MP15 Sport accuracy question

[SFCRangerDoc]

So I got a crazy idea the other day to make my mp15 sport into a mini DMR rifle. It has the 5r barrel in it and is pretty accurate as is. I'm thinking I'm going to free float the HG/low pro gas block, and then put a solid rear stock on it. I already have a 3 baffle brake on it which makes follow up shots very quick. So I guess my question is this: Have any of you guys done similar work to your sports and what was your accuracy post work? Also did you find any particular ammo types gave better accuracy with the 5r barrel? I love the fact that S&W basically gave us a seemingly match grade HBAR style barrel in their "value" model

Doc

 

[thecatch8]

fixed stock, trigger, and a good scope and you are GTG from 500 yards in. Absolutely no reason you can't reach out and touch someone with your rig from distance. The only variable holding you up is the 1:9 twist rate, but stick to the right ammo and you will be fine.

 

[SFCRangerDoc]

fixed stock, trigger, and a good scope and you are GTG from 500 yards in. Absolutely no reason you can't reach out and touch someone with your rig from distance. The only variable holding you up is the 1:9 twist rate, but stick to the right ammo and you will be fine.

the 5r barrel is 1:8 not 1:9 i believe...i think they swapped to 1:9 after they stopped shipping the 5r barrels.

 

[gunny4053]

Adding a solid stock should be interesting, I'd like to see that. There's been a lot of free floating Sports, and I can't think of anyone complaining about accuracy.

Here's my Sport with the 15" Troy, although with the collapsible stock.



Due to some unplanned heart surgery, I haven't had a chance to really put it on some bags and see what it will do. What I can tell you, based on the off hand shooting I did, I wouldn't want to be a bad guy in front of me.

Good Luck with your project, and good shooting.

 

[SFCRangerDoc]

Adding a solid stock should be interesting, I'd like to see that. There's been a lot of free floating Sports, and I can't think of anyone complaining about accuracy.

Here's my Sport with the 15" Troy, although with the collapsible stock.



Due to some unplanned heart surgery, I haven't had a chance to really put it on some bags and see what it will do. What I can tell you, based on the off hand shooting I did, I wouldn't want to be a bad guy in front of me.

Good Luck with your project, and good shooting.

Ooo i like that rail...Yeah i havent seen one with a solid stock yet, but i would think combine that with that awesome barrel/3 baffle brake I have and FF hg it would be a tack driver.

here is my MP15 in its current setup. The RIS rail is not FF on this currently.

 

[Chew]

Have fun chasing a more accurate rifle!

You have a great platform to start with, IMO.

 

[rojodiablo]

I'm not one to drink the 5R kool aid. I had one and didn't think it was more accurate than any other decent carbine. I sold it and now have a newer 1:9 sport. For me they shot the same. My new rifle with a good trigger is much more accurate. Than the old stock rifle.

All I've done aside from furniture and an inexpensive Vortex scope is a good Geissele trigger.

I haven't experimented a lot with loads, and I don't reload.

I'm not sure free floating the barrel would make much difference on mine.

I pulled one on this group. This was over a backpack at my local MO conservation range.

Sent from my iPad using Tapatalk

With absolute certainty, the 1/9 barrel with 55gr ammo IS more accurate than the 5R 1/8 barrel. Are we spitting hairs? Yep. Does the 5R 1/8 barrel like 62gr ammo better? Yes, it does. But it's accuracy DOES NOT BEAT the 1/9 barrel with 55gr.

At least not the 16" unit. Maybe if you go out to 400yds and start playing with barrel lengths and powder charges, you might see some different results. But for store bought ammo? This is the basic result we have seen. Then again, once you go to 400yds with the 223, the wind means much more to you than anything else.

 

[cyphertext]

With absolute certainty, the 1/9 barrel with 55gr ammo IS more accurate than the 5R 1/8 barrel. Are we spitting hairs? Yep. Does the 5R 1/8 barrel like 62gr ammo better? Yes, it does. But it's accuracy DOES NOT BEAT the 1/9 barrel with 55gr.

At least not the 16" unit. Maybe if you go out to 400yds and start playing with barrel lengths and powder charges, you might see some different results. But for store bought ammo? This is the basic result we have seen. Then again, once you go to 400yds with the 223, the wind means much more to you than anything else.

I have to question the "absolute certainty"... where is the data to support this? From some of the guys who no longer post here, the 5R barrel was more accurate with the lighter loads, like the 55 grain dogtowns.

Not saying that Chew's group is not decent, but Grover has posted up much tighter. Somewhere on here is a post where he has .303 MOA grouping...

Most of us are not really going to be able to tell the difference, especially with off the shelf ammo, but the reloaders can get different results...

 

[SFCRangerDoc]

I have to question the "absolute certainty"... where is the data to support this? From some of the guys who no longer post here, the 5R barrel was more accurate with the lighter loads, like the 55 grain dogtowns.

Not saying that Chew's group is not decent, but Grover has posted up much tighter. Somewhere on here is a post where he has .303 MOA grouping...

Most of us are not really going to be able to tell the difference, especially with off the shelf ammo, but the reloaders can get different results...

Yeah I'm confident based on the grouping's ive gotten with factory ammo this gun is capable of sub MOA with custom loads. I plan to make up some match grade ammo and see what she'll do.