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Posted: 4/19/2015 1:48:38 PM EDT
| I put together a 6.8 spc, Yesterday I was out to test fire it, It was short stroking [fire a round and eject..but not pick-up and chamber the next round] It is a 18" mid length with a rifle length stock and buffer. I tried the carbine buffer and spring out of my mid-length carbine and the 6.8 functioned nicely with that....but I seem to hear the spring way too much. question is...which carbine buffer should I use...and can I use a rifle length spring with it? |
| If you are running a rifle stock, you need to run a rifle buffer and spring. What ammo were you using? Manufacturer of barrel? What mag are you using and did you try a different mag? Is there an adjustable gas block on your rifle? Where was the brass ejecting to? I have a few 6.8 rifles but I use collapsible stocks, carbine buffer, carbine spring and adjustable gas blocks. |
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I put together a 6.8 spc, Yesterday I was out to test fire it, It was short stroking [fire a round and eject..but not pick-up and chamber the next round] It is a 18" mid length with a rifle length stock and buffer. I tried the carbine buffer and spring out of my mid-length carbine and the 6.8 functioned nicely with that....but I seem to hear the spring way too much. question is...which carbine buffer should I use...and can I use a rifle length spring with it? No parts from the carbine buttstock system interchange with the rifle buttstock system. If the rig functions with a telestock (carbine buttstock system) then maybe the rifle buffer weight and rifle spring are a little too much. There is a lighter weight rifle buffer, but it's a bit pricey....http://www.brownells.com/rifle-parts/receiver-parts/recoil-parts/recoil-buffers/ar-15-m16-low-mass-recoil-buffer-prod27116.aspx. There is also a Reduced Power action spring available....SKU 16505....http://www.gunsprings.com/Rifles%20%26%20Shotguns/COLT/AR-15,%20CAR-15,%20M-16,%20M4,%209mm%20SMG%20AND%20SPORTER/cID2/mID1/dID79 I'd probably try the action spring first....cheaper. You could also enlarge the gas port, but there's no do-over on that. |
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I suggest you run some rounds through to break in your rifle. Sometimes a new rifle needs some break in time. It is frustrating, but it gets better.
My 6.8 AR pistol build short stroked the first time out. It wouldn't function on factory ammo or my reloads at the top of my ladder. I tried the upper on my SBR and pistol lowers. Each had different springs/buffers. Before my second trip, I polished the contact surfaces of the bolt and carrier. I also loaded up some hotter rounds. I also got some constant spring rate buffer springs. On my second trip, my pistol slowly started to function. I nearly made it through a 20rd mag by the end. For my next trip, I loaded out 50rds at the high end of the scale. |
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I am going to deal with the gas block first and see what happens there...I am using a clamp on lo-pro and it's possible it's not quite lined up. I just ordered a "jig" that I can use to dimple the barrel. The gas port on the block is usually over-sized to help with slight fitment errors. You should see a "carbon track" around the barrel's gas port (which is smaller) when you remove the gas block. This visual will tell you how your alignment was. |
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Something else to try to help determine whether it is actually "short-stroking" is to load one round in the mag and fire. See if the BCG locks back on the Bolt Stop. And with that does it lock back(fully) manually?
Also it might help to cycle the BCG quite a few times to help wear in components...lubed of course. |
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Something else to try to help determine whether it is actually "short-stroking" is to load one round in the mag and fire. See if the BCG locks back on the Bolt Stop. And with that does it lock back(fully) manually? Also it might help to cycle the BCG quite a few times to help wear in components...lubed of course. The bolt is rather stiff...as I had to use the FA on the first round out of each mag. |
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The bolt is rather stiff...as I had to use the FA on the first round out of each mag. Quoted:
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Something else to try to help determine whether it is actually "short-stroking" is to load one round in the mag and fire. See if the BCG locks back on the Bolt Stop. And with that does it lock back(fully) manually? Also it might help to cycle the BCG quite a few times to help wear in components...lubed of course. The bolt is rather stiff...as I had to use the FA on the first round out of each mag. When you say "bolt is rather stiff" do you mean doesn't go into Battery easily? Just thinking out loud here but dragging on full mag? Dragging period? Weak recoil spring? With no ammo or magazine in place what happens if you slowly follow the BCG with the charging handle? How does the bolt go in to battery? Also the Remington ammo is known to be rather weak. Ko-tonics barrel? Old one? Used? |
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If you need a lighter rifle buffer, buy a second rifle buffer and remove the aluminum spacer.
A second rifle buffer is a LOT cheaper than the light rifle buffers you'll see on the market. That spacer is exactly the length of two of the steel weights. Remove two weights form your buffer and replace them with the aluminum spacer. This will get you down to around 4oz. Note rifle buffer construction at bottom. 
Never use a carbine length buffer in a rifle receiver extension, the BCG will impact the lower and crack it. |
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Are you sure that once assembled the gas tube is not hanging in the carrier gas key?
I have seen this problem before. As has been stated make sure it locks back after firing one round with an empty mag. This is the best test to see if the gas system is working properly. Never use 6.8 Remington ammo to break in or trouble shoot a 6.8 rifle. Its substandard and unworthy of purchase. |
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IIRC- correct me if I'm wrong. Didn't Ko-Tonic/Cardinal go out of business because of a problem with the chrome lining? The problem occurred after he switched from Kotonics to Cardinal Armory branding. The problem was some barrels got too much chrome and he did not have the proper equipment or sufficient funds to rent it to determine which were GTG. I have 2 Cardinal Armory barrels and a Kotonics, all are fantastic shooters with never a pressure sign. I've run the hottest commercial (SSA 85 TSX Tactical) and hot hand loads in a variety of bullets through all three with no problems. |
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The problem occurred after he switched from Kotonics to Cardinal Armory branding. The problem was some barrels got too much chrome and he did not have the proper equipment or sufficient funds to rent it to determine which were GTG. I have 2 Cardinal Armory barrels and a Kotonics, all are fantastic shooters with never a pressure sign. I've run the hottest commercial (SSA 85 TSX Tactical) and hot hand loads in a variety of bullets through all three with no problems. Quoted:
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IIRC- correct me if I'm wrong. Didn't Ko-Tonic/Cardinal go out of business because of a problem with the chrome lining? The problem occurred after he switched from Kotonics to Cardinal Armory branding. The problem was some barrels got too much chrome and he did not have the proper equipment or sufficient funds to rent it to determine which were GTG. I have 2 Cardinal Armory barrels and a Kotonics, all are fantastic shooters with never a pressure sign. I've run the hottest commercial (SSA 85 TSX Tactical) and hot hand loads in a variety of bullets through all three with no problems. OK, thanks, It was a shot. (No pun intended). |
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