Looking for AR builders, a little help please

[osprey]

We are either being punked or op is way in over his head and needs to get professional help as I suggested earlier.

 

[Cannonman]

BCG dimension of different platforms and manufacturers. I've excluded some rows and this does not include details of the bolt dimensions, which become relevant when addressing headspace.
View attachment 828485
View attachment 828487

Thank you for this. I know it takes time away from you to help me and I can't thank you enough. This is very interesting and I'll enjoy studying the charts.

 

[Cannonman]

Nah.
It's difficult to help because the OP does not have a complete understanding of the system and doesn't know proper nomenclature, so he can't describe the problem to people trying to help him troubleshoot.
Frustrating on both ends.

True. And poignant. I'm in a town of some 2,500 in the middle of nowhere. I'm retired and have taken on learning about guns as a hobby. New to the area I know of no one near here to ask for help. Help I've gotten in the past, traveling about 100 miles, resulted in a damaged Glock slide. I joined this forum and THR looking for help with this problem. To be called, "in over my head" may well be true. However, there are less than $2k in parts in this build and the friend I'm working on this build for would probably say something, "So you do make mistakes. About time!" At which time I'd just send the whole thing in somewhere or just shelve the project. Cost and time are not an issue. Wanting to meet new people and learn more about these skill sets is the issue. Pranking, punking or trying to waste your times is the furthest from my concerns. I do wish to thank all of you who have taken the time to help. Perhaps the better question is if you were me, a guy with a strong desire to learn, financially stable and who has no local person to help, where would you go and what questions would you ask? More to the point, I can't thank all of you who have attempted to help. I've learned much even if I''ve been asking the wrong questions. Thanks.
For what it's worth, here are the two guns I've been mentioning. The green upper fits the Black Rain lower but the green lower does not fit the BR upper. Anyway, Why doesn't the green pick up founds from the mags?

 

[spookshack]

Time to throw up the bat signal.... @Velzey

 

[Velzey]

On duty

 

[Xanthri]

I put a AR 10 in .308 together and it has feeding problems. Mostly it does not want to go into full battery. This upper does not have an assist. The first thing that came to mind was a buffer weight. Then, buffer spring, gas, bolt, ??? I have one other .308 and was thinking of changing out parts from the working model. The spring and weight seem the same. Not 100% sure of the spring. So, If you have an idea I love to hear it. Last, I never thought ammo would be a problem with a build. Or how to use the least amount of ammo to find the problem. I've re-loaded a fair amount of bottle neck cartridges but I fear I might be adding another unknown.

First make sure your magazine let the bullets move freely...I know this causes issues with the smaller framed ARs.

Next check your feed ramp....sometimes you need to polish or Drexel some of the bolt locking star...I know that isn't the official name but that describes it well.

And yes definitely check buffer weight and make sure you have a heavier buffer spring....it will definitely help.

Also....make sure that the bolt.is well oiled. Many people forget but most of the bolts get dry and the added friction slows the mechanism...

And if the inside of the upper is a little rough take some 300 5/600 and 1200 grit sandpaper and make it feel smoother

 

[Cannonman]

Time to throw up the bat signal.... @Velzey

Geeeze Ya! Sorry about this thread. Really long in the tooth. I'm learning a lot and can't say how much I appreciate all of you!

 

[Cannonman]

First make sure your magazine let the bullets move freely...I know this causes issues with the smaller framed ARs.

Next check your feed ramp....sometimes you need to polish or Drexel some of the bolt locking star...I know that isn't the official name but that describes it well.

And yes definitely check buffer weight and make sure you have a heavier buffer spring....it will definitely help.

Also....make sure that the bolt.is well oiled. Many people forget but most of the bolts get dry and the added friction slows the mechanism...

And if the inside of the upper is a little rough take some 300 5/600 and 1200 grit sandpaper and make it feel smoother

Will do! Thanks. I plan on changing the parts from the working model one by one to see if something changes. I'll certainly heed your advice.

 

[DirectDrive]

Unlike the small frame AR15, in large frame AR's there are two "patterns"
1) Armalite (AR10)
2) DPMS (AR308)

You have DPMS pattern.
And even within your pattern there are parts that don't play well with each other.
So swapping large frame uppers and lowers back and forth isn't a thing I'd be interested in.

Here's a Bolt Carrier Group (BCG) from a AR15 which is similar to your large frame AR.
The two main components are the Carrier and the Bolt.
Also you can see the gas key clearly labeled.
It's important to understand the various parts and what they're called when trying to get online help.

 

[Cannonman]

Unlike the small frame AR15, in large frame AR's there are two "patterns"
1) Armalite (AR10)
2) DPMS (AR308)

You have DPMS pattern.
And even within your pattern there are parts that don't play well with each other.
So swapping large frame uppers and lowers back and forth isn't a thing I'd be interested in.

Here's a Bolt Carrier Group (BCG) from a AR15 which is similar to your large frame AR.
The two main components are the Carrier and the Bolt.
Also you can see the gas key clearly labeled.
It's important to understand the various parts and what they're called when trying to get online help.


View attachment 829082

 

[Cannonman]

Great advice and I thank you for the time you took to helping me to learn as well as how to ask questions . I'm getting two answers as to how far the gas tube should go into the gas key. I'm not sure what to do when this sort of thing arises. Presently I'm going to switch threads with the same problem. I found out that the new gun works fine with the old .308's lower. If I switch the buffer weight I have the same problems. Same with buffer spring. I'll be asking what the differences are and if there is anything I can do to the new lower to solve this problem. Thanks for the extra time DD! Good to know your out there!

 

[Cannonman]

First make sure your magazine let the bullets move freely...I know this causes issues with the smaller framed ARs.

Next check your feed ramp....sometimes you need to polish or Drexel some of the bolt locking star...I know that isn't the official name but that describes it well.

And yes definitely check buffer weight and make sure you have a heavier buffer spring....it will definitely help.

Also....make sure that the bolt.is well oiled. Many people forget but most of the bolts get dry and the added friction slows the mechanism...

And if the inside of the upper is a little rough take some 300 5/600 and 1200 grit sandpaper and make it feel smoother

Thanks. I did try the working weight of the BR .308 and then the spring. No change. I'm going to change this thread to look at the lower. Great having your input sir!

 

[Mr Smith]

it's not unheard of to have an out-of-spec upper receiver or out of spec lower...

One of my 308 builds had a bad upper receiver. It didn't line up with the lower properly and caused the buffer retention pin to crew at the edges of the buffer as the carrier was not pushing the buffer away from the pin properly. It also had an out of spec rail causing the scope to be waaaaaaaay off. I had to have the scope practically bottomed out just to get on paper. I exchanged the upper and they sent me an aero upper as a replacement since their billet upper was out of spec, and the aero upper fixed the scope angle issue, and fixed the carrier/buffer alignment/spacing issue as well. So it's always possible especially with billet parts to have something out of spec if the machinist didn't line up the billet with their mill properly it throws every cut and pass out of whack.

 

[Mr Smith]

There's my carbine 308 buffer after being mated to that bad billet upper receiver. It caused the carrier to not push against the buffer while the upper and lower were mated together which caused the buffer to slap the retention pin every pull of the trigger due to it riding against the pin rather than being held out of the way by the carrier.

That buffer is just a spare part now as I changed the lower to a rifle stock+buffer and mated a forged upper to it instead of a billet upper. haven't had a problem with it since.




So you may just end up having a bad lower receiver itself, or a bad upper receiver... if they aren't within tolerances of spec then they will cause all kinds of issues.

 

[WTC]

There's my carbine 308 buffer after being mated to that bad billet upper receiver. It caused the carrier to not push against the buffer while the upper and lower were mated together which caused the buffer to slap the retention pin every pull of the trigger due to it riding against the pin rather than being held out of the way by the carrier.

That buffer is just a spare part now as I changed the lower to a rifle stock+buffer and mated a forged upper to it instead of a billet upper. haven't had a problem with it since.

View attachment 830369
View attachment 830370

So you may just end up having a bad lower receiver itself, or a bad upper receiver... if they aren't within tolerances of spec then they will cause all kinds of issues.

They make an offset pin to fix this issue in slightly out of spec lowers fwiw

 

[titsonritz]

There's my carbine 308 buffer after being mated to that bad billet upper receiver. It caused the carrier to not push against the buffer while the upper and lower were mated together which caused the buffer to slap the retention pin every pull of the trigger due to it riding against the pin rather than being held out of the way by the carrier.

That buffer is just a spare part now as I changed the lower to a rifle stock+buffer and mated a forged upper to it instead of a billet upper. haven't had a problem with it since.

View attachment 830369
View attachment 830370

So you may just end up having a bad lower receiver itself, or a bad upper receiver... if they aren't within tolerances of spec then they will cause all kinds of issues.

They make an offset pin to fix this issue in slightly out of spec lowers fwiw

Yes there is.
https://gallowayprecision.com/offset-buffer-retainer-for-AR-15-rifles
Personally, I think it is pathetic there is an entire industry dedicated to "fixing" out of spec garbage.

 

[Mr Smith]

Yes there is.
https://gallowayprecision.com/offset-buffer-retainer-for-AR-15-rifles
Personally, I think it is pathetic there is an entire industry dedicated to "fixing" out of spec garbage.

It is indeed. And almost $20 for that goofy little pin to fix a problem that should be covered under any product warranty for a clear manufacturing defect.

Which btw mine was... They sent me a replacement forged upper on their dime for shipping because of the billet upper being out of spec. They also discontinued the billet upper. (Not sure if my case had any connection there to the discontinuation of the billet upper)

 

[arakboss]

I put a AR 10 in .308 together and it has feeding problems. Mostly it does not want to go into full battery. This upper does not have an assist. The first thing that came to mind was a buffer weight. Then, buffer spring, gas, bolt, ??? I have one other .308 and was thinking of changing out parts from the working model. The spring and weight seem the same. Not 100% sure of the spring. So, If you have an idea I love to hear it. Last, I never thought ammo would be a problem with a build. Or how to use the least amount of ammo to find the problem. I've re-loaded a fair amount of bottle neck cartridges but I fear I might be adding another unknown.

Out of curiosity what type/platform of AR10 did you build is and is the other AR10 the same type/platform?

 

[Cannonman]

Out of curiosity what type/platform of AR10 did you build is and is the other AR10 the same type/platform?

Thanks. Life is getting in the way of retirement hobbies. I so hope I get off a PM or some pics for you. I've been looking for any builders around here and have come up with nothing. Good old small town living!