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Posted: 2/8/2011 7:57:21 PM EDT
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I am planning on putting a AR-15 together and wanted to get a little feedback. I want to get the Adams Arms Carbine Tactical upper, but I was wondering how involved changing the barrel is.
The gist of it is that although I think the 5.56 round is fine, I'd prefer to have a gun with 6.8 standard. However, 6.8 is to spendy to shoot for fun. So I thought I would get a 5.56 rifle and pick up a 6.8 barrel. Keep the 6.8 on for home defense purposes, but switch to the 5.56 for the majority of range time. Is it feasible and is there a upper better than the Adams Arms one for this purpose? PS. I've heard that Adams Arms is getting a .308/7.62 compatible upper, does anyone know if that shoots other calibers? |
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Well, even when you have the tools it's not that easy to simply swap the barrels. If you do buy a AA Carbine Tactical Upper, this is what you'll have to do to put on a 6.8 SPC II barrel:
(Compiling this off the top of my head) Tools needed: Vise Drill Press Drill (not sure the size, but has to be able to cut through steel) Armorer's tool or GI barrel wrench Torque Wrench Upper receiver action block or Barrel clamps. Feeler gauge Spare crush washers, or reuse old ones punches (if you use brass, you'll probably destroy them) Hammer Procedure: Make sure the weapon is clear. Remove the BCG and Charging Handle Remove the piston system (push in the detent on the plug, 1/4 turn counter clockwise, all the piston parts will come out) Remove the AA/Samson rail (only 4 allen bolts) Place upper in action block or use the barrel clamps and put it in the vise. Using the GI barrel wrench or Armorer's tool, remove the flash hider. take the upper out of the vise and remove the taper pins out of the gas block with punches and hammer (various ways to do this. I more often than not end up cutting of FSBs). I don't know which direction to hammer the pins. Sorry. Remove the gas block. Place the upper back in the vice and use the barrel wrench/Armorer's tool to remove the barrel nut and remove the barrel. Now it's time to install the 6.8 SPC barrel. ... You know what... don't do it. Just don't do it. 
You're better off getting two separate uppers. The AA .308's are complete rifles. P.S. Barrel clamps suck. |
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Hmm, well I've looked into getting a LMT setup (they sound awesome), but those uppers are almost twice as expensive as the Adams Arms one.
Does anyone else have a decent priced piston upper that makes it easy to change barrels but is priced in the sub $1k range? I'm trying to build a rifle for $1500 (not counting an extra barrel). |
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Well, my suggestion would be to save and get exactly what you want. If you don't mind compromise, have you thought of just getting the AA Tactical Carbine upper and just keeping some 75gr TAP ammo at home for protection? I know that bullet weight isn't ideal for the 1x9 twist on that upper, but unless you live on a ranch or farm engaging a target beyond 50 yards is not likely.
The other option is to build or buy a 6.8 SPC II upper and call it a day. |
| Thanks for all the replies, you have been very helpful. I'm leaning towards either saving for a LMT or getting a 5.56 upper now and a 6.8 later. Any 6.8 upper recommendations? What are the best priced sites for getting a LMT upper? Also I keep seein 6.8 spc II what is the difference with spc I? |
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There are 2 standardized, but different, chambers for the 6.8 SPC which yield different results. Only the rifles chambered with the newer specified chamber(aka 6.8mm Spec II chamber) can safely use the higher powered/higher pressure ammunition. All other rifles should only be used with the standard cartridge pressure loadings.
http://en.wikipedia.org/wiki/6.8_mm_Remington_SPC Can't really help you with LMT upper pricing beyond Google product search. They are roughly around $1400 though. CMMG makes a very affordable piston 6.8 SPC II upper $649.99. I'm not a big fan of their design, but you can't beat the price considering LWRC and PWS are significantly more expensive. They do have rails when this one does not though. http://www.primaryarms.com/product.sc;jsessionid=53BDDC540A6CB8F87275D4E4D132D04E.qscstrfrnt03?productId=1057 Keep us posted on what you decide to do. |
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