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Riflespeed gas adjusters with Smoke Composites hand guard

Ape_Factory

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May 23, 2020
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Short version. A Riflespeed adjustable gas block might not work with your Smoke Composites hand guard or at the very least, will need modification to work. Read on.

Just a PSA, I'm always tweaking and made a few changes to my 300 blackout SBR. I had the Superlative Arms adjustable gas block but it was a pain to adjust on a pistol-length gas system with the suppressor on the gun. I moved on to the JP gas block and despite the side adjustment screw which was really easy to access through the hand guard, I did not realize there was a set screw at the front. Back to square one.

I'd been eyeing the Riflespeed adjustable gas blocks for some time but you really have to watch your gas system, barrel and hand guard length if you're trying to use existing components. I went from a 10.5" barrel to an 8.5" and my 10" Smoke hand guard covered the end of the barrel. Even with the 10.5" barrel, there wasn't a Riflespeed model that would work.

I ended up ordering a custom length 7" hand guard from Smoke and the Riflespeed RS7533 per their recommendation. Smoke Composites has an off the shelf 7.25" which "might" work but it'd be tight trying to get fingers in there to adjust the gas with a suppressor on.

Everything arrived and I began to put it together. I then realized, due to the straight gas tube design, the Riflespeed gas block, but not the gas tube, was a bit too tall for the Smoke Composites hand guard.

Luckily, the hand guard has machined slots below the pic rail on top (M-lock slots) and all I had to do was cut out the bridged material between two slots. The top of the gas block protrudes through the slot and does not touch. Whew! It does take some facilitating to get the hand guard on and off with the gas block as a unit though so there is a downside. The hand guard's rigidity isn't affected. These things are incredibly strong and they should be given their price.

Really hoping the Riflespeed's stock plunger will cover the gun's gas needs with subsonic and supersonic ammo. They include a second plunger and offer about a dozen others to dial it in. Otherwise, I'm impressed. Very easy to adjust and despite the small gap in my setup, it's easy to access which was the goal all along.

I added a Law Tactical folder which might require some buffer mods as I'm using a titanium BCG from RCA and a very light buffer. The extra mass of the extension might cause cycling issues. To that end, I have an Odin Works adjustable buffer if the need arises. Beyond that, going to a red dot tube or holographic 1X and removing the scope to shrink the form factor a bit more and make it more bump in the night usable. If HUXWRX ends up doing a Flow 7.62 K version, I'll likely go with that too. It's currently the 7.62 Ti. Never ends.

You can sort of see how it's protruding in the slot in this photo. Looks like it's touching but it's just the angle. Tough to get a good photo straight on.


Gas adjustment end of things. Very easy to access and I think the off the shelf 7.25" hand guard would work but I didn't want to risk it and I personally wouldn't want it any tighter.


Pre-Law folder, naked, it's a mid 4-pound gun. I've added quite a bit of weight with the accessories but it's still a pretty handy weapon overall and this cures my desire to get the Sig MCX which IMO, has too short of a barrel.


 
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Brief update. Got to the range and could not get the rifle to cycle with subs. I was at setting 10, first rotation, with supers.

For those that have the Riflespeed gas block, you'll understand the first rotation thing. For those that don't, here's an explanation. Even though you have clicks from 1-12, if you push in on the top tab, it'll allow you to rotate past the stop and have additional gas adjustment. There are more gas setting there BUT there's no stop so you can literally unscrew the gas adjustment collar at this point if you rotate too far.

Ideally, you want a setting for supers at the lower end of the spectrum, 1 being closed. There is a plunger, small metal rod with a round radius and notches. This ultimately determines how much range of gas adjustment you have. It's pretty easy to change the plungers.

There are two plungers included with the gas block and others can be purchase separately. IMO, they need to also offer options on the plungers for people running say pistol length vs. rifle length. Included are #917 and #937 with #917 installed (runs most .223 setups just fine) and #937 being for .308 generally.

I'm running an 8.5" Rainier Match 300 blackout barrel, pistol-length gas and with the stock #917 installed, I was already at setting 10 for supers and could not get it to cycle with subs on the first rotation. I ordered two more plungers which UPS promptly lost and Riflespeed sent out a new set ASAP so good customer service!

The shorter the plunger the more gas it lets in. The shorter the part number number, the shorter the plunger. In my case, with the pre-installed #917 plunger, supers locking the bolt back at setting #10 (Barnes TSX), I want to move it down to #4. Each plunger moves the setting two notches. If I went with the next shortest plunger, my setting would be at #8 for supers. Since I wanted #4, I went to the smallest plunger the #887. I also ordered an #897 just in case.

I'll head to the range tomorrow to test but I should have more than enough adjustment on the first rotation for supers and subs with three more settings for supers if I ever need to close off the gas a bit more.

Hope this helps a bit. Consider your gas length and setup and possibly order additional plungers when you order the gas block. Will save you shipping dollars, time and effort.
 
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What size gas block are you using? The .750 or .625? If you can, set a steel rule on top of the barrel and take a measurement to the top of the gas block. I'm waiting for the .875 to become available, but looking at the dimensions on the website for the .750 gas block and comparing to various handguards that I could find dimensions for, looks like quite a few handguards will have a fit problem with the riflespeed gas blocks.
 
It's the .750 version. Let me see what I can do on the measurement.

I have another Riflespeed inbound, going on a 16" mid length and I kind of wonder if my Coda carbon hand guard will fit. I have an extra Smoke Composites 10" hand guard not being used and I may just use it if the CODA doesn't work out. Otherwise I'll go back to the Superlative Arms since it'll be very easy to adjust with the shorter hand guard.

The main issue is that it uses a straight gas tube which has it's benefits but makes the gas block taller than it needs to be. I've seen one installed on the POF Revolution DI which has a .750 gas block and a straight gas tube from the factory. The POF us very easy to adjust but I'll take tool-less over easy to adjust with a tool any day.
 
I've seen their diagram. I was wanting something a little more visual. But, don't go out of your way to disassemble your rifle to do it. I imagine the .875 might be a little taller, hope not. So far from what I've found, doesn't look like the .750 will fit under a KAC handguard, JP handguards are probably a no go as well, SLR handguards should work but will be tight, should fit PRI handguards. Haven't looked into any other brands as those are the ones I'm looking at for a large frame build.
I'll take tool-less over easy to adjust with a tool any day.
Agree 100% there
 
At this point it's not easy to disassemble the rifle without taking off a lot of stuff honestly, including components that are now zeroed in. I can try to take a few photos but yeah, I'd measure everything very carefully if using a Dremel to clearance is out of the question. The actual "peak" above the portion of the gas block where the gas tube secures is actually quite small in width. So if there's a slot in the top of the hand guard, it may work.

The weather sucked all morning (dense fog) so I didn't make it to the range today but headed there tomorrow to hopefully get it functioning 100% with subs and supers.

I can't see the .875 being any taller as the straight gas tube, regardless of whether it's a .625, .725 or .850 all has to go through the same gas tube port at the front of the upper. That would require each gas block to have the same height.
 
I've been testing various components and didn't have any luck getting factory loaded Hornady 190 Sub-X rounds to cycle. I removed all the weight from the buffer and I still couldn't get the carrier to lock back or extract the brass completely. The 190's don't always chamber due to the shape of the bullet. Hornady really needs to rethink them.

Supers were no problem, worked like a charm with the shorter barrel.

So...I took a step back and re-installed the Faxon 10.5" barrel which, from day one, has shot everything consistently, supers or subs, and has been very accurate. The extension is a tighter fit than the Rainer too, I have to freeze the barrel and heat the upper to install. I moved up one plunger size in the Riflespeed gas block based on intuition. I also switched to my own hand loads, Berry's 200gr. over CFE Black. CFE Black is dirty but it cycles every setup I've tried.

Loading up the Hornady 190's first, no luck, couldn't get it to cycle no matter what the gas setting. I tried supers and again, no issues there cycled perfectly. I then used my hand loads, confirmed subsonic, and they worked. I was able to get the subs to cycle on the 12 setting and supers on 4, same rotation. This is important. There's a mechanical stop with the dial adjuster on the Riflespeed. You can turn from 1-12 clicks and it'll stop at 1 or 12 and won't allow you to rotate further. If you push the tab on the outer ring downward, it'll allow for another rotation. Ideally, you'd want both in the same 1-12 rotation which is what I now have.

I will say the one downfall to the Riflespeed is it does need to be sprayed at a precise spot with a bit of CLP after each session. It'll get hard to turn if you don't. I'm going to experiment with other lubricants to see if it helps. It's not from carbon blocking the plunger but the metal wave washer/outer ring interface. It'd probably help if the adjuster was a bit longer so I could get more purchase on it. With the 10.5" barrel, I have more room for a longer adjuster and those can be purchased separately for $80 or so.

Ultimately I should have tried my hand loads with the 8.5" but I just joined a new indoor range and didn't realize I could use hand loads. So I've been testing factory stuff only. I read through the fine print and didn't see any mention of hand loads so I brought them today to see if it'd get me tased. I really thought an indoor 100 yard range would be the bees knees (no wind) but man, with a silencer mirage is worse than it is outdoors despite the flow of air back to front. Testing a load for my bolt gun and there were times I couldn't make out the target at all. There's always something.
 
I've been testing various components and didn't have any luck getting factory loaded Hornady 190 Sub-X rounds to cycle. I removed all the weight from the buffer and I still couldn't get the carrier to lock back or extract the brass completely. The 190's don't always chamber due to the shape of the bullet. Hornady really needs to rethink them.

Supers were no problem, worked like a charm with the shorter barrel.

So...I took a step back and re-installed the Faxon 10.5" barrel which, from day one, has shot everything consistently, supers or subs, and has been very accurate. The extension is a tighter fit than the Rainer too, I have to freeze the barrel and heat the upper to install. I moved up one plunger size in the Riflespeed gas block based on intuition. I also switched to my own hand loads, Berry's 200gr. over CFE Black. CFE Black is dirty but it cycles every setup I've tried.

Loading up the Hornady 190's first, no luck, couldn't get it to cycle no matter what the gas setting. I tried supers and again, no issues there cycled perfectly. I then used my hand loads, confirmed subsonic, and they worked. I was able to get the subs to cycle on the 12 setting and supers on 4, same rotation. This is important. There's a mechanical stop with the dial adjuster on the Riflespeed. You can turn from 1-12 clicks and it'll stop at 1 or 12 and won't allow you to rotate further. If you push the tab on the outer ring downward, it'll allow for another rotation. Ideally, you'd want both in the same 1-12 rotation which is what I now have.

I will say the one downfall to the Riflespeed is it does need to be sprayed at a precise spot with a bit of CLP after each session. It'll get hard to turn if you don't. I'm going to experiment with other lubricants to see if it helps. It's not from carbon blocking the plunger but the metal wave washer/outer ring interface. It'd probably help if the adjuster was a bit longer so I could get more purchase on it. With the 10.5" barrel, I have more room for a longer adjuster and those can be purchased separately for $80 or so.

Ultimately I should have tried my hand loads with the 8.5" but I just joined a new indoor range and didn't realize I could use hand loads. So I've been testing factory stuff only. I read through the fine print and didn't see any mention of hand loads so I brought them today to see if it'd get me tased. I really thought an indoor 100 yard range would be the bees knees (no wind) but man, with a silencer mirage is worse than it is outdoors despite the flow of air back to front. Testing a load for my bolt gun and there were times I couldn't make out the target at all. There's always something.
Wondering how things shaked out with your testing? I have a similar set up as you Faxon 10.5,RCA titanium BGC,SLR adj Ti gas block JP Scs buffer system. Have the riflespeed on a MK12 build I just got done with I’m curious how things shaked out and what buffer weight you are using? Any info or guidance will be appreciated.
 

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I was using the Odin Works adjustable buffer. I'm now using a different system, the Unrivaled two-stage dead blow competition buffer system. Functions perfectly with supers. I don't use the Hornady subs in it since they don't feed correctly. Bought a Sig Spear LT in 300 blackout for that. Expensive solution.

I still have the Odin buffer, can weigh it and report back.
 
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I have a 14.5 in 5.56 that I run the RCA titanium BGC with the JP scs and an slr that I tuned easily and runs like a sewing machine this is my first 300 so it will be a learning curve I have different weights and springs I can play with on the JP scs just trying to get a base line starting point plan on running it suppressed you running a can on yours?
 
I am running a suppressor but it's a Flow 762 so it doesn't have any effect on function since it's low back pressure. I do have the JP SCS in another rifle, the SBR version, I can swap them over and report back. It'll likely be a bit though as I'm on a 7 day a week work cycle for the for likely the next month or two.
 
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What barrel extensions are you guys using for 300 Whisper/BLK?

They benefit from ramp enlargement, de-edging, blending, and polishing.