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05-09-2021, 09:50 PM
(This post was last modified: 05-09-2021, 09:59 PM by Thelaststraw.)
Brief background first...
I'm from the communist territory of NY originally and moved to Louisiana
Discovered I could easily buy firearms
Bought firearms
Started shooting USPSA about 5 years ago
I let my pistol primer stash get low and hit the rifle primer lottery a few times....
Present time....ran across a 20" Monster barrel a few weeks back and had a lonely Aero M4E1 Enhanced receiver set laying around so everyone here knows what had to be done. I was interested in the cartridge from launch but wanted to be sure it wasn't another Valkyrie first. I'm fairly certain it's here to stay and it's the real deal. I never shot past 100yds before nevermind zero a scope. I tend to research stuff to death and overanalyze everything...I don't know, it's subconscious, but helps me sometimes.
I'll get some pics when I get a chance but it's nothing spectacular currently, still waiting on some backordered items still in a production run. My entry rig to PRS/NRL type events before dropping big coin on a chassis. I did a rough sight in and tracking test at 50yds and took her to 100yds. Had a rough time with first extraction problems then feeding issues. Big dummy forgot to open my SA adjustable block....at all! LOL Still think its not lined up right and have it too far back from muzzle to the shoulder. I'm new to the AR platform but have built a few and nailed it in the past. Short Blackouts with pistol gas, maybe the ports are bigger and less fussy? I'll have to feeler gauge it like I should have.
Anyways, after a hasty, and I mean hasty 1.5MOA zero at 100 I dialed in for the 600 yd steel. This is what amazed me about the 6ARC....18mph gusty/switching wind 90 degrees to shooting azimuth, 24' elevation, 82 degrees and 70% humidity, only 4.1mil elevation and 0.4mil windage.....not ideal atmospherics for the new guy I imagine, and it was within 1 foot POA-POI with no chrono data and a noob driving! I meant to feed geoballistics 2625 velocity but put 2725 and it hit low for what ever reason. I didn't range the target but I was impressed as you can tell I'm sure.
So quick question, am I on the right track with the gas block being too far back and undergassed? (Brass ejecting between 3 and 4 with authority just not feeding next round at all or jamming on ramps, regular carbine buffer, 108 ELD Match factory loads.)
****HMMMMM, need to figure out HOW to post pics now...lol****
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Welcome to the forum! For the Monster barrel, as I recall Krys makes them so the gas block can seat back against the back shoulder of the journal, no feeler gauging required. Double check me on his vendor page he has the details. That can be a concern with various barrels but the ones I really like are set to back up against the shoulder. The gap thing was originally for use of the front ring of the original type of handguards. Not necessary for the nowadays free floaters in use.
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05-09-2021, 10:18 PM
(This post was last modified: 05-09-2021, 10:23 PM by Thelaststraw.)
![[Image: UoNUCbc.jpg]](https://i.imgur.com/UoNUCbc.jpg)
I figured it out! Nothing out of this world but still in infancy and teething.
Interesting, thank you Grayfox. I'll check that and hopefully the Superlative Arms adjustable block isn't off from whatever that is. It behaves like it's short stroking yet locks back on an empty mag always and extractly with authority. I'll keep troubleshooting or single feeding! Hahahahaha
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PSA
I just discovered that ASC is making 6ARC specific magazines that make the round sit a little higher than with Grendel magazines/followers. That may be what I need as most of the failures to feed it appeared the bolt would skim right over the top of the round judging by the marks on the brass. The rest were just jams into the top of the feed ramp or else it would not fully engage the bolt. I can't rule out the gas yet but 6ARC specific mags may be a good thing for all interested parties.
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Sounds like you're on the right track. The ASC mags for 6ARC definitely have the cartridge sitting higher. My guess is that will correct your failure to feed. If not, you may need to dial gas back just a touch. IF the BCG is moving too quickly, it can sometimes cause FTF. Change only one thing at a time, and you'll get it sorted in short order.
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05-10-2021, 12:55 AM
(This post was last modified: 05-10-2021, 12:57 AM by Old Bob.)
Are these ASC 6 ARC mags different from their original first issue of the mag? I have 4 of their original 6 ARC mags (red followers). The cartridges definitely do not sit higher than in a 6.5 Grendal mag. Looking from the bullet end of the mag, it appears that the round sits higher, but that's because the top of the mag has a deeper scallop which keeps the bullet tips from contacting the top of the mag when loaded into a chamber.
If the cartridges are actually sitting higher in ASC's newest 6 ARC mags, are the feed lips slightly wider apart or a little shorter so the cartridge will sit higher? The only difference I see in their followers is the color. I measured the distance between the feed lips on one of my ARC mags & a Grendel mag. The distances were close between the two mags with the 6 ARC slightly wider. The ARC Mag tapered from .475" to .490". The Grendel mag tapered from .475" to .485". By eyeball, that's not a big difference.
The trick is growing up without growing old. -- Casey Stengal
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05-10-2021, 01:31 AM
(This post was last modified: 05-10-2021, 01:38 AM by Thelaststraw.)
The new magazines appear to be the same body as Grendel magazines with a RED follower. Currently they don't offer followers only on their website but I bet they are coming soon. From the picture I saw on....please don't judge me....AR15.com, it's hard to tell for me. I was desperately exercising my google-fu to sort my gas/feeding issues and stumbled on it. The height difference is very obvious and perhaps to people more experienced the shape could be too. I understand completely about the dimensions but looking at the length of the red follower it may alleviate diagonal feeding some as the base exits the magazine, which may be what I was experiencing compounded by gas system being over or undergassed a bit. I'll try to find it again to link the post w/pic.
https://www.ar15.com/forums/armory/Relia.../2-515397/
Last post has the pic.
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That picture appears to be the same one from this 6.5 Grendel thread:
https://www.65grendel.com/forum/showthre...hlight=ASC
The Grendel magazines from ASC now come with a scalloped front (purchased both Grendel and ARC magazines back in February). I see no other differences other than the color of the follower.
Do the magazines that you are using have a non scalloped front like in the picture? If so, perhaps modifying it like mel did in the 6.5 Grendel forum topic to see if that helps at all.
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What mag(s) are you using now? A 6 ARC doesn't need to sit higher if the manufacturer gets the front lip right. I've gotten 10, 15 and 25 round ASC' Grendel mags over the years and NONE of them were ever able to feed a Grendel round due to the lips being too high. I sold the 10s with a disclaimer, the 15s work fine with my 243 LBC (6mm Grendel) and my 25s won't even feed a 6mm, let alone a 6.5. The only reason I bought the 25s is because the shape is much better than Duramag's for monopodding. QC is atrocious. This is a .308 mag with one 6.5 CM round in it which promptly got sent back to Midway:
I've used ASC 5.56 mags for 6x45 since they allow for a 2.31 COAL. I bought a 5 pack of 20s when I bought the 25 rd Grendel's a few months ago. They worked fine until I had trouble loading one ........
End rant.
Welcome aboard!
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Currently using ASC grendel magazines with the blue follower. I couldn't understand what could be different since there really is no difference in that dimension between the two cartridges.
I should have known that it's not likely that a noobie like me could bring much to the table information wise with so many experienced people here. Just passing along a discovery that seems to not even be a problem. Lol
I bet I'm just overgassed and the bolt is passing right by the next round or forcing it up the ramp so hard it jams up and left. I appreciate help here, I knew this would be a good forum from the grendel forum.
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Thank you for the link BehindEnemyLines, very helpful. Does the scalloped edge help prevent nosediving under the ramps, deflecting upward causing a FTF like I was, or both?
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(05-09-2021, 10:18 PM)Thelaststraw Wrote:
I figured it out! Nothing out of this world but still in infancy and teething.
Interesting, thank you Grayfox. I'll check that and hopefully the Superlative Arms adjustable block isn't off from whatever that is. It behaves like it's short stroking yet locks back on an empty mag always and extractly with authority. I'll keep troubleshooting or single feeding! Hahahahaha Off topic but my google foo is failing me. What stock is this?
Thanks pavementends
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(05-10-2021, 11:28 AM)Thelaststraw Wrote: Thank you for the link BehindEnemyLines, very helpful. Does the scalloped edge help prevent nosediving under the ramps, deflecting upward causing a FTF like I was, or both?
I'm honestly not sure. Only thing I could come up with is that maybe with the front of the magazine edge being flat that it was perhaps pushing the bullet up too high causing issues. I thought it was interesting that they added the scallop to the 6mm ARC version and also at some point added the scallop to the Grendel mags as well. If mel sees this perhaps he could weigh in on what made him add the scallop to his Grendel mags.
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05-10-2021, 04:22 PM
(This post was last modified: 05-10-2021, 04:29 PM by StoneHendge.)
Having a feed lips that's too high will make one add a scallop. The top of the mouth is forced into the lip at a 90 degree angle (after scratching the bullet):
And that's an ARC in a Grendel mag. With a 6.5 Grendel, the mouth will be 0.25 mm lower.....
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I do Gas Blocks with the 'ole pencil line and straight edge through the center of the ports (barrel/block) method. I then confirm with a $30 Borescope off of Amazon, on a Windows 10 Tablet. I doubt the .020 thousandths matters, as the GB port is a lot larger. I have an SA AGB, and it is 40 clicks "out" with a Sprinco Orange Spring, and an H3 Buffer. I shoot with a Can (Rugged Razor - so not extremely restrictive, but there is some), so that is just for me, with an 18" BA barrel.
My experience with ASC mags has not been a positive one. KM Tactical just had a bunch of Orange Follower ones, so I bough one of each capacity. The 10 rounder - holds 9, but it feeds. The larger capacity one (I forget if it's 15/20/25) pops out of the magwell on each shot. I'm sticking with Duramags, all capacities of which, are perfect.
If I were you, I'd first get a Duramag. If that doesn't work, I'd remount the block and if you can afford it, borescope it to confirm. Then I'd open the SA block all the way (usually about 45 clicks) and fire one. Repeat (going 4 clicks at a time, to save ammo) until you get Lock Back, then go one or two more for fouling.
If you get lock back with that AGB all the way "out" (open). you'll need to up the spring and or buffer. I prefer upping the spring rate first, as why add mass if you don't need it. Sprinco has Blue, Red and Orange, which are all above their White, which is stock Carbine rate.
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I adjusted the gas block initially to default setting, 18 out which is supposed to be equal to normal block. Bolt locks on last round every time and ejects 3 to 4 reliably but hammers off the deflector hard. Curling necks and even side dings sometimes.
Problem is it slides right over the next round scratching and gouging the hell out of it. If it happens to grab the next round, either the bolt lugs don't engage or the bullet launches up diagonal left and jams. Feed ramps are smooth enough to not gouge anything so I'm suspecting too much gas so it's moving too fast.
I'll try some duramags, thanks for the tip. I like having a couple different kinds for anything I load for since some handle different bullets and COAL better than others.
By the way.....Brownells was just showing Starline Grendel brass in stock if anyone needs any.
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CPD DuraMags in 10 and 20 rnd. have worked flawlessly for me. I am approximately 300 rounds into my 6mm Arc. For perspective 18” BA Barrel with RLGS STD YHM block. H2 Buffer and Blue Springco spring. This keeps my brass looking good with factory Hornady and handloads with Lever. Definitely a little Gassy. First post by the way Hi All
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AHHHHH, I may have chosen buffer weight poorly....rather embarrassing this is if so. I have an Armaspec Silent Recoil Spring but the Carbine weight (3.3oz equivalent/6.2oz actual) that has worked great in previous builds.
You're running an H2 that's 4.5oz=/-???? Hmmmmmm....I'm a relative noob with the AR platform so let's see if I get this right. I may need a heavier buffer to slow things down or speed things up? I could have swore that I found that I should run a carbine tube and buffer and could tune with gas block both suppressed and unsuppressed no problem.
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Armspec sells replacement weights for about $15 on their site. Easy swap
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