Building a PCC and have a Couple Questions:

[bwalker36]

I received my Aero EPC-9 Lower today and submitted my form 1 to SBR it. It will have also have Dead Air Ghost 45M with it.

1. Barrel Length, I was thinking 8.3, Still Short, gives me something to actually grip, and with the can won't be longer then a normal rifle. My thoughts are this length would keep heavier 9mm sub still and give me a good middle ground without going to something like a 5.5".
2. Buffer system - I have heard cycling on these things is sometimes iffy and you need to find the right combo of spring and buffer weight, just seeing what any of you used that was successful.
3. Triggers, I have also heard because its direct blowback they beat up triggers. Wondering what people here all use that has seen some decent round count.

thanks!!

 

[hoardingthemanual]

I have an Aero PCC too. I run an 8.3” barrel and any shorter I would stick my hand out too far and shoot it off. As far as the buffer, I read some stuff that convinced me to run a standard buffer spring despite Aero marketing a 308 buffer spring. I also ditched their buffer for a heavier, sliding tungsten weight buffer. The bolt itself is a Foxtrot Mike bolt. The only point of concern that I watched was the weight of bolt and buffer. Again, per the articles I read, I tried to middle-to-heavy total weight. Lastly, the trigger is mil-spec. I haven’t noticed any problems so far. It’s a precise barrel. I’m really wanting to make another one in 40 S&W.

 

[bwalker36]

I have an Aero PCC too. I run an 8.3” barrel and any shorter I would stick my hand out too far and shoot it off. As far as the buffer, I read some stuff that convinced me to run a standard buffer spring despite Aero marketing a 308 buffer spring. I also ditched their buffer for a heavier, sliding tungsten weight buffer. The bolt itself is a Foxtrot Mike bolt. The only point of concern that I watched was the weight of bolt and buffer. Again, per the articles I read, I tried to middle-to-heavy total weight. Lastly, the trigger is mil-spec. I haven’t noticed any problems so far. It’s a precise barrel. I’m really wanting to make another one in 40 S&W.

Thanks for the info. I was thinking about putting a JP Silent Capture in it so I can buy one product and adjust as needed lol.

 

[Dave DeLaurant]

Cool project -- looking forward to photos!

What kind of buttstock do you have in mind?


===

Also, if I may I ask, I have a general SBR question:

If you register a lower as an SBR, is it OK legally to mount additional compatible uppers for it either long or short of the 16" barrel limit?

I think the answer is yes (ala TC Encore etc. being either pistol or rifle), but I suspect someone here can be more definite.

 

[bwalker36]

Cool project -- looking forward to photos!

What kind of buttstock do you have in mind?


===

Also, if I may I ask, I have a general SBR question:

If you register a lower as an SBR, does it matter legally whether additional compatible uppers for it be long or short of the 16" barrel limit?

I think the answer is yes (ala TC Encore etc. being either pistol or rifle), but I suspect someone here can be more definite.

Have not thought about Stock yet to be honest.

As far as I know and I'm no lawyer as long as you can easily get it back to its original configuration, You can swap barrel uppers to be longer and shorter as long as it doesn't break any other law. So 5" or 16" its good to go.

 

[TonyAngel]

Just a word of caution. If you're going to go spending $100 here and $100 there, which is easy to do, chasing the perfect buffer system; in the end, you may have been better off just building a delayed blowback system like from cmmg. It shoots about like an mp5.

I should also have added this .....

If you are building the pcc as a trainer, the straight blowback more closely mimics a 5.56 AR. The delayed system shoots a lot softer. For my trainer, I run a springco blue spring and a vltor stainless A5SH4 buffer. I just bought whatever buffer I could get cheap and stacked it up with tungsten weights.

 

[marvin02]

Good source of information about AR9s:

https://blowback9.wordpress.com/blog/

 

[LiveLife]

FYI, short stroke bolt/buffer set up has primary application in 3-gun matches where multiple targets need to be engaged requiring fast follow up shots. Depending on combined bolt/buffer weight and recoil spring rate, full stroke bolt/buffer set up can allow the bolt/buffer slap of buffer tube to jerk/move the front sight in recoil away from POA/target.

Short stroking allows the bolt/buffer to just clear the magazine to reliably extract/eject spent case while stripping the next round from magazine to chamber and keeping muzzle/front sight flat/steady on target (This is similar to "shooting flat" for compensated open division race guns).

Here's link to post where different types of PCC bolt/buffer set ups are compared including delayed blowback and CMMG Radial Delayed Blowback System™ - https://www.thehighroad.org/index.php?threads/9mm-pcc-bolt-choice.903452/#post-12248344

"Short" history of short stroking PCC to tame harsh recoil to keep front sight on target/flatten the muzzle while maintaining LRBHO (Not comprehensive or chronological):

• Using heavier buffer weight to produce 19-22 oz combined bolt/buffer weight to tame recoil instead of harsh recoil produced by 16-18 oz combined weight - https://www.thehighroad.org/index.p...rts-did-you-use-and-why.825314/#post-10623572

• Using quarters behind recoil spring to "preload" spring to just barely clear the magazine to tame recoil yet maintain reliable cycling - https://forums.brianenos.com/topic/290385-how-to-short-stroke-pcc/

• Using stiffer .308 recoil spring and heavier/custom buffers to tame recoil further and maintain reliability - https://forums.brianenos.com/topic/297980-short-stroking-my-pcc/

• Adjustable buffer 3-stage Taccom (Allows for BHO) - https://taccom3g.com/product/taccom-pcc-adjustable-buffer-system/

• Air Cushion 3-stage buffer (Eliminates BHO) - https://taccom3g.com/product/pcc-3-stage-air-cushion-recoil-system-ar-9mm/

• Magnetic Delayed buffer system (For blowback action, increases "dwell" time case remains in contact with chamber to improve consistency of chamber pressures - Eliminates BHO) - https://taccom3g.com/product/delayed-blowback-9mm-recoil-system/

• Extreme "short stroke" bolt (Allows for BHO) - https://taccom3g.com/product/extreme-short-stroke-9mm-bolt-essb/

Result of Extreme "short stroke" bolt and Delayed buffer system (Very flat shooting with no muzzle rise and faster trigger reset) - https://www.facebook.com/watch/?v=3526785537439787

 

[bwalker36]

I'm looking at the short stroke JP silent capture, but I'm gonna finish it before I try something new. Its just a fun gun, with no real purpose so not going to dump a ton into it.

 

[bwalker36]

So I forgot Aero has threaded rear takedown pins Took me a minute to figure out what the little screw I had left over was hah. I'm just ignoring it though. Have zero interest taking the buffer off to add it in.

 

[Steven_Seagull]

I had to install a "feed ramp" for my AR9 so it would reliably feed JHP. I had to notch the upper and JB weld the ramp into place for a tighter hold than just "fitted".

Runs like a sewing machine now, before that it wouldn't run HST or XTP.

I like the idea of the 8.3" letting you squeeze more performance out of the 9x19.
I went 5.5" and wish I went longer.

 

[Professor Gascan]

KAK makes a 9mm buffer kit with a mix of al, steel, and tungsten weights that's 10oz in it's heaviest configuration. I liked the way my blowback AR9 shot with the buffer in it's heaviest configuration before I moved on to CMMG radial delayed.

 

[powermad]

Generally for a blow back 9mm you will want about 22oz total mass for the BCG and buffer using a rifle (green) spring and carbine buffer tube.
I used a Vltor A5H4 (8oz) buffer with a Law Tactical folder and the 2oz adapter for a total mas of 23oz.
Vltor now has heavy steel PCC buffers.
A5SH0 (6.35oz) - A5SH4 (9.6oz)
https://www.vltor.com/shop/ar/buffer-components/vltor-a5-buffers-stainless/

For a PCC trigger I used a CMC PCC 3.5lb trigger.
A sloppy grip will do a mag dump so be careful who shoots it.
I usually started someone off with 5 rounds if they were not used to it.

 

[powermad]

I had an 8" barrel and the supplied 7" handguard was a bit short for me.
I went with an Aero 10" handguard with a KVP XL linear comp, the standard one just peeked out the end and I wanted it out a bit more.

 

[bwalker36]

So as an update to this. My form 1 was approved today, so I ordered my barrel, stock, and handguard. Went with a basic Aero guard to match the cerekote and one of their barrels. 7.5 handguarnd 8.3" barrel. Grabbed a CTR from magpul. Need an optic, I can't do red dots as they are not dots and annoy the crap out of me cuase of an astigmatism. Was thinking a green holo from holosun something fairly inexpensive but will be fun. Thoughts on a holosun?


ALso can I change thread titles was going to update this and make it a build thread instead of starting a new one.

 

[halfmoonclip]

Good read; I've a Colt 9mm, SBR'd to 10.5", like the actual subguns.
It has always run well; I've had a Geissele SSA in it, which has, thus far, given no trouble. The Colt bolt is ramped, which is reputed to save the triggers. Geissele will neither confirm nor deny its use in 9mms.
It has the pinned in feedramps, and will run HPs with some brands of mags, and not others.
Haven't really pursued which is what, because it runs great on FMJ, and that's what it normally sees.
For the PP who asked, yes, the ramps need to be held firmly. The Colts are pinned, which could be drifted out if I wanted to use a 5.56 upper.
The lower is the "item of record".
I'll keep track of this discussion.
Thanks,
Moon

 

[Nuclear]

I have used a green circle dot reticle Holosun on a pistol and like it a lot.

I use a Timney PCC trigger, it works well, but I haven’t run it in competition, so I can’t say how it will hold up to anything over a few hundred rounds.

 

[halfmoonclip]

...I use a Timney PCC trigger, it works well, but I haven’t run it in competition, so I can’t say how it will hold up to anything over a few hundred rounds.

Nuclear, can you tell us more about the Timney PCC trigger?
Thnx,
Moon

 

[czhen]

Thank you, Live Life.

 

[Nuclear]

Nuclear, can you tell us more about the Timney PCC trigger?
Thnx,
Moon

It looks a lot like an AR trigger, except it has a polymer section on the back, maybe to absorb shock from a blowback action?

 

[halfmoonclip]

It looks a lot like an AR trigger, except it has a polymer section on the back, maybe to absorb shock from a blowback action?

The portion that cams the hammer back, when the bolt cycles?
That's interesting, thanks.
Moon