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MEGA w/ ultra match WTF?

RED

RED

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Full Member
Minuteman
Jan 18, 2010
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Kodiak
Well, I've got a Mega w/ an 18" ultra match and I'm unable to keep it under 1moa with anything. I've tried a lot of different things including changing out the shooter. I've tried different seat depths, case sizes, bullets etc... I've tried different glass, bases, triggers and different match loads, AA11/m118, fggm, hornady. I had high hopes but I think I'm to the point of trying a new barrel. But I'm hesitant as this is the second UM barrel for this build. I know they are supposed tho be good barrels but I want .75moa. I don't think that's too much to ask.
Which leads into, where can I find a match barrel 18-20".
Any advice would be greatly appreciated

FYI gun specs:
Mega ambi receiver
PRS stock
Troy rail
Guyslee dmr trigger
Bushy HDMR
Aadmount
DPMS BCG
I couldn't be more frustrated.
 
How much torque did you use when tightening the barrel nut?
 
It lined up at about 45lb on both barrels. Maybe a little higher on the second like 50.
 
What is the twist rate on the barrel? Maybe the bullets you are trying are a bit too heavy.
 
I've heard great things about these barrels but are they just too light, this was my largest concern when I ordered it. I was able to determin that the first barrel was not a shooter a few weeks after it arrived and rainier took it back without a fuss even though I had painted it. Great customer service. With this one however it was a while before I could get to load development due to deployments and baby's and wives and such so I'll probably be posting it for sale and looking for a heavier contour from Kreisler, bartlien, LW or some other good company. I'd even take a chance on a DPMS SASS. I've seen good results from them
 
If you want a true true match barrel then perhaps a custom Krieger or Bartlien but I have no don't they (UM included) shoot under MOA.
Mine were very close in high wind, a chrono attached and shooting rather fast, no gun rest, just shooting to chrono load velocities.
No complaints here on an Ultra Match Barrel from me.
 
With the first barrel a swapped bolts with a friend to see if anything changed. I'll try that with this one.

Anybody got a line on a high end barrel
 
It should shoot better than that all the ultra match barrels I've seen have been accurate.

Is there any rhyme or reason to the groups like a consistent flier? Or are they just like shotguns all the time?
 
Actually, it dose seam to send 1/3 the rest are (usually) decently grouped. Hence the swapping of optics bases and bolts. But to be honest, what else can I change. I've lost that warm and fuzzy. If the flyer were always in the same area that would tell me something but its sporadic. It has made some decent group, like a 1.5" group at 500 but that's NOT the norm
 
First you have realize it's not a bolt gun, if you truly want ultimate accuracy get a bolt gun.
I doubt seriously that a barrel change will make all the difference in the world.
There are too many unanswered factors to consider, IMO.
Good Luck.
 
I had the same issue with a Rainier Ultramatch barrel on my MATen as well. Groups weren't even good enough to post on AR-15.com ;) . I also had issues with punching primers on FGGM 7.62x51 ammo. I tried 168s, 175s, 185s, factory and hand loaded ammo, ect and nothing worked. I got sick of it and pulled it off and shipped it back. Rainier didn't want to warranty it because it had been almost a year at the time that I returned it, but they ended up taking it back. I've been waiting on a Krieger for about 6 months now.

I'm not saying they're bad barrels. Several people have said good things about them but I think they're putting out the occasional lemon here and there.
 
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First they shouldn't be called an "ultra match" If anything Krieger and Broughton should be ultra match and everything else should be match. I've had Bartleins, Harts and Liljas that all shot well but in 15+ years I have never seen a crooked Krieger. It doesn't matter how slick the bore is lapped if the bore isn't straight.
Is the rifle over-gassed? If it is it will never shoot right.
When loading try to adjust your resize dies where the cases are only .003-.004 under the chamber size, use a RCBS case mic to check.
Not to offend but, follow through on the trigger is very important.
A good solid hold works best on an AR, at least for me it does.
 
Have you changed the nut behind the rifle?
 
Chambering has a lot to do with it and matching a proper load is critical to accuracy.
In my three Ultra Match Barrels ~ the 16" and 18" are very close in specification while the 20" is much tighter.
I originally (before I started reloading) had pressure issues with my first 18" and sent it back to Rainier where they replaced it.
At the time all I was doing was plug and play ~ a lot more to 308's than a typical AR15.
However, since actually measuring things and chrono-ing loads I see the ammo I was having problems with (Black Hills and Nosler) was really better suited for my 5R bolt gun.
You also have to realize that a gas gun is no match for bolt gun accuracy.
YMMV
 
smschulz: what kind of accuracy are you getting from your UM rigs and w/ what loads
 
BusterHyman said:
Actually, it dose seam to send 1/3 the rest are (usually) decently grouped. Hence the swapping of optics bases and bolts. But to be honest, what else can I change. I've lost that warm and fuzzy. If the flyer were always in the same area that would tell me something but its sporadic. It has made some decent group, like a 1.5" group at 500 but that's NOT the norm
Click to expand...

I had the same problem using a QD mount and a telescoping stock I could never get quite the right cheekweld and the mount wasn't 100% as tight as fully torqued rings. At least with the ADM mount and a heavy scope perhaps a different mount or a lighter weight scope would have been different. As soon as I swapped to torqued rings the groups went for around 1-1.25 to .75-1" and with an A2 stock I shot much more consistently.

Bipod is another one unless I am prone I don't shoot a bipod as well as from bags.

Also don't swap bolts I mean really that bolt is headspaced to your barrel let them grow together. Swapping them potentially puts you in a situation where headspace is too tight or too lose. They don't "headspace themselves".

Plus those group pics really look like 4 shots into 3/4 or less and then the last round mag flier a little high and left or right.

edit: if it were me I'd move the scope farther forward on the FDE rifle and then try to shoot nose to charging handle. Another trick is to mess with seating depth I have had semis in the past who loved bullets seated deep and otherwise didn't shoot better than 1-1.5".
 
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I'm having similar problems with my Maten MKM Mega build with a Rainier Ultra Match 20" barrel. It is a pretty light contour for the 16-20" Ultra Match Barrels (.750 gas block similar to an AR 15 barrel). I'm going to return mine but I was looking at the 24" Ultra Match Barrel. It's a little longer than I wanted but it's a heavier contour (with a .936 gas block). Adds a pound and 7 oz to the overall rifle too which would be unfortunate, but if the accuracy is there I'll deal with it. It would be nice to have the heavier contour in a 20" barrel. Any opinions if you have the 24" barrel cut down to a 20" by a professional gunsmith if there's a good chance that it would affect accuracy (damage to the crown)?
 
went back to the range today, tried some different bullets/weights and different seat depths. my ladder tested hand loads still hold as the most accurate (175 SMK, 42.9g varget, CCI 200s, LC brass) at about 1.25moa (from 1-500yards). this is not good enough for me, especially after seeing my buddy consistently shoot .2-.7 with his blackrain/dpms sass which i helped him build! so ill be in the market for a heavier contour 18-20"er (along with half the other members here). wish me luck.
 
usmcmk12 said:
I'm having similar problems with my Maten MKM Mega build with a Rainier Ultra Match 20" barrel. It is a pretty light contour for the 16-20" Ultra Match Barrels (.750 gas block similar to an AR 15 barrel). I'm going to return mine but I was looking at the 24" Ultra Match Barrel. It's a little longer than I wanted but it's a heavier contour (with a .936 gas block). Adds a pound and 7 oz to the overall rifle too which would be unfortunate, but if the accuracy is there I'll deal with it. It would be nice to have the heavier contour in a 20" barrel. Any opinions if you have the 24" barrel cut down to a 20" by a professional gunsmith if there's a good chance that it would affect accuracy (damage to the crown)?
Click to expand...

First thing to remember is the words "ultra-match" is a title...gimmick. Many production grade barrels will shoot under an inch. If the "UM" wont then it sure isn't an ultra-match. Personally I would much rather have a 20 than a 24" and as long as the gunsmith crowns the barrel right it should shoot better than the lightweight 20 just because there is extra weight holding the front end down. If the stress relief was done correctly the barrels should not walk (string shots) as they heat up.
One thing to check on your light barrel, try it without a muzzle device to see if accuracy improves.
 
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bustin said:
One thing to check on your light barrel, try it without a muzzle device to see if accuracy improves.
Click to expand...

yeah i tried this with the first barrel. of course the POI changed but accuracy remained consistent. i don't want to bash the UM barrel line as iv heard great thing and Rainier has been good to me, i just don't want to be limited by the barrel because Im to lazy or comfortable to change something. i know that Larue manages terrific accuracy out of a light barrel, is theirs an in in house barrel or like say a Krieger. dose anyone have a suggestion for another component that my be taking down accuracy.
 
RED, this is not a dig on you at all...but what kind of accuracy are YOU capable of with a known accurate .308 gas gun? Have you had a "known good" shooter shoot your rifle?

Gas guns are not bolt guns. There are times I struggle to get the most out of mine. They are a little more pick about position, follow through, etc. My Noveske AR10 is about a 1-.75 MOA rifle, but if my concentration lapses at all, it opens up quickly.
 
LoneWolfUSMC said:
RED, this is not a dig on you at all...but what kind of accuracy are YOU capable of with a known accurate .308 gas gun? Have you had a "known good" shooter shoot your rifle?

Gas guns are not bolt guns. There are times I struggle to get the most out of mine. They are a little more pick about position, follow through, etc. My Noveske AR10 is about a 1-.75 MOA rifle, but if my concentration lapses at all, it opens up quickly.
Click to expand...

Both red and I went to school shooting 'accurized' m14 ebrs. I consistently should sub moa with my ar-10 granted its chambered in 6.5 creedmoor not .308 but the recoil mechanics and follow through dont really change.

I have shot the gun with both barrels and I think I have managed one group that was respectable out of it but that was more of a fluke as I couldn't reproduce it. I am not gods gift to shooting but I am at least relatively consistent on both my bolt and gas guns and this gun of Red's just won't shoot below the sub moa rainier guarantees with factory match ammo.


Sent from my iPad autocorrect at your own risk.
 
I am capable of mutch better accuracy than what I'm getting. Again not to toot my horn but iv had instruction and practice and i can consistantly shoot .5, rifle provided. again Duck; I hate you.
 
RED said:
I am capable of mutch better accuracy than what I'm getting. Again not to toot my horn but iv had instruction and practice and i can consistantly shoot .5, rifle provided. again Duck; I hate you.
Click to expand...
What a stupid screen name I have. Anyhoo, I love you, buddy. I can vouch that it's not the shooter. I still blame gremlins....
 
Just ordered a Lilja in 20" (.308 1-11). They had them in stock so I went for it. I've heard good things on this forum about them. Anyone have any first hand experience with a Lilja barrel on a .308 AR?
 
RED said:
-
dose anyone have a suggestion for another component that my be taking down accuracy.
Click to expand...

Like I said I wonder if you are having repeatability or parallax issues with your scope and mount. Handloads that aren't concentric can do it too but it sounds like you have tried factory so probably not an ammo issue.

Also if you are counting the last round flier from the magazine then you'll be frustrated til the cows come home as I've never been able to get that one totally under control. 308 ARs are notorious for throwing the last round in the mag differently.

Finally Rainier could have had a bad run of barrels. It happens and with the rush on components a lot of lemons came out everywhere.
 
usmcmk12 said:
Just ordered a Lilja in 20" (.308 1-11). They had them in stock so I went for it. I've heard good things on this forum about them. Anyone have any first hand experience with a Lilja barrel on a .308 AR?
Click to expand...

Make sure you post a range report. I was interested in those too, I'm just a little leery of all barrels that arn't 4 pounds right now. I'm sure it will perform.
 
"Like I said I wonder if you are having repeatability or parallax issues with your scope and mount."
This was my initial thought too. With the first barrel I tried two different scopes, with the second I tried different scores and bases, 3 to be exact. A PST, a MK4 and the HDMR w/ aadmount. I have to admit thoug, smacking large pieces of steel at a little bit or range is still a good time with a semi auto.
 
Got a 20" lilja on mega .308 for about a year now and it's phenomenal. You'll be happy!!
 
The accuracy that he is wanting is possible out of a gas gun. This is the grouping shot from the black rain with (DPMS SASS barrel) that he was talking about in an earlier post. First two at the top left were cold bore and the next 3 were follow up shots.(measuring about a .2in but nvr been more than a .6) This is also the gun made from parts he recommend (except the BRO receiver my choice ftw) that we assembled while partaking in adult beverages in his basement. Thanks RED!
_DSC2252.jpg
_DSC2260.jpg My AR to the left/REDS to the right.....twins..almost?
 
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OP: Try a Mega Arms barrel. I got a 20" 1:10 barrel for my MATEN, and despite my fat finger and lack of practice, it will shoot nice MOA groups with M118LR. I'm sure a competent shooter can do much better than that.
 
RED said:
"Like I said I wonder if you are having repeatability or parallax issues with your scope and mount."
This was my initial thought too. With the first barrel I tried two different scopes, with the second I tried different scores and bases, 3 to be exact. A PST, a MK4 and the HDMR w/ aadmount. I have to admit thoug, smacking large pieces of steel at a little bit or range is still a good time with a semi auto.
Click to expand...

Fulton has decent drop in barrels for not a lot of money they are both heavy and light profile. Or just order a custom from someone like Brux/Krieger/Lilja.

Weird to me that you've had 2 in a row that won't shoot tight though as I've done tons of ARs over the years and have only had 2 bum barrels in that time. And usually a bum barrel won't be 1.1MOA it'll be 2+ MOA.
 
M_2_B said:
The accuracy that he is wanting is possible out of a gas gun. This is the grouping shot from the black rain with (DPMS SASS barrel) that he was talking about in an earlier post. First two at the top left were cold bore and the next 3 were follow up shots.(measuring about a .2in but nvr been more than a .6) This is also the gun made from parts he recommend (except the BRO receiver my choice ftw) that we assembled while partaking in adult beverages in his basement. Thanks RED!
View attachment 9451
View attachment 9452 My AR to the left/REDS to the right.....twins..almost?
Click to expand...

My DPMS SASS shot like that too only reason I sold it was because it was heavy as hell.
 
Here is my Rainier UM. I did pretty well with a 10x scope at 100 yards I believe putting three shots within 1/2 inch. I need to work on my trigger pull but I believe the rifle is solid.



 
RED said:
I am capable of mutch better accuracy than what I'm getting. Again not to toot my horn but iv had instruction and practice and i can consistantly shoot .5, rifle provided. again Duck; I hate you.
Click to expand...

No worries.

I have a pretty extensive background, but then I am having problems with a piece of equipment I always step back and ask myself if it could be me causing the problem. Usually it isn't........but sometimes it is.
 
Thanks for the thread as this interests me. I just picked up a 18" Rainier UM and have the rifle assembled. I initially built this rifle to sell, but now I want to keep it. I wanted to wait for optics, but now I am really wanting to test fire this rig. Just curious, when did you order your barrel or what year is the barrel? Mine is a 2013.

Blessings,

BC
 
I've been reading this thread with interest as I also have a 20" Rainier UM rifle built with a DPMS smooth side upper and carbon fiber ff tube. Sweet light weight rifle that runs like a top, but it is fickle afa what it likes. I couldn't find anything except 110 gr vmax loads with H4895 that shot better than 1 moa, untill today. 41 and 41.5 gr of H4895 under a 168 amax shot slightly under 1 moa. These same bullets shoot around 1.5 moa with Varget and 4064.

I think maybe that's as good as it will get for that light of a profile barrel? IDK, time will tell if I can tune the load in any better.

FWIW, this is the 3rd barrel on this build, the first 2 were Rainier Selects. The first one was abysmal, nothing shot well at all, and different bullet weights would shoot 6 to 8" different poi. The second one was way better but still not satisfactory. So I went for the UM and it's head and shoulders better than the Selects. I can say I haven't seen more responsive customer service than I got from Rainier. They traded out the barrels no problem.
 
Make sure you get the bolt and barrel headspaced properly, especially when they are coming from different manufacturers, and not assembled and tested at the factory.
 
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I purchased the first um in October 12 and the second in feb 13. Rainier was terrific about the exchange and in all honesty would probably hook me up again but I feel like that would be taking advantage. If it was a real fault of the part I would return it. As it is I'm just going to let it go here on the hide. I'll put it on the for sale board tomorrow. I have a DPMS on its way, we'll see how that plays out. Range report to follow. So if anyone wants this ultra match 18", I'll let it go for $300. I feel like selling based on this thread is the most legitimate way to promote it. I thought about running Tubb's final finish through it but just didn't get that far. I'm curious what your opinions are on that.
 
Hey Red,
Sorry to hear about your problems. A lot of "smart than me" folks offering good advice. Listen to them and don't give up.
I don't have a 308 ultra match but I do have a 223 16" ultra match which I built myself in a seekins upper/lower.

I can tell you that you have to eliminate as many possible error as you can. These small errors multiple. 1MOA ammo and 1MOA gun = 3MOA groups

1. Start with match grade ammo, not reloads. Too many variables unless you've been reloading for 20 years.
2. Try different match ammo types if you can. I have the best luck with 55gr Hornady in my 223 and 168gr FGMM in my 308 bolt gun.
3. Don't use a bipod. Also don't move the gun for 2 seconds after each shot.
4. Do use a big power scope.... the Bushnell you have will do I'm sure.
5. Do remove copper fowling after 20 or 30 shots. Ask any benchrest guy. They spend a lot of time shoot groups.

I seem to shoot better groups at 200 yds than 100 yds, not sure why. Perhaps its the aim small, shoot small concept. At 1600+ rounds I still get consistent 3/4" groups at 100 yds and 1 MOA groups at 400 yds from my 223.

Chaos694-m.jpg


Here is 400yd steel.
400yd_0680D.jpg


IMG_5684m.jpg
 
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When your mind is made up ~ it is made up.
I seriously doubt there is anything wrong with the barrel.
Mentally for you it is probably the right thing to do.
Good Luck
 
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