I am an idiot. Ordered a DPMS AR10 BCG and Armalite barrel

[HRnightmare]

So I went to have my headspace checked on my PSA AR10. Th egunsmith said it was way off. I called rainier Arms who made the barrel and Palmetto State Armory who makes the BCG and was advised the PSA upper, lower receivers and BCG are DPMS patterns.

The Rainier arms barrel was sent to me in Armalite.

So at this point I am going to buy a RAINIER arms brand BCG. Just for personal mental satisfaction. Question is:

Will an Armalite pattern BCG operate in a DPMS upper receiver? MY gunsmith seems to think not but he swears up and down the barrel is DPMS even though Rainier showed me paperwork that says it is.

Rainier offered to take the barrel and headspace it to one of their bolts. If I do that I have to completely disassemble it and remove the JL Billet handguard and barrel nut which is proprietary and I don't have the crowsfoot wrench to do it (I had the gunsmith do it). And risk it still not headspacing properly and having to send it back again...

Or maybe can I send the the whole upper receiver to Rainier and tell them to headspace check it with one of their bolts, if it fits sell me the BCG and if it doesn't, fit it to one and pay them to disassemble and reassemble the upper....if they will do that?

 

[Reloadron]

Is an Armalite barrel and barrel extension compatible with a DPMS LR-308 Upper Receiver? – Yes, Dimensionally the measurement from the back of the lugs to the breach face is within .001″-.002″ on the Armalite and DPMS bolts. Note: You must use a properly headspaced bolt that matches the barrel extension type. This means you need to use an Armalite Bolt in an Armalite Barrel Extension and likewise for DPMS.

The above quote was taken from here. I wouldn't be too hard on yourself as the entire AR 10 thing can get into a confusing mess. Given the options and tools available to you I would give thought to calling Ranier and inquire as to sending them what you have.

Ron

 

[otrman]

Yes, you will need to change one or the other. I don't know what the exact differences are, but bolt and extension must be same pattern. I would prefer the "DPMS" pattern, not because it is better, just available from more suppliers. Easiest thing to do where you are is to just get an armalite bolt and call it a day. Switch back to DPMS pattern when you shoot out the barrel. See if PSA will accept return on the BCG, if not, someone like me would be more than happy to buy it from you.

 

[HRnightmare]

PSA offered to return the BCG...

So an Armalite pattern BCG will run in a "DPMS" version upper?

 

[Lycidas Janwor]

You have to be very careful when building an AR10 platform rifle. I thought about doing it but the more I researched the more I realized it is just too frustrating and very much not as easy or modular as an AR15 platform rifle. Also, Armalite stuff (in AR10) generally does not match up with DPMS stuff. If you build an AR10 pattern rifle, pick a brand other than Armalite. If you go Armalite, just go ahead and buy all the Armalite pieces because for whatever reason, Armalite makes it difficult to crossover with other manufacturers.

 

[otrman]

So an Armalite pattern BCG will run in a "DPMS" version upper?

Has nothing to do with actual upper that barrel attaches to, all upper/lowers are brand specific. A PSA upper will only fit a PSA lower, and so on, most all cut the radius by the buffer tube differently. The internal dimensions for the FCG and where the BCG ride are all the same, or at least close enough not to matter. There is an armalite barrel extention and armalite bolt and dpms barrel extention and dpms bolt. The two will not interchange. Not sure if this will help but you can take a brand new factory built Armalite rifle replace the barrel and bolt with a DPMS pattern barrel and bolt and it will work fine. I know it can be confusing and sometimes things don't make sense over the web so if you would like to discuss over the phone, PM me your number or I can PM mine.

 

[carbine85]

If your DPMS BCG fits your upper correctly I would buy a DPMS barrel and make sure it's head spaced correctly. Return the parts you can and sell what you can't. DPMS is one of the best ways to go in the AR10 rifles.

 

[HRnightmare]

This has gotten so convoluted and odd:

So Rainier Arms confirmed it is in fact an Armalite barrel. Palmetto states an armalite barrel and BCG will work in their DPMS style upper receiver. Rainier disagrees.

I apparently ordered a DPMS version gas block and gas tube and paid to have it factory installed. Well Rainier Arms installed it onto the Armalite barrel. Granted, they did what I asked for but at no point did they decide to call the customer and say "hey dude, I think your confused"

This makes me sort of not want to deal with them again.

 

[otrman]

Ok, uppers are not pattern specific except for the fact they may only properly mate with lower of same manufacturer. There are two patterns for the bolt, not the carrier just the bolt, and the barrel extension and they can not be interchanged. Gas blocks are not pattern specific, they are not even AR-15/AR-10 specific, as long as it is correct diameter for the barrel it is GTG. Same for gas tubes, just need correct length for the gas system you have. Just swap the DPMS bolt out with an Armalite bolt, which it sounds like PSA will do from ealier post. Just a thought about Rainier, how were they to know you ordered a DPMS bolt from PSA when you ordered a barrel with Armalite extension from them?

 

[TanklessPro]

Why not buy the right stuff for each and build two?

 

[brian923]

thehighroad needs to put a like button on post.

when it comes to AR10's, you really need to pick a company and stick with it for the build. its not worth the hassle to save a couple bucks bargain hunting for cheaper parts.

 

[HRnightmare]

Aside from the PSA "shell" and the PSA BCG I would say it is all premium brand or at least higher end brand parts. I just did not know the difference. It totals around $2K when all is said and done. I am not concerned with brand name on a stripped upper and lower...

otrman - My problem with Rainier is they are telling me the gas tube and block hole is not the correct one for the barrel, they said there is a DPMS and Armalite version but the website said nothing of the sort and these items mentioned neither version. Do you believe that there is only one standard gas tube / port hole size? They said it was something like 1000th of an inch difference. I don't remember if they said DPMS was the samller or longer but they are claiming whatever was installed on my barrel was incorrect.

So if I did order the DPMS gas block and tube and an armalite barrel and paid to have them dimple the barrel and install the gas block and tube from factory, shouldn't they have realized I purchased the wrong items and corrected it or called me to advise me of the error instead of slapping incompatible items together.

What's most frustrating is my gunsmith, PSA and Rainier arms will give me 3 different answers to a question when I ask them.

At first PSA told me there BCG was proprietary only to their barrels, but their website says differently.

My gunsmith who head-spaced it said it is without a doubt a DPMS barrel because of the lug spacing, Rainier Arms says that is not accurate.

PSA says an Armalite barrel and BCG will work properly in their upper and lower, Rainier says it will not.

Its frustrating to have three "experts" telling me conflicting stories.

 

[TheLostOtter]

I went through this mess last year. You can use an Armalite pattern barrel in a DPMS pattern upper receiver as long as you use an Armalite pattern bolt. Or vice versa. Important thing is that the barrel extension and bolt are the same pattern.

As far as I know, Rainier makes all of their 308 barrels with a regular AR15 rifle length gas system so you will want to use a standard rifle length gas tube. I have one of their Armalite pattern Match barrels and used a BCM rifle length tube. Works fine. The Armalite gas tube is slightly longer. Gas blocks will interchange as long as you buy the correct size for your barrel. My Rainier barrel has a .750" gas block journal.

 

[otrman]

My problem with Rainier is they are telling me the gas tube and block hole is not the correct one for the barrel, they said there is a DPMS and Armalite version but the website said nothing of the sort and these items mentioned neither version.

Sounds like a new employee. As long as the gas block is correct diameter for the barrel, has nothing to do with the gas port just the fit on the barrel. Gas tubes are all the same expect for length, carbine, mid, and rifle(and the various length for pistols). The gas port in the barrel will vary slightly in size for the length of the gas system. That hole is what determines the amount of gas allowed into the system. I have built and help build over a dozen AR-10s and have never seen a specific AR-10 gas block, much less a DPMS or Armalite specific gas block.

At first PSA told me there BCG was proprietary only to their barrels, but their website says differently.

I would send it back for refund. Have no experience with PSA and their AR-10 offerings but have heard of enough issues with it that I have no interest in them.

My gunsmith who head-spaced it said it is without a doubt a DPMS barrel because of the lug spacing, Rainier Arms says that is not accurate.

Ok, earlier you said you ordered a Armalite barrel but now it is a DPMS? That needs to be nailed down definitively before you can proceed. Do you still have the invoice for the order? It should say what it is. Did you create an account at Rainier? If so, should be able to pull up order and see exactly what you ordered.

PSA says an Armalite barrel and BCG will work properly in their upper and lower, Rainier says it will not.

PSA is correct and Rainier is wrong. Uppers are not pattern specific, they may only properly mate with lower of same manufacturer. The only difference in the lowers is that Armalite makes one that will only use propitiatory Armalite mags or modified M14 mags, they also now make one that uses Pmags and any DPMS pattern mag. The only two pattern specific items are the bolt and barrel extension, and the differences are internal. The OD and length of both are the same on either barrel extension.

 

[HRnightmare]

Quote:
My gunsmith who head-spaced it said it is without a doubt a DPMS barrel because of the lug spacing, Rainier Arms says that is not accurate.
Ok, earlier you said you ordered a Armalite barrel but now it is a DPMS? That needs to be nailed down definitively before you can proceed. Do you still have the invoice for the order? It should say what it is. Did you create an account at Rainier? If so, should be able to pull up order and see exactly what you ordered.

Yes It was an Armalite I ordered (accidently) and Rainier says its an Armalite. I believe my gunsmith is incorrect.

 

[WinThePennant]

When it comes to AR10s, always stick to the same manufacturer. I'm building a PSA AR10, and I will only buy parts from PSA. Price of admission...

 

[HRnightmare]

When it comes to AR10s, always stick to the same manufacturer. I'm building a PSA AR10, and I will only buy parts from PSA. Price of admission...

I just wasn't impressed with their barrel options.

I went back and ordered the same barrel but in DPMS pattern and an ultra match BCG made by them.