PCC Carbine Recoil Modulator (Illudium Pew-36 type)

[pontiac428]

So, I've been deviating a little bit and adding PCC to my match schedule. It's stupid fast and lots of fun. One thing we all want is less bounce from the red dot. Less bounce is faster follow shots, which is lower time on the clock. There is a company that makes an AR9 buffer like this, but I figured I could do better. I got a 15-lb flat-wound spring intended for a 1911 to give me much more travel before reaching coil bind. I chose the weight because the original was a 20-lb spring. I was going 25% under because I'm increasing the travel on both sides by 1/2", or 25%. Everything fits and function checks. I decided to cut down the length by 1/2" to better resemble the standard carbine buffer after the pictures were taken. Took the weight down to 5.9 oz. Anyway, it will be nice to get this thing to the range and ring some steel.

 

[silverhawk]

I am curious to see how this works out.

Sent from my SM-T500 using Tapatalk

 

[pontiac428]

I tried the commercial version in that carbine and it made quite a difference. Follow-on shots were definitely quicker, and the target never left the objective on the red dot. The main thing with the one I made is that it reaches the same spring tension at full travel, but has an extra 1/2" of travel to get there, so it should flatten the curve a bit. It's got to be reliable, or it won't be competitive. I also want my last round bolt hold open to work, which is the first thing people lose when they preload their springs to coil bind trying to tame these blowback-operated carbines. The AR9 is going to be my travelling back-up gun now, since I decided to give the CZ Scorpion Evo a try.

 

[pontiac428]

Here's a better look at the design.

 

[WW111]

Are you allowed to use light subsonics? You could work the other end of the equation as well.

 

[Janderso]

Pontiac,
I don't mean to sound like I know what I'm doing.
I am pretty familiar with the platform as I have built over a dozen.
The thing that blew my socks off was a Benny Cooley compensator when on the bench.
I could stay on target with that thing installed. I had to wear double ear protection though
I'll be watching this one.
Interesting.
I didn't know the 9mm were not gas operated.

 

[Shootymacshootface]

When I first got my 9mm pcc together, I had an A2 rifle stock on it. I also copied that popular manufacturers design, but with a couple of differences. Mine is captured by a rollpin and there is a place near the head od it for a wave spring. It is for a rifle stock, not a carbine, so its bigger and heavier. I'm running something simpler in my USPSA blaster now because I have a collapsible carbine stock on it now.
I do have plans for this big heavy buffer. I am building another pcc in .45ACP. The big heavy 3 stage buffer should be right at home in a bigger gun.

This buffer weights over 10 oz. It shoots extremely flat for some very close double taps.
There were some reliability issues with the wave spring installed under the head piece. Sometimes when experimenting with different combinations of springs and weights things can get unbalanced. A slow motion video with a phone will usually capture what the problem is. Poor extraction or a bolt bounce is usually the culprit on these.

 

[pontiac428]

I went to a match last weekend and had time to test fire the PCC with the buffer... wow, what a difference. I didn't shoot enough to comment on the cycle time, but the recoil reduction is huge. It's gentle as a kitten. I tried PF 130 loads with Titegroup, which is too snappy in carbines, and HS-6 which is smoother from a long barrel, and both loads felt the same, where before there was a strong difference. This has motivated me to try two-stage springs in other setups. The overload spring is a good idea!

 

[Shootymacshootface]

That is awesome!