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View Full Version : AR15 ejecting brass at 1:30-2:pm area (overgas?)


problemchild
05-24-2012, 11:05 AM
My new build (16" mid length) is ejecting the brass forward. So far this is what I have tried:

Used two different kinds of ammo
Used two different mags
Used lower from wifes DD rifle
Swapped buffer weight from H to slashes heavy st-t2
Swapped buffer spring from standard to cs flatwire +20%
Swapped spikes BCG with wifes DD BCG

Raineer says send it in and they will look at it for a fee, plus I pay shipping. My gut tells me the barrel (raineer ultra match) has too big of a gas hole. They installed the gas block and tube. They also suggest I try an h2 or h3 buffer. I told them the buffers cost money and you want me to buy two of them at 40ea, I already bought one? Not doing that!


The build:
RA ultra match 16" mid barrel
Vltor upper
Spikes boron BCG
Mega lower
H buffer now swapped to slashes st-t2 buffer
CS flatwire buffer spring, swapped from standard spring

So whats everyone's take on why the brass is ejecting so far forward? Over gassing? Barrel?

tonyxcom
05-24-2012, 11:10 AM
Does the rifle feed, shoot and eject reliably? Then who cares were the brass lands.

How does that barrel shoot BTW? I am getting an upper built that uses a 14.5" UltraMatch.

Edit: Heck, it could even be the shape of the Vltor brass deflector.

Hoop
05-24-2012, 11:23 AM
If it isn't beating on the brass/throwing it abnormally far and the ejection pattern is consistent I wouldn't care.

PS-I have one of those barrels and it ejects at 2 o'clock and it doesn't bother me. only AR's I've had that ejected right at 3 were rifle gas.

people get too hung up on AR ejection patterns imo

problemchild
05-24-2012, 11:29 AM
If it isn't beating on the brass/throwing it abnormally far and the ejection pattern is consistent I wouldn't care.

Everything I have been told is a good running rifle ejects 3Pm and back. An over gassing rifle is in front of 3pm. Over gassing causes or is harder on the rifle and parts causing premature wear and excessive recoil. A properly tuned rifle will last longer and have less recoil.

Is this not correct information? The rifle also has erratic ejection. One will go to 1pm then one to 2pm then two to 1pm then repeat. Its not ejecting consistent into one area.

waawaaweenie
05-24-2012, 11:31 AM
seems to me if the brass lands in a uniform location, that is a good sign. it isn't going to be changed unless you change the extractor and or the ejector. or ad an O-ring to the extractor spring. You could also modify the ejector spring.

I know on my 308, if I use any powder other than Varget, the brass hits me in the face since my upper has no case deflector

tonyxcom
05-24-2012, 11:32 AM
Its funny my Larue Stealth ejects the Hornady Steel Match cases about 3 benches over. I occasionally take one to the forehead since I shoot left handed. LOL.

My UltraMatch barrel is going in a VLTOR upper too. Hope it ships today so I can shoot it Sunday.

Hoop, how does your barrel shoot?

tonyxcom
05-24-2012, 11:36 AM
Everything I have been told is a good running rifle ejects 3Pm and back. An over gassing rifle is in front of 3pm. Over gassing causes or is harder on the rifle and parts causing premature wear and excessive recoil. A properly tuned rifle will last longer and have less recoil.

Is this not correct information? The rifle also has erratic ejection. One will go to 1pm then one to 2pm then two to 1pm then repeat. Its not ejecting consistent into one area.

I think we can add that to the list of AR Wives Tales.

Yes, overgassing is bad. But ejection pattern and overgassing aren't 100% correlated.

RHT447
05-24-2012, 11:44 AM
I trim about 2&1/2 coils off my ejector springs so my AR's toss brass at 2-3:00 so I can find it to reload.

bombadillo
05-24-2012, 11:46 AM
I'd say overgassed. Try playing with your ejector spring and seeing what you can do with that. I prefer mine to shoot at 4:00 myself as its easier on the components, brass, and people sitting at a bench next to me.

steve92407
05-24-2012, 12:04 PM
I would not be concerned about it unless you have ejecter smearing on your brass. wow to hard for me to explain. randall has pictures on his sight under how di system works[ar15 barrels]

problemchild
05-24-2012, 12:08 PM
I would not be concerned about it unless you have ejecter smearing on your brass. wow to hard for me to explain. randall has pictures on his sight under how di system works[ar15 barrels]

I do have ejector smearing and extractor claw marks. Would an H2 or H3 buffer do anything to resolve this?

Munny$hot
05-24-2012, 12:11 PM
You can buy an adjustable gas block/FSB to limit the amount of flow,
http://www.jprifles.com/1.4.6_gs.php

BigBamBoo
05-24-2012, 12:37 PM
Again....ADJUSTABLE GAS BLOCK! If you have never used one you are in for a BIG treat. Your rifle/carbine will NEVER be over or under gassed again. You can tune the bolt velocity to all kinds of loads....light varmint rounds to heavy target loads and everything in between.

Cost wise it will be cheaper and yield much better results then messing around with buffers.

But what do I know....

FeuerFrei
05-24-2012, 12:49 PM
^^ yes. JP is my gas block of choice. These cure an over gassed AR rifle without all the buffer/spring and extractor gadgets you would have to mix and match to just slow down the cycle.

steve92407
05-24-2012, 12:57 PM
Yep it is a major indicator it is over gassed.springs and buffers are rarely going to change the dwell time of unlock to extractor ingagement.the port maybe drilled towards the upper dia of .090 for a 14.5 barrel mid gas not a 16.the galling is usually the indication the shell is being extracted to early before the pressure wave has dropped.Increased chamber contamination,reduced life of the bolt and extractor.

Hoop
05-24-2012, 1:03 PM
I do have ejector smearing and extractor claw marks. Would an H2 or H3 buffer do anything to resolve this?

My 2 cents is that Rainier has a warranty and you aren't happy...so might as well use it. Especially if you have tried several different bolts and buffers and it's still the same.

Like I said mine land at 2 o'clock also case heads look like this:

http://i197.photobucket.com/albums/aa195/Hooperinius/S5003372.jpg

Those have been fired 3x times now and it's a hot load. No brass shavings, heavy ejector swipe, no H3 buffer, etc. If yours are beat to **** with factory loadings and you've tried other lowers I would send it back. Don't throw money at heavy buffers it should run with a factory weight one 100%.


Hoop, how does your barrel shoot?

http://i197.photobucket.com/albums/aa195/Hooperinius/S5003338.jpg

Random groups from awhile back. Shot off a bipod with a 3-9 vx-r scope. I haven't done load development for it either I just make 1 of 2 different loads and go shooting.

edit:

targets from yesterday same TAC load that was grouping about 1-1.25" in the above pics

http://i197.photobucket.com/albums/aa195/Hooperinius/S5003375.jpg

http://i197.photobucket.com/albums/aa195/Hooperinius/S5003374.jpg

All of them were at 100 or so yards...if they look like 4 rounds or 10 rounds...they probably are.

Haven't figured out how to keep it from throwing the last round in the mag low yet.

Nathan Krynn
05-24-2012, 1:08 PM
Are you sure it is not bouncing off your defector?

problemchild
05-24-2012, 2:55 PM
My feeling is why the heck should I have to spend 125 on a gas block if they drilled too large a hole in the barrel. NO other DI gun I have does this. The LMT and DD both eject to 4:00 in a nice neat pile. Something is wrong with the barrel.


Again....ADJUSTABLE GAS BLOCK! If you have never used one you are in for a BIG treat. Your rifle/carbine will NEVER be over or under gassed again. You can tune the bolt velocity to all kinds of loads....light varmint rounds to heavy target loads and everything in between.

Cost wise it will be cheaper and yield much better results then messing around with buffers.

But what do I know....

bombadillo
05-24-2012, 3:48 PM
Again....ADJUSTABLE GAS BLOCK! If you have never used one you are in for a BIG treat. Your rifle/carbine will NEVER be over or under gassed again. You can tune the bolt velocity to all kinds of loads....light varmint rounds to heavy target loads and everything in between.

Cost wise it will be cheaper and yield much better results then messing around with buffers.

But what do I know....

Trust this man. He has quite a bit of experience with adjustable gas blocks. I doubt the company you bought it from will do a darn thing, and I adjustable gas blocks are the shiz.

BigBamBoo
05-24-2012, 5:18 PM
My feeling is why the heck should I have to spend 125 on a gas block if they drilled too large a hole in the barrel. NO other DI gun I have does this. The LMT and DD both eject to 4:00 in a nice neat pile. Something is wrong with the barrel.

Well first off I don't know where your getting your prices. But RETAIL JP blocks are around $70.00 and if you have a Brownells account they are even cheaper. Link here: http://www.brownells.com/.aspx/pid=7592/Product/AR-15-M16-ADJUSTABLE-GAS-BLOCK

Next...the gas system on a AR is a generic, "one size fits all" setup from the factory. A compromise so your rifle should shoot pretty much any ammo you feed it.
But the trade off is most of the time your over gassed. Yes...they work. But one not install a adjustable gas block and then YOU have CONTROL over how your rifle runs?

And if you ever get your cabin in the woods in UT or wherever your planning on moving and you buy a can you use the gas block to keep from getting a face full of gas.

So...you can either keep posting the same thing on different forums and keep getting the same answer.
Send the rifle back.
Or "fix" the problem and enhance your rifle with a very cheap and easy "fix".

Good luck.

gemini1
05-24-2012, 5:58 PM
Hmn, my 16' middy BCN spits 62/55 gr LC, Feds or Win brass at 1 or 2 o'clock, but when I use Tula, it's at 4 o'clock. No scratches or any marks from the ejector, be it brass or steel case. I should be good, right?

FX-05 Xiuhcoatl
05-24-2012, 6:00 PM
if it ain't broke don't fix it :cool:

problemchild
05-24-2012, 6:20 PM
OK OK I will get a gas block. I was looking at the jp low pro block.



Price: $119.95 + shipping
http://www.jprifles.com/cart_pix/ph/2212.jpg


Well first off I don't know where your getting your prices. But RETAIL JP blocks are around $70.00 and if you have a Brownells account they are even cheaper. Link here: http://www.brownells.com/.aspx/pid=7592/Product/AR-15-M16-ADJUSTABLE-GAS-BLOCK

Next...the gas system on a AR is a generic, "one size fits all" setup from the factory. A compromise so your rifle should shoot pretty much any ammo you feed it.
But the trade off is most of the time your over gassed. Yes...they work. But one not install a adjustable gas block and then YOU have CONTROL over how your rifle runs?

And if you ever get your cabin in the woods in UT or wherever your planning on moving and you buy a can you use the gas block to keep from getting a face full of gas.

So...you can either keep posting the same thing on different forums and keep getting the same answer.
Send the rifle back.
Or "fix" the problem and enhance your rifle with a very cheap and easy "fix".

Good luck.

BigBamBoo
05-24-2012, 7:01 PM
You will be really happy with it. The only down side is your gonna want all your AR's to have one!
I wont have an AR without one. Once you tune it to the load you shoot, the recoil impulse is much smoother. Add a low mass carrier and it is like shooting a loud .22.

Here are a couple of videos of my 18" and 16" JP upper builds with the gas system tuned. Look at the lack of recoil or muzzle jump.

Post up how it turns out for you and how it shoots with the new block.

xZQg06ddMNA

wVQjXOLb6Sw

shadowofnight
05-24-2012, 7:43 PM
I used JP's newer version adj gb in my 260 remington AR, really nice to be able to tune the gas when I tried the Varget loads vs the 4350 loads.

They do black and stainless.



http://www.jprifles.com/buy.php?item=JPGS-5S




http://www.jprifles.com/cart_pix/ph/2176.jpg

Personmans
05-24-2012, 7:50 PM
Interesting, the bead-blasted outside makes it look like anodized aluminum, you can tell from the drill marks that it's stainless though.

ott1
05-24-2012, 9:38 PM
What about testing a cheap upgrade to the extractor? An o-ring or d-ring.

http://www.weaponevolution.com/forum/showthread.php?373-Extractor-Spring-Upgrade

problemchild
05-24-2012, 9:43 PM
Does it have the same plunger lock as the other above? How is the gas screw adjusted and locked into place?


I used JP's newer version adj gb in my 260 remington AR, really nice to be able to tune the gas when I tried the Varget loads vs the 4350 loads.

They do black and stainless.



http://www.jprifles.com/buy.php?item=JPGS-5S




http://www.jprifles.com/cart_pix/ph/2176.jpg

problemchild
05-24-2012, 9:46 PM
Both bolts tested have the item you linked to. All manuf's are running this in their bolts now.

What about testing a cheap upgrade to the extractor? An o-ring or d-ring.

http://www.weaponevolution.com/forum/showthread.php?373-Extractor-Spring-Upgrade

shadowofnight
05-24-2012, 10:10 PM
Does it have the same plunger lock as the other above? How is the gas screw adjusted and locked into place?

I like that plunger lock, but no...all the other JP's use loctite for screw retention ( You can adjust them many times before needing to reapply , never had one move on its own yet )

I actually installed a shorter stainless set screw in mine, the factory screw is LONG ( To be able to shut off gas entirely , I dont need that function ) ...I pick a length that engages all the threads but doesnt stick out of the gas block so far when opened to clear the entire gas tube orifice .

ott1
05-24-2012, 10:11 PM
Both bolts tested have the item you linked to. All manuf's are running this in their bolts now.

Mine doesn't have the o-ring on my LWRC one-piece bolt or on the FailZero bolt. So not all manufacturers are using it yet. I put one on one of my bolts and the shell dropped less than 5 ft away. I have since removed it. I like mine going 20+ ft.:D

All manufacturers are using the extractor spring insert, but I'm unsure on the o-ring or d-ring usage.

Hoop
05-25-2012, 7:34 AM
Hmn, my 16' middy BCN spits 62/55 gr LC, Feds or Win brass at 1 or 2 o'clock, but when I use Tula, it's at 4 o'clock. No scratches or any marks from the ejector, be it brass or steel case. I should be good, right?

The TL;DR version is yes you are fine.

TheExiled
05-25-2012, 8:41 AM
My brass goes about 1:30-2, never had a single issue with a couple thousand downrange so far, where my buddy's rifle built at the same time (with bushmaster 20" upper) ejects about 5 o'clock and he has FTF issues every 30 or so rounds

problemchild
05-25-2012, 9:39 AM
OK I ordered this one. Be here in a week.

http://www.jprifles.com/cart_pix/ph/2212.jpg

Here is the gun ejecting at 1-1:30 position. First two came out at 2:45 position then the rest went to 1:15pm on the clock. Maybe the fresh oil on the bcg?

http://youtu.be/MMGPS0RPFvs

tonyxcom
05-25-2012, 9:44 AM
Looks fine to me. You can see the brass hit the shell deflector. Maybe the shells are bouncing of the MUR different.

tonyxcom
05-25-2012, 9:46 AM
Is this not the same gun? http://youtu.be/vDt74qfDcxE brass is going to 3.

problemchild
05-25-2012, 11:00 AM
Is this not the same gun? http://youtu.be/vDt74qfDcxE brass is going to 3.

It is. As the gun got broken in the brass starting moving forward more. In that video the brass was flying all over. The second rifle is a DD and watch the brass all go in the same 4:00 position nice and neat.