From Behind Enemy Lines

[ducky]

well the 308 AR bug bit me kind of late. I just got the idea in my head a few weeks back and have been assembling the parts for my first 308AR. I was a bit frustrated with the part availability out there but in the end I came close to what I wanted. I ended up with the following...

 

1. Rainier 18" SS barrel

2. DPMS upper receiver

3. JP enterprises 15 in handguard

4. JP enterprises compensator

5. Shadow Ops BCG - couldn't pass up the deal on them right now

6. PRS magpul stock - like them and have them on my HKs

7. Lower TBD...

8. Lower parts kit for now from DPMS...will upgrade later

9. A2 buffer tube, spring, buffer I had in the shop already..

10. gas tube is DPMS and I did the yankee hill cheapo GB for now. If I hate it I will swap it...

11. UTG bipod..could see dropping money on a harris..I know I know I got cheap here at the end..BUT good god 308 AR stuff makes HK stuff look cheap.

12. Peoples Republic of California compliance button..soon to be illegal...:(

 

I ordered pretty much everything yesterday still some odds and ends like headspace gauges for ensuring the BCG and barrel work together. If they don't my question is will I have to send back the barrel to Rainier with the BCG and pay them to headspace it for me?

 

I have built a ton of other types of firearms in my day. From AKs to HKs to AR70s...but my ARs I bought years and years ago from Stag and Colt..they run like tops and never hard to worry about headspace on them..I don't shoot them much..

 

Glad this site is here, sad I didn't hear about it till yesterday..but hey..Now I know you guys are here to bounce questions off.

 

Cant wait to get this built and running..Shoot it as much as I can before Moonbeam shuts us down out here..but a friendly state is just a few miles away and maybe its time to buy a piece of property there..move my collection and call it a day! Not give Sacramento anymore tax dollars..

 

One last important question...Who has cheap match ammo!?

[Microgunner]

Welcome from Florida.

[unforgiven]

Welcome from Indiana brother ducky.Cheap and match ammo don't go together but Palmetto State Armory had so good promos with free shipping not long ago.Sportsmans guide has promos all the time also.Aim surplus and DSG to name a few.

[Robocop1051]

9. A2 buffer tube, spring, buffer I had in the shop already..

You can't use the A2 buffer and buffer spring on a .308AR.

[shibiwan]

You can't use the A2 buffer and buffer spring on a .308AR.

 

^^ listen to the man. The 308 requires a buffer that is around 3/4" shorter than their 5.56 counterparts.

 

Welcome from neighboring AZ.

 

Federal FGMM 168gr/172gr BTHP can be found for $26-$28 and can't be beat for the value for match grade ammo. Even for general plinking, Federal(lake city) 7.62x51 XM80C (under $20) or Federal American Eagle (around $20-$22) works well for me and they are super consistent.

Edited September 14, 2013 by shibiwan

[blue109]

Welcome! Glad you made it.

[ducky]

Why does Magpuls website seem to say to use a standard A1 or A2 rifle length buffer tube. Seems to imply you can use an A1 or A2 buffer tube spring buffer. That not the case?

 

Is it because the 308 requires a more robust spring and buffer?

 

Features

• Mounts to rifle-length receiver extension tube without A2 spacer (not included)

 

NOTE: The PRS is a direct replacement for an A1 or A2 fixed stock. Fitting to a carbine with a collapsible stock will require a rifle-length receiver extension tube, rifle buffer and spring (not included).
The PRS AR10/SR25 stock may be used on AR15/M16 rifles to provide additional charging handle clearance. Stock is not compatible with Bushmaster BAR-10 and Rock River Arms LAR-8 due to additional charging handle to cheek riser interference issues.

 

pulled this off the specs section of the 7.62 PRS part of their site.

 

Its a bit misleading...or am I just misreading it? I don't see anywhere on their 7.62 site page where it says not to use the A1 or A2 tube?

 

Anyway thanks for the heads up...I assume magpul is just meaning a A1 or A2 308 version?

Edited September 14, 2013 by ducky

[edgecrusher]

It says you can use it with a 5.56 rifle to allow for extra clearance. To get your .308 at to function properly, you will not be able to use 5.56 parts. The buffer size is different, as well as spring coils and tension. They do share the tube.

[blue109]

the 308 and 5.56 use the same buffer tube (receiver extension if we want to be proper) but the spring and buffer are specific to the platform. You will need the 308 rifle buffer and rifle spring for that PRS.

As far as A1/A2...the only difference is a small spacer. An A2 stock is longer, so a small spacer sits on the end of the standard milspec rifle buffer tube to take up the extra space and a longer screw is used. A1/A2 only refers to the stock length and doesn't play into buffers or springs.

The PRS is A1 length so 1) standard rifle length tube and 2) 308 specific rifle buffer and 3) 308 specific rifle length spring is what you need. No spacer needed. The PRS should come with a screw, but if not an A1 length screw will work.

If I just told you a bunch of stuff you already figured out, sorry :) might help someone else doing a search down the road.

This is assuming DPMS patterned rifle. There is no standardization so if were talking AR10/larue/sig/RRA/etc all bets are off lol.

Edited September 14, 2013 by blue109

[planeflyer21]

Another AZ welcome!

[DNP]

Welcome from SoCal. If you want to keep things local, check out JD machine out of San Diego for a lower.

[shibiwan]

Why does Magpuls website seem to say to use a standard A1 or A2 rifle length buffer tube. Seems to imply you can use an A1 or A2 buffer tube spring buffer. That not the case?

 

Is it because the 308 requires a more robust spring and buffer?

 

Actually, the main reason is that the action on the 308 requires extra travel so it can load in the longer .308 round (longer compared to the 5.56). To keep everythig else the same for a longer travel, the buffer has to be shorter. 

 

The heavier spring is there to make up for the larger reciprocating mass of the BCG and the additional gas return due to the .308 round.

 

Good choice on the PRS (make sure you get the .308 version), The PRS reduced a good bit of recoil due to the longer buffer tube reuirement compared to the carbine length tube on my .308.

[ducky]

OK so now that you guys helped me prevent one problem...I have ordered the correct buffer tube assembly for the magpul stock from midway USA yesterday. Should be here midweek. One more question if I may. Am I going to want an adjustable gas block on my 308? I have them on a few others, like a Yugo M76 and once they were dialed in I don't really mess with them on 8MM loads. I normally shoot the same stuff so for the M76. On this 308 I am wondering if I will want an adjustable gas block based on shooting different loads vs the hankyhill cheapo lowprofile one I got.

 

I am in for a penny in for the pound on this build so whats another $100 at this point. :(

 

Thanks again for your guys help on the stock. I wondered about that when I picked the Magpul..

Edited September 15, 2013 by ducky

[blue109]

I have a $20 YH on mine and it works just fine. I run a pretty standard setup. It eats junk ammo and runs smooth. Its not broke so im not going to mess with it.

I'd suggest building it with the standard block since you have it. One less thing to troubleshoot if you have any initial problems. If she runs and you decide you want to fiddle with gas pressure after, its a 5 minute job to swap blocks.

[ducky]

Welcome from SoCal. If you want to keep things local, check out JD machine out of San Diego for a lower.

I would but I am way up north from you. way above sacto...there is a guy in Sacto I need to check out. Sounds like JD to a large extent. Has his own CNC shop and will lease you his machine for a price. I may go the 80% with him on the lower..Mill out the internal sections and laser inscribe the outside at the same time. Then its really only the anodation process to sort thru but I will figure that out. Half the fun of this stuff is figuring out ways to do it...

[Rsquared]

Gas blocks are a matter of preference my man. If you plan to run suppressed, you'll probably want an adjustable block. If you hand load and want to try dialing in different weights, you might want an adjustable block. Otherwise I wouldn't worry about it. A Yankee Hill lo-pro is just fine. It'll get the job done. I've got adjustable blocks on some....and fixed blocks on others. It really depends on what you wanna do with any given rifle. And, as I started with......everybody has their own preference. No really right or wrong answer.

 

Oh.....and welcome aboard Ducky.

[ducky]

I have a $20 YH on mine and it works just fine. I run a pretty standard setup. It eats junk ammo and runs smooth. Its not broke so im not going to mess with it.

I'd suggest building it with the standard block since you have it. One less thing to troubleshoot if you have any initial problems. If she runs and you decide you want to fiddle with gas pressure after, its a 5 minute job to swap blocks.

I was hoping that was the case. The idea of yet another order to midway for something I needed was making me want to throw up in my mouth yesterday. I placed an order at midway in the morning for torque wrench barrel nut adapter they have for 308 for $22 that I had forgotten on my order on Friday. Then when I realized I needed the correct buffer spring etc I placed a second order in the afternoon...after you guys saved me some anguish...

 

I am hoping yesterday afternoons order was the last one...I think I have everything I need at this point and down to stuff I can get local at hardware stores.

 

On the JP handguard I need to figure out/research which locktight goo to use. Red, Blue or Silver...or none...They recommend Red in what I read.

 

The red stuff as I recall hardens up pretty good and can only be loosened down the road via a fair amount of heat.

[ducky]

Gas blocks are a matter of preference my man. If you plan to run suppressed, you'll probably want an adjustable block. If you hand load and want to try dialing in different weights, you might want an adjustable block. Otherwise I wouldn't worry about it. A Yankee Hill lo-pro is just fine. It'll get the job done. I've got adjustable blocks on some....and fixed blocks on others. It really depends on what you wanna do with any given rifle. And, as I started with......everybody has their own preference. No really right or wrong answer.

 

Oh.....and welcome aboard Ducky.

Ok well then that's easy behind the lines as I am there is no suppression allowed. If I move to a real 2A state then I can swap blocks.

 

Coolbeans. Thanks for the fast feedback. I am now just waiting on all the upper parts. And with luck could be at assembly next weekend! Got a nice pair of headspace gauges from midway. Nice to see that they are now sticking it too us with their prices. Midway has always been a fair priced shop if you need general everyday stuff.

 

I have some decisions on the lower. I liked the idea of an 80% for the challenge and mostly cause I have not done one before. There are a few locals around with CNCs that will lease the machine out to you for a price usually $80 an hour which is cheap for CNC actually. I have a mill and could do it by hand and eye but CNC seems to be the way to go on an AR. I can get away with slop on some other rifle types but ARs..well +/- seems a more serious concern with them albeit the areas you mill yourself probably could have some slop less the pin holes but I like the idea of precision.

 

I am getting more and more excited about building this big boy AR. My other ARs I purchased I am a southpaw so I went with Stags and they run like tops. Out the box perfect never an issue. I didn't swap out a few parts here and there over the years. I also have a colt AR I inherited but that one is pretty much a safe queen. More from a posterity standpoint than anything else that it sits in there, I want to give it to my son in the condition I got it.

 

I have built just about every other type of rifle system over the years except ARs.. not sure why that is just how it worked out.

[Rsquared]

I hear ya. I think that most of us around here enjoy (read as have fun) building up a rifle. After all, that's how we get exactly what we want. Or.......don't have anybody but ourselves to blame when something doesn't quite work out. <laughs>

[ducky]

the real question now is who's couch can I sleep on once the wifey finds out I spent all that on yet another rifle!:)??????????

 

she is not going to be pleased that's for sure. I ended up having to cancel the handguard order from one place and place it with Rainier because the original place was out of the part(website said otherwise). The only item I am not sure about is the BCG I ordered form Shadow Ops Saturday with the discount for AR308 members. I didn't get an email or anything from them when I placed the order. Got a number only...which is kind of strange. Normally most places send you an email confirm once you place your order that you are GTG...Wonder if they don't send a confirm until they ship? I know they are slammed as I have a contact that works there. Hoping he can validate my order is in their system.  I haven't added up what I spent on this bad boy and I am not sure I want to. I am sure its over $1500 and then some by now. The wife is going to $%^& when she sees the CC card..But you gotta do what you gotta do and after this weeks sad events one can only assume new EOs are on their way...A sad reality for our hobby/lifestyle...

 

Of interest I should note the cheapo Baraska SWAT scope I ordered was almost as expected. its not nearly as nice as my high end glass but it is better than I thought. The glass is clear and overall the fit and finish were impressive. Sometimes Russian optics can be just as good or better than their competitors. I should be fun to get it out and see what it can help this rifle achieve.

 

I did end up doing the 80% lower as I think it will be interesting to CNC the trigger area and I want to take a swing at Anodizing...I have done all kinds of other types of finish including home niterblue. Basically you take lye and sodium nitrate in specific combination. Same chemical makeup as bluing salts you pay WAY more for. I restored a BHP and it came out fantastic. As far as caustic chemicals go that probably cant be beat. As long as safety is followed the anodizing process seems pretty doable.

 

I might do some custom engraving beyond serializing the lower. Truly make the lower one of a kind...part of the fun of building vs buying. I don't think I will buy another new rifle unless its a shotgun to replace my super black eagle...I have way to much fun smithing/restoring/modifying firearms...You learn so much doing it too. The learning part is what I enjoy the most.

[unforgiven]

I tell the ol'lady its either firearms or the Shamrock bar you decide....I been having a great time at the Shamrock with the bros.Just sayin. >:D  <lmao>  But I still need some uppers. :eek: