My first build - parts list

[Yoda]

My first 308 build!  Here’s my parts list.  Some are on order.

 

AeroP M5 upper/lower receiver

AeroP LPK

AeroP buffer kit (carbine)

AeroP charge handle

Magpul CTR + Enhanced .70” pad

Magpul alum trigger guard

Aimsurplus Nitride BCG

Mega 16” barrel

Syrac adj gas block + mid length gas tube

Griffin compensator

Midwest industries key mod 12” handguard

DWilson BCG rebuild kit

Vortex 30mm 3” offset scope mount

Vortex Viper HS 2.5-10x scope

Magpul 20rd mags

Clymer Go/No-Go 308 gauges

 

I’m interested to see the AIM BCG.  I had one for my AR15 and it was great.  Hopefully this one works well.  I always keep a spare so I’m likely getting another BCG so I’m open to suggestions.  I thought about getting a Fulton NiB or a Fulton chrome carrier + JP enhanced bolt.  Not sure yet but I plan to put a lot of rounds through this gun so I definitely want a good bcg and a spare.

I also want 1 x 5rd mag for hunting. Any suggestions for a quality/reliable one? 

 

I’ll post pictures when I get stuff shipped.  In particular the AIM bcg.

 

thanks!

[FaRKle!]

My first 308 build!  Here’s my parts list.  Some are on order.

 

AeroP M5 upper/lower receiver

AeroP LPK

AeroP buffer kit (carbine)

AeroP charge handle

Magpul CTR + Enhanced .70” pad

Magpul alum trigger guard

Aimsurplus Nitride BCG

Mega 16” barrel

Syrac adj gas block + mid length gas tube

Griffin compensator

Midwest industries key mod 12” handguard

DWilson BCG rebuild kit

Vortex 30mm 3” offset scope mount

Vortex Viper HS 2.5-10x scope

Magpul 20rd mags

Clymer Go/No-Go 308 gauges

 

I’m interested to see the AIM BCG.  I had one for my AR15 and it was great.  Hopefully this one works well.  I always keep a spare so I’m likely getting another BCG so I’m open to suggestions.  I thought about getting a Fulton NiB or a Fulton chrome carrier + JP enhanced bolt.  Not sure yet but I plan to put a lot of rounds through this gun so I definitely want a good bcg and a spare.

I also want 1 x 5rd mag for hunting. Any suggestions for a quality/reliable one? 

 

I’ll post pictures when I get stuff shipped.  In particular the AIM bcg.

 

thanks!

Solid looking build!

Would you be opposed to taking a 10rnd PMAG and blocking 5rnds out? That's what I'd do.

[Yoda]

Interesting.  How did you modify the mag?

 

thanks

[FaRKle!]

Interesting.  How did you modify the mag?

 

thanks

Magpul M3 LR/SR10 PMAG + -5 round block.

[Yoda]

nice!  thanks!

[darb]

Perhaps a trigger upgrade, two stage?

[LeatherNuts]

No need for a trigger guard on the M5, it's part of the receiver. I would look into the differences between keymod and mlok and see what the interwebs are seeing about the two of them. Spoke with the guys from Rev and they said that because of Magpuls backing of Mlok it's getting ready to take over the world which is why the don't/won't be offering it anymore.

[Yoda]

Perhaps a trigger upgrade, two stage?

I may do that eventually. 

 

 

No need for a trigger guard on the M5, it's part of the receiver. I would look into the differences between keymod and mlok and see what the interwebs are seeing about the two of them. Spoke with the guys from Rev and they said that because of Magpuls backing of Mlok it's getting ready to take over the world which is why the don't/won't be offering it anymore.

Thanks for the info.  I guess I'll post my trigger guard for sale.

[FaRKle!]

Thanks for the info.  I guess I'll post my trigger guard for sale.

Nonsense! If you really want to fit in here, I say you keep it and watch it morph into it's own complete gun ;)  <lmao> .

[Yoda]

haha i did that already with AR15s.  learned my lesson.

[Yoda]

Finished the build yesterday. I lubed it up with slip 2000 (bolt, charge handle, chamber, ramps ect) and tried to chamber a round out back and bent several rounds near the base of the bullet.  I let the charge handle back all the way and let go, also tried doing it slowly to watch the round and see if it was hanging up anywhere but didn't notice anything.  I used a few 308 rounds and also 7.62 with similar results and all 4 of my Magpul gen3 mags.  Unfortunately I don't have other mag brands to test.  

 

The AIM bcg and Mega barrel passed the go/nogo headspace test.  I have another AIM bcg on the way so I can test.  I may order a different mag brand to test as well.  I wonder if the Mega chamber is just very tight.  Kinda disappointing after over $1.6k.  The 2 successful chambers out of 10 attempts has the bcg lock in and the round extracted fine so I'm stumped at the moment.  Any suggestions?  

[Yoda]

This is when I drop a round in by hand. There's a small scuff below the neck.

 

And here is an attempt to charge with full spring action.

Bent round.

This was done with all factory 7.62 L2A2, Hornady sst 150 grain and Federal bthp 168 match.

Edited April 18, 2015 by Yoda

[survivalshop]

  Check you Extractor to see if works correctly . How do the feed ramps on the Barrel Extension fit with the Upper Receiver ,Photo maybe ?

 

  That does look like a Mag. problem .

Edited April 20, 2015 by survivalshop

[ironmonster]

So how much space do you have behind the bolt face and the bolt catch when the charging handle is pulled all the way to the rear?

 

What are you running for a buffer and spring?   

 

Does it act any different when you have the bolt locked back and let the bolt slam home by hitting the bolt catch lever?

 

It does seem like a poorly seated mag but since you have tried three that seems unlikely.  

 

I have two rifles with Aero uppers and lowers,  One has an Aero BGC the other an AIM's both seem to feed flawless with PMAG's (both rifles have less than 100 rounds so its hardly a definitive claim)

 

I had issues with my buffer/spring combo but I did not use Aero's buffer tube.    I would be interested to know how deep the Aero buffer tube is and what there buffer measures.

[Yoda]

The extractor works fine.  When I help a round into the chamber i can extract it normally.  The ramps are definitely a problem:

 

Here's a shot of the bolt spacing with the ch-handle locked back.  It looks fine to me.  Everything is Aero precision M5 parts except the barrel which is Mega so the spring/buffer are M5 kit parts.  I tried releasing the ch-handle from all the way back, pressing the bolt stop and letting slam forward and helping it forward to watch it all resulting in bent rounds 90% of the time.  I can easily drop a round in by hand and slam the bolt forward so I don't think the chamber is the problem.  Seems like either the feed ramps or the barrel extension is the problem.  I'm sending a pic to Aero tomorrow then talking to AIM about possible returning the barrel if they'll take it back. I may just have to stick with Aero parts.  Open to suggestions.

 

I sent AIM these pics also since I bought the barrel through them. It might be painful but perhaps the barrel will have to be replaced with an Aero since the whole build is pretty much Aero parts.  I don't think I want to start dremel cutting the upper.  Ugh!!!

 

thanks all!

Edited April 19, 2015 by Yoda

[washguy]

  Check you Extractor to see if works correctly . How do the feed ramps on the Barrel Extension fit with the Lower Receiver ,Photo maybe ?

 

  That does look like a Mag. problem .

Survival is right on !  pmags let the cartridge sit low to the ramps vs metal mags because of the short plastic lips for one thing....if you have an asc or dpms metal mag or best yet a lancer mag try that....it is not the  barrel! different mfgs have the mag catch relief machined in slightly different placements we are talking thousandths...thereby placing the mag at different heights in relationship to the bolt stripping the round off and up into the chamber...if you have metal mags you can tweak the lips upwards giving the bullet an upward angle and also letting it sit higher  solving what I believe is your problemo.......a plastic pmag can be tweaked but its beyond your pay grade right now

your pic of the cartridge sitting in the mag...if thats what i see....doesnt have a chance   :) Wash

 

Is it me? am I the only one seeing a trend on Aero?...seems like  all the problem folks are using Aero  stuff.....or is it a bad run of builders showing up here?  <dontknow>   Wash

Edited April 19, 2015 by washguy

[Yoda]

Just ordered a few ASC mags.  Look forward to seeing if/how they work.  Hopefully this is the problem although I love Magpul magazines.  I guess worse case I can sell my 6 Magpul magazines here.  

 

I sent pics to Aim, Mega and Aero to see what they think about the feed ramps/chamber.  I measured the ramps at .222" wide.  Seem pretty small.  I'll post more info as I get it.  

 

thanks!!!

[unforgiven]

Cost for me I the bottom line at this time.That is why I went with Aero lower complete, to eliminate issues.On sale today for $275.00 blk, free shipping.Thier LPK,extension tube,buffer and spring.The common dinominator with function problems 99% of the time is the mixing of components.Also when you mix parts seems to make it harder to get factory warrantty support.Just my 2 mags.

Edited April 19, 2015 by unforgiven

[washguy]

Yoda I want the least amount of my bullet tip hitting the ramps.... here's a pic that shows you the difference of angles from different mags

a pmag...well you cant adjust the angle very easy.... take a look at the lancer mag and the angle of the bullet....that bullet nose wont get dinged by the ramps at all and will feed like a champ...you see how much lower the bullet sets in the pmag....pmags are awesome,but sometimes very rarely you get a feed problem...like when it wont strip or it gets hung up and bent loading to chamber  :) Wash

 

 

[survivalshop]

  Just match the feed ramps & polish  ( use a " Machinist in a can" , " a Dremel Tool " ), if your in to that or take the upper to a Gunsmith & they should have no problem matching & polishing the feed ramps . No real need to open them up any more than is needed to match the feed ramps of the Upper Receiver & Barrel Extension .

  I use a fine cone shaped stone & then polishing compound , after I recut or grind the feed ramps to match . Doesn't take long , the polishing can take a bit , depends if you want them to have a mirror finish or not .

  Its also a timing thing with the Cartridge feeding , mess up that timing & with all the force of a 308AR Buffer spring & mass of the BCG , its bend city if the cartridge is not in position at the key time . Like if it hangs up on a feed ramp . 

  Like Wash said , the lancer with a higher feed angle , will probably work fine , but I would match the feed ramps , for all mags to have a chance to work . 

 

  As far as the question of the Extractor working right , it can also be too stiff or hang up & it won't let the Cartridge Base enter the Bolt face . Just one more thing to inspect .

Edited April 20, 2015 by survivalshop

[Yoda]

That's interesting Wash.  I can see copper on my barrel extension so it looks like the rounds are hitting it hard.  I'll order a Lancer for testing also.  Thanks!

[Yoda]

Survivalshop, I'll likely trim the feed ramps and polish them.  I'd like all mags to work eventually.  Hopefully the metal mags work for now.  The bolt/extractor seems to work fine when I drop a round in by hand.  The cartridge base has no problem entering the bolt face and extracting.  Hopefully by the end of this week or early next week I can find the culprit. 

 

thanks

[Yoda]

Update! I got my backup bcg in the mail today and swapped it out and was able to chamber several rounds from each of my 4 magpul mags witihout any problems. When I compared the 2 bcg's i noticed the ejector on the failing bolt was out just a tad more than the new one. I removed the pin and spring and replaced them with new ones from my bolt spare parts kit. The only thing I noticed is the original retainer pin is very thin and slightly bent. I might have caused this when I checked headspace last week. Either way, now the original bcg cycles without any hangups after several rounds from each of the mags. Now I can move on to actual test firing and adjusting the gas block!

thanks everyone

[Malig8r]

Woo hoo!!! Congratulations on the "fix". Glad it seems to have been resolved.

[98Z5V]

  Just match the feed ramps & polish  ( use a " Machinist in a can" , " a Dremel Tool " ),

 

Good advice, and very, very easy to do.

 

Survivalshop, I'll likely trim the feed ramps and polish them.

 

Dremel's own "Chainsaw Sharpening Bit" is the bit to use.  Straight stone, very small in diameter.  Easy to use to blend the lower to those wide feedramps, in this/your case.  You'll be removing softer aluminum, and won't damage the harder barrel extension.  Polish afterwards, easy job completed.

 

Yes, I saw that you came up the the ejector cure - blend the lower and feedramps anyway...  <thumbsup>