Matrix Aerospace Matched Billet Set Build

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9 years 2 months ago #45981 by jtallen83
Replied by jtallen83 on topic Matrix Aerospace Matched Billet Set Build
I decided to drill the gas port myself. From a post by X-Caliber on another forum it became clear they are not familiar with my specific gas system on a 16 inch barrel. The port was drilled at .0805 from the factory. I've been going up a couple sizes at a time to .0975 and I'm still a little under gassed. It is getting real close though so I think it will end up at about .1005. It has started to run well with the hotter MK 319 ammo so I know I will get the M80 ball dialed in soon.
The d. wilson BCG has been spectacular with the NiB coating, absolutely amazing how easy the carbon wipes off. I have 100 rounds on the rifle and there is barely a trace of wear on the bolt lugs with the QPQ finish and the carrier doesn't show a scratch!
The AP buffer system was a bit off. I needed to notch the tube to get another turn on the tube then add 2 quarters under the buffer spring so the bolt couldn't go far enough back to damage the receiver. The bolt pulls back to about an 1/8th inch past the bolt catch now .
Accuracy wise the barrel has been good. I've been hitting 5 inch steel plates at 100 yards with no problem with all three types of ammo. The bore cleans up real easy now, after 5 rounds two patches and it is clean, third one comes out clean. The dimple for the gas block is dead on with the block up against the shoulder the port is dead center on the block with no leaks anywhere.
The SLR brake is shockingly loud but does a great job of soaking up recoil, the bolt going into battery causes more movement than the actual shot.
The weapon weighs in at 10 pounds 3 ounces with a P-mag, 4x-16x PA scope, on an ADM QD mount. Eventually it will get a Bushnell tactical Elite 1x-6.5x but I need an extended ADM mount for the best results on that scope so it will have to wait a bit.
Even though it isn't dialed in yet I can see myself doing more of this in the future, I've got all the tools now! :usa:
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9 years 2 months ago #45982 by jtallen83
Replied by jtallen83 on topic Matrix Aerospace Matched Billet Set Build
Got it! I went to a .1005 " gas port, no more short strokes but the empty ZQI cases were still mostly left sitting on the mag. I sprinkled a little Armalite love on it with an extractor spring set(spring, doughnut, and plug) and it didn't miss a beat after that!
I've severely depleted my match ammo stash but as soon as it recovers I'll get some groups posted.
I'm loving the Nib coated wilson carrier, it cleans up soooo easy.
I doubt I ever do a build with anything else from here on! :usa:
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9 years 2 months ago #45983 by Akai
Replied by Akai on topic Matrix Aerospace Matched Billet Set Build
Good to hear! Not to far off on the hole size then always better to remove a little at a time and that's a sweet little trick using the dowel :clap:

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9 years 1 month ago - 9 years 1 month ago #46023 by jtallen83
Replied by jtallen83 on topic Matrix Aerospace Matched Billet Set Build
Did some ammo function tests and checked some for accuracy today, all at 100 yards. Ran 20 rounds each of Perfecta 147 gr. FMJ, "still" case COLT 168 gr. FMJBT,Federal XM80, and a 3 rounds of Freedom Munitions 175 gr match( I'll save the explanation of why only 3 rounds for the end.)

Here is 20 rounds of Perfecta, started with a cold bore and shot them as fast as I could get back on target, as the barrel heated it opened up but still managed just a hair over 2 MOA;


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The Colt functioned fine but the group was not worth a picture.

XM80 held just under 2 MOA on a 10 shot string at a brisk pace, missed 2 out of the remaining 10 on the dueling tree, again at a brisk pace.


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I ran into issues with the Freedom remanufactured 175 gr. match. The first round keyholed on the target and did not extract. I sent the bolt back home after removing the magazine and had to mortar the rifle to get the case out. Next round hit good and extracted but the third round failed to extract and mortaring it took off enough rim that I had to call it a day and use the wood dowel at home. It popped right out with just a whack from my palm. I noticed that beside both issues coming from Freedom remanufactured stuff both cases were head stamped TAA 06 with the NATO cross. I thought the NATO stamp would mean it was good to go even being Taiwan stuff but when I compare the rim thickness with all the other brass I have the only other type with as thin a rim is POF stuff and it still functioned so I think the brass may be softer on the TAA cases. For now I'm going to chalk the issue up to junk remanufactured ammo, I have noticed that this last batch was not up to the usual standard for accuracy in my AR-10 but I have never had a keyhole before on any ammo?????


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I'm also seeing the same odd look on the primer I pictured early in the thread, a crater look but no flattening. I'm betting the firing pin hole is a touch oversized. Is this something to concern myself with?????


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When I get some more quality match stuff I'll try some 5 shot groups with time to cool in between and see what the barrel will do then, so far though I'd call it a 2 MOA barrel.
Last edit: 9 years 1 month ago by jtallen83.
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9 years 1 month ago #46029 by GRA
Replied by GRA on topic Matrix Aerospace Matched Billet Set Build
Thanks for all the information and specifics on all the ammo. This will help us all out in the future.

Impressive build indeed and nice groups. I hope my Spikes does half this well.

Some folks at the gun show tried to convince me to build an Aero instead of going with the ArmaLite I bought and the Spikes I built but I was not familiar with Aero and therefore pursued the other agenda.

I know a lady that has built an Aero .308 with the hexagonal rifling and she swears by it.

Maybe in the future ... :twothumbs:

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9 years 1 month ago - 9 years 1 month ago #46162 by jtallen83
Replied by jtallen83 on topic Matrix Aerospace Matched Billet Set Build
Freedom is going to credit my account for the bad ammo, nice fast customer service!
Got a few more groups in today. I zeroed with 168gr FGMM, 1st shots were always dead on but the follow ups would climb as the barrel heated;

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The MK 319 did well with the first five shot group of the day being the best. The ten shot group started to spread and I blew one low left otherwise not to bad for my rapid pace;

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My basic chrome lined 20 inch AR10 still outshoots this Ex-Caliber barrel.
Last edit: 9 years 1 month ago by jtallen83.
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9 years 1 month ago - 9 years 1 month ago #46167 by GRA
Replied by GRA on topic Matrix Aerospace Matched Billet Set Build
Nice groups. It appears the .308 barrels heat up faster than I expected. Much faster than 5.56 caliber. I'll have to keep that in mind. I know my 7.62 x 39 heats a slight bit more than the 5.56 does in any given 10 round string of fire but not much. Seems about 1-2 rounds faster than the 5.56

Did you ever decide if you have firing pin issues?
Last edit: 9 years 1 month ago by GRA.

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9 years 1 month ago #46169 by jtallen83
Replied by jtallen83 on topic Matrix Aerospace Matched Billet Set Build
I picked one of the lighter profiles, SPR-1.150" chamber to .850" to the .750" gas block then .730" for the last couple inches. A heavier contour may have helped even out the heat better. I'm told the barrel will need a couple hundred more round to "settle in" before I know exactly what I have, lugs on the bolt and extension are still mating at this point.
It sure cleans up easy, very little evidence of any copper fouling. The patches start coming out clean after 6-7.
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9 years 1 month ago #46170 by GRA
Replied by GRA on topic Matrix Aerospace Matched Billet Set Build

jtallen83 wrote: My basic chrome lined 20 inch AR10 still outshoots this Ex-Caliber barrel.


What is the rate of twist in your 20" ArmaLite barrel?

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9 years 1 month ago #46171 by jtallen83
Replied by jtallen83 on topic Matrix Aerospace Matched Billet Set Build
The standard Armalite 11.25 twist.
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