G19.5 with PMM JTTC Ultra Barrel and Comp

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Early Impressions

Gun itself has a low round count, less than 1k.
Barrel and Comp have perhaps 300.

Barrel length, including threads, is about a quarter inch more than a G19 stock barrel.
Overall length, including comp is about a quarter inch shorter than a KKM barrel and comp. Overall length of the gun is between a G17 and G34. Fit and finish is great. Install was easy. I used red Loktite per the instructions, and it doesn’t seem like it plans on coming off without intention. Additionally, the “wings” may prevent it from untwisting by more than a degree or two, even if it comes loose.

Precision has been good, both with the stock barrel and the PMM. I’m using a 508t. I’ve not measured groups, but I’m center-punching whatever I aim at, out to 25yds. The trigger seems to lend itself better to precision than my harem of 19.4s, but thats hard to quantify at the moment.

The comp is very effective. It has two baffles, like the KKM, but no side ports. It is more effective at mitigating muzzle rise than the KKM on a G19.4. Even with standard pressure ball ammo, it is very effective, and flat shooting. It seems slightly less loud to neighboring shooters than the KKM.

***UPDATE: IT RUNS NOW***Reliability with the comp has been very poor, so far. I’m not sweating it yet, because I had some growing pains with the KKM, also. But I have had feed issues and failures to lock back. Occasional failures for the slide to even go far enough back to try to grab the next round, mostly with factory 115 ball. With heavier or hotter ammo, or hanging onto it like a deadlift bar, the stoppages are less frequent. I’ve tried 115, 124, and 147 grain standard pressure loads so far. I also tried lubing the shit out of it with ALG Go Juice. Tonight after I got back from the range, I swapped the factory recoil spring for a worn factory spring from a 19.4. We’ll see if that gets me anywhere. That spring was working very reliably with the KKM barrel and comp that gave me fits with factory ball ammo when it was new, so I’m hopeful it will run. I’m also grabbing some book max 147 and 115 loads, and some +p factory ammo. Hopefully I can find some 124+p around here, but I poked around earlier today to no avail. I think I’ve got a box of 135gr+p floating around my house, though.

More to follow as I shoot it more.

[DaBigBR]

I have an Ultra JTTC on a Glock 45. My experience has been similar to yours EXCEPT that mine is boringly reliable, even with almost all 115 grain ammo. Gun was a couple thousand rounds in when the comp went on. It now has probably 5k. It has been cleaned once in its life and I have added small amounts of oil to the rails and barrel periodically.

Really dig the Ultra JTTC. My only other comp is a CGS Qube on a 19 and while it is also reliable, it is not as effective.

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Today, I grabbed a couple mags of standard-pressure 124gr Gold Dots and XTPs, and a box or two each of Winchester 124gr NATO, Fiocchi 147 FMJ, Fed American Eagle 124 FMJ, Blazer Brass 124gr, plus mixed lot of 147gr coated handloads, and a random 115 (I think) Fmj round I found in my cupholder.

It ate all of it, flawlessly. Locked back on every mag, including the rando 115. I shot a course of fire based on the FBI qual, a bunch of times, as fast as I could. I also ran it once strong-hand only, and once weak-hand only. I hit the C zone 4 times, sadly. That’s on me.

Its curious that it went this way. My KKM was the same way. Constant stoppages when new, then all of a sudden, overnight, it ran perfectly and would eat anything for the remainder of the time it was in use.

Sidenote: did Glock stop putting that coppery anti-seize looking stuff inside the gun with the Gen 5?

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[DaBigBR]

There is probably some level of "forced fitting" occuring that would explain some of it. The fact that you stopped when you did is likely coincidental.

[LowSpeed_HighDrag]

I have two PMM comps, one on my duty G45 that is dead nuts reliable and accurate with 115 to 147. The other on my carry 43x that took a little breaking in. During that break in I found that it doesn’t like a particular Shield mag of mine, but runs just fine with others and with stock mags. My experience has been very positive, and my measured FAST and Bill Drill times with these guns are noticeably faster.

[17K]

What would you guys recommend on a Glock 45?

I’m considering KKM, PMM, or the Agency/Sage.

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What would you guys recommend on a Glock 45?

I’m considering KKM, PMM, or the Agency/Sage.
PMM if you’re using a dot, Agency if you don’t.

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Over the past few days, I’ve measured a few hundred splits using the above 19.5 with JTTC Ultra and a dot, and a 19.4 with a Griffin threaded barrel and a dot, no comp. Firing two shots only at the beep. Both are otherwise stock. I shot 115s with CFE in 3 charge weights, 147s with Titegroup, 244, and CFE, and factory 124s. All were ~140PF. The 115s were +p, and the 124s and 147s were pretty standard. I compared a variety of loads in the comped gun, and then I compared comped vs un-comped back to back, using the same loads in each. Conclusions:

1) Minor PF loads definitely drive a comp; don’t let anyone tell you otherwise. It was noticeable how much easier it was to track the dot, and the splits were faster comparing the two G19s back to back. We’re talking almost a tenth faster at 10yds, 8” target, and the 10-split averages were consistent in showing that. And hotter wasn’t always better comparing one load to the next in the comped gun, so the “only Major loads drive a comp” bit is bullshit.

2) splits with both guns were faster with lighter bullets, even though they were all the sameish PF, and the lighter ones were higher energy.

3) the heavier bullets had less perceived recoil, but the timer was consistent in showing that was an illusion. Even with the 147s, the comped gun was significantly faster on average.

4) fastest splits with the comp were with 115gr Blue Bullets and 5.6gr CFE Pistol. I slowed down with 5.8gr or 5.4gr.

5) the further out I tested, the more significant the differences on the timer became.

6) POI with various 115 and 147gr loads were essentially the same at 25yds. The 124s however, were low-right at that distance.

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At this point it eats most anything. Lockback is somewhat inconsistent with cheap, factory 115gr ball, which should be expected if its doing its job. Recoil is silly light with those. Feels like someone left out like half a grain of powder. With +p 115, and any 124s or 147s, it runs and runs and locks back. Performance is excellent from both the barrel and comp.