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Thread: Pistol caliber carbines
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6 December 2018, 19:36 #16
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7 December 2018, 17:04 #17
I guess we'll see, then. In the meantime, if I were in the market I'd probably pick up one of these:
CMMG Banshee 9mm SMG
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25 December 2018, 08:59 #18New Member
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Merry Christmas to all, I keep seeing this thread pop up in my Tapatalk email so I finally read it, and now I made an account to reply.
The one thing left out of this discussion that is the importance of delayed cycling (or delayed blowback) in PCCs. I'm no professional, take with a grain of salt.
All of this assumes your PCC is suppressed. The primary point of a PCC is indoor shooting.
With a PCC, I vote to always go with a delayed blowback gun...never a straight blowback. Straight blowback isn’t terrible, but not ideal either.
Straight blowback is louder at the ejection port and (in an AR platform) requires a heavier buffer and heavier overall weight (no bueno, but a heavier buffer can help balance a heavy suppressor on the front end). A stout buffer spring is also helpful. The benefits of a straight blowback is that its simple, cheap, and reliable so long as you don't beat your trigger group to hell in the process. Have a good "ramped" bolt and appropriate trigger. Keep the ramp polished and lightly greased, not oiled. Wipe down the bolt after every outing (I never keep my sh-- clean). Take an air compressor to the trigger group regularly. Don't use a fancy precision trigger. Use a stout group that has a good enough feel to you. Pick up on the timing of the girl, and get into a rhythm when shooting. But I don’t like it cuz of the loud bark out the ejection port (even when suppressed). These have been called the highpoint of the AR pcc world, and for good reason. I really got sick of my first AR stright blowback 9mm because the recoil impulse was so sharp. I was shooting a sharp angry b---- rather than a pleasant mellow b----. It's not that the recoil was strong, but the impulse was sharp. Hard to explain. But if you shoot so much in a day that you get sick of it, and then keep shooting a whole lot more that day, you will pick up on these things.
A DI or gas impingement action is the nicest to shoot, but like all DI systems are dirtier in the action and can grit up the locking lugs. For "normal" people, this is usually never a problem. I've never seen a 9mm DI gun, but I've read discussions of them. 10mm is good with DI because has heavy charge weight. 45ACP is apparently doable, but I have not done it. And 45Super is..imo…the most ideal PCC cartridge. You can put a ton of (clean slow burning) powder in a 45Super and get some righteous velocities in longer bbls (think 6-10” range). The benefit to DI is that it keeps the bolt locked closed longer and you don’t get that “loud bark” out of the ejection port. Also, it smooths out the recoil impulse (unlike straight blowback). People overlook this and sometimes never even notice it, but the pulse curve of the recoil impulse is so important to the feel of the weapon (and followup shots). I think the MP5 has the best recoil impulse and the impulse is the reason everyone likes it…even if they don’t realize that’s the reason. But MP5 is NOT gas operated. Also, a gas operated action can take a lot of effort to refine and make perfect, i.e., dialing in your exact charge weight and gas port pressure, adjusting the gas block possibly (if you have an adjustable gasblock on a PCC), adjusting the buffer and buffer spring. Then again, you don't have to tune the rifle to the nth degree.
Turning to non-gas operated delayed blowback (such as radial or roller or vector or whatever), these are a good happy medium ground. They don’t blow carbon on the action like a DI but they keep the bolt face closed (not fully “locked”, tho) and reduce the bark from the ejection port. Win-win. If the delaying mechanism is well done (e.g., MP5), you can get a real nice recoil impulse that makes follow up shots soooo sweet. This is why all the super duper commando whatevers liked the MP5 (so I've read). One downside is that you can’t tune this cycling to the same extent you can tune gas operated cycling. For most people, that is a benefit because it also mean its not as finicky with different ammo. The more you tune something, the more finicky it will be. Some ppl don’t love tuning the cyclic rate and impulse curve of their rifles / PCCs. I think it’s fun, but I only ever shoot at paper enemies.
https://en.wikipedia.org/wiki/List_o...wback_firearms
PS. Technically, gas operated is not "blowback"....it's neither straight blowback nor delayed blowback. But it has some of the desirable effects of a delayed blowback because the unlocking of the bolt delays the cycling of the action.Last edited by prussianfrank; 25 December 2018 at 09:22.