Well guys, I have an issue with my new MK12 variant. I just put a WOA MK12 barrel on my rifle and shot it this weekend. After reviewing all the MK12 post i could I had high expectations for this rifle. Needless to say, it didn't perform the way i hoped. Im running Nosler 77grn BTHP w/ Remington brass, IMR 4895 - 21.5 grns. From my calcs this is running around 2530fps. I set up around 85 yards and shot 5 shot groups with none less than 1 1/2 moa. Im running a Vortex Viper PST 4-16 so I'm pretty sure its not the optics. Ive got 32 rounds through it and am hoping that its just a break in problem. My plan, unless told otherwise, is to run some cheaper 556 through it to get to around the 200 round count mark and then see what it does after that. I know that rifles like specific loads but to me 1.5 moa is a little much. Any tips would be welcome.
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Mk12 not up to par
- Thread starter Houston Fire 34
- Start date
Not enough of powder more than likely as that is a fairly anemic load at only 21.5grn and only ~2500fps or so. You should be able to get a bigger powder charge (up to 23.5grn MAX IIRC) and MV out of that bullet. I'd start there, but only after confirming that everything checks out with your optics mount/rings/etc. in terms of being properly torqued down and secure on the rifle.
Didn't mean to sound like a prick.
I have a WOA service rifle upper and my starting loads(first down the tube) with 4895 were higher using a 69 Sierra.
They were also under 3 moa at 100 with irons, my best with irons was 1.4 MOA with an average CTC of .661MOA.
I'd up the charge and and agree with ORD on the top end.
I have a WOA service rifle upper and my starting loads(first down the tube) with 4895 were higher using a 69 Sierra.
They were also under 3 moa at 100 with irons, my best with irons was 1.4 MOA with an average CTC of .661MOA.
I'd up the charge and and agree with ORD on the top end.
77 grain projectiles have been known to have issues at 100 yards, they typically start to group better as you get out past 200 yards. Try running some 69 grain projectiles or move your targets out further.
I've got a number of WOA SPR barrels. They all shoot under 1/2 MOA (sometimes way under) with SMK 77s and Varget. They're running 2640fps. 18", 1-7.
I'm using the Nosler 77's with 24.0 of Varget (2700fps) in a 1/7.7 Wilde chamber Krieger and it is .5 MOA at 100. Try some Varget and see if the groups change.
I use Varget in my 77gr loads as well. Both Nosler and SMK projectiles.
The 77gr can one hole at 100yd/m no problem with a good loading.
The 77gr can one hole at 100yd/m no problem with a good loading.
18" BCM Barrel twisted 1-8" (5.56mm USMC SAM-R Chamber) with Nosler 77 gr CC over, 24.5 grains RL15, CCI 450 Primer, in a Speer case, and is good for 2701 FPS and .76" @ 100 yds for an average of five- 5 shot groups.
For IMR 4895 23.0 grs. is max for a .223 Chamber, with a 5.56 Wylde chamber you could work up a bit more....
For IMR 4895 23.0 grs. is max for a .223 Chamber, with a 5.56 Wylde chamber you could work up a bit more....
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I wolud purchase some 69 or 77 match grade ammo federal or black hills etc... (77 gr mk 262 by black hills is really good stuff) and use it as a control to make sure your rifle is a shooter. If they do well then work on your load...I would try and load to at least 2600 ft per sec with the 77 gr smk....best of luck let us know how you make out.....
I second this. WOA and 77 grainers with R15 shoot as well as my Kreiger service rifle. Keep working on that load.
Thanks guys. Gonna work on some loads now. does anyone have a max on the 223 wylde with IMR 4895. cant find it in my books. 23 is the max they show on the 223and only gets you to 2708. Is there any wiggle room on it?
PS. Tried to post pics but they are too big for the sight. is there another way?
PS. Tried to post pics but they are too big for the sight. is there another way?
You won't find a book load worth anything on loads at 5.56 velocities for 5.56 chambers. It's a liability issue for any commercial enterprise because some yahoo is going to try them in a 223 chambered rifle as sure as the sun rises in the east.
Rather, look towards a reasonable velocity. 2700 FPS is a good target with any 77 grain bullet from a 18" barreled 5.56mm. Loaded to the stops Factory BH 5.56 MK12 ammo and Atlanta Arms 5.56 Mk12 ammo of the types sold to Big Green only generate about 2750 FPS in most 18" barrels, and the the military does not care a fiddlers fart about reloading the brass. Hodgdon the source of the 23 grain IMR 4895 load @2706 FPS usually uses a barrel longer than 18" for their published velocity.
So work up carefully to 23.0 grains, watching for pressure signs. If you get there and your chrono does not give you near 2700 FPS, work above that limit carefully in 0.1 to 0.2 grain increments until you can hit 2700 FPS or so without pressure signs. Then call it a day if your accuracy is where it needs to be for your application.
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I have that same barrel, bullet, and primer with LC brass and 24.1 RL15 / 23.8 Varget @ 2.245" are my loads. About 2650fps for either one on my chrono.
As far as 4895 goes Quickload says 24gr for 55k PSI and 2700fps from a 18" barrel with a 77. So somewhere between 23-24 should be what he's after.
I just shot a WOA barrel yesterday for the first time with a real scope. It put down a 5 shot group that measured 0.160" CTC, the best I've ever shot from any rifle. SMK 77, 24.0g Varget, Tula small rifle magnum primer, 2,640 FPS, SD=7.
As others posted Another vote RL15 and i has over 14,000 rounds threw the same barrel.. Its a hammer.. If memory serves me well 24.5 rl15 lc case cci 400 75/77 pills do it to it..
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[MENTION=33182]TimK[/MENTION] "I just shot a WOA barrel yesterday for the first time with a real scope. It put down a 5 shot group that measured 0.160" CTC, the best I've ever shot from any rifle. SMK 77, 24.0g Varget, Tula small rifle magnum primer, 2,640 FPS, SD=7." Balls out dude, that is solid work.
It is totally unfair to the rifle to try one load or type of projectile and then condemn the barrel.
Others have said it all before, but really... think about this... try several types of ammo and give the tube a chance.
Others have said it all before, but really... think about this... try several types of ammo and give the tube a chance.
As others posted Another vote RL15 and i has over 14,000 rounds threw the same barrel.. Its a hammer.. If memory serves me well 24.5 rl15 lc case cci 400 75/77 pills do it to it..
Nice paint job I like it.
