AR 10 Handguard

swpc629

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I have finally gotten another AR after 30+ years. It is an AR10 in 308. I want to put a different handguard on it. I am wondering if AR10 and AR15 handguards are different in size or are they thecsame?
 

P7M13

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Same? Not in my experience. My first AR10 build was an Aero low profile (G2) upper/lower. Not a single AR15 handguard that I had would fit. Some wouldn't even pass cleanly over the gas block & tube.
Add to that, I've never seen a handguard listed as "compatible with AR10 / AR15"
Also learned, quickly, that not all AR10 handguards play nicely with uppers. Two "DPMS" compatible uppers, different handguard fittment, may not fit with different lowers.
It's not a milspec platform, so manufacturers do modify some dimensions.
Best suggestion, call the vendor to ensure that the handguard will fit your upper.
 

cohunt

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Same? Not in my experience. My first AR10 build was an Aero low profile (G2) upper/lower. Not a single AR15 handguard that I had would fit. Some wouldn't even pass cleanly over the gas block & tube.
Add to that, I've never seen a handguard listed as "compatible with AR10 / AR15"
Also learned, quickly, that not all AR10 handguards play nicely with uppers. Two "DPMS" compatible uppers, different handguard fittment, may not fit with different lowers.
It's not a milspec platform, so manufacturers do modify some dimensions.
Best suggestion, call the vendor to ensure that the handguard will fit your upper.
Aero precision clouds the water a little with their "gen 2" components---- they are referring to their own 2nd generation of parts that offer more/different features than their fist generation of 308 components. They are NOT compatible with DPMS gen 2 rifles ( which is what is commonly referred to a "gen2" 308)
DPMS Gen2 rifles and componants are mostly property in nature but do use common ar15 barrel nuts and handguards...as far as I know, the only other 308 AR upper that uses ar15 barrel nuts and handguards is the "nextgen" by Harrison Bean --- the design and rights were sold off to a different person located in Colorado that last I heard had rebranded them as the "regulator" BUT I'm not sure he has any for sale at this time.

The "gen2" mixes ar15 and ar10/lr308 components to create a much lighter 308 rifle--- they also use some proprietary parts (such as bolts, extractors, ejector, and barrels)

As others have said, the 308 AR platform isn't really milspec- therefore there are quite a few proprietary components that won't necessarily "cross over" in fitment from one brand to another like with ar15 parts. There are different designs of uppers/lowers, magazines, buffer/spring lengths, barrel nuts, handguards, bolts, etc.
Gotta do your homework before purchasing components for the 308 AR type rifles
 

P7M13

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Aero precision clouds the water a little with their "gen 2" components---- they are referring to their own 2nd generation of parts that offer more/different features than their fist generation of 308 components. They are NOT compatible with DPMS gen 2 rifles ( which is what is commonly referred to a "gen2" 308)
DPMS Gen2 rifles and componants are mostly property in nature but do use common ar15 barrel nuts and handguards...as far as I know, the only other 308 AR upper that uses ar15 barrel nuts and handguards is the "nextgen" by Harrison Bean --- the design and rights were sold off to a different person located in Colorado that last I heard had rebranded them as the "regulator" BUT I'm not sure he has any for sale at this time.

The "gen2" mixes ar15 and ar10/lr308 components to create a much lighter 308 rifle--- they also use some proprietary parts (such as bolts, extractors, ejector, and barrels)

As others have said, the 308 AR platform isn't really milspec- therefore there are quite a few proprietary components that won't necessarily "cross over" in fitment from one brand to another like with ar15 parts. There are different designs of uppers/lowers, magazines, buffer/spring lengths, barrel nuts, handguards, bolts, etc.
Gotta do your homework before purchasing components for the 308 AR type rifles
My bad for citing "Gen 2", as that alone can be confusing once you get outside DPMS. Didn't Remington kill the DPMS brand?
Back to my point, there's "low profile" "high profile" and then whatever they called it, the small form-factor AR10. As I understand, the SFF AR10 offerings were rarely interchangeable with any other brand, and many designs were full of problems.
Whether you have a high profile or low profile is measured in the thickness of the tang above the charging handle, as shown in the pic from Team 15. Lots of great LR308 build resources out there, like 308 ar dot com.

rs=w:800,h:800
 

swpc629

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The one I have has a Palmetto lower and I can't find anything that says what brand the upper is. I don't thing it is a Palmetto because the bolt will not lock open on an empty magazine. And been told that is a common problem with Palmetto lowers if the upper is not a Palmetto.
 

cohunt

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The one I have has a Palmetto lower and I can't find anything that says what brand the upper is. I don't thing it is a Palmetto because the bolt will not lock open on an empty magazine. And been told that is a common problem with Palmetto lowers if the upper is not a Palmetto.
Might be a magazine issue-- have you tried other magazines? Could be the bolt catch also.

Iirc the psa are dpms gen1/lr308/sr25 compatible ar308--- they would use the standard dpms handguards and barrel nuts ( not the tall, but the low style) BUT iirc also, they have a few "small parts" internally that are just a bit different

Aug 2009 was the cut off date for dpms lr308 upper changes-- before that date they were "high" after that date they were "low" --- most lr308/sr25 hand guards will be the "low" style and the most common barrel nut size is 1-7/16"x 16 tpi
 
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