Newbie Question

[Retired Mike]

Well, here is my first newbie question. Please pardon my inexperience if this has been previously answered, but so far I haven't found it yet. I recently purchased a RRA LAR-8 to upgrade from  my AR-15 for night Hog hunts. Experience has shown my that the 308 is a lot more forgiving to less than perfect shot placement with the smaller 223/5.56. After a five month wait, it finally arrived at my dealer only to be lost by the Post Office for a month. I've now been able to shoot it and it works great and very accurately without my suppressor, but it will not work with the suppressor with feed and ejection issues. In talking with other users, they all agreed the suppressor was causing too much bask pressure and I needed an adjustable gas block. I called RRA and they also confirmed this.

Here's my question, actually two:

    1. Can anyone recommend a good gunsmith here in Central TX? I live near Centerville off I45 half way between Dallas and Houston.

    2. What adjustable gas block would you recommend?

Attached are some slow motion and normal speed videos showing my problem when shooting with the suppressor. Feedback will be appreciated.

Retired Mike

[unforgiven]

I have a Lar8 Standard Operator. I was going to suppress it, I had put on a Battle Comp compensator right after I got it. I got Slash's heavy buffer kit for RRA Lar8 and haven't used it much.

Edited January 6, 2021 by unforgiven

[jtallen83]

4 hours ago, Retired Mike said:

  2. What adjustable gas block would you recommend?

SLR makes a great adjustable gas block.

https://slrrifleworks.com/gas-blocks/

Edited January 6, 2021 by jtallen83
added link

[Retired Mike]

5 minutes ago, jtallen83 said:

SLR makes a great adjustable gas block.

https://slrrifleworks.com/gas-blocks/

When I talked with RRA's today, the recommended this one from Superlative Arms. are you familiar with it?

[jtallen83]

Just now, Retired Mike said:

are you familiar with it?

I have one and was not impressed. It has two different settings, by-pass and restricted. It works like any other gas block in restricted mode, the bypass mode is the big selling point but with the 308 it will not allow enough gas by to be effective, can't open it enough to get a failure to eject as the direction say. Here is the review thread;

 

[98Z5V]

I knew you'd be in here, brother...  

[392heminut]

On 1/6/2021 at 4:17 PM, Retired Mike said:

When I talked with RRA's today, the recommended this one from Superlative Arms. are you familiar with it?

I have one and I love it! I did a build with one of the 12.5" Sig barrels that CDNN was recently blowing out and used that gas block on the build. Once I had it dialed in it has worked really well both with and without the suppressor. I'm probably going to take off the adjustable gas block (don't remember the brand offhand) that is on my 16" barreled Matrix build and replace it with one of these.

[jtallen83]

31 minutes ago, 392heminut said:

Once I had it dialed in it has worked really well both with and without the suppressor.

Does it work on the bleed off setting? Can you open it enough to get a failure to lock back? Only tried mine on a 16 inch rifle gas but it would never bleed off enough to reach that point. I have plenty of those shortys' if it will work on them.

[98Z5V]

@Retired Mike, were all three of those vids while shooting suppressed?   That BCG is FLYING.  You gotta cut that gas down, or get one heavy buffer in there.

If you get the chance, get a couple vids of it firing without the suppressor...   What's the weight of the buffer that's in there right now?

[Retired Mike]

1 hour ago, 98Z5V said:

@Retired Mike, were all three of those vids while shooting suppressed?   That BCG is FLYING.  You gotta cut that gas down, or get one heavy buffer in there.

If you get the chance, get a couple vids of it firing without the suppressor...   What's the weight of the buffer that's in there right now?

Yes, all three were suppressed. I don't have any without the suppressor, but it appears to work quite well with a couple of different Hornady loads, all 150 gr. I have no idea what the buffer weight is as the rifle is just a stock RRA 308 X series. Right now, it is all apart waiting for the new adjustable gas block. which is due here on Monday. The manual shows the buffer as shown in the attached. Please remember, I know little about the working and details of AR's, but I love to shoot Hogs with them at night. Where I hunt, the use of the suppressor is a must so I need to get it sorted out. On my AR-15, I have absolutely no issues either with or without the suppressor and a wide range of different ammunition. I guess that coupled with my lack of experience is what surprised me so much when I went to initially shoot it with the suppressor, but I'm quickly learning and appreciate all the help I can get.

[98Z5V]

If it's the RRA Operator CAR Stock, it's running the 7.000" internal-depth receiver extension, and I can see that in the pic you provided.  RRA BCGs are a 1/4" longer than DPMS or Armalite based BCGS, so the buffer is another 1/4" shorter.  Normally, to run a regular .308AR with a 7.000" internal-depth extension, you must use a 2.500" buffer.  The RRA guns have to use a 2.250" buffer.  I'm betting that things weighs 3.8oz, or a little less.   You need toget that buffer weight up to around 5.4oz, and the only place that I know of that makes one is Slash - Heavybuffers.com.  This link is the buffer, and the price includes the correct recoil spring that you need:

http://heavybuffers.com/rra308car.html

Specific notes from Slash on these buffers, and call him/email him if you have any questions on what you have/what you need:

Please note:

If your gun uses FN-FAL magazines this is the correct buffer.

If your gun uses ArmaLite mags, DPMS mags or Magpul P-Mags please click here: CAR-10 .308 Carbine Buffer

Contact me via email prior to ordering if you have any doubts as to which product you need.

A RRA-10 buffer will allow you to use any AR15 collapsing stock (Magpul/LMT/VLTOR/Ace/etc) on your Rock River Arms .308 AR. Standard carbine length stocks cannot be used on these rifles with regular carbine buffers. This is strictly a 'Drop-In' part, no gunsmithing or modifications are required.

This product is specifically recommended by Magpul for use with their carbine stocks on RRA.308s. (Call them!) RRA-10 buffers also work great with any other stock using a standard 7" carbine buffer tube.

RRA-10 buffers are shorter and heavier than standard carbine buffers (and other .308 carbine buffer). Constructed of 303 Stainless Steel with a sliding Tungsten anti-bounce counterweight. Heavy buffers reduce felt recoil for the shooter, and minimize wear and tear on the gun. Some users have reported that the RRA-10 buffer significantly increased the reliability of their firearms.

Note: Not compatible with .223 ARs. This buffer is designed specifically for use in RRA .308 ARs with 7" receiver extensions (buffer tubes). If you have an RRA extended length buffer tube (8") please see the XH Carbine buffer & .308 Rifle Buffer Spring (EA1095).

 

Edited January 8, 2021 by 98Z5V

[392heminut]

17 hours ago, jtallen83 said:

Does it work on the bleed off setting? Can you open it enough to get a failure to lock back? Only tried mine on a 16 inch rifle gas but it would never bleed off enough to reach that point. I have plenty of those shortys' if it will work on them.

My bad! That gas block IS NOT the one I bought! I saw the lever on the front and like a dumbass I posted without thinking! The one I have is the Seekins Select Adjustable gas block;

https://www.opticsplanet.com/seekins-precision-0011510065-select-adjustable-gas-block-750-steel-black-mel.html

[jtallen83]

4 hours ago, 392heminut said:

The one I have is the Seekins Select Adjustable gas block;

I just bought one of those on Joe-Bob's Christmas sale, it sure looks like solid stuff, can't wait to set it up.

[Retired Mike]

22 hours ago, 98Z5V said:

If it's the RRA Operator CAR Stock, it's running the 7.000" internal-depth receiver extension, and I can see that in the pic you provided.  RRA BCGs are a 1/4" longer than DPMS or Armalite based BCGS, so the buffer is another 1/4" shorter.  Normally, to run a regular .308AR with a 7.000" internal-depth extension, you must use a 2.500" buffer.  The RRA guns have to use a 2.250" buffer.  I'm betting that things weighs 3.8oz, or a little less.   You need toget that buffer weight up to around 5.4oz, and the only place that I know of that makes one is Slash - Heavybuffers.com.  This link is the buffer, and the price includes the correct recoil spring that you need:

http://heavybuffers.com/rra308car.html

Specific notes from Slash on these buffers, and call him/email him if you have any questions on what you have/what you need:

Please note:

If your gun uses FN-FAL magazines this is the correct buffer.

If your gun uses ArmaLite mags, DPMS mags or Magpul P-Mags please click here: CAR-10 .308 Carbine Buffer

Contact me via email prior to ordering if you have any doubts as to which product you need.

A RRA-10 buffer will allow you to use any AR15 collapsing stock (Magpul/LMT/VLTOR/Ace/etc) on your Rock River Arms .308 AR. Standard carbine length stocks cannot be used on these rifles with regular carbine buffers. This is strictly a 'Drop-In' part, no gunsmithing or modifications are required.

This product is specifically recommended by Magpul for use with their carbine stocks on RRA.308s. (Call them!) RRA-10 buffers also work great with any other stock using a standard 7" carbine buffer tube.

RRA-10 buffers are shorter and heavier than standard carbine buffers (and other .308 carbine buffer). Constructed of 303 Stainless Steel with a sliding Tungsten anti-bounce counterweight. Heavy buffers reduce felt recoil for the shooter, and minimize wear and tear on the gun. Some users have reported that the RRA-10 buffer significantly increased the reliability of their firearms.

Note: Not compatible with .223 ARs. This buffer is designed specifically for use in RRA .308 ARs with 7" receiver extensions (buffer tubes). If you have an RRA extended length buffer tube (8") please see the XH Carbine buffer & .308 Rifle Buffer Spring (EA1095).

 

I pulled the buffer out and it is even lighter than you figured at 2.9 oz. It has a sliding weight inside and the tube length measures 8" inside, while the spring is 13.5" in length uncompressed.

[98Z5V]

1 hour ago, Retired Mike said:

 

That buffer weight doesn't surprise me.  That's damn near half of what your buffer weight should be, to run a .308AR.

You need to email Clint @ HeavyBuffers.com...   

Those two tubes are exactly what you think - they fit CR123 batteries.

Email him:   clint@heavybuffers.com

Make sure you tell him that .308AR.com sent you...  

Edited January 9, 2021 by 98Z5V

[shooterrex]

Double check the internal depth of your buffer tube 8" sounds like an odd measurement. Ar15's are 7" and Armalite's carbine buffer tube is 7 5/8".

[392heminut]

15 hours ago, jtallen83 said:

I just bought one of those on Joe-Bob's Christmas sale, it sure looks like solid stuff, can't wait to set it up.

It's pretty straightforward to set it up. Adjust it down to where you you don't have bolt lock back and then open it up to where you do. Open it up a couple more clicks and lock the lever down with it on the right side of the gun. You're done! When you run the suppressor just flip the lever all the way to the left.

[Retired Mike]

9 hours ago, shooterrex said:

Double check the internal depth of your buffer tube 8" sounds like an odd measurement. Ar15's are 7" and Armalite's carbine buffer tube is 7 5/8".

Using both the depth gauge on a 12" set of calipers and a metal scale, the tube the spring fits into clearly measures 8" from where the spring bottoms to the face of the tube. Also, the spring measures 13.5" in it's free state and when inserted 5.5" remains exposed when uncompressed, confirming the 8" tube length.

[Rsquared]

15 hours ago, 392heminut said:

It's pretty straightforward to set it up. Adjust it down to where you you don't have bolt lock back and then open it up to where you do. Open it up a couple more clicks and lock the lever down with it on the right side of the gun. You're done! When you run the suppressor just flip the lever all the way to the left.

That seems pretty slick. I think I'm gonna have to give one of these a try. Seekins is a pretty solid manufacturer,

Thanks for finding that brother.

[Armed Eye Doc]

On 1/8/2021 at 9:12 PM, Retired Mike said:

I pulled the buffer out and it is even lighter than you figured at 2.9 oz. It has a sliding weight inside and the tube length measures 8" inside, while the spring is 13.5" in length uncompressed.

I checked my RRA LAR-8.  It has a carbine receiver extension that is 8 inches deep.  I didn't measure the spring.    The buffer is 3.263 inches long and 4.70 oz.  It is light and I don't know why I have not ordered a buffer from Heavybuffers.com. 

 

[98Z5V]

16 minutes ago, Armed Eye Doc said:

I checked my RRA LAR-8.  It has a carbine receiver extension that is 8 inches deep.  I didn't measure the spring.    The buffer is 3.263 inches long and 4.70 oz.  It is light and I don't know why I have not ordered a buffer from Heavybuffers.com. 

 

This makes perfect sense, mathematically.

Normally, in the RRA LAR-8, you'd have to run a 2.250" buffer to run the standard 7.000" internal-depth AR15 Carbine Receiver extension. As mentioned earlier, the RRA LAR-8 BCG is 1/4" longer than DPMS LR-308 and Armalite AR-10 BCGs (same OAL for those two brands).  SO, that longer BCG needs a shorter buffer, to be able to fit into the same space (length of extension).  Got it...

Now, by MOVING to an 8.000" internal depth carbine receiver extension - they can use a buffer that's exactly 1.000" longer, follow?   What's that new buffer length...   3.250"...   Standard AR15 carbine buffer length, which is...  Armalite AR-10 Carbine Buffer length. 

Makes perfect sense to me for them to switch to that.  Makes perfect sense to me, also, as to why Slash has his warning/advisement in his buffer listing. 

@Retired Mike - that buffer you're running is just a 3.250" long standard AR15 carbine buffer - you listed 2.9oz, the AR15 exact part should weigh in at 3.0oz, for standard carbine.  What I'm saying is - that not even an H1 buffer (3.8oz), it's not even an H2 buffer (4.6oz), and it's definitely not the H3 buffer (5.4oz).

Quick fix it this - just toss any old AR15 H3 Carbine Buffer.  Or use the Armalite AR-10 Carbine buffer, because those are all H3-weighted...  

Solved, brothers.  And we know why. 

Subnote - now, I know why @sketch ended up a few years ago with a PA-10 Carbine extension that was 8.000" internal depth - someone at PSA copied what RRA was doing, and made those extension that way - but they didn't know why, what it would impact, or what the differences were between the major platforms...

Hmmm...  

Edited January 11, 2021 by 98Z5V

[Armed Eye Doc]

15 minutes ago, 98Z5V said:

This makes perfect sense, mathematically.

Normally, in the RRA LAR-8, you'd have to run a 2.250" buffer to run the standard 7.000" internal-depth AR15 Carbine Receiver extension. As mentioned earlier, the RRA LAR-8 BCG is 1/4" longer than DPMS LR-308 and Armalite AR-10 BCGs (same OAL for those two brands).  SO, that longer BCG needs a shorter buffer, to be able to fit into the same space (length of extension).  Got it...

Now, by MOVING to an 8.000" internal depth carbine receiver extension - they can use a buffer that's exactly 1.000" longer, follow?   What's that new buffer length...   3.250"...   Standard AR15 carbine buffer length, which is...  Armalite AR-10 Carbine Buffer length. 

Makes perfect sense to me for them to switch to that.  Makes perfect sense to me, also, as to why Slash has his warning/advisement in his buffer listing. 

@Retired Mike - that buffer you're running is just a 3.250" long standard AR15 carbine buffer - you listed 2.9oz, the AR15 exact part should weigh in at 3.0oz, for standard carbine.  What I'm saying is - that not even an H1 buffer (3.8oz), it's not even an H2 buffer (4.6oz), and it's definitely not the H3 buffer (5.4oz).

Quick fix it this - just toss any old AR15 H3 Carbine Buffer.  Or use the Armalite AR-10 Carbine buffer, because those are all H3-weighted...  

Solved, brothers.  And we know why. 

Subnote - now, I know why @sketch ended up a few years ago with a PA-10 Carbine extension that was 8.000" internal depth - someone at PSA copied what RRA was doing, and made those extension that way - but they didn't know why, what it would impact, or what the differences were between the major platforms...

Hmmm...  

Awesome summation brother. 

[sketch]

shits i cant remember buying any (psass )10 so you can't quote me on that. I bought the wrong slash buffer for my lar8 and I gave it to you .  

[98Z5V]

5 minutes ago, Armed Eye Doc said:

Awesome summation brother. 

Thank you, Mi Amigo.   ❤️

21 minutes ago, 98Z5V said:

Quick fix it this - just toss any old AR15 H3 Carbine Buffer.  Or use the Armalite AR-10 Carbine buffer, because those are all H3-weighted...  

@Retired Mike - we know what you need for a buffer, but lets address that spring as a next step, if necessary.  Get the new (correctly weighted H3, 5.4oz) buffer in there first, and run the gun.  If we have a spring issue, the quick, cheap fix is to just use an Armalite EA1095 spring.  That's their AR-10 recoil spring.  They run that same spring in their AR-10 Carbine Recoil System, AND in the AR-10 Rifle Recoil System - and it just works.  Every time.

You'll have an extension is 8.000" internal with a buffer of 3.250" moving inside it.  That's 4.750" of movement inside the extension, that the spring must control. 

AR-10 Carbine is 7 5/8" internal (7.625") with a 3.250" buffer = 4.375" of movement/spring control.

AR-10 Rifle is 9 11/16" internal (9.688") with a 5.200 AR-10 Rifle Buffer length = 4.488" of movement/spring control.

That's how the same spring works in both recoil systems.  Coil bind (compressed length) on the EA1095 spring is 2.448".  I'll bet it would work fine, but maybe there's a very specific reason that Slash offers his very own spring for the RRA LAR-8s.  If you get the H3 buffer, and it doesn't solve everything, and you need to make a spring change, and you use that EA1095 spring on my recommendation - and it doesn't work...   Then you'll need Slash's spring, and we'll all know that in the future.  If that is what all happens, I'll buy that EA1095 spring for what you have to pay for it, with shipping that you had to pay, plus shipping to me for it.  I can always use a spare, and Slash is WAY SMARTER on Recoil Systems than I am...  

[98Z5V]

16 minutes ago, sketch said:

shits i cant remember buying any (psass )10 so you can't quote me on that. I bought the wrong slash buffer for my lar8 and I gave it to you .  

That bitch was laser-engraved with the PSA logo and PA-10 right on the bottom of it, brother, and that thing was 8.000" internal depth.  We swapped one of my 3.250" H3 buffer in there, and STILL had to stack some quarters in the tube, to keep your BCG from slamming the ears on the lower...

Maybe RRA was the ones making those for PSA, and engraving them for PSA - and it ended up on your RRA instead.  And you had a short buffer...