Modern Sporter - Build Discussions

My barrel fit loosly as well, I tried a couple different ones and it was the same for all of them. Didn't really think much of it as they tightened up just fine with the barrel nut.
 
If it was a barrel problem then how did this same barrel fit my SLR? I also tried this barrel in a spare upper I had kicking around and it fit snug. I tried my ballistic advantage barrel in my MS upper and it was also loose.


greg olmstead said:
Sounds like a barrel problem not an upper problem. Both of my uppers fit the barrels very tight and I had to use the barrel nut to seat the barrel completely
Click to expand...
 
It still fits the Ms upper. Every dimension on the uppers are checked after they get them back from ano and if it's not within spec they don't ship it out. Tolerance stacking is a problem. If you have a barrel extension on the small side and an upper on the bigger side of the tolerance its going to be loose. If you are worried about it send it back to atrs and get them to double check it with your barrel.
 
greg olmstead said:
It still fits the Ms upper. Every dimension on the uppers are checked after they get them back from ano and if it's not within spec they don't ship it out. Tolerance stacking is a problem. If you have a barrel extension on the small side and an upper on the bigger side of the tolerance its going to be loose. If you are worried about it send it back to atrs and get them to double check it with your barrel.
Click to expand...

My question was should I be worried about it. Everything is put together and shoots good so idk. I just don't have experience with this particular issue is all. I emailed them anyways, so ill see what they say when they get back to me.
 
Patt08 said:
My question was should I be worried about it. Everything is put together and shoots good so idk. I just don't have experience with this particular issue is all. I emailed them anyways, so ill see what they say when they get back to me.
Click to expand...

There is no safety concern in regards to what you are describing. If a tighter fit is desired I have heard from some folks that they bed their barrel extension into all upper receivers using loctite 620. This is not a method that I have experience using myself, and am merely passing along a customers recommendation. Use at your own risk. [Although I am told there is no risk]
 
Patt08 said:
My question was should I be worried about it. Everything is put together and shoots good so idk. I just don't have experience with this particular issue is all. I emailed them anyways, so ill see what they say when they get back to me.
Click to expand...

One option I’ve seen is people use Indian head (brand name) basket shellac compound. Check out “fifty%” on YouTube. He swears by the stuff. I’d sooner use than that a locktite, at least this you can remove easily.
 
The green loctite 620 isn't a thread locker, it's a retaining compound designed for cylindrical applications, seems perfect. We use this stuff at work all the time, it will fill a gap of 0.015.

I never thought of using it, but I will definitely "borrow" a few drops from work if needed for my barrel/upper.
 
ATRS Shaun said:
There is no safety concern in regards to what you are describing. If a tighter fit is desired I have heard from some folks that they bed their barrel extension into all upper receivers using loctite 620. This is not a method that I have experience using myself, and am merely passing along a customers recommendation. Use at your own risk. [Although I am told there is no risk]
Click to expand...

Just remember, 620 is permanent. You would need to heat it up to over 500deg F to get the loctite to break it's bond before you hammer it out. Lots of people do it, but I would rather not since I change my mind on barrels pretty often.
��
 
RobbieLaidlaw said:
Not seeing many builds, lets see more photos guys. :)
Click to expand...
YsSkmOQ.jpg

8ff38LI.jpg

3h4Pygo.jpg

"Mk12 mod 1" Modern SPRter

ATRS MS receiver
Custom ATRS SPR barrel 18.6"
Ops Inc. 12th Collar and brake
DD mk12 gas block
Knights Armament mk12 mod 1 free float RAS
Knights Armament flip up M4 front sight
Knights Armament folding micro rear sight
PRI M84 gas buster charging handle
LMT FA BCG
Larue Tactical LT104 QD SPR mount
Nightforce NXS 2.5-10x24 MD
ARMS #32 Bipod Mount
Harris Engineering BRM-S w/ KWM Pod-Loc
KAC hand stop
VLTOR A5 buffer system
B5 Sopmod stock
KAC end plate sling mount
ERGO grip
Geissele SSA-E trigger
Geissele LPK

T57Fw9b.jpg

Non Restricted!
 
I'm sure this has been covered in 1 of the 154 pages but my DPMS ejection port cover wont open with a Brownells Lightweight BCG. Is it the cover or the bcg or both?

Also, theres quite a bit of play between the receivers....any fixes other than some bits of electrical tape on the rear screw?
 
Zee705 said:
I'm sure this has been covered in 1 of the 154 pages but my DPMS ejection port cover wont open with a Brownells Lightweight BCG. Is it the cover or the bcg or both?

Also, theres quite a bit of play between the receivers....any fixes other than some bits of electrical tape on the rear screw?
Click to expand...

Problem is the ejection port is "relocated" to more "outside" location, therefore the lightweight BCG doesn't touch it.
 
I put mine together last night. I hate trying to post pics here. I built it using an iBi barrel chambered in 7.62x40WT. The pics are on Slam Fire Radio's FB page and my Instagram.
 
Zee705 said:
Would a dab of JB weld on the center portion of the cover do the trick? Were there any other solutions other than changing bcgs?
Click to expand...

Yeah, I read in other posts of guys doing that and it working. I think it's the same case for the strike industries dust covers as well. I'll have to do the same.
 
Patt08 said:
I hope thats not the case. I had to order one of the adjustable strike industries dust covers because none of mine would stay shut.
Click to expand...

The SI will stay shut but may not open when the bolt cycles. A dab could probably fix that. I just let my brass open mine for me.
 
You must log in or register to reply here.
Back
Top Bottom