ChiefArmamentGroup

Big I don't know where the extra power Glock mag came from, all I know is that I dropped it in and it ran. And ran some more. Plus it is a little easier to take apart due to the oval shape of the spring instead of the rectangular shape of the traditional spring. Chris

I have both the RRA and the C-Products versions. Currently I am running the extension the RRA version with an extra power Glock spring due to its rounded angles. The spring I got from a close friend because the extension did not come with an extra power spring. I didn't know the one that I ordered from SC didn't come with the spring... just the extension. Works fine for me, even with 42 rounds loaded up. Hope that helps Big! Chris

I am pretty sure this could turn into a crazy long list of comps due to all of the knock-offs and eBay specials out there, but I haven't seen a list posted anywhere of good comps that work for PCCs with first hand feedback. Granted I know it is still an area of debate as to whether or not they actually work on longer barreled guns and the lighter loads typically used in the PCC world...but it would be nice to have a consolidated thread for people to use as a reference. Personally I only have experience with two comps. 1. DSG - I use their old micro comp and it seems to work ok for most loads. I think there are probably better comps out there, but for the price it is hard to beat. 2. JP 2-port - This comp seems work a little better than the DSG. But it is hard to also tell due to them not being on the same rifle. However it seems like it is a proven baseline comp. 3. JP 3-port - I wonder if it is necessary if you are running loads closer to minor PF minimums. 4. MBX - Looks like an interesting concept. I want to actually try it but haven't seen many reviews on it yet besides a guy running a MPX. 5. Lantac Dragon - Holy expensive comp batman! Is it worth the $160 price tag on it? Wow!?! 6. UM Tactical RAGE - Again, pretty pricey. I know their 556/223 variants work really well but I do not know about their 9mm version. 7. McDonald Precision Miculek style comp - Have heard great things about it...especially at the price point. I know there are several more out there and many variants, but does anyone have any real world feedback on these comps? Thanks and hopefully this thread will help out people looking to change theirs/pick one for a build. Chris

Mikie, you going to video the match this weekend? Im curious to see it run! And good luck by the way! Chris

L9, that is crazy! It makes sense though. I thought the longer throats would have something to do it. I guess that is why I see a lot of guys running JP barrels also tend to use some sort of coated bullet...seeing as the obturate to the bore more efficiently. Chris

I tend to agree with almost every aspect on this except the weight part. I can see it going both ways really. Granted it might be like comparing apples to oranges, but a full steel 1911 shoots a heck of a lot better than one of the scandium versions. More weight to "absorb" that recoil. In regards to PCC, the only part that really moves is the BCG and buffer system(over simplification, I know). I can see how a lighter BCG would be beneficial as it is less reciprocating mass (basic physics, right?). So the lightest weight possible while still allowing the gun to cycle properly makes sense. I've seen a lot of numbers thrown around, but for the most part the 19-20 numbers for both BCG and buffer seem to be pretty consistent. It really comes down to the ammo you run. Factory ammo would be closer to major PF numbers while loads tuned to the PCC world would be closer to the 130-140 PF range. You citing that the 5lb rifle was a little too snappy seems to agree with the too light version= too snappy comparison with the 1911s. Kind of like trying to find just the right balance it seems. So would a 6lb 16" barrel with a hefty comp actually be beneficial? More so because of the weight at the end of the barrel than actually the ports working. Akin to a tungsten guide-rod for a 1911 or a full length dust cover. Chris (Sorry if it is a hectic post. Got a lot of different things running through the head. Tough to get it on paper in an orderly fashion. haha)

I know the "skeletonized" their bolt to allow their SCS to work properly, but I was still under the impression their bolts were on the lighter side of things. Hmm... Ill have to take the scales to the range next time I go and actually weigh a few different bolts along with a JP and see. Thanks for the tip Big, didn't know that. Chris

Mahamoti, with Jtrump's rifle we both have the Blitz setup...same springs...same buffer. Only difference is the bolt weight. His doesn't have the mass whereas mine still does. When comparing the two 16" guns I literally swapped uppers. Granted there is a little bit of variance due to the two triggers (one a CMG and the HF 24c), but it shouldn't have caused a 40-60fps variance. To a numbers guy like myself I find it interesting. Somethings work great for certain people and some things don't. I love making machines work to their top potential, but in the end it comes down to the user of said machine 99.9% of the time. If not I'd just buy one of Rob Latham's guns and call it quits! Chris

Mikie, great thread. What made you start tinkering with the mid-length popple-port? I mean I know its been around for years on open guns. Was real big back in the day. But it seemed that they started going away from that and just hanging comps on the end. Watching this thread has really got me thinking about the theory behind this and if there is something to be had there with a barrel that short. Obviously its working for you with the photograph of the handkerchief. How would you compare this with a full length barrel and comp at the end? I wonder too if a comp is really doing that much on the end of 16" barrels with minor PF loads. Im looking at trying a few different ones out there just to test and get personal feedback. Currently I have an older DSG on there but thinking of switching to maybe a JP 3-port or MBX. The MBX looks interesting. I will keep an eye on how this develops. Might have to start tinkering myself. Good luck! Chris

Nice rig. Just weighed mine today after a bunch of changes/additions/subtractions/etc. Came in at around the 6.38 mark. I left my mass in my bolt as per Brian at Blitz. Haven't shot it yet without the mass. I know guys running the same buffer with JP bolts (no mass) and they are having great success. So I guess it is more of a case by case reliability issue with the ammo you shoot. Good luck. And +1 on the Railway. I love mine. Chris

L9, great explanation on the heavy for caliber theory. I think that is also why the Blitz buffer has been such a huge success. That theory is pretty much inverted for open guns. Light projectile/slow burning powder. But it is very hard to develop a load that will work well in all guns, even within the same model of the firearm for that matter. For instance I have shot with Jtrump a lot. Great shooter and a good friend. We have literally taken taken the same loads and seen a 150 fps difference between two guns. Granted his JP has a 14.5" barrel (my 16" barrel will give a little bit extra oomph, but not THAT much). Even when tested with other 16" barrels I would see 40-60fps spreads in the two guns. Personally I love 147s in handguns and 115s in PCCs. Open guns are an entirely different breed as well. Haven't shot enough of them to really give my opinion. With that said, is everyone else also seeing slow JP barrels? Or is this more a one off thing? Curious to see what everyone says. Chris

Barry, have you shot your setup (BK buffer and JP Carbine spring) with a non JP bolt? I know the JP bolts are really light(no rear mass). I ran their SCS for a little while with the mass taken out of my bolt and it was ok. Wasn't super soft shooting, but it functioned, and I just didn't have the time to tune it. When I switched over to the Blitz, I called Brian and asked him specifically what his take on the bolt mass issue with his buffer system was. Based on his recommendation I put the mass back in my bolt and have since left it there. I haven't shot the two options back to back to see if there is any felt recoil differences yet. Was just wondering if you have. Chris

Granted I am not running Glock mags, I agree with the TF +10s for Colt style mags. I have one and it runs fine. Zero hiccups and very clean looking. Chris

Barry, did you get the JP rifle spring with the buffer or the carbine spring? After trying the JP carbine spring, I was amazed! I shot it with PCC tuned ammo and some factory as well. Both ran flawlessly. Chris

A couple things I have noticed since I just jumped into the PCC world about a month ago trying to develop some loads for a client is that the ammo plays a huge part in it along with the buffer system in regards to felt recoil. Over the past two weeks I have tried four different buffers, three different springs and about 15 iterations of load development. If you run factory ammo, you are going to have some powerful stuff. I know people running 4.8 grains of Tightgroup with a 115 grain FMJ screaming at over 1440 fps. Thats major power factor! Considering most store bought ammo has a 135ish PF in handguns with 4"-5" barrels, thats high velocity with a 14.5 or 16" barrel. Originally I had a rifle length setup with a fixed low-pro stock and an old A2 buffer that weighed 5.0. I was having problems with the cases not wanting to eject. It would start to chamber the next round while the spent case was still in the chamber. With this set-up the gun was super soft to shoot. But the malfunctions were killing me, and I wanted to get that fixed since I was shooting matches with it. So I started with the cheap stuff. So off I went trying different buffer setups. I switched to a carbine length buffer system with an H2 buffer at 5.5. The gun seemed to run ok. It was bit more "perky" and direct as far as cycling went, but I still was getting problems every so often. So I switched again to a custom 6.8 buffer and thought that would do the trick since I knew that system worked in another PCC carbine. It failed me too however. I was miffed. I couldn't figure it out. I knew the BCG was clean and I thought it wasn't damaged, but I could be wrong. Start with the cheap stuff first, right? Lastly I took the mass out of the bolt and took the buffer plunger out and stuck a JP SCS in. It functioned a friends JP GMG13 fine. Zero malfunctions over a 200-400 round session with many different loads through it. His softer 135ish PF loads and my factory loads that were much hotter both ran flawlessly. Once I put the JP SCS in, the gun began to cycle very fast. It took my super soft shooting gun that was kind of mushy feeling and turned it into a jack hammer that shot brass to the next county. I shot the last competition with it and had zero malfunctions but it still gave me hiccups in practice. Not to mention my accuracy started to suffer due to the recoil impulse. It didn't help that I was still running my factory loads either though. I was pushing close to major PF because I didn't have the time to load my own. I am switching to the Blitz system this week though. I am curious to see how it feels in my carbine. After testing with it in JP carbine it was buttery smooth. To the OP, I really can't see how the recoil in your carbine would be bad. I know its a long reply but I wanted to give you my feedback on what all I have tried. The dot literally didn't move for me. Double taps at 25 yards were almost connecting. To be far I ran specific PCC ammo through it to do that. But even with my factory stuff it wasn't nearly as bad as my rifle with the JP setup. I know you can tune the JP system to a specific load, but after feeling that Blitz system, I don't think I would choose another. I hope you figure out your issue. But like others are saying, I think it might just be your ammo and/or your positioning while shooting. If you load your own, go load a few batches and chrono' them. I think you will be surprised at what a difference that will make alone. Good luck! Chris