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Page AR-15 » AR Piston Systems
AR Sponsor: bravocompany
Posted: 8/11/2016 11:53:37 PM EDT
As some of you already know, I recently built a 14.5 pin/weld piston AR at about 5 lbs to show people that piston rifles don't need to be 8 lbs like my Adam's Arms XLP kit. Well I wanted to get lighter and the only way I could do that is lightening the carrier. So I really wanted to use a different carrier, specifically the low mass one from Adam's Arms, for my Sup Arms kit (since it's the only low mass 1pc on the market). I dremeled the op rod down as nice and precise as I possibly could because flat face carriers don't have the dimple.  I have achieved 4lbs 11.1oz without sights and 5lbs 0.1oz with Aimpoint T2/mount which is pretty impressive. Now to compare that to my EXACT same AR but DI, everything else is the same but has a Ti carrier, Ti Bolt catch, Ti gas block and v7 inconel gas tube, it's at 4lbs 5.2 oz (w/o sights) which is a 6.1oz difference between the piston and DI AR.






I don't mind buying the $30 op rod as a replacement for the one I destroyed if I get a crack or it doesn't work out for me. if all works well I'm going to buy another V7 Titanium carrier with an Adam's Arms strike key and see how that turns out. That would bring the margin of difference in weight between my DI and Piston to 5.3 oz. It's risky, but might be worth it.
Link Posted: 8/12/2016 6:45:51 PM EDT
[#1]
Nice job. I see the Adams carrier is 7.5oz on their website and I thought SupArms carrier was 9.45oz which is just 2oz different. Is that what you got on the scales between the two?
Link Posted: 8/12/2016 7:17:22 PM EDT
[#2]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Nice job. I see the Adams carrier is 7.5oz on their website and I thought SupArms carrier was 9.45oz which is just 2oz different. Is that what you got on the scales between the two?
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I haven't really checked, but it did make it lighter, at about 2 oz. If all goes well I'm going to be buying a Titanium Carrier in which I will put an Adam's Arms Piston Carrier Key on, w/ higher torque screws than the one the key comes with, which will reduce the weight to around 5.7oz (another 1.7 oz shaved).  I have a PWS Anti-Tilt Buffer Tube on my builds which should solve carrier tilt issue seen with piston carriers w/o skis.

I also have a Wolff Reduced Power Springs and Taccom LW Buffer in which I hollowed out to 0.9oz. I'm all about the new lightweight setups now so 2-4oz is a hefty amount for us LW guys. My entire reasoning to light up this rifle (even more than it is) in comparison to her sister DI rifle is to lessen the margin of weight when comparing both builds.  

I called Superlative Arms up about a week ago to ask about their low mass carrier in which they will release and told him my plans to dremel the Piston Rod in order to use other carriers. He obviously advised against it because the Piston Rod is Nitrided H13 Steel, however the Nitriding while raising the RC Hardness and toughness, won't protect shitty metal and H13 is pretty damn strong to constant forceful impact. Since impact will be less with the lighter carrier/spring/buffer weight I'm not too worried about the Piston Rod breaking or having a catastrophic failure such as cracking or worse.
Link Posted: 8/14/2016 2:53:54 AM EDT
[#3]
So what did Superlative arms say about their lightweight carrier? Any release dates.
Link Posted: 8/14/2016 4:03:29 PM EDT
[#4]
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Quoted:
So what did Superlative arms say about their lightweight carrier? Any release dates.
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He said for sure before Christmas.
Link Posted: 8/14/2016 5:29:24 PM EDT
[#5]
Would the Titanium Carrier be weaker than the Adams Arms strike key grade 8 bolts? I know the strike key has pin that goes in carrier but if the carrier key happened to work lose it might pull the threads out of the titanium bolt carrier before snapping steel bolts.
Link Posted: 8/14/2016 6:35:15 PM EDT
[#6]
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Quoted:
Would the Titanium Carrier be weaker than the Adams Arms strike key grade 8 bolts? I know the strike key has pin that goes in carrier but if the carrier key happened to work lose it might pull the threads out of the titanium bolt carrier before snapping steel bolts.
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The problems people reported a while back were most likely attributed to over torquing the screws. The problems people were having is with the screws themselves breaking inside the carrier. Doing a Ti carrier most likely would alleviate any issues than using a steel carrier. The reason being would be that it would take less force to strike the carrier key to the rear than a regular steel carrier.

Ive already ordered stronger bolts than grade 8, which can exceed 170k PSI, torx plus ones too. A dude in another thread said he used an aluminum carrier with the AA piston key, however he said he suffered from carrier tilt. I have a PWS EBT Mod 2, which is an Anti-Tilt Buffer Tube. If need be, I can dremel the "skis" myself.

On a side note. I'm going to be test firing this one today.
Link Posted: 8/14/2016 8:13:37 PM EDT
[#7]
Just got back from the range. It shot beautifully. I only needed to open the gas literally like 1 click. For some reason however, recoil is lighter than my same rifle with a DI. It's significantly lighter actually. No cracks in the rod or any issues.
Link Posted: 8/15/2016 9:19:40 PM EDT
[#8]
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Quoted:
Just got back from the range. It shot beautifully. I only needed to open the gas literally like 1 click. For some reason however, recoil is lighter than my same rifle with a DI. It's significantly lighter actually. No cracks in the rod or any issues.
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That is awesome news.  Do you have any pics of the modified oprod and the Ti carrier?
Link Posted: 8/16/2016 2:13:41 PM EDT
[#9]
I haven't polished it yet so it looks dull. I did slightly file the edge to a tiny bit of rounding edge so that the middle hits the carrier rather than a possibility of the edge hitting it. This should be fine considering the cone shape of the stock rod.

Link Posted: 8/17/2016 4:43:14 PM EDT
[#10]
Do you use Adams Arms bolt spring & do you use POF roller can pin? I seen info that the bolt spring helps with can pin wear on Adams Arms kits. SupArms kit does not come with bolt spring but other pistons kits do use spring on bolt.
Link Posted: 8/17/2016 5:18:05 PM EDT
[#11]
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Quoted:
Do you use Adams Arms bolt spring & do you use POF roller can pin? I seen info that the bolt spring helps with can pin wear on Adams Arms kits. SupArms kit does not come with bolt spring but other pistons kits do use spring on bolt.
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I use the Hydra-fire cam pin. The reason why AA uses the bolt spring( as do a lot of other mfg) is because the bolt itself gets pushed open by the DI piston bolt system (when gas flows through), but since the Gas Piston system we see in piston ARs don't utilize this, the bolt, cam pin, upper, and carrier can see more wear because more more force is exerted and forced. Adding the piston bolt spring theoretically lightens the tension of the aforementioned parts, thus can help reliability and wear.

But yes, I use it.
Link Posted: 8/30/2016 8:48:41 AM EDT
[#12]
So cutting the ball end off the op-rod worked.  I had to shorten an AA op-rod once because of a lack of standardization of pistol-length gas systems.  The end mushroomed after a few hundred rounds and I had to dremel the end of it off, in the upper, to get it back out.  Ended up replacing the barrel to move the gas port further away to fix the problem.  This was with the AA lightened carrier, btw.

What I'm wondering is would it be worth replacing the op-rod with a complete one and having a ball end mill create a dimple in the AA gas key replacement.  You get the advantage back of a load spread out over a larger area (1/2 a sphere vs a flat end) and the self-aligning again.  You also don't risk the mushrooming problem I had.  Now I do understand the Ti is lighter than the steel, but it's still mass being smacked pretty hard over and over.

Anyway just a thought.  Glad it ran for you though.  It's about the same weight now as my 10.5" 300BO pistol with the AA XLP.  Impressive.
Link Posted: 8/30/2016 2:03:19 PM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
So cutting the ball end off the op-rod worked.  I had to shorten an AA op-rod once because of a lack of standardization of pistol-length gas systems.  The end mushroomed after a few hundred rounds and I had to dremel the end of it off, in the upper, to get it back out.  Ended up replacing the barrel to move the gas port further away to fix the problem.  This was with the AA lightened carrier, btw.

What I'm wondering is would it be worth replacing the op-rod with a complete one and having a ball end mill create a dimple in the AA gas key replacement.  You get the advantage back of a load spread out over a larger area (1/2 a sphere vs a flat end) and the self-aligning again.  You also don't risk the mushrooming problem I had.  Now I do understand the Ti is lighter than the steel, but it's still mass being smacked pretty hard over and over.

Anyway just a thought.  Glad it ran for you though.  It's about the same weight now as my 10.5" 300BO pistol with the AA XLP.  Impressive.
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what do you mean it mushroomed after a few hundred rounds? Did it end up crushing in on itself from the repetition?
Page AR-15 » AR Piston Systems
AR Sponsor: bravocompany
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