tyler2you

I've got an SBR'd MPX and an AR-9. I shoot the AR-9 better in most situations. I'm quicker and more confident on transitions due to the longer handguard as mentioned. I have also been able to tune the AR with recoil components and loads to run quick with consistent dot return. Those same loads make the MPX sluggish (heavy bullet, fast powder). I need to do some more experimentation with lighter bullets in the MPX to see if I can get it to run to my liking. Here's my quick take/experience on each platform: MPX (SBR): - Expensive + Very low recoil implulse + Short barrel excels around tight obstacles - Limited ability to tune the recoil system - Limited aftermarket trigger options - Slightly complex gas operated system - Running coated bullets leads up the gas valve and tappet - Less tolerant of running dirty + Excellent/reliable magazines built by Lancer - Slower for me to reload AR-9: + Less Expensive - Slightly harsher recoil impulse + Extensive tuning options (buffers, recoil springs, etc.) + Quicker/more confident transitions with longer handguards + Lots of trigger options (although some can have reset issues or double depending on the bolt) + Simple blowback operation + More tolerant of running dirty - Fragile firing pins - Magazine system adapted from other platforms, requires optimal feed angle and barrel opening + Faster for me to reload with pistol size magazines

Anyone tried one of these: S7 Tool steel Bulletproof 9mm Firing Pin http://shopwilsoncombat.com/Bullet-Proof-9mm-AR-Firing-Pin-S-7-Tool-Steel/productinfo/TR-AR9FP/

Since the Hiperfires seem to be contributing to the problem, what's the next best option for a trigger in an AR-9?

Add me to the list. Third shot of an indoor match this evening. It would fire 2 shots and then light strike. Pulled it out at the safe area and sure enough it was in 2 pieces. Pretty disappointing as the bolt only had around 400 rounds on it.

Nothing says you can't have a carbine or rifle tube (receiver extension) on a pistol. Plenty of people install the Thorsden brace on a standard carbine extension.

Yeah, my comment was related to what is considered a stock. I understand a rifle has a stock, but bobert1 was asking how you would know the difference between a stock and a brace (you have to look at it's design/intended purpose).

The ATF actually refers to it as a "shoulder stock". It all comes down to intent/purpose in their recent rulings. If the "thing" attached to the back of the weapon was intended to be shouldered, it's a stock. If it was intended to stabilize the weapon without being shouldered, it's not a stock. For a short time, the ATF had ruled that an end user could actually "repurpose" a stabilizing brace into a stock by shouldering the weapon, thus creating an illegal SBR. That has since changed. The companies that have designed stabilizing braces for pistols have asked the ATF for clarification and I believe most of them (KAK, SB, Sig, Thordsen) have letters stating that the ATF doesn't view their products as a stock. So, long story short--you would need to look at each product in question to see how the company designed it and how they intended for it to be used.

The PCC rules state that it "must have stock attached. . ." Bottom line is the Shockwave Brace isn't a stock, so not legal for PCC.

For those of you looking for more space to stuff in Smalley Springs, Quarters, cut down buffers, etc., Primary Arms has the Vltor A5 Receiver Extensions on sale for a good price: http://www.primaryarms.com/vltor-re-a5-a5-receiver-extension-re-a5

147 gr. BBI with 3.4 gr. HP-38 at 1.110. 131 PF in a G-17

Yep, mine works great as well. From what I remember, the Taccom Extreme Bolt is built from the same milling as the Faxon Bolt. Taccom uses a different approach for the key, mills the face to work with ramped barrels, and has them finished in Nickel Boron. So, the Faxon Bolt should be compatible with most AR-15 triggers as well.

I've had good luck using Loctite 620 with their primer. However after having one clock on me at a major match this year, I installed set screws on my comped guns.

1. Sig MPX, 8" barrel, Gen II (factory gas port), Hiperfire 24c 2. BBI 147gr 3. 3.7gr HP-38 4. S&B SPP 5. 1.115 OAL 6. Very reliable 7. Accurate enough out to 50 yds 8. Shoots soft and the dot tracks straight up and down I do plan to have the gas port opened up so I can run a lighter load (this one comes in at almost 150 PF). When I tried to run my pistol loads in the MPX (3.4gr HP-38, 147gr BBI), reliability suffered. In my AR-9 with a 7.5" barrel I can run the same bullet with 3.0gr of HP-38 at 130PF and it's 100% reliable.

Another option is Garrett Precision LLC in Arizona. His prices and turnaround times are fantastic. His website is mostly geared towards precision rifle stuff, but he does Glock slide work as well.

Has there been a clarification to 8.2.3? Or are you talking about unavoidable touching with the lower arms?

"Loaded Firearm : A firearm having a live round, empty case or dummy round in the chamber or cylinder, or having a live or dummy round in a magazine inserted in the firearm." The bullet alone isn't a live or dummy round, so no penalty/DQ.

Looks like you're seating die isn't adjusted properly. It appears you're crimping before the bullet is fully seated.

Depends on your frame. I typically center the holes on the available height of the dust cover in the y axis. For the "sideways" location, I try to get the mount as far back as possible while still clearing my slide stop thumb rest and racker in the x axis. Depending on your mount/optic, you may also need to build in a 1 degree down angle on the holes. Some mounts have the angle built in some don't. Also, some optics will zero just fine without the angle compensation.

I had to work a lot on the keyways in the frame that the grip slides on to. They're difficult to file since the area is small and recessed. I could have removed the material from the pads on the grip, but chose to work on the less expensive part and also so that I could move the grip to a different frame if I decide to do that in the future. I also had to remove material from the top concave/convex parts of the grip that mate with the radiuses at the bottom of the frame to get it to seat fully. With both the PT and L-10 frames, the grip mated up with almost no fitting required.

Really the only "issue" I had with the CK frame was the amount of fitting required to get it to work with the PT steel grip and some minor tool marks I had to clean up. Otherwise, it was dimensionally correct and well finished.

I recently built a gun using the Brazos Lightning Slide (Caspian version). I'm pretty sure it was already angle cut for the comp, but I don't remember for sure. I used a KKM threaded barrel, so I can't comment on the rest of your question. The slide was done very nicely and is working great. I posted a picture in the Open gun picture thread (page 56 about halfway down)

Take a look at L-10 frames as well. They make nice stuff. I've built on both PT and CK frames and both were serviceable. Both had some minor minor issues that were easily worked. I wouldn't pay the premium for a PT frame over the CK if those were my choices.

Does your slide stop have an indent in the end where it contacts the detent in the plunger tube. If it doesn't you could add one or make it deeper. You might also replace the detent and spring if it's weak. I wouldn't suspect wear on the slide stop to be causing the issue.

You can do that, but to what end? You would simply be investing more time mating up the parts for no performance gain.

There should be enough material on the frame rails to get a good fit to the slide. As far as the barrel goes however, the primary fitting is done by removing material from the barrel's lower lugs and not by removing material from the frame. Like I said above, you probably won't have contact between the lower lugs and slide stop during lock-up and your slide isn't going to be even with the rear of the frame.