ysrracer Posted December 16, 2022 Share Posted December 16, 2022 Just kidding, there is no definitive answer First a little house keeping. I'm no chaos, and I'm certainly no blowback, I'm just a guy with a couple of AR 9s, a little free time, and some 9mm ammo. I don't have any sophisticated electronic measuring devices, or any unsophisticated electronic measuring devices for that matter. The ammo I used is my standard 9mm PCC load. It's a 124gr jacketed RMR bullet in front of 3.8gr of 231. Out of a 16" barrel it's going 1140fps giving a power factor of 140. The test guns were both 16" barrels that I shoot in PCC in USPSA. The first one is a Juggernaut Tactical AR9 with a Scheel Roller Delayed Blowback buffer. The buffer has little rollers that "lock" into little windows in the buffer tube. The amount of "lock" is controlled by little springs in the buffer that push out on the rollers. It's adjustable via spring change. The second one is an Aero build with a CMMG RDB Radial Delayed Blowback barrel and bolt carrier. It has lugs on the bolt like an AR15, and matching lugs on the barrel. It's non adjustable. Both of them try to accomplish the same thing, keep the gun in battery longer. The tests were: 1. The Juggernaut with the Scheel Roller Delayed Blowback buffer 2. The CMMG RDB Radial Delayed Blowback, with a 3oz buffer 3. The CMMG RDB Radial Delayed Blowback with a 1 oz buffer 4. The CMMG RDB Radial Delayed Blowback with a 6oz hydraulic buffer The results The Juggernaut with the Scheel Roller Delayed Blowback buffer is very soft. Next to no for bounce, in fact the dot just wiggled to the right. The CMMG RDB Radial Delayed Blowback, with a 3oz buffer, is "sharp" with much more recoil and dot bounce The CMMG RDB Radial Delayed Blowback with a 1 oz buffer is MUCH softer than the 3oz buffer. Much softer. Not quite as soft as the Scheel, but pretty close. The CMMG RDB Radial Delayed Blowback with a 6oz hydraulic buffer is the softest of them all. It's like shooting a .22. No bounce, no recoil. I'm waiting on my dual weights and flat spring from Midway so I can build blowback's “Gentle Recoil” 9mm AR Project. Questions? Answers? Anybody want to buy me lunch? Link to comment
ViktorCistic Posted December 16, 2022 Share Posted December 16, 2022 I have CMMG RDB 2y. My best setup is with hydraulic 308 buffer KynSHOT KynSHOT RB5005 Soft and mimimum dot bounce with 124grs Jakub Link to comment
Gregg K Posted December 16, 2022 Share Posted December 16, 2022 42 minutes ago, ViktorCistic said: I have CMMG RDB 2y. My best setup is with hydraulic 308 buffer KynSHOT KynSHOT RB5005 Soft and mimimum dot bounce with 124grs Jakub Out of curiosity I clicked on your link to the RB5005 and the following was in their specifications, I wonder why.. DO NOT USE IN 9mm AR-15s. For 9mm AR15s use KynSHOT P/N RB5007, RB5015HD, or RB5020SS. See Selection Matrix for proper buffer choice. Link to comment
ViktorCistic Posted December 17, 2022 Share Posted December 17, 2022 Maybye do not use for blowback AR9. Works well without any issues 2y. Link to comment
ysrracer Posted December 17, 2022 Author Share Posted December 17, 2022 Keep in mind guys that barrel length, bullet weight, powder and powder charge all affect how the gun recoils and feels. Link to comment
Krgolob Posted December 19, 2022 Share Posted December 19, 2022 I've combined Scheel with CMMG; it has the softest recoil. Much better than Scheel with standard blow back. Standard blowback is better with hydraulic buffer, there is less dot bounce, but CMMG is better with Scheel than with standard or hydraulic buffer. CMMG + Scheel = the softest shooting by far. But... CMMG has this mushy feeling, slight delay before kick in the shoulder. It feels like there are two kicks with CMMG; before opening and after opening (slamming of the bolt). And those two kicks resonate in more dot movement. It is even more pronounced with Scheel, you have to time Scheel and CMMG all together. There is also the problem with reliability. CMMG is notoriously bad with FTE because of poor ejector spring. Fixed ejector rod is much better solution. Scheel; it also eats those small springs. When they are new, you have to break them in, because they are not optimal. Than they are in their happy place for thousand rounds until they "fade away" and you have to repeat the process. Link to comment
dmshozer1 Posted December 19, 2022 Share Posted December 19, 2022 On 12/17/2022 at 12:48 PM, ysrracer said: Keep in mind guys that barrel length, bullet weight, powder and powder charge all affect how the gun recoils and feels. Don't forget that how you hold the gun is very important. Sometimes more so than even with the best set up! Link to comment
ysrracer Posted December 19, 2022 Author Share Posted December 19, 2022 19 minutes ago, dmshozer1 said: Don't forget that how you hold the gun is very important. Sometimes more so than even with the best set up! Agreed, there are tons of variables. Short of having a bunch of identical rifles (with different recoil systems) locked into some kind of measuring device, it's all just speculation. And even then everybody handles recoil differently, and at some point you're chasing unicorn farts. Link to comment
dmshozer1 Posted December 19, 2022 Share Posted December 19, 2022 2 minutes ago, ysrracer said: Agreed, there are tons of variables. Short of having a bunch of identical rifles (with different recoil systems) locked into some kind of measuring device, it's all just speculation. And even then everybody handles recoil differently, and at some point you're chasing unicorn farts. Agreed! Link to comment
ViktorCistic Posted December 20, 2022 Share Posted December 20, 2022 (edited) 19 hours ago, Krgolob said: I've combined Scheel with CMMG; it has the softest recoil. Much better than Scheel with standard blow back. Standard blowback is better with hydraulic buffer, there is less dot bounce, but CMMG is better with Scheel than with standard or hydraulic buffer. CMMG + Scheel = the softest shooting by far. But... CMMG has this mushy feeling, slight delay before kick in the shoulder. It feels like there are two kicks with CMMG; before opening and after opening (slamming of the bolt). And those two kicks resonate in more dot movement. It is even more pronounced with Scheel, you have to time Scheel and CMMG all together. There is also the problem with reliability. CMMG is notoriously bad with FTE because of poor ejector spring. Fixed ejector rod is much better solution. Scheel; it also eats those small springs. When they are new, you have to break them in, because they are not optimal. Than they are in their happy place for thousand rounds until they "fade away" and you have to repeat the process. Never had any issues with FTE. Changed extractor spring (BCM), ejector spring (Tubb) and extractor. This extractor made in Finland, by Hannu Uronen. Edited December 20, 2022 by ViktorCistic Link to comment
1911smith13 Posted February 5, 2023 Share Posted February 5, 2023 On 12/20/2022 at 2:50 AM, ViktorCistic said: Never had any issues with FTE. Changed extractor spring (BCM), ejector spring (Tubb) and extractor. This extractor made in Finland, by Hannu Uronen. Do you mind sharing who sells that finnish extractor ? Link to comment
ViktorCistic Posted February 20, 2023 Share Posted February 20, 2023 On 2/5/2023 at 7:39 PM, 1911smith13 said: Do you mind sharing who sells that finnish extractor ? Probably no one in the US...here in Europe I can buy it relatively easily Link to comment
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