mahamoti

I like having options: 20rd Metalform w/TTI Glock+0 = 26rds. 32rd Metalform w/TTI Glock+0 = 35rds. 32rd Metalform w/TF+10 = 42rds. 32rd + 20rd Metalform w/Taccom splice = 57rds. The Glock basepads aren't a perfect fit, but a couple wraps of electrical tape keep them solidly in place. The Taccom splice wobbles a bit, so electrical tape on the base of each mag helps it lock up solidly w/o warping the splice plates. For pouches, Ghost 360s hold them well. I use a couple 20rders in pouches for classifier reloads and to cover "oh crap" situations, and a DAA magnet to hold the big stick before LAMR.

No, that was definitely a failure caused directly by Freedom Munitions stepped brass. Besides the FM headstamp, you can clearly see the step, exactly where the case fractured. The fact that they as a company put this shit out in the wild, while claiming to be supporters of competitive shooting sports, pisses me off so damn much.

My process now includes filling a 45ACP 50rd tray from my 9mm brass bucket, then flipping that over onto my bench top. Let’s me weed out stepped brass and crimped primers in one go.

You can thank Freedom Munitions for that stepped brass atrocity. When you're reloading, especially for PCC or 9mm Major, you'll want to discard cases with FM, IMT, and AMMOLOAD headstamps.

Well not exactly... you’re entitled to the calibration process, which screws more people than it helps. Loading sub-130pf also means living dangerously at the chrono for majors.

I’ll actually be adjusting that up a bit. I like to be around 132pf, for stubborn poppers. Had a one that didn’t fall last weekend and cost me an M classifier.

Wow. PD 124 FMJ over 3.5gr TiteGroup only gets me 127pf out of a JP 16".

There is a new option for Glock mag conversions... https://getstern.com/products/mag-ad9

What PF are you getting with 124gr over 3.5gr TG? With the same load in my JP barrel, I was getting 127pf, and having some trouble with steel not falling. 3.6gr for me from now on.

The slotted barrels must be brand new; I’ve had my eye on one of these for a while. Wonder why they changed? The change at least explains the discount on the ones with holes... just clearing out old models.

Did you have to do anything to your upper/lower? CMMG says uppers "may require modification." Do you need to remove the ejector from the lower as well?

Downloading mags isn't a problem, because you should only need to do so for mags on your belt meant for mandatory reloads, which you shouldn't need full anyway. At Make Ready, load your full big stick to an open bolt.

Unless JP configures it differently for their prebuilt rifles, they should have been the same: Mine is set up the way it came from the factory, and the GMR was stock.

I run a BCP Colt lower in my rig. It's been perfect. Upper/lower fit is very, very, tight; that'd be my only complaint. Need a punch to knock out the takedown pin. For how solid it locks up though, it's probably a good thing.

Had a chance this weekend to shoot my Colt pattern PCC next to a GMR15. With identical barrel, bolt, and SCS, the difference in felt and observable recoil between my Colt pattern and the GMR was obvious. The Colt pattern carbine recoiled *much* less. Got me wondering... do Colt mags, presenting the next round parallel to the bolt travel, impart more drag on the bolt, slowing the cycling down? The GMR was even heavier than my build, with the stock JP handguard vs my lightweight Odin Works setup. Only other possible difference is in the comp, stock JP 3-hole vs a NERD Nano on mine, but this was running the same 132pf ammo through both... can't imagine any comp would make that much difference, with the amount of gas they have to work with.

Not OP, but https://www.odinworks.com/Zulu_2_0_Adjustable_Stock_Kit_p/os-zulu-kit.htm

https://www.weare-nerd.com/kitchen-knives/nc-nano-9mm-brake

Difference in bolt/buffer weight and lock time, maybe? I don't know the truth of it, but I've heard talk of some blowbacks starting to cycle before the bullet leaves the barrel, which would have to cause some loss of velocity. Someone w/more knowledge of the forces and timeframes involved might be able to chime in on that, though.

Finally got to a chrono. JP 16” barrel, JP bolt, JP 9mm SCS (stock config), BCP Colt pattern lower. 124gr Precision Delta FMJ CCI SPP500 1.16” OAL 3.4gr Titegroup =126pf 3.5gr = 132pf Cycles 3.0gr at 109pf just fine, and still locks bolt back. 1.16” is super long, but the JP barrel and Metalform mags handle it with no problems, even the Taccom coupled mag feeds great.

I don't have their new Glock lower, but I *do* have their Colt lower. It's quality. I'd have no problems giving the Glock version a shot if I were inclined to.

That was more of a “because I could.” Standard config is a 20 and a 32, or a 32 with basepad.

Get bigger mags. Three possibilities: MBX Mega basepad, Taccom's basepad, or Taccom coupler.

If the GMR suits your needs, it's hard to beat. It didn't suit mine: Heavy handguard, no lefty mag release, and I wasn't already invested in Glock mags. So I built my own off a BCP Colt lower, but used JP barrel, bolt, and SCS. Runs great so far.

I'd only change a few things on this rifle to make it a "dream" build... Proof barrel, Swaro 1-8 in an Aero mount, SJC Titan comp. Current: Aero lower Odin Works upper Stretch 16 barrel SLR adj gas block PWS FSC556mod2 comp BCM KMR15 Elftmann 3G trigger JP LMOS/SCS Trijicon 1-8

You can thank Freedom Munitions for that atrocity. FM, IMT, AMMOLOAD headstamps are "stepped" brass. Likely to shear at the step, leaving brass in the chamber, especially after reloading.