Aircooled6racer

Hello: Shoot it off hand not on the rest and see how it shoots. Thanks, Eric

Hello: I knew something was up. After your MPX breaks in you will be able to shoot lower power factor loads. Tite Group is a little dirty but it is easy to clean the residue off. N320 is nice but not twice as nice as Tite Group You may want to try WST as well. Thanks, Eric

Hello: I think the breaking problem is that they are a bad design more than a hardness issue. I was a Tool & Die maker in a past life so I worked with a lot of different materials. A lot of the firing pins are stainless steel and have sharp corners where the stress crack can form. A smooth radius and good material would do a lot and also the correct heat treatment. Thanks, Eric

Hello: Take it apart and oil the bolt assemble and the recoil spring shafts. Shoot it some more. It will take about 500-1000 rounds before it is broken it. Factory loads will be in the 145-155PF range typically with fast powders. Give it some time and enjoy your MPX. Thanks, Eric

Hello: My Acme 122 grain load for a 16" AR9 was 3.1 grains WST which gave me 125.1-128.2 PF. I would bump it up to 3.3 grains and chrono it. I like 131-134PF in my AR9's. Thanks, Eric

Hello: The KAW Valley/Faxon 16" barrel only weights 19ozs and is a fast barrel. At least the ones I have seen and used. Comps on the end add a little weight which helps keep the muzzle down some. Lightweight handguards and upper receivers are also out there. The big thing that does the most is a good load and a great buffer/bolt setup for the AR9mm. I think you may see more gas operated 9mm's in the future. Thanks, Eric

Hello: How many rounds through your MPX? What mag setup are you using? 4.0 grains of N320 should get you there since that should be around 140PF unless you got a real slow batch. Make sure the bolt is well oiled as well. My 16" Gen 2 can run120-123PF loads with a stock barrel and gas port but it also has over 2000 rounds through it. Thanks, Eric

Hello: I have two more for a Sig MPX 16" factory barrel. 115gr Xtreme 3.7gr Tite Group WSP and a OAL of 1.145". Next one is 124gr Xtreme 3.4gr Tite Group WSP and the same 1.145" OAL. Both are in the 131-134PF range and cycle perfectly. I have not enough of the 124's so I am not sure which load I like more. The Sig likes lighter bullets. Thanks, Eric

Hello: So your buffer weight was too much and the spring was too strong. Try the green spring with the 3 steel weights and 1 tungsten. It will feel great and work well. Thanks, Eric

Hello: I would agree about the lighter powder charge so that is why I like the 16" barrels. My load for 124's is only 3.1 grains of Tite Group and is 131PF. Thanks, Eric

Hello: If was around $175 I would try one. At $300 there are other options out there that are less expensive. Thanks, Eric

Hello: Those are some pretty cool PCC's. Thanks, Eric

Hello: That will be a great option for those with an SBR AR lower already. Thanks, Eric

Hello: I have 2 Gen 2's and there is differences in those also. Sig has been changing things as time goes on. I think there maybe another change coming for the Shot Show since prices on Gen 2's has been coming down. You are going to love the Sig MPX for PCC or a house/truck gun. Thanks, Eric

Hello: The ejection may also be weak since you are over sprung. Look for a shinny spot on the ejector and also check to see if the block is loose. Thanks, Eric

Hello: I think you need to bend the ejector over a little so it hits the brass more. Also check to see if the bolt is rubbing on the top of the ejector. Your buffer setup is pretty stiff for that load. I would shorten your reloads to 1.145" and try it again. Thanks, Eric

Hello: Gen 1 is not key mod and with a flat rail. Gen 1 also has a different bolt than the Gen2. Barrels are different to match the bolt. If you phone Sig with the serial number they will tell you which Gen it is. Thanks, Eric

Hello: This one weights 5lbs 10 ozs with C-More railway, which is pretty light. I would have to start cutting things up to reduce more weight. Thanks, Eric

Hello: An upper like this will be a good starting point. It only weights 2lbs 3ozs with no bolt or charging handle. Another option would be a tricked out Ruger 10/22. My sons used one with a Nordic AR conversion and a Taccom hand guard. Here is the lightweight upper. Thanks, Eric

Hello: My AR9 PCC load with a 16" barrel is 2.8 grains of Tite Group and 147 grain Acme. This gives me 131-134PF. Thanks, Eric

Hello: Then why not just shoot your Limited gun for now without a dot? Going to a full size open pistol and loading 9mm for it as well as a good retention holster is going to put a dent in the budget. If you can do it I would get a full size 9mm open pistol and don't look back. Thanks, Eric

Hello: How about a carry optics setup? Slide mounted dot on a production gun. Cheaper and you will have more holster options. Thanks, Eric

Hello: Have it hard chromed. Thanks, Eric

Hello: Get the reverse plug from EGW as well. The original STI one may have the hole in the end that is too large and may cause the spring to jam in the reverse plug. Thanks, Eric

Hello: I don't know if this is the lightest Sig MPX carbine but it is lighter than it was. Mission First Tactical stock, Thordsen adapter, Isler 12 1/4" carbon handguard, Hogue grip, Hiperfire 24C or 3-gun(still testing). I still have to weight it but it is lighter on the front and back. Thanks, Eric