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Posted: 1/17/2016 2:58:52 PM EDT
[Last Edit: ARMT-Guy72]
Just wanted to restart this thread over here so it doesn't get buried in the PCC section.
How have developments gone so far? Does it look like DI will be the way to go or can blow back be made to work reliably? How about any feed issues with Glock magazines and such? |
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I ran into a few issues with the new mag...pretty sure we have them solved......I will be back on the sig as soon as we get it (45 mag) in production....just have to decide weather we go with a machined follower or an injection molded one.
I'm still thinking blowback is viable...just need to slow the bolt down a little....thinking tungsten powder might be the answer ....if Not, I'll be whipping up a DI shortly.... |
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Builder Specializing in both DI and Blowback pistol caliber uppers....Endorsed by CNC Guns, GWACS Defense, and Quartercircle 10
45 ACP, 10mm, 40S&W, 9mm and 7.62 Tokarev. |
Originally Posted By Mad-Machinist:
I ran into a few issues with the new mag...pretty sure we have them solved......I will be back on the sig as soon as we get it (45 mag) in production....just have to decide weather we go with a machined follower or an injection molded one. I'm still thinking blowback is viable...just need to slow the bolt down a little....thinking tungsten powder might be the answer ....if Not, I'll be whipping up a DI shortly.... View Quote Cool deal. Hopefully, the BB method of operation won't be operating on the edge of tolerances, ( if that makes any sense ) and potentially cause stress on the system/weapon. Whichever method of operation looks to be the most reliable and can function just as well if SBR'd. |
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I hope the .357 sig mags will double as .40 mags.
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"Destroy the earth?! But that's where I keep all my stuff!" - The Tick
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Originally Posted By Grendelsbane:
I hope the .357 sig mags will double as .40 mags. View Quote Do you mean the Glock factory magazines? I don't see why they wouldn't. I have a bunch of the .40 marked, twenty-two round mags with +5 Arredondo extensions on them waiting for the eventual completion of this PCC. I've tested these mags in both of my .357 SIG Gen 4 Glocks and they're functioning just fine. I believe that caliber specific followers are available as well. I know Lone Wolf carries them and I'm sure other outfits do, too. |
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All testing I have done is with 40 mags......feeding hasn't been an issue......just case head separation....
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Builder Specializing in both DI and Blowback pistol caliber uppers....Endorsed by CNC Guns, GWACS Defense, and Quartercircle 10
45 ACP, 10mm, 40S&W, 9mm and 7.62 Tokarev. |
Rudy, a question for ya concerning bolts for these PCCs.
I know the BB system bolt in a Colt 6450, ( I own one ) has a solid back end instead of the open area as seen on rifle caliber AR bolt carriers. Would I be correct in assuming a BB bolt in a .357 SIG PCC would be similarly blocked off? Now, what if the PCC was to use a DI system instead? Reason I'm asking about PCC bolts is that I'm considering an order for one of the Law Tactical side folder AR stock assemblies. We've installed a number of these at work on customer rifles and while it's unfortunate the AR can not be fired with the stock folded to the side, it does make for a much smaller, compact weapon for storage and transport. What's your take on this, Rudy? |
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Originally Posted By ARMT-Guy72:
Rudy, a question for ya concerning bolts for these PCCs. I know the BB system bolt in a Colt 6450, ( I own one ) has a solid back end instead of the open area as seen on rifle caliber AR bolt carriers. Would I be correct in assuming a BB bolt in a .357 SIG PCC would be similarly blocked off? Now, what if the PCC was to use a DI system instead? Reason I'm asking about PCC bolts is that I'm considering an order for one of the Law Tactical side folder AR stock assemblies. We've installed a number of these at work on customer rifles and while it's unfortunate the AR can not be fired with the stock folded to the side, it does make for a much smaller, compact weapon for storage and transport. What's your take on this, Rudy? View Quote The blowback bolts I am using are solid......DI would be a standard M16 carrier.....IF I can solve the case head separation on the blowback......I could always machine a pocket in the bolt I use for the application you have in mind....just need to know how deep it needs to be.... |
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Builder Specializing in both DI and Blowback pistol caliber uppers....Endorsed by CNC Guns, GWACS Defense, and Quartercircle 10
45 ACP, 10mm, 40S&W, 9mm and 7.62 Tokarev. |
Originally Posted By Mad-Machinist:
The blowback bolts I am using are solid......DI would be a standard M16 carrier.....IF I can solve the case head separation on the blowback......I could always machine a pocket in the bolt I use for the application you have in mind....just need to know how deep it needs to be.... View Quote View All Quotes View All Quotes Originally Posted By Mad-Machinist:
Originally Posted By ARMT-Guy72:
Rudy, a question for ya concerning bolts for these PCCs. I know the BB system bolt in a Colt 6450, ( I own one ) has a solid back end instead of the open area as seen on rifle caliber AR bolt carriers. Would I be correct in assuming a BB bolt in a .357 SIG PCC would be similarly blocked off? Now, what if the PCC was to use a DI system instead? Reason I'm asking about PCC bolts is that I'm considering an order for one of the Law Tactical side folder AR stock assemblies. We've installed a number of these at work on customer rifles and while it's unfortunate the AR can not be fired with the stock folded to the side, it does make for a much smaller, compact weapon for storage and transport. What's your take on this, Rudy? The blowback bolts I am using are solid......DI would be a standard M16 carrier.....IF I can solve the case head separation on the blowback......I could always machine a pocket in the bolt I use for the application you have in mind....just need to know how deep it needs to be.... Gotchya. Just before it comes time for you to begin setting up for this build, let me know and I'll send you the bolt carrier extension that comes with the kit, and the other parts we discussed using previously such as the upper receiver, 12" DD SLiM rail and PWS FSC. If you end up going the DI route with this build, the Law Tactical bolt carrier extension simply presses right into the back end of the carrier body. |
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Looks like I figured out what was causing the case head separation......, ran 150 rounds through a 16 inch barrel today with no issues. no failures of any kind...feed eject or case separation.
Gonna run at least 1000 to make sure the issue is solved.....and then we'll be making Sig uppers on a special order basis unless the floodgates open...... |
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Manufacturer specializing in both DI and Blowback pistol caliber uppers.
45 ACP, 10mm, 40S&W, 9mm and 7.62 Tokarev. |
Originally Posted By Mad-Machinist:
Looks like I figured out what was causing the case head separation......, ran 150 rounds through a 16 inch barrel today with no issues. no failures of any kind...feed eject or case separation. Gonna run at least 1000 to make sure the issue is solved.....and then we'll be making Sig uppers on a special order basis unless the floodgates open...... View Quote Excellent news. Did you end up going with DI? Would that 16" barrel be a good candidate for SBR'ing to around 10" or 11" later down the road? Any issues with installing after market rails such as something Daniel Defense? |
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No, actually I wound up with a blowback......clearing the magazine feed lips and getting the height and angle correct are just as bad as they are with 10mm. It all revolves around buffer mass and headspace....
I'm running final tests on a 16 now.....if it can handle a 16 the shorter barrels are no sweat. I don't recommend shortening 16 inch barrels as it can lead to concentricity issues at the muzzle. As far as handguards....as is a blowback....it'll run with anything you want.... |
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Manufacturer specializing in both DI and Blowback pistol caliber uppers.
45 ACP, 10mm, 40S&W, 9mm and 7.62 Tokarev. |
Originally Posted By Mad-Machinist:
No, actually I wound up with a blowback......clearing the magazine feed lips and getting the height and angle correct are just as bad as they are with 10mm. It all revolves around buffer mass and headspace.... I'm running final tests on a 16 now.....if it can handle a 16 the shorter barrels are no sweat. I don't recommend shortening 16 inch barrels as it can lead to concentricity issues at the muzzle. As far as handguards....as is a blowback....it'll run with anything you want.... View Quote Any updates on how the final tests went with the 16" barrel? If everything is running great, I'd like to go over details of an upper configuration and place an order. I can fire off an e-mail for working everything out, just let me know. |
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Well the first one we built for sale is out the door and has 500+ rounds I know of with out a hiccup and I still have my prototype in my office............and I found a source of material for a buffer heavy enough to work that isn't $300 plus for a stick
so feel free to send an email or call me at the shop......(478) 474-2990 we are running 9mm barrels right now in 5, 5.5, 8.5 and 16 inch......if you are certain on 16 inch...I'll pull one and chamber before we send them to nitride Rudy |
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Manufacturer specializing in both DI and Blowback pistol caliber uppers.
45 ACP, 10mm, 40S&W, 9mm and 7.62 Tokarev. |
Originally Posted By Mad-Machinist:
Well the first one we built for sale is out the door and has 500+ rounds I know of with out a hiccup and I still have my prototype in my office............and I found a source of material for a buffer heavy enough to work that isn't $300 plus for a stick so feel free to send an email or call me at the shop......(478) 474-2990 we are running 9mm barrels right now in 5, 5.5, 8.5 and 16 inch......if you are certain on 16 inch...I'll pull one and chamber before we send them to nitride Rudy View Quote Good deal. Yes, I would like one of those 16"ers for nitride, please. I'll have an e-mail headed your way later today for an order. |
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Got my upper headed your way.
Really looking forward to the end result! |
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Manufacturer specializing in both DI and Blowback pistol caliber uppers.
45 ACP, 10mm, 40S&W, 9mm and 7.62 Tokarev. |
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Originally Posted By NightOwl:
Rudy advised against trying to use the Law Tac with this build since removing material from the rear of the bolt body to allow for installation of the Law Tac bolt body extension would probably cause problems due to the reduced mass of the bolt body. How is the 357sig out of the 16" compared to a 9m anyway? Pick up some speed/distance? I don't have a chronograph, so I can't say for sure, but looking at a velocity table, it's easily picking up a couple hundred FPS, ( or more ) from the 16" barrel. Before I fired the .357 today, I ran 15 rounds of 9mm, ( 124gr GA Arms ) through my Colt 6450, then I ran 13 rounds of .357 SIG, ( 125gr GA Arms ) through the new one and there was a VERY noticeable differenence. I was tagging some random bowling pins that the out door range leaves on the 100 yrd berm and they were displaced rather harshly about when struck by the .357 SIG. Brass pretty well thrown, ( and I mean thrown ) back about 15' to 20', consistently to the 3:30/4:00 position. I was only able to run about six mags worth, ( four of the twenty seven round extended then thirteen and fifteen round G32/G31 mags ) before my Aimpoint H1's reticle began to blink off then come back on at setting 11, ( low battery? ) so I decided that was enough for the day. |
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as soon as I get time..... I'm gonna look at getting one of the extensions and seeing if I can make a counterweight that will incorporate it.
Been doing some research and looks like it will add mass...that is a good thing... |
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Manufacturer specializing in both DI and Blowback pistol caliber uppers.
45 ACP, 10mm, 40S&W, 9mm and 7.62 Tokarev. |
My brother was always a 357 SIG fan and I enjoyed shooting his, but ammo has never been plentiful around me so I sort of forgot about it. I see so many LE trade in 229's in 40 (which I don't like), I always think about getting back into the 357, but...
If I was going to get back into a "caliber I need to order", I'd probably grab another 38 super first anyway. The rifle of yours has got to be a fun machine though. :) Brownells has the Law Tac on sale and had a discount coupon a couple days ago, so I bought another one that I think I'll use for a 9mm (current one on 300blk) pistol down the road. Going to get into 80% stuff, then I can make a 45 lower that doesn't have oddball emblems or stuff on it. :) |
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