, 2014

try slowing it down with either less gas or a heavier buffer

racnsoonr · Dec 13, 2014

Did you chrono anything?

Dan Haught · Dec 14, 2014

If I go down a couple clicks on the gas block it won't lock back on the last round. I have an LWRC that is over gassed to the point that it kicks the brass out in front of the firing line and it's brass comes out looking great. This new rifle's got a standard weight rifle buffer and spring right now and a standard BCG. I was wanting to go lighter on all the reciprocating mass when I can afford the LMOS components. Going with heavier components seems counter intuitive. Could it be that the BCG speed is too high despite the gas being at almost the minimum level to function?

No to the Chrono. I didn't have the time to check any of that today. Once I get the functioning and accuracy lined up I'll chrono some stuff to see where my drops are going to be for my reticle.

Wall · Dec 14, 2014

just suggested going to a heavier buffer to lessen the speed of the BCG. I don't really see a problem with the bent brass as long as it runs.

Dan Haught · Dec 14, 2014

I don't care about the brass so much either. Just wondered what the difference was. So far the gun runs fine. This is my first go at setting one up so I'm not totally sure what the interactions are in the system between mass, spring rate, gas pressure etc. It's been a good learning experience so far though.