Carbine Buffer weight and reloading

[Bailey7]

What is the weight of the buffer for the  carbine? I bought the 16" barreled rifle with the fixed stock and swapped my stock out for a collapsible unit. I purchased a DPMS "carbine" buffer from a vendor on line [Not Brownells] and when it came it had absolutely no markings and seemed seemed fairly light. Weighs in at 3 3/8 oz. As I read more on the subject I wondered if there was any relationship between the buffer weight and the slight pressure signs I was seeing with factory ammo in the 165-168 grain range. I read more on the problems that the M14 system and op rods had with heavier bullets and although I know it is a completely different system the physics of gas and heavier bullets [compared to the stock NATO 144-147 grain, 7.62x51 cartridges] might explain the slightly flattened primers etc. My immediate fix was to drop the powder charge way down. Of course I am already losing some velocity in the 16" barrel. I was disappointed having to drop down to a low end match velocity [from a 24" barrel] which translates to less than 2475 fps in the short barrel [chronographed, Oehler 35]. I am very happy to report consistent sub-MOA groups with Varget powder and several 165 grn bullets including the Hornady A-Max. The Hornady TAP 165 grn. loads also shoot 1/2" cloverleafs but is on the edge of the pressure signs in hot weather.

Then I noticed at least one other seller of special buffers and springs state that the stock DPMS carbine buffer weighs 3.4 ounces but they recommend a 5.4 ounce buffer and a specially modified AR10 buffer spring. For a nice chunk of change. I sent my question into DPMS to see what the optimum buffer weight should be and received no response so I thought I would ask for the experiences here. What kind of safe velocity are you seeing in the 165 grn weight class with the 16" pipe. I won't ask for the load just your velocity. What weight buffer tube are you running? Should I drop to the 155 grn Palma bullet from Sierra and push it out a little faster to make up for the velocity loss with a 165 or does the bearing surface of the Palma bullet add enough pressure that you are still limited on velocities? I have been reloading mostly for bolt guns for more than a couple of decades and am not asking to hot rod the rifle. Just want to build an optimum load and am not sure if I am focused in the correct area or if DPMS takes care of the pressure with something simple like the gas port built into the 16" rifle/gas block.

[SWshooter]

Sounds like an adjustable gas block might solve your problem better than a buffer weight change.

[Bailey7]

Thank you for the response, I was beginning to think I had posed a complex or incompetent question with easily found answers that only I could not find. I had thought about an adjustable gas tube/block but thought it was a complicated solution if I intended to stay with a single load or perhaps one medium load and one for the longer range. 

Having said that, what would you recommend? I have purchased the fiberglass freefloat forend in hopes of cutting a bit more weight and reducing the blistering AZ heat on that metal forend puppy I have now. About 5 rounds in our 105 degree morning temp and you better have that asbestos glove on, or be prepared to leave  a good part of your palm out there. In fairness this holds true for any metal forend, even on a .223; or slip foreward on a shotgun barrel, an AK47 wooden HG or anything else with a few rounds through it. You get the idea, but it is a dry heat.

Been lurking for some time and I see that I need to be prepared to use a torch; first on the tube and then on the barrel nut in order to break loose the Loctite. Then reheat Loctite on the new nut and tube to set them up tight on the reconstruction. Since I also want to install a swivel on the new forend I have been working up the courage to take on the project. Might as well add an adjustable gas tube/block in the process. Is there a consensus that this is the best way to control wear and tear with the 168/175 grain loads? Or as I asked before, should I stick with the 155 grn Palma weight and leave the geometry alone?

If I go with the adjustable gas tube/block what works best in the .308 platform? Any suggestions on how to work up the right loads or adjustments: or a link to the correct threads with the technique for adjusting the gas flow on the loads? Or do they come with good instructions? Thank you in advance for helping me get this tuned up for the optimum performance.

[SWshooter]

I'm new to the AR-10 type rifles also. Can't give you much help with the gas block except for general gas adjust wisdom. Start with the gas set low and slowly increase until positive functioning achieved. Whatever you use for a float tube, use the three piece type that allows you to index the rails or swivels. Use a good barrel nut wrench or you can damage the barrel nut. I have a DPMS and it works well. I didn't need to heat mine, it came off fairly easily. I suppose it depends on the rifle and who put it together. I think Hogue makes a rubber cover for the aluminum float tubes, should help. Look around and you will find a number of threads on reloading.