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Looking for the basics on large-frames

ShortShooter1908

Sergeant of the Hide
Full Member
Minuteman
Feb 22, 2018
105
22
Central Ohio
1. I want to build.
I don't want to replace parts. I want to be able to spread the cost out over time.

2. I don't necessarily want budget. I want the best bang for the buck. (Pun intended)
I have things I will spend money on, looks and name brands aren't one of them.

3. I want to go 308.

I have no 308. I have a 6.5cm bolt gun.

------

In general I am looking to build an effective PRS/tactical gasser. I have built 3 small frames. I know that large frames are another thing unto themselves. Is there a thread that can let me know what I do not know?

TIA
 
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Are you looking for parts recommendations?

Biggest issue with large frame is lack of mil spec. Most are designed for dpms headspace, a few for armalite. Also with the frame fit, some have rounded uppers and others are slanted.

I think aero is considered the best bang for buck receiver wise
 
I am basically stupid when it comes to the differences in the large frame. DPMS/Armalite/sr25 I know there are differences. I don't know what they are. I am looking for the particulars that will help me judge if the added cost of one pattern justifies the additional costs. Sure, I would love to go to Knights, or whomever, and get whatever top end they have. Not in my budget.

If a quality basic tier will fulfill what I foresee as my needs good. If I need to bump up a tier, I want to know so I can save money and not waste it on something I'll sell when I find that out.

Things are in a planning phase. I'm not sure how much what I want costs. I am looking for a 5/8"-3/4" gun. As stated, going with 308 so probably 22"-24" barrel to get to a max of 1000. This is honestly "you tell me" kind of thing. I have no basis in this platform. I would like to get the receivers in the safe soon if the laws change so if there is a grandfather clause I'm covered.
 
I currently have a “proof of concept” rifle that I built just to see if it could be done.
I have a GAP-10, a KAC SR-25, and a couple bolt guns. So, I’m not “a poor”.

I’m messing with an Aero Precision 18” 6.5CM that CONSISTENTLY shoots sub MOA. It started life as a .308, but I changed the barrel to an 18” 6.5CM.
I can not say enough that it is a really fun project gun that shoots far better than it should, or I ever thought it would. I have laid down and shot multiple 5 round groups that fall into the .79-.81 moa range.
If I were to start from SCRATCH, I’d do this: Aero Upper/Lower
Ballistic Advantage match barrel
or a Ranier Ultra Match barrel
Any solid bolt/ BCG
Geiselle SSA-E or SD-E trigger
SureFire Suppressor Mount

I really, really think this combo can/will give you the basis for an awesome rifle.
I absolutely just did it to see if a guy, ANY guy, could build a rifle, for under $1500, that can/will shoot 5-1000 yds.
Based on my Ballistic ap, I am supersonic to well past 1000yds. I can put a 4-16 scope on it with an Aimpoint in a 45* offset sight and shoot from contact distance to “all the way” out.
As a “proof of concept”, the rifle has been a resounding success. I literally don’t know what a fella could do different.
All for under $1500.
WELL worth the $$$
 
I currently have a “proof of concept” rifle that I built just to see if it could be done.
I have a GAP-10, a KAC SR-25, and a couple bolt guns. So, I’m not “a poor”.

I’m messing with an Aero Precision 18” 6.5CM that CONSISTENTLY shoots sub MOA. It started life as a .308, but I changed the barrel to an 18” 6.5CM.
I can not say enough that it is a really fun project gun that shoots far better than it should, or I ever thought it would. I have laid down and shot multiple 5 round groups that fall into the .79-.81 moa range.
If I were to start from SCRATCH, I’d do this: Aero Upper/Lower
Ballistic Advantage match barrel
or a Ranier Ultra Match barrel
Any solid bolt/ BCG
Geiselle SSA-E or SD-E trigger
SureFire Suppressor Mount

I really, really think this combo can/will give you the basis for an awesome rifle.
I absolutely just did it to see if a guy, ANY guy, could build a rifle, for under $1500, that can/will shoot 5-1000 yds.
Based on my Ballistic ap, I am supersonic to well past 1000yds. I can put a 4-16 scope on it with an Aimpoint in a 45* offset sight and shoot from contact distance to “all the way” out.
As a “proof of concept”, the rifle has been a resounding success. I literally don’t know what a fella could do different.
All for under $1500.
WELL worth the $$$
That's what my experience building small frames told me. I have an Aero receiver set that I built out with a WOA barrel and Geissele trigger that outshoots me. I was looking at what the different patterns brought to the table. I don't know if there is a pattern that gives a significant boost over another.
 
Aero p upper lower. Faxon 65creed barrel. Trigger
 
check out the aero m5ei 'enhanced' upper/handguard combo's. i just bought two sets of these in the ar-15 pattern (m4e1) and the handguard mounts are super solid, similar to the mega ones. then i'd fill it with all the JP parts you can. i would go 24" barrel just for the extra velocity (rainier ultramatch). geissele ssa-e two stage trigger. all dpms-pattern which seems to give the most availability and certainly cheap pmags.
 
check out the aero m5ei 'enhanced' upper/handguard combo's. i just bought two sets of these in the ar-15 pattern (m4e1) and the handguard mounts are super solid, similar to the mega ones. then i'd fill it with all the JP parts you can. i would go 24" barrel just for the extra velocity (rainier ultramatch). geissele ssa-e two stage trigger. all dpms-pattern which seems to give the most availability and certainly cheap pmags.
Do you have a point of reference to compare to a Geissele rail?
 
Do you have a point of reference to compare to a Geissele rail?
no experience with geissele rails but heard good things. what the aero 'enhanced' has is a flanged upper to which the handguard bolts, vs screwing to the barrel nut. definitely a stronger, sturdier connection. perhaps it's overkill. their rail itself is nice, plenty of attachment points, has light stippling on it for better gripping. assembly is just a hair easier as you don't have to worry about alignment for the gas tube. i just mostly built out the one set (awaiting stock, buffer tube) and fit and finish are excellent.

 
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Just a few comments.

IMHO, go DPMS pattern. The parts seem to be far easier to find in stock.... generally speaking. ( Since there is no "Mil-Spec" guidelines )

So go with a large manufacturer for the upper and lower... and use their LPK's

While the enhanced AERO upper is a good idea.... it limits the aftermarket handguard choices.. so maybe a conventional upper would be more practical.
If you install an Adj. GB... you are going to want plenty of room inside the handguard... especially considering your long barrel will most likely be pretty fat contoured.

DPMS barrels seem a-plenty... I really like Criterion's IMHO the extra 100 bucks is money well spent, helping to insure better precision.

Be sure to lap / true the upper receiver face. Easily done with a 30 dollar tool.

Dependent on your gas system length... consider a +2 version or if using a RLGS , consider an Adj. GB>

An Adj. GB will help tame the "kick" ... easier on the parts, easier on the follow up shots, easier on you
 
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Just a few comments.

IMHO, go DPMS pattern. The parts seem to be far easier to find in stock.... generally speaking. ( Since there is no "Mil-Spec" guidelines )

So go with a large manufacturer for the upper and lower... and use their LPK's

While the enhanced AERO upper is a good idea.... it limits the aftermarket handguard choices.. so maybe a conventional upper would be more practical.
If you install an Adj. GB... you are going to want plenty of room inside the handguard... especially considering your long barrel will most likely be pretty fat contoured.

DPMS barrels seem a-plenty... I really like Criterion's IMHO the extra 100 bucks is money well spent, helping to insure better precision.

Be sure to lap / true the upper receiver face. Easily done with a 30 dollar tool.

Dependent on your gas system length... consider a +2 version or if using a RLGS , consider an Adj. GB>

An Adj. GB will help tame the "kick" ... easier on the parts, easier on the follow up shots, easier on you
The JP low profile block will fit under any handguard
 
As far as gas blocks, I’ve had excellent experiences with Superlative Arms.
They have no parts “inside” to get corroded or frozen by carbon etc.
Not saying they’re the end all be all, as I’m sure there are others that work. I’ve just used them and can recommend them.
I used one on my Aero build, and have one on my GAP-10. They tame the gas enough to REALLY take it easy on the brass. I BARELY have any ejector swipe, and my brass isnt beat up much more than on my bolt guns.
There is quite a bit of gas in the .308 or even the 6.5CM. MOST of that gas isn’t needed. You can do wonders with about half of it. This, Adj GB are a big deal on large frames.
 
Are you looking for a rifle you can lube up then beat the shit out of it without failure? Are you lookin for a rifle you can suppress and run w/o a can without “adjusting” anything?

If you answered yes to either of those two—don’t build.
 
I currently have a “proof of concept” rifle that I built just to see if it could be done.
I have a GAP-10, a KAC SR-25, and a couple bolt guns. So, I’m not “a poor”.

I’m messing with an Aero Precision 18” 6.5CM that CONSISTENTLY shoots sub MOA. It started life as a .308, but I changed the barrel to an 18” 6.5CM.
I can not say enough that it is a really fun project gun that shoots far better than it should, or I ever thought it would. I have laid down and shot multiple 5 round groups that fall into the .79-.81 moa range.
If I were to start from SCRATCH, I’d do this: Aero Upper/Lower
Ballistic Advantage match barrel
or a Ranier Ultra Match barrel
Any solid bolt/ BCG
Geiselle SSA-E or SD-E trigger
SureFire Suppressor Mount

I really, really think this combo can/will give you the basis for an awesome rifle.
I absolutely just did it to see if a guy, ANY guy, could build a rifle, for under $1500, that can/will shoot 5-1000 yds.
Based on my Ballistic ap, I am supersonic to well past 1000yds. I can put a 4-16 scope on it with an Aimpoint in a 45* offset sight and shoot from contact distance to “all the way” out.
As a “proof of concept”, the rifle has been a resounding success. I literally don’t know what a fella could do different.
All for under $1500.
WELL worth the $$$

I agree with this 100%. Just built my first one to see how it would compare to my JP LRP 07 and I’m impressed.

Aero M5E1 set on sale
Ballistic advantage premium barrel
Superlative Arms adjustable gas block
Geissele SSA-E trigger.

She shoots great. My only issue was using the JP silent capture spring which causes the bolt to not lock back sometime and was finicky adjusting the gas, which I posted vids of here and fitness great advice. My brother used the same aero set, BCG, silent capture spring but with a Faxon barrel and he hasn’t had zero issues.

I’d go with a heavy buffer if I did it again. Other than that, solid build under $1,600. Only taken her to 400 yards so far but I just guessed on the dial up, 1st shot hit and 4 more right after. Too easy!
 
I agree with this 100%. Just built my first one to see how it would compare to my JP LRP 07 and I’m impressed.

Aero M5E1 set on sale
Ballistic advantage premium barrel
Superlative Arms adjustable gas block
Geissele SSA-E trigger.

She shoots great. My only issue was using the JP silent capture spring which causes the bolt to not lock back sometime and was finicky adjusting the gas, which I posted vids of here and fitness great advice. My brother used the same aero set, BCG, silent capture spring but with a Faxon barrel and he hasn’t had zero issues.

I’d go with a heavy buffer if I did it again. Other than that, solid build under $1,600. Only taken her to 400 yards so far but I just guessed on the dial up, 1st shot hit and 4 more right after. Too easy!
Do you happen to remember what the thread title was where you posted those videos? I have the JP silent capture in 2 of my small frames and love them.
 
I agree with this 100%. Just built my first one to see how it would compare to my JP LRP 07 and I’m impressed.

Aero M5E1 set on sale
Ballistic advantage premium barrel
Superlative Arms adjustable gas block
Geissele SSA-E trigger.

She shoots great. My only issue was using the JP silent capture spring which causes the bolt to not lock back sometime and was finicky adjusting the gas, which I posted vids of here and fitness great advice. My brother used the same aero set, BCG, silent capture spring but with a Faxon barrel and he hasn’t had zero issues.

I’d go with a heavy buffer if I did it again. Other than that, solid build under $1,600. Only taken her to 400 yards so far but I just guessed on the dial up, 1st shot hit and 4 more right after. Too easy!
There is a heavy version of the SCs and a regular version. Make sure you get the heavy version.

 
Ok. I've been convinced to go with Aero upper and lower. I never looked for the greatest deal when I was getting my small frames. Are they famous for having great deals on holiday sales? What's the best price I should expect new from a retailer?
 
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I have built several 308’s using the rainier arms ultra match barrels. They have always been very accurate and I have beat the hell out of a couple of them. They run suppressed or unsuppressed with very little Maintance.
 
Ok. I've been convinced to go with Aero upper and lower. I never looked for the greatest deal when I was getting my small frames. Are they famous for having great deals on holiday sales? What's the best price I should expect new from a retailer?

As someone else mentioned, look for them from other retailers. Aero’s website isn’t often higher than other stores. If you do buy them from aero, definitely wait for a sale or check their blemished sale.
 
Juggernaut tactical makes a nice matched receiver set and a hanguard to match.
 
In my opinion the most important part of an AR10 build is the gas system. SLR makes a 15 position gas block, JP makes the best bolt and carrier, and their silent capture spring.
These 3 components will ensure that your AR always shoots well and is adjustable so you will never over or under-gas your rifle.
 
My .02 cents
The more parts you can get from one company the more each part is engineered to work together and the more reliable it should be. Not that a mix of quality parts wont be any less.

Not all uppers and lowers work together. Some hanguards wont work with certain uppers. Some buffer and springs wont work with some tubes, stocks/tubes, etc.

Some things dont matter. Any 308 trigger should fit any lower. Almost any barrels will work with any upper. Parts kits should be universal.

Start with a Matched reciever Set
upper/lower and possibly handguard

Things that matter:
Barrel
Bolt
Bolt carrier
Adjustable Gas block
Buffer spring
Buffer
Buffer tube

The gas system: gas block, BCG, buffer and spring all work together and each piece can be had in different weights and adjustability.

I highly reccomend looking at JPrifles.com and their youtube videos explaining the different parts and effects they can have on a rifle.

Everything else you put on your rifle is looks and feel personal preference.
 
I have built a number of these for people. The first one I built (which I still own cost me $2500+ to build. Unfortunately this was around the Newtown shooting so prices were stupid high. With that said I used a Mega MATEN set (now ZEV) and built it around a Rainier Match 16" barrel. It is a consistent 1/2 MOA gun and I've rung steal out to 1200yds with it. Can't say enough about Mega (ZEV) or the Rainier barrel. That being said I have built most of the guns around the Aero receivers and they are definitely the way to go if you're not looking for ambi bolt release and integrated hand guards. These guns have been considerably less money, generally hovering around the $1k mark. I've used a number of Mega barrels, not even sure if you can get them any more and also used Ballistic Advantage. Both have been sub MOA on every gun I've built. So for $1k less I'm pretty much achieving the same level of accuracy

Like others have stated, I would recommend going with the DPMS platform as it's the most common. However to make things more complicated DPMS has released a Gen2 variant. The bolt headspace are different between the DPMS and Armalight platforms, but the receiver/rail heights are also different as well. So make sure whatever rail you decide on is compatible with your upper receiver.

And like others have noted, an adjustable gas block is a must with these guns. They can be extremely finicky so being able to adjust the gas to suit your specific loads is essential.
 
Just get the LaRue Ultimate Upper .308 kit, pick your barrel length, and don't worry about all the compatibility issues.

When people say "just use DPMS pattern", DPMS has 3 different receiver designs alone within the LR-308/AP4, not counting the new GII.

A nagging problem I'm seeing on a fairly regular basis now is BCGs incompatible with lowers. Since the shops that actually machine bolt carriers are not working off of a complete TDP that knows what kind of lower the upper is going on, the bottom carrier guide rails are slamming into the RET threads or RET boss on the lower, even when people finally figure out the "correct" combination of buffer, RET, and action spring (something usually screwed up out of the gate with a lot of builders).

It's really best to source all your parts from one competent shop who had actually tested everything together for years if you want a working rifle that isn't a tinker trap.
 
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Just get the LaRue Ultimate Upper .308 kit, pick your barrel length, and don't worry about all the compatibility issues.

When people say "just use DPMS pattern", DPMS has 3 different receiver designs alone within the LR-308/AP4, not counting the new GII.

A nagging problem I'm seeing on a fairly regular basis now is BCGs incompatible with lowers. Since the shops that actually machine bolt carriers are not working off of a complete TDP that knows what kind of lower the upper is going on, the bottom carrier guide rails are slamming into the RET threads or RET boss on the lower, even when people finally figure out the "correct" combination of buffer, RET, and action spring (something usually screwed up out of the gate with a lot of builders).

It's really best to source all your parts from one competent shop who had actually tested everything together for years if you want a working rifle that isn't a tinker trap.
Just buy the upper? what about a lower?
 
Just get the LaRue Ultimate Upper .308 kit, pick your barrel length, and don't worry about all the compatibility issues.

When people say "just use DPMS pattern", DPMS has 3 different receiver designs alone within the LR-308/AP4, not counting the new GII.

A nagging problem I'm seeing on a fairly regular basis now is BCGs incompatible with lowers. Since the shops that actually machine bolt carriers are not working off of a complete TDP that knows what kind of lower the upper is going on, the bottom carrier guide rails are slamming into the RET threads or RET boss on the lower, even when people finally figure out the "correct" combination of buffer, RET, and action spring (something usually screwed up out of the gate with a lot of builders).

It's really best to source all your parts from one competent shop who had actually tested everything together for years if you want a working rifle that isn't a tinker trap.
I get where you are coming from. I could see getting BCG, barrel, buffer, and gas block. Everything else I don't want. I'm going to upgrade the trigger, buttstock, and I am not a huge fan of the handguard.
 
Just buy the upper? what about a lower?
It includes everything but the stripped lower, which you can order or select which pattern interface you want.

You get LPK, RAT stock, LaRue precision-machined RET that isn't sloppy with the RAT, MBT-2S 2-stage trigger, quality buffer, quality action spring, and everything to complete the upper.
 
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It includes everything but the stripped lower, which you can order or select which pattern interface you want.

You get LPK, RAT stock, LaRue precision-machined RET that isn't sloppy with the RAT, MBT-2S 2-stage trigger, quality buffer, quality action spring, and everything to complete the upper.
I get that, do you have a recommendation for one that is proven?. This is the trap with 308, you can buy an upper and not know what lower is 100% compatible. In my experience always buy a matched set upper and lower unless it's a proven combo or you are taking a chance on fit and function.
 
Bolt catch breakage is an issue in the large frames. Pay close attention to carrier speed. Either run an adjustable gas block, a heavier buffer, or an upgraded bolt catch. The other key points revolving around large frame ARs have already been discussed.