CMMG Guard vs Blowback PCC with Specialty Buffers

[BartCarter]

On 2/16/2019 at 10:27 PM, MemphisMechanic said:

 

I never got the gun reliable on colt mags.

 

I’m 99.9% now on Glock mags but I’m not running the Guard lower, so feeding could be a totally different animal due to mag height and angle... and my ejection port is gigantic.

 

The design of the Guard lower seats the Glock mags is the correct position for the barrel and bolt.  After building many PCCs, I feel this is one of the Guard's best features.  I would never build another Guard without using the Guard lower.  My Guard runs 100%.  Maybe 12,000 rounds now.  I did have to replace my ejector spring and extractor recently, so I am planning on some preventative maintenance in the future.

 

The Guard buffer and spring run fine, but I prefer the Kynshot buffer.

[ViktorCistic]

Someone tried in Guard Taccom adjustable buffer ? THX

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[bwikel]

6 minutes ago, ViktorCistic said:

Someone tried in Guard Taccom adjustable buffer ? THX

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I have tried a lot of different buffer combinations including the taccom. Using the taccom buffer system with a carbine buffer tube and short stroke additions will not work, the stroke is to short to pick a round from the mag. It would work with an A5 or rifle buffer tube but it  created more dot movement than some of the other buffers combinations I used. 

[ViktorCistic]

It is a pity. Here in Czech republic we do not have the possibility to buy eg blitzkrieg.

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[BartCarter]

17 minutes ago, ViktorCistic said:

It is a pity. Here in Czech republic we do not have the possibility to buy eg blitzkrieg.

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How about Kynshot?  They make the Blitzkrieg.  They also make the standard size AR buffer that you can just add a 3/4 spacer behind the spring.  Many use the Kynshot instead of the Blitzkrieg.

[ViktorCistic]

This AR buffer ?

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[HoMiE]

5 minutes ago, ViktorCistic said:

This AR buffer ?

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That looks like the rb5000 for standard AR. They make one specific for 9mm carbine 5007 and the latest 5015hd

[mellino19]

On 12/16/2018 at 6:31 PM, Bwillis said:

From one of Memphis’s post in another thread I bought and tested the blitzkrieg buffer 5015hd with the jp 308  rifle spring, jp 308 carbine spring, and red sprinco. I tested all the above with and without a 95 inch/lbs wave  spring and 1/2 delrin spacer. Also tested against my mbx buffer with all the supplied springs. I shoot a direct blowback ar9, 124 gr at 1130fps 140.12pf.

 

In a carbine  buffer tube red sprinco, wave spring, spacer and blitzkreig I had the fastest splits and kept the dot on target the easiest. Lrbho is disabled with this setup.

 

I have the 2 oz weight from blitzkrieg arriving Monday to try. 

 

 

Any updates on this setup with the weight from Blitzkrieg?

 

I just setup my PCC this weekend with the 2.6oz weight, 5015HD, and JP .308 rilfe spring and it's crazy soft but I'm curious of the wave springs...I also ordered the red sprinco to see the difference as a lot of PCC guys seem to be using them. My ammo PF is a bit lower though, I'm at 132 so I may be cutting reliability close with more.

[ViktorCistic]

That looks like the rb5000 for standard AR. They make one specific for 9mm carbine 5007 and the latest 5015hd

Thank you ! I will try Brownells CZ. if I wanted to try classic buffer with spring, whats best weight buffer and spring ? Flat Wire spring is better ? 308 ? Sorry im newbie in 9mm AR [emoji2960] 

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[Bwillis]

44 minutes ago, mellino19 said:

Any updates on this setup with the weight from Blitzkrieg?

 

I just setup my PCC this weekend with the 2.6oz weight, 5015HD, and JP .308 rilfe spring and it's crazy soft but I'm curious of the wave springs...I also ordered the red sprinco to see the difference as a lot of PCC guys seem to be using them. My ammo PF is a bit lower though, I'm at 132 so I may be cutting reliability close with more.

 

So I put the weight on hold for a while, it would hold up in my tube causing issues. I got bored one night and sanded with 400-800-1500 wet sand and finish with 000 steel wool. The weight is perfect in my tube now, I’ve used it  with 5015 red sprinco, jp 308 carbine and 308 rifle. The red sprinco and carbine produced a lot of jolt and a thud in recoil. The jp rifle is a different story I prefer it over the 5015 with red sprinco delrin spacer and wave spring. The feel isn’t much different but my hits are. 26 oz total, Working transitions yesterday 3 uspsa targets 1 yard apart 10 yards 2 shots per target. my fastest with bcg weight, blitzkrieg weight 5015 and jp rifle was fastest was 1.91, average was 2.06 giving .5 seconds non a. Out of 15 runs with each gun I had 4 c 0 d and 0 m. Also tried 5015 red sprinco 1/2 delrin spacer, wave spring fastest was 2.08 average 2.18 had 8c 0d 0m. It’s not sluggish and my dot doesn’t move at all I can still get .12-.14 splits. my 3 favorite buffer setup are 

1) 5015hd, jp 308 rifle, blitzkrieg weight, bcg weight 

2) 5015hd, red sprinco, 1/2 delrin spacer, wave spring bcg weight

3) mbx green internal yellow spring 2nd stage with delrin spacer (if you need lrbho there’s nothing better than this) 

 

 

[Bwillis]

1 hour ago, mellino19 said:

Any updates on this setup with the weight from Blitzkrieg?

 

I just setup my PCC this weekend with the 2.6oz weight, 5015HD, and JP .308 rilfe spring and it's crazy soft but I'm curious of the wave springs...I also ordered the red sprinco to see the difference as a lot of PCC guys seem to be using them. My ammo PF is a bit lower though, I'm at 132 so I may be cutting reliability close with more.

 

Buy the delrin spacer from mbx, it’s 1/2” long pre loads the main spring 1/4”.  the remaining 1/4” sits inside the spring. Unlike quarters proloading the spring the full 1/2”. At least that’s my take on it 

[mellino19]

54 minutes ago, Bwillis said:

 

Buy the delrin spacer from mbx, it’s 1/2” long pre loads the main spring 1/4”.  the remaining 1/4” sits inside the spring. Unlike quarters proloading the spring the full 1/2”. At least that’s my take on it 

 

I have the New Frontier spacer and see where you're going with this. The only problem is, I've tried the 5007 with the 2.6oz weight and the new frontier spacer and the stroke was so short it wouldn't cycle - insanely soft and flat, once...so if I bet if I tried it with the 5015 it would be similar.

 

But it won't hurt to try. Especially if I test the red sprinco as well.

Edited February 19, 2019 by mellino19
I can't type sometimes.

[Bwillis]

1 minute ago, mellino19 said:

 

I have the New Frontier spacer and see where you're going with this. The only problem is, I've tried the 5007 with the 2.6oz weight and the new frontier spacer and the stroke was so short it wouldn't cycle...so if I bet if I tried it with the 5015 it would be similar.

 

But it won'y hurt to try. Especially if I test the red sprinco as well.

 

Yes it would be the same outcome. If you’re using a carbine tube you can use the blitzkrieg weight and blitzkrieg buffer with no spacer it’s already ss by the weight. 

 

Try with 308 rifle spring, buffer and weight in front of buffer. See if that allows gun to cycle 

 and trigger reset. (No spacers)

 

I’ll take a picture of my setups and post them later tonight 

[mellino19]

6 minutes ago, Bwillis said:

 

Try with 308 rifle spring, buffer and weight in front of buffer. See if that allows gun to cycle 

 and trigger reset. (No spacers)

 

 

That's exactly what I have right now and it runs great using the carbine tube. I should probably not change anything