Clean sheet pick, "best" PCC

[alma]

13 hours ago, GJM said:

Is this the Timney trigger that you are suggesting for the MPX, and if so, flat or curved, long or short?

 

timneytriggers.com/shop/AR-Targa-2-Stage-Short-Trigger-P77.aspx

 

 

Yes, that's the one thing that Timney recommends for the 9mm PCCs including the MPX. The other details would be be personal preference but I would go with short and flat... 

[GJM]

Thanks. 

Can't remember if I mentioned it, but in my first range session with the MPX, I had many stoppages using PMC 115. With full mags, rounds would not chamber, except in a 20 round mag, loaded with about ten cartridges. I left magazines loaded overnight and shot today. Initially I had some stoppages today, and then the gun settled in, and I ran 100 rounds of Lawman 147 and PMC 115 without issue. 

I have read elsewhere, that the extractor can be tight when new, and some people are removing an O ring? 

Hoping my MPX is over the hump.

[GJM]

My MPX still won't feed a round from a full, or nearly full magazine, inserted with the bolt forward. I need to remove 5 or 6 cartridges to get it feed. It does feed with the magazine inserted with the slide locked back.

I called Sig CS today, and they were quite helpful. They told me that the MPX was not designed to be able to strip a cartridge from a full magazine with bolt forward, that there just is insufficient bolt speed to make that work. I explained that was a problem with empty USPSA starts, and they suggested that I remove an O ring from the extractor, leave the magazines fully loaded to weaken the springs, and with time they should strip a round after the mag springs weaken.

Not the answer I was hoping for, but I appreciate their candor. 

[Carmoney]

"Not designed to be able to strip a cartridge from a full magazine with the bolt forward"?  

 

My friend, that is pure exquisite BS.  Personally, I would start over with something else, but I have a very low threshold for guns that malfunction.  

[Gooldylocks]

On December 3, 2016 at 10:08 PM, MikeRush said:

In terms of "clean sheet" I am looking forward to the Grand Power Stribog which should be coming to the US next year.

I agree that somebody needs to do a roller or other form of delayed blowback upper for thr AR platform. I don't care if the upper doesn't use standard parts- it would open a superior action type to AR ergos, trigger, etc. I think the availability of mags, lowers, etc would be a huge plus. Also, someone needs to make a lower with a big magwell that will sell individual lowers.

One thing I haven't seen discussed a whole lot is a DI 9mm AR. There are a couple of shops producing them and if anyone really wants to work a comp you have that option. I had a DI upper for a while- recoil is incredibly soft, but runs on slow powder handloads only. I got reliable bolt lock back on empty with a mid range book load of HS6. I think if USPSA were to allow 9mm Major in PCC that would be the dominant choice. The one I had had the barrel nut shaved to install the gas block- the port is that close to the chamber! At the time, I really wanted to get ready for the Red Oktober match and the bump and recoil of a blowback gun seemed beneficial as a trainer. If I were going with the take no prisoners approach that is what I would do. It is like Open for PCC. I am enjoying PCC, but my heart belongs to another division.

What shops do make them? A buddy and I were talking about this very thing not too long ago, how if a company built a DI AR it would be super awesome. We were thinking that a 95-115 grain load of Power Pistol/HS6/AA7/AA9 at around 140 pf would be incredibly easy to shoot. Imagine it, a 90 grain bullet with some stupid charge of AA9 to make gas for the comp and action. Seems cool to me, even if it is a reloader only gun; open guns are reloader only too and we all have no issues with it.

You could probably get away with (need?) an incredibly lightweight BCG and buffer/spring setup, which would just add to the softness of shooting it. 

Edited December 7, 2016 by Gooldylocks

[Carmoney]

Isn't there a limit of 1600 fps to prevent damage to steel poppers and whatknot?

My 95-gr. production load makes right around 1500 fps out of my PCCs, and it's not a violent load to shoot.

Seems to me that any load with enough poop to operate a DI system or run a comp would well exceed the 1600 fps speed limit.

[SpaceMan]

11 minutes ago, Carmoney said:

Isn't there a limit of 1600 fps to prevent damage to steel poppers and whatknot?

My 95-gr. production load makes right around 1500 fps out of my PCCs, and it's not a violent load to shoot.

Seems to me that any load with enough poop to operate a DI system or run a comp would well exceed the 1600 fps speed limit.

 

We have a club around me that wont let PCC shoot there because he doesn't know enough about it and the pressures created with a PCC

[dcloudy777]

We dunderhead types are kicking around a thread on Arfcom's "Pistol Caliber" forum about a roller-lock gun. 

Basically a propose-built upper with non-recip left hand charging, a "right-sized" 9mm ejection port and brass deflector, and recesses for the rollers of an MP5 bolt head.  Every thing else would be pure AR pattern, slaps on to AR lowers, uses AR barrels, AR-type 1913 rail.

The other proprietary part would be, naturally, the bolt itself.  In addition to the addition of the MP5 roller assembly, the bolt could be substantially lighter (which is the whole point of this... less reciprocating mass), and wouldn't need to be ramped, which would allow for the use of pretty much anyone's AR trigger.

Using the MP5 guts should keep costs halfway reasonable, and tons of "tuning" options for roller sizes are out there.

Basically this would be a "best of all worlds".  No gas system to worry about (not much gas in a 9mm), smooth shooting like an MP5 or MPX, form factor and configuration options of the AR.

Anyone know how to CAD stuff? 

[IntenseImage]

My MPX still won't feed a round from a full, or nearly full magazine, inserted with the bolt forward. I need to remove 5 or 6 cartridges to get it feed. It does feed with the magazine inserted with the slide locked back.

I called Sig CS today, and they were quite helpful. They told me that the MPX was not designed to be able to strip a cartridge from a full magazine with bolt forward, that there just is insufficient bolt speed to make that work. I explained that was a problem with empty USPSA starts, and they suggested that I remove an O ring from the extractor, leave the magazines fully loaded to weaken the springs, and with time they should strip a round after the mag springs weaken.

Not the answer I was hoping for, but I appreciate their candor. 

Pure horse shit ... My MPX will chamber a round from bolt closed on a full mag

[hgr2]

So far my MPX has been Great! Very soft shooting and reliable. At 50 yards using a 4x meopta scope with 125 gr Zero JHP bullets and 4.1 TG reloads it shoots ragged hole groups. It opens up to 4 or 5 inches at 100 though.  I'm using a JP trigger with the stock Sig hammer, time will tell how it holds up. As far as stripping rounds from full mags, no problems yet.

Mags may be a little pricey but how many are you really going to need? a hundred? for me not an issue.

[GJM]

Shot 150 rounds through my MPX today. All my magazines now live fully loaded.

My MPX still would not strip a round from the full magazine today, but worked fine when loaded with an open bolt. Installed a Timney trigger, as recommended by Alma above, and that worked fine. 

Pulled the RMR off and zeroed a 6 moa C-More. Shot one ragged hole at 25 yards with PMC 115 ball.

[IntenseImage]

Shot 150 rounds through my MPX today. All my magazines now live fully loaded.

My MPX still would not strip a round from the full magazine today, but worked fine when loaded with an open bolt. Installed a Timney trigger, as recommended by Alma above, and that worked fine. 

Pulled the RMR off and zeroed a 6 moa C-More. Shot one ragged hole at 25 yards with PMC 115 ball.

It's still tight ... Couple hundred more through it and it will prob strip rounds just fine.

[alma]

One more note on the Gen II MPX. I gas port runs smaller than on the Gen 1 and today Taylor Pickerell mentioned some variability even among the Gen II. If you are running light loads and it isn't cycling reliably (assuming you you lubed up) then Pickerell can open up your gas port a bit. 

[IntenseImage]

One more note on the Gen II MPX. I gas port runs smaller than on the Gen 1 and today Taylor Pickerell mentioned some variability even among the Gen II. If you are running light loads and it isn't cycling reliably (assuming you you lubed up) then Pickerell can open up your gas port a bit. 

Specifically Gen2 cut to 4.5 and suppressed running 147s

[MikeRush]

On 12/7/2016 at 1:07 AM, Gooldylocks said:

What shops do make them? A buddy and I were talking about this very thing not too long ago, how if a company built a DI AR it would be super awesome. We were thinking that a 95-115 grain load of Power Pistol/HS6/AA7/AA9 at around 140 pf would be incredibly easy to shoot. Imagine it, a 90 grain bullet with some stupid charge of AA9 to make gas for the comp and action. Seems cool to me, even if it is a reloader only gun; open guns are reloader only too and we all have no issues with it.

You could probably get away with (need?) an incredibly lightweight BCG and buffer/spring setup, which would just add to the softness of shooting it. 

Mine was from Ron Williams at RMW Xtreme. Shooting 135s at 140 pf with HS6 was so soft it made me laugh the first time I pulled the trigger. I would like to revisit the idea at some point- I might send him the handguard I want to use and see if he can make a setup fit. It did make 100 fps less than the same load in a blowback gun. I guess having the gas port immediately in front of the chamber bleeds a lot of pressure over the 16" of barrel.

I used a milspec carrier and buffer with a modified bolt he sells.

If we could score major in PCC it is probably the only option I would consider. If he could make one with the KMR Alpha handguard...

[wheelie]

In .45 ACP only right now with 9mm coming:

https://flintriverarmory.com/

 

 

[dmshozer1]

On 12/6/2016 at 11:45 PM, Carmoney said:

"Not designed to be able to strip a cartridge from a full magazine with the bolt forward"?  

 

My friend, that is pure exquisite BS.  Personally, I would start over with something else, but I have a very low threshold for guns that malfunction.  

Right on!!!!!!!!!!!!!!!!!!!!!!!

Especially the leaving the mags loaded will weaken the springs. That is a total BS. myth.

New springs will take a "set" but will not weaken when left compressed.

My carry gun is 25 years old. Same mag springs. No malfunctions mag related in all that time.

It has been proven that loading and un-loading is the cause of weak springs.

[andyglidewell]

We dunderhead types are kicking around a thread on Arfcom's "Pistol Caliber" forum about a roller-lock gun. 

Basically a propose-built upper with non-recip left hand charging, a "right-sized" 9mm ejection port and brass deflector, and recesses for the rollers of an MP5 bolt head.  Every thing else would be pure AR pattern, slaps on to AR lowers, uses AR barrels, AR-type 1913 rail.

The other proprietary part would be, naturally, the bolt itself.  In addition to the addition of the MP5 roller assembly, the bolt could be substantially lighter (which is the whole point of this... less reciprocating mass), and wouldn't need to be ramped, which would allow for the use of pretty much anyone's AR trigger.

Using the MP5 guts should keep costs halfway reasonable, and tons of "tuning" options for roller sizes are out there.

Basically this would be a "best of all worlds".  No gas system to worry about (not much gas in a 9mm), smooth shooting like an MP5 or MPX, form factor and configuration options of the AR.

Anyone know how to CAD stuff?  [emoji185]

Can you link to the thread? I'm an aerospace engineer that can do cad stuff. I'm curious what y'all are coming up with.

Sent from my SAMSUNG-SM-G891A using Tapatalk

[SergioSF]

On 11/20/2016 at 5:48 AM, GJM said:

If you were free of all constraints, budget and otherwise, what PCC would you choose?

i have a JP GMR-13, that I recently got. I like a lot about it, but I am not keen on the mag release, and it seems like the upper could be lighter, to speed transitions. Of course I wished it would lock back on an empty magazine.  I don't know enough about other AR options, Palmetto and otherwise, to know how they stack up. 

I have heard that the MPX is softer shooting, as it is not blow back. Not sure about stock options, but I heard it can be a problem installing triggers, as there are plastic pieces in the MPX that interact with an after market trigger. This is second hand info.

i have been told that an HK is the softest shooting, due to its method of operation. Trigger work a challenge, and mag changes slower due to the button/paddle and tightish mag well? Are there extensions that work with the OEM 30 round magazines?

I have never seen an AUG with a 9mm conversion, although the short length would seem an advantage on field courses.

Suggestions/comments?

Congrats on the GMR-13. Are you really looking for another gun for PCC? Why not another GMR-13 for your back up?

But to answer your question (and maybe for the benefit of other newbs like me):  clearly the AR is the popular platform in PCC, and lots of folks have built frankenguns with some success, juggling bolts with buffers and loads, etc. But it seems that the only turn-key,reliable options seem to be the JP or an MPX, or the Scorpion. Being a CZ fan, I picked the Scorpion  (It's also the least expensive option, by over $500)

It has been 100% reliable, it chows through every kind of round I feed it, and just needs very minimal mods to start playing in PCC division. 

I think it checks off all your boxes: It's completely ambidextrous with safety, charging handle, mag release. It locks back on an empty mag. The trigger is an easy/simple/cheap upgrade. Soft shooting too.

[dcloudy777]

On 12/13/2016 at 10:35 AM, andyglidewell said:

 

Can you link to the thread? I'm an aerospace engineer that can do cad stuff. I'm curious what y'all are coming up with.

Sent from my SAMSUNG-SM-G891A using Tapatalk
 

Sure.  It's kinda cooled off this week, but there's some interesting discussion.

 

http://www.ar15.com/forums/t_3_15/706097_Anyone-ever-think-about-an-HandK-style-roller---.html