Modern Sporter - Build Discussions

rommelrommel said:
You want a 223 wssm if you want that kind of performance in a AR15 length action.
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The 223 wssm is way to big around to even try and fit in a small frame like the sporter. The fastest 22 cal round you can cram into the sporter would be the 22 grendel or 22 valkyrie. The 22 grendel is the faster of the 2
 
Thinking of doing 7.62x39. Is it really finicky? I need to pay for assembly. And I’m not that patient. Anything I should do to avoid having to debug and raise the probability of working first try? TNA or MRA bolt/barrel combo most likely since price is nice there and I can splurge on a trigger then.
 
there's lots of info about the 7.62x39 not being a very reliable cartage for the AR pattern design.

If you wanted something similar (arguably) I'd look into 300BLK. MRA has barrels on sale, and it uses the same bolt as .223
 
greg olmstead said:
The 223 wssm is way to big around to even try and fit in a small frame like the sporter. The fastest 22 cal round you can cram into the sporter would be the 22 grendel or 22 valkyrie. The 22 grendel is the faster of the 2
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Olympic arms has been putting 223wssm in AR15’s for over a decade. Jard and Dtech also do it. With the 50 Beowulf sized ejection port I think it’s possible in a sporter, although I’m not exactly sure if they use modified uppers.
 
rommelrommel said:
Olympic arms has been putting 223wssm in AR15’s for over a decade. Jard and Dtech also do it. With the 50 Beowulf sized ejection port I think it’s possible in a sporter, although I’m not exactly sure if they use modified uppers.
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Its impossible to use a standard ar15 barrel extension and bolt for the 223 wssm. The bolt would have no material between the bolt face and lug. Dtech is using what seems to be a modified ar10 bolt which requires a custom barrel extension and a proprietary upper receiver. There would be next to nothing for material in the barrel extension if you made it fit a standard ar15 and with the pressures the wssm cases run you would be shearing lugs off left right and center.

Is there an upper out there in 223 wssm that fits a standard ar15 lower? Yes there is. Can the parts be swapped to the modern sporter? No they cant. The fastest 22 caliber cartridge that will fit in the modern sporter is the 22 grendel. Which gives up very little to a 22-250 as is and it burns less powder. The 223 wssm is also a lot longer than the 22 grendel.

From what I've read is that they use an ar10 sized barrel extension and an ar15 upper that is the same size as the ar10 where the barrel goes. So in conclusion no you can not shoot 223 wssm out of a modern sporter. Well you could but just once
 
lj007 said:
Thinking of doing 7.62x39. Is it really finicky? I need to pay for assembly. And I’m not that patient. Anything I should do to avoid having to debug and raise the probability of working first try? TNA or MRA bolt/barrel combo most likely since price is nice there and I can splurge on a trigger then.
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I would definitely avoid all TNA branded parts. They are the lowest grade Chinesium and cause more issues than they are worth.
 
greg olmstead said:
Its impossible to use a standard ar15 barrel extension and bolt for the 223 wssm. The bolt would have no material between the bolt face and lug. Dtech is using what seems to be a modified ar10 bolt which requires a custom barrel extension and a proprietary upper receiver. There would be next to nothing for material in the barrel extension if you made it fit a standard ar15 and with the pressures the wssm cases run you would be shearing lugs off left right and center.

Is there an upper out there in 223 wssm that fits a standard ar15 lower? Yes there is. Can the parts be swapped to the modern sporter? No they cant. The fastest 22 caliber cartridge that will fit in the modern sporter is the 22 grendel. Which gives up very little to a 22-250 as is and it burns less powder. The 223 wssm is also a lot longer than the 22 grendel.

From what I've read is that they use an ar10 sized barrel extension and an ar15 upper that is the same size as the ar10 where the barrel goes. So in conclusion no you can not shoot 223 wssm out of a modern sporter. Well you could but just once
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Bummer but thanks for the good explanation of what they do to make it work.

I want to do something different with my second upper... 30 ar is impossible to get a barrel and bolt for any more. I don’t really want to make brass.

Maybe 7mm Valkyrie if they get the Starline brass going.
 
rommelrommel said:
Bummer but thanks for the good explanation of what they do to make it work.

I want to do something different with my second upper... 30 ar is impossible to get a barrel and bolt for any more. I don’t really want to make brass.

Maybe 7mm Valkyrie if they get the Starline brass going.
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Why base it off of the valkyrie with hopes of starline brass? When you could base something off the grendel that has lapua brass readily available. The grendel is a far superior case design.
 
Ahhh you people and your builds .....I like the ideas that people come up with .....I’m super pumped for mine to come in .....277 wolverine....the 30 ar ...the 39...all seem like sweet projects .....hmmmm I guess I’ll have to buy more uppers
Atrs you guys are the best .....with your product ...please keep up the good work

People keep the ideas coming and also please do tell where abouts to get the parts to build them

Thank you all
 
lj007 said:
Is MRA bad?
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I have 4 MRA barrels, from what I experience they are very nice. They get their blanks from IBI, which are high quality.

The 4 barrels I have from them is a pencil .223 wylde RL, 2x .223 wylde ML (my favorite), and a 300blk CL. I plan on buying their grendel barrel for another upper.

I have yet to shoot the 300blk barrel, so I guess I can't really say much about it, but the others I shoot have been good. One of the .223ML barrels has seen over 10,000 rounds at this point, the other .223ML is still new in package.


Also, for a point of interest the MRA handguards fit the MS upper really nice, the lines of the guard and upper match nicely. (I can post a pic later, I haven't received my 2nd run order yet, but I bought another upper privately that I have at home)
 
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iBi 19" 7.62x4WT barrel
Superlative Arms .936 adjustable gas block
Maple Ridge SLW 15" handguard
Phase 5 BCG
G2 Trigger
Rainer Arms tube, spring and buffer
BCM Medium charging handle
Vortex Viper HS-T 4-16x44 with ATRS Scope Rings of course
That's the cool stuff.
 
Bought the bolt/barrel combo for about $280 shipped direct from MRA. Now I’ll strip my wife’s AR down and see what happens.

ColinD said:
I have 4 MRA barrels, from what I experience they are very nice. They get their blanks from IBI, which are high quality.

The 4 barrels I have from them is a pencil .223 wylde RL, 2x .223 wylde ML (my favorite), and a 300blk CL. I plan on buying their grendel barrel for another upper.

I have yet to shoot the 300blk barrel, so I guess I can't really say much about it, but the others I shoot have been good. One of the .223ML barrels has seen over 10,000 rounds at this point, the other .223ML is still new in package.


Also, for a point of interest the MRA handguards fit the MS upper really nice, the lines of the guard and upper match nicely. (I can post a pic later, I haven't received my 2nd run order yet, but I bought another upper privately that I have at home)
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purplezuk said:
MRA builds a quality product, and is made in Canada
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Just FYI...MRA will be producing a full rail version of their V1 M-Lock handguard, available early next year. I contacted them last week regarding this and that was the timeline I was given.
 
Does Any one have a weight on just the SS receiver set (upper and lower)? I'm planning on doing a light weight build here when I get my other receiver in but can't find the weight on ATRS' website.
 
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