Modern Sporter - Build Discussions
- Thread starter ATRS Shaun
- Start date
Going to be running the same setup: rifle length gas, .750 non adjustable, milspec weight BCG, JP SCS standard, did you/would you suggest playing with the different springs for the JP?
OK, my first report for my first of a few builds.
The build specs.
Lower;
ATRS of course
Trigger tech AR diamond
DD pistol grip
DD adjustable stock
V7 titanium safety, bolt catch, mag release (black)
DD buffer tube
Brownells silicone coated buffer spring
Spikes carbine buffer
Upper;
ATRS SS
18.6 MRA .223 wylde mid length gas (the best gas)
superlative adjustable gas block
MRA 15" V1 handguard
Geissele ACH
Brownells lightweight BCG
SI dust cover
optic;
Nikon Black 1-4x24
Nightforce unimount
I'll start with the mags, I used LAR15 (10 body, 20 body, 30 body), CPD 50 beowulf, AA 50 beowulf (30 body), IMI 50 beowulf, and 458 socom (30 body).
No fully loaded mag locked in on a closed bolt except for the IMI beowulf mag. However, that IMI mag would not work at all. The bolt won't pick up a round on the way home, no matter how much I tired or prayed.
All the mags I used dropped free, unloaded. Spit out like a hot potato.
The shorter mags like the LAR15 10, 20 bodies and the CDP beowulf gave me trouble when closing the bolt on the first round. The bolt would grab the round and it seemed to just get stuck between the bolt and feed ramp. I'd have to pull the bolt back with the CH to get the needed inertia. The 30 body mags did not have this problem. The guns favorite mag was the 458 socom.
I shot 500 rds today using each mag as equal as possible.
As for the rifle, it was well worth the 13 months I waited. Assembly with this build was a breeze. My upper and lower fit together really tight. There is a slight movement, but much less than all the AR's I have. We are talking very very minor, I have to almost force the wobble. I don't even know why I brought it up?
Another observation is the upper receiver "tang" that meets with the charging handle doesn't stick out far enough to close the gap on top, and the machined part that the hook of the charging handle rests in seems to be too far back. I'm guess that was on purpose? The first few mags worth of ammo I shot I noticed the CH moving backward 1/8-3/16". That seemed to have stopped altogether now.
I had ATRS cerakote my receivers, handguards, and barrels. It was well worth the extra couple weeks and $. The uniform color between receiver and handguard make it look like it came straight from a factory or something. Very ###y. I chose black, and for the barrel I went with vortex bronze.
I would have taken pictures of it in the wild, but "they" still can't make a smartphone that doesn't die from -15C weather. I"ll put one up later in the photo thread.
The only issues I had in 500rds were the ones I talked about regarding mags. I have a couple more reports to do once I finish building my other receivers.
This build, with optic is 7.8lbs using a bathroom scale.
The build specs.
Lower;
ATRS of course
Trigger tech AR diamond
DD pistol grip
DD adjustable stock
V7 titanium safety, bolt catch, mag release (black)
DD buffer tube
Brownells silicone coated buffer spring
Spikes carbine buffer
Upper;
ATRS SS
18.6 MRA .223 wylde mid length gas (the best gas)
superlative adjustable gas block
MRA 15" V1 handguard
Geissele ACH
Brownells lightweight BCG
SI dust cover
optic;
Nikon Black 1-4x24
Nightforce unimount
I'll start with the mags, I used LAR15 (10 body, 20 body, 30 body), CPD 50 beowulf, AA 50 beowulf (30 body), IMI 50 beowulf, and 458 socom (30 body).
No fully loaded mag locked in on a closed bolt except for the IMI beowulf mag. However, that IMI mag would not work at all. The bolt won't pick up a round on the way home, no matter how much I tired or prayed.
All the mags I used dropped free, unloaded. Spit out like a hot potato.
The shorter mags like the LAR15 10, 20 bodies and the CDP beowulf gave me trouble when closing the bolt on the first round. The bolt would grab the round and it seemed to just get stuck between the bolt and feed ramp. I'd have to pull the bolt back with the CH to get the needed inertia. The 30 body mags did not have this problem. The guns favorite mag was the 458 socom.
I shot 500 rds today using each mag as equal as possible.
As for the rifle, it was well worth the 13 months I waited. Assembly with this build was a breeze. My upper and lower fit together really tight. There is a slight movement, but much less than all the AR's I have. We are talking very very minor, I have to almost force the wobble. I don't even know why I brought it up?
Another observation is the upper receiver "tang" that meets with the charging handle doesn't stick out far enough to close the gap on top, and the machined part that the hook of the charging handle rests in seems to be too far back. I'm guess that was on purpose? The first few mags worth of ammo I shot I noticed the CH moving backward 1/8-3/16". That seemed to have stopped altogether now.
I had ATRS cerakote my receivers, handguards, and barrels. It was well worth the extra couple weeks and $. The uniform color between receiver and handguard make it look like it came straight from a factory or something. Very ###y. I chose black, and for the barrel I went with vortex bronze.
I would have taken pictures of it in the wild, but "they" still can't make a smartphone that doesn't die from -15C weather. I"ll put one up later in the photo thread.
The only issues I had in 500rds were the ones I talked about regarding mags. I have a couple more reports to do once I finish building my other receivers.
This build, with optic is 7.8lbs using a bathroom scale.
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onetwentyish
CGN Ultra frequent flyer
- Location
- East Central AB (AKA Northern Texas)
Might want to get a better smartphone. All my Galaxy Note series of phones have proven to be reliable as low as -40°c for as long as I can stand to use them at that temp.
Feralmetal
Member
- Location
- Saskatchewan
anyone running an aero precision atlas r-one handguard on their modern sporter? hows the quality/colour matching?
You would have to cut it in order to fit it flush with the upper. A guy on here posted a picture, I don't think he ended up using that handguard.
Idk about R-one but S-one needs a hacksaw.
Edit I looked at the R-one, grab a hacksaw also lol
Feralmetal
Member
- Location
- Saskatchewan
Is there a list of compatible handguards around? I'm guessing none of the aero rails would work then
PinaKaleada
CGN Regular
- Location
- South of most
Finally fit the Geissele MK14 handguard and the M4A1 RIS II. Both needed a lot of fitting but it was worth it.
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I emailed ATTS about this and here the response
“Our standard ejection port size on MS uppers is large enough to fit the big bore cartridges but we have not tested them to see if they will eject properly. That being said, the first several hundred slick side uppers we did had larger ejection ports to ensure they would eject the big bore cartridges. We also did a small number of FA uppers with this larger ejection port. ”
We then went on to making sure I was able to get one of the FA uppers that had an enlarged ejection port for when my order is ready to be shipped out. Give them a shout and see if they’ll help you out! They’re super easy to deal with!
Asked here before, he replied, but I never saw any indication if it is working yet.
I may be stuck with a fa upper instead of slick side just simply because of what is on the shelf so would like to hear from people with the big bores.
Genuinely surprised there is not a ton of big bore modern sporters yet
