Halo09

I wonder if this came about through their partnership with cmmg. You will need to modify a Glock / Colt mag lower of you go with this system. The mag catch sits too high in a Glock mag lower. I bought the cmmg rotary bolt, barrel combo when it first came out only to find that I needed their lower or needed to modify my mag catch or my mags...neither one sounded reliable. The factory barrel, bolt, lower combo in my Gibbz upper has been flawless though.

First, I’d try and take the weight out and see if that makes a difference. It did with my setup, but I’m also not running a barrel that short. The JP systems is a rock solid design. I haven’t played around with the MBX system. The Taccom and he Blitzkrieg systems are the only 2 that I’ve used that have regular springs and I think I’ve settled in on the blitzkrieg with 308 carbine spring

The 150’s will feel really sluggish in the JP based on my humble personal experience. If all you’re doing is pulling the trigger slowly, it feels nice, but when you’re double tapping it just didn’t feel right.

Factory blazer 115’s felt the fastest and best out of my JP

I’m running the CMMG Rotary bolt with their barrel, bolt, and lower, all paired into a Gibbz upper. I’ve put a lot of federal 130 PCC ammo through it with no issues. I’m not 100% sure what their OAL length is, but it is a saami spec round so I don’t think they are loaded long.

Good news is...holdovers would stay the same, so as long as you know your dope, you could dial until you see the targets and go from there.

Are you talking about the dog eat spring aka lifter spring from Benelli being too weak? If so, I don’t think that’s true. The stamped steel on the JK lifter isn’t that strong and in the example above, o bet you it’s twisting on the way up, moving the shell out of position. The strongest is the MOA Precision one, but they seem to be battling some personal issues within the company.

What shells are you using? Is this with all shells? Brand and specifics please?

Unless they have changed recently, they charge shipping per spring...per spring...so if you order 10 springs, they charge you shipping 10x. I know they are new to the market, but their customer service and communication is lacking. Mine sits in the box it came in.

The owner of MOA is trying to ramp up production, but had a few personal setbacks. I’m trying to be patient while waiting for mine

I took mine out after it would randomly let an additional shell out on my lifter. Went back to my TTI extended lifter and haven’t had an issue

Eek! I’d had about 150 rounds through mine, then it started randomly putting 2 on the lifter, thereby jamming it up. Back to my TTI lifter until they figure things out a bit more. (Yes, I have a strong dog ear spring, newer mag tube spring, and a smooth shell latch).

Problem with modifying the mag catch, is you have to pull the mag back down after insertion and there’s always a chance that it could move up during operation creating a jam. You could file down on the top and add material on the bottom, but it was easier to buy their lower.

Forgot to mention that I built mine on the Gibbz standard rifle upper.

Bringing up an old post. I’m running the Cmmg 9mm radial bolt with their 16” barrel in a Gibbz side charge upper receiver. All of this on the Cmmg Glock lower. You almost have to run their lower unless you want to modify mags or mag catch height. I have just a standard .308 spring and 308. carbine buffer weight. With the side charger you need to cut the gas key extension on the bolt so it will allow the bolt group to fit into the barrel receiver during operation. I’ve got about 1500 rounds through it and it’s become my go to for matches. I’ll probably end up cutting the barrel down to a 13.5” and see how it handles.