MemphisMechanic

Holosun 510C over the CMore all day long. Loctite all the screws on the riser and the optic shield and never mess with it again. Clearer, brighter, and the battery lasts all year long (when left on for 8 hours of match day.) Heavy JP spring and a Blitzkrieg buffer. Short-stroke the gun so it doesn’t come back far enough to engage the bolt catch. I’m a big fan of JP barrel and bolt carrier group in a QC10 reciever set. Just runs and runs.

I agree. I’m a big fan of my KE arms lower now. My gun is an odd duck because I had to lower the magazine position about 3/16” to clear the fat bolt head the CMMG Guard upper uses. Ran like a top on the maiden voyage last night: After 6 months hunting for reliability feeding it from colt mags, I couldn’t get beyond a jam every 50-100 or so rounds. She went 350 or so last night without a single malfunction. Everything from heavy slow 150gr 130PF to hot fast 115gr loads. Lousy camera angle, but:

This! Always this. Find your max OAL by seeing how long you can go until rounds don’t drop in and spin freely... because they bullet is rubbing the rifling. Shorten them up until it spins freely again, and that’s as long as you *can* load that bullet in that particular gun. How long should you load? Well that’s a combination of experimenting for the best combination of pressure, power factor, accuracy, and reliability. For that bullet. In that gun. Generally you load as long as your gun will allow as your starting point - particualrly with Open.

Again: Explain a barrel change in all three of these guns causing a quadruling in group size... with multiple brands of 115, 124, and 147gr factory ammo, and the same shooter. It is not impossible that MBX is being less than straightforward with the test results. It’s not something I think is likely, but they do have a lot of reputation and money at stake here. I do have to say that their customer contact attitude with my friends has certainly left me disinclined to buy anything they make at this point. Emailing your customers back after half a week of sending repeared emails... and then coming back with phrases like “the supposed accuracy issues with your barrel” leaves a very great deal to be desired.

Explain a barrel change in all three of these guns causing a quadruling in group size... with multiple brands of 115, 124, and 147gr factory ammo, and the same shooter.

It’s kinda hard to paint you as an MBX hater with a mediumweight barrel in your gun and their extensions on all your mags.

I’ve watched one of the guys in question shoot damn near a 1-hole group with a 5.56 at 100yd. The same 9mm ammo shot about 1.5” through a JP barrel, and won’t break 5” through the MBX.

Suddenly I wish I had the time to buy a hundred high-quality JHPs (typically the most accurate bullet in handguns.) Mount a scope on my PCC. Crank it down solidly in a high end sled.... and shoot groups for a definitive answer on that topic.

Are you asserting that accuracy at distance through a 16” 9mm barrel requires a heavy 9mm bullet? If so, I’m going to respond that you’re incorrect here. And offer match results from top shooters running PCCs in matches with lots of 25-100yd shooting to prove it.

My PPQ frame is 4-6oz heavier than stock. Mostly in the backstrap, which I hollowed out and filled with tungsten weights (meant for pinewood derby cars) and epoxy.

Anyone who claims the 7.5 triangle is anywhere near as bright as the dot... needs to spend more time with the 2.5 It is so much easier to shoot on a really bright day.

Looks normal and fine. Run it. But first do like @Hi-Power Jack suggested and pull a bullet. There should be no sign of the case being crimped into the side of the bullet. The most important things to do for coated bullets is give the mouth plenty of flare and then BARELY return the case wall to straight. Delete all the belling and stop there.

I run the KE Arms ambi lower because the lack of an ambi mag release isn’t acceptable in USPSA.

Everyone is glossing over something. You specifically listed a lack of speed as your biggest issue with improving. Open is the speed demon division. Hammering hits into the targets with the agression of someone who knows that charlies don’t hurt if you shoot fast enough, and shooting as many targets on the move as you can? These are Open division expectations for A class. It’s the “go like a bat out of hell” division. And the classifier hit factors reflect that. In addition, if you shoot with the same level of (non) agression toward the targets, you will finish lower in Open than in Carry Optics against the other shooters.

QC10 not cq I have a QC10 Colt mag lower with a giant @bmiller magwell on it that I’ll be looking to sell here in the classifieds after the first of the year. I’ll probably have to re-cerakote it though. It doesn’t match anything.

Yes, the single-action trigger reset on a CZ or Tanfo - particularly with lightened springs - will be very subtle. However you’ll also notice the trigger resets at the same time it stops moving forward. Once you get used to not having the click to work with, and learn to work with the trigger simply finishing its forward movement, it’ll be just as easy as the Glock was to work fast. I’m also a huge fan of finding the point where your overtravel and pretravel screws give you just enough movement to drop the hammer on the bench at home... then loctiting both, and backing them out 3/4 turn to give things a bit of play. It’ll feel crappy on the bench, but you will NOT notice the difference when firing live ammo. Except for the part where your gun runs 100% on a hot day, a cold, day, in the pouring rain, while it’s filthy.

@random_guy7531 a gun doesn’t need to be on safe if the hammer is down. Only if it’s back. It doesn’t really matter though. Only a handful of guys are crazy enough to pay SVI money for a production gun. They’ve priced themselves out of relvance to our sport.

His chrono seems like the biggest suspect variable to me. I had sketchy luck with that brand of chrono in the past. My current ProChrono Digital almost doesn’t care what light you use it in. As long as it has some. I’d borrow a buddies chrono and line them up so you can shoot through them both, personally.

I’m running a KE Arms ambi lower. Really like it. The ambi mag catch works perfectly and the magwell is better than anyone else is making. Downsides to colt mags: 1. They are a pain to seat under a closed bolt, even with 6 rounds missing from an extended 42rd mag, you really need to drive it home AND give the mag a palm heel strike. (A 47rd Glock mag downloaded to 46 seats as easily as popping a factory mag into a Glock 17.) 2. Feed issues. You just don’t have nearly the same support keeping the nose of the first round up as Glock mags give you.

This is what I do. I want to know if I’m at 3.72gr or 3.79gr *average* charge weight. A sub-$100 scale isn’t precise enough to tell me until I’ve taken an average of 4 to 5 drops. I take a ten drop average once I’m completely dialed in, and that goes into my loading data. I laugh at guys measuring their crimp with calipers, too. Your $40 digital calipers are only rated to +/- .001” in most cases. Measuring bullet or case diameter requires far more precision than they offer. Use a micrometer which has the resolution for this task, or simply eyeball it against a striaghtedge and remove all traces of belling.

Shoot multiple divisions. I load a 115gr Everglades plated with titegroup under it for PCC. (Coated bullets or FMJ will build gunk up in the compensator.) A 147 bluebullet with Prima V under it for my carry optics, and my girlfriend’s production load. I know exactly what settings will get my powder drop setting on the money. Roll the micrometer to the proper setting and go. It’s also handy when working up a load: Figure out how much rotation approximates 0.2 gr and it’s easy to load a ladder with a new bullet or powder to 3.0 ... 3.2 ... 3.4 ... 3.6gr and so forth.

Those are good to go for reloading. I’ve never understood why guys chase shiny brass. It runs through the press and the gun the exact same as stuff that’s clean but somewhat dull.

Choose your maximum OAL by conducting a plunk and spin test to find the longest you can load your bullets in your particular barrel. Never choose a length because some guy on the internet, or even some reloading manual, said to do so. Not without testing things yourself, anyway. (Load up a dummy round and see if it will drop into your gun’s chamber and spin without any drag. If if won’t, you’re engaging the rifling and accuracy or relability may suffer.)

I have the uniquetek and like it a lot.

No idea. I run a JP, and it can take a PCC’s beating all day long without caring, so I haven’t been looking at the newer offerings.