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Posted: 9/17/2018 5:06:49 PM EDT
[#1]
Aluminum case 9mm is generally NOT recommended in blowback guns like the AR9. Several manufacturers warn against it.
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Posted: 9/17/2018 5:06:50 PM EDT
[#2]
Pics?
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Posted: 9/17/2018 6:14:09 PM EDT
[#3]
Quote HistoryQuoted:
Aluminum case 9mm is generally NOT recommended in blowback guns like the AR9. Several manufacturers warn against it. |
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Posted: 9/17/2018 6:16:23 PM EDT
[#4]
Quote HistoryQuoted:
Pics? |
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Posted: 9/17/2018 6:20:49 PM EDT
[#5]
Quote HistoryQuoted:
NOW you tell me! ;). Thank you. Hopefully there is no damage to it. Other than the parts falling off, the receiver doesn't look damaged. Quote HistoryQuoted:
Quoted:
Aluminum case 9mm is generally NOT recommended in blowback guns like the AR9. Several manufacturers warn against it. Ammo that runs thru my AR9 has a more significant bulge in it once fired, I assume because of the blowback design. My assumption is the aluminum doesn't give as much and is more prone to splitting/cracking. I LOVE Federal/CCI aluminum case ammo for practice.... it is usually all I buy and use, even in competition. |
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Posted: 9/17/2018 10:32:15 PM EDT
[#6]
Quote HistoryQuoted: I have a QC10 setup - and I have run some Federal aluminum case stuff in mine.... but I got the first and only hiccups in my gun that day I did. I only did it because my mags were already loaded with it. Ammo that runs thru my AR9 has a more significant bulge in it once fired, I assume because of the blowback design. My assumption is the aluminum doesn't give as much and is more prone to splitting/cracking. I LOVE Federal/CCI aluminum case ammo for practice.... it is usually all I buy and use, even in competition. |
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Posted: 9/17/2018 11:05:36 PM EDT
[#7]
Quote HistoryQuoted:
Just curious what weight buffer ae you running.....I get no bulges in cases..... Quote HistoryQuoted:
Quoted: I have a QC10 setup - and I have run some Federal aluminum case stuff in mine.... but I got the first and only hiccups in my gun that day I did. I only did it because my mags were already loaded with it. Ammo that runs thru my AR9 has a more significant bulge in it once fired, I assume because of the blowback design. My assumption is the aluminum doesn't give as much and is more prone to splitting/cracking. I LOVE Federal/CCI aluminum case ammo for practice.... it is usually all I buy and use, even in competition. |
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Posted: 9/18/2018 4:05:39 PM EDT
[#8]
Quoted:
Built my first AR-9 last week (have done many 5.56s). Foxtrot Mike's upper, lower, buffer and spring. Trigger group from Brownells. Took it to the range today. Factory ammo, Federal aluminum case 115gr. After 20-25 rounds...BOOM! My cheek was peppered, slight cuts (I'm left-handed). Smoke coming out of every hole for a few seconds. When I separated upper and lower, the bolt catch/LRBGO bar came off. Anyone have any idea what would cause this? How much Buffer? Any Spacer? (Brass is supposed to be made out of brass.) |
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Posted: 9/21/2018 4:53:40 PM EDT
[#9]
With a stock carbine buffer and spring, my 9mm ARs would shred aluminum cases. This isn’t a flaw of the aluminum cases. My light buffer didn’t keep the bolt closed long enough. I’m willing to bet your bolt, or your buffer (or both) aren’t heavy enough.
A 5oz or heavier buffer is usually called for, but it’s possible to overdo. Some people go full stupid and buy 8+ ounce buffers before they even get the rest of the gun, then they wonder why they have problems ejecting light rounds. I would go with a 9mm-specific buffer (like KAK Industry’s 5.5 oz buffer) and see how it works with both aluminum and brass ammunition Now that the weather is getting less terribly hot, I plan to take both of my SBR lowers (standard AR and dedicated Glock) to the range with both my 16” and 10” uppers, and I’ll see if the heavier buffer I have helps with aluminum cases. |
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Posted: 9/21/2018 7:30:09 PM EDT
[#10]
He said he has the Foxtrot Mike's buffer. If he has the correct one - theirs is 6.4 ounces and the correct length for 9mm, unless someone sold him the wrong one.
https://fm-products.com/heavy-buffer/ 
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Posted: 9/21/2018 9:02:39 PM EDT
[#11]
I had to look up Foxtrot Mike, and they have enough different products that I can see an "oops" happening. A 6.4 oz buffer should be fine, which makes me wonder what else might be going on. I am very curious what length barrel he has on that gun, and who made it.
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Posted: 9/22/2018 1:27:27 PM EDT
[#12]
Hit us up we are here to help, this is the first we have heard of this...
You can always reach us at [email protected] Shoot us an email and we will help you with your build, happy to help. |
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Posted: 9/22/2018 1:31:42 PM EDT
[#13]
We will always take care of our people if there is a problem, we offer a lifetime warranty on all our stuff.
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Posted: 9/24/2018 7:49:21 PM EDT
[#14]
Sorry...been away.
Yeah, its the Foxtrot Mike heavy buffer. I've been doing a bit of research and there are a couple of articles warning against the use of Aluminum ammo. Foxtrot Mike was quick to connect and said they will examine the weapon see what happened. |
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Posted: 9/24/2018 9:02:11 PM EDT
[#15]
We will take care of you man, everything we offer comes with a lifetime guarantee. My go to ammo is tula or wolf steel cased.
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Posted: 9/27/2018 8:44:28 PM EDT
[#16]
Quote HistoryQuoted: I was running a heavy buffer which didn’t have this, but switched to a hydraulic 9mm Kynshot. It is not as heavy, but damn the recoil is soooooo much better. 
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Posted: 9/27/2018 8:55:40 PM EDT
[#17]
Quote HistoryQuoted:
Not a fan of Hydraulic buffers in blowback.....problem is the bolt doesn't "see" the mass of the buffer until it begins to compress......Love 'em on a DI 5.56 gun.....but locked breech and blowback are entirely different critters as has often been stated.... Quote HistoryQuoted:
Quoted: I was running a heavy buffer which didn’t have this, but switched to a hydraulic 9mm Kynshot. It is not as heavy, but damn the recoil is soooooo much better. Do you have evidence to the contrary? |
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Posted: 9/27/2018 9:16:34 PM EDT
[#18]
Agreed on the hydraulic buffers, we seen them blow seals during testing too...
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Posted: 9/27/2018 9:17:38 PM EDT
[#19]
I do like what they do the recoil impulse, but we seen the ones we tested blow seals, so we steered clear of them.
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Posted: 9/27/2018 10:42:13 PM EDT
[#20]
Quote HistoryQuoted:
I do like what they do the recoil impulse, but we seen the ones we tested blow seals, so we steered clear of them. I always heard about this with the old enidine buffers.... so I stayed away from them. Then a TON of people I shoot with started using them - and never had any issues, over years time. They finally convinced me. Mine has been flawless, but I only have a couple thousand rounds on it. Even if it only lasts for 5000 rounds - thats $1,000 in ammo already spent.... so replacing the $125 buffer isn't a big hill to climb. With the drastic recoil reduction, worth every penny. However - they come with a 10 year/1,000,000 round warranty - so if they ever did fail, I'll just get it replaced for free. If you buy it from Brownells - you get lifetime guarantee. The cool thing is - even is seals DID fail - nothing stops working, they are also spring loaded, and they still reduce recoil even with no hydraulics. |
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Posted: 9/28/2018 8:12:07 AM EDT
[#21]
No horse in the race and I have not run a hydraulic buffer in a blowback... however...
If I was going to do the dynamics simulation to try and run a development, a spring and mass will only have a little extra term called Coulomb friction along with the mass and stiffness. Coulomb is the dry friction that is not affected by velocity. If I were to model a hydraulic buffer, the main term is the Viscous drag, along with a much smaller mass to accelerate, plus a stiffness, and a little Coulomb friction for things that rub. The proportion of mass, stiffness, dry friction versus viscous friction between the different buffers would mean the dynamics would also be dominated by those differences. So, the way the BCG moves versus time and position would be very different between the two. I’m sure one could “tune” either system for a blowback, but my first guess is that a hydraulic designed for a DI isn’t going to be identical to one designed for blowback just based on the difference in the position versus time plot differences between blowback and DI. The main difference being the velocity profile, which makes a hydraulic buffer’s viscous term more important. I’m guessing, but I would bet if someone could tune one, a hydraulic would end up being easier to tailor than a simple spring and mass because you have a damping term to work with as well as mass and stiffness. |
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Posted: 9/28/2018 11:00:15 AM EDT
[#22]
Normal shooting and brain cases I never see issues but if I run CCI Blazer Aluminum through my 9mm build I get a decent amount of OOB discharges when I shoot fast. Typically these are due to out running the action. Pulling the trigger before the bolt is back in battery. It basically slam fires as the hammer is riding the bolt home. Any hang up on the nearly nonexistent feed ramp and boom. Not all rupture cases, some bulge a little, others a lot. Some grenade. I'm a righty or I'd be a lot more concerned.
For the record, mine is a 4.5" pistol build running a heavy modular BCG and a 9 or 11 oz buffer with a rifle spring in a carbine length pistol extension. |
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Posted: 9/28/2018 9:56:02 PM EDT
[#23]
May have been Endine, it was over 2 years ago before we launched the upper. My go to is a 80z buffer with a flatwire recoil spring. We have a few pro shooters using our stuff, they speak highly of the JP captured spring. That is my next one to try. Ill dig up the box with the test parts and try to do an update on what we were using back then.
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Posted: 9/28/2018 9:59:30 PM EDT
[#24]
We found the BCG is moving so fast it messes with the dwell time needed to reset reliably. Testing found that if the buffer was longer than a certain length, the gun would have a higher likelihood of burst fire. Testing also showed that in some cases issues with reset could be helped by a heavier buffer, but only if it did not exceed a certain overall length.
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Posted: 9/28/2018 10:13:56 PM EDT
[#25]
Quote HistoryQuoted:
May have been Endine, it was over 2 years ago before we launched the upper. My go to is a 80z buffer with a flatwire recoil spring. We have a few pro shooters using our stuff, they speak highly of the JP captured spring. That is my next one to try. Ill dig up the box with the test parts and try to do an update on what we were using back then. First I had just a 9mm 5.4oz buffer and standard spring. Then went to the SCS. It was smoother feeling when manually pulling the charging handle, but recoil was very similar to a standard buffer. My shooting partner was running a Blitzkrieg/KynShot and both of use the same configuration SBR - QC10 glock lower, 4.5" or 5" barrel, shooting suppressed and unsuppressed. Every time I shot his, I'd get damned jealous, it was a significant difference. So I switched to the Kynshot 9mm buffer (mine is 5.7 ounces, they advertise 6 ounces today) and the JP polished and ground .308 carbine stainless spring combo, and it made a world of difference. I have 2000 rounds on it so far, and I just pulled it out today to inspect it. It looked like new, even the bumper on the end of the buffer looked new. I'm convinced at this time - nothing is smoother. Certainly not the JP SCS. |
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Posted: 9/28/2018 10:17:47 PM EDT
[#26]
Quote HistoryQuoted:
We found the BCG is moving so fast it messes with the dwell time needed to reset reliably. Testing found that if the buffer was longer than a certain length, the gun would have a higher likelihood of burst fire. Testing also showed that in some cases issues with reset could be helped by a heavier buffer, but only if it did not exceed a certain overall length. |
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Posted: 9/29/2018 9:56:10 AM EDT
[#27]
Im gonna pickup this set up and check it out. Thanks for the suggestions.
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Posted: 9/29/2018 4:42:24 PM EDT
[#28]
Quote HistoryQuoted:
With a stock carbine buffer and spring, my 9mm ARs would shred aluminum cases. This isn’t a flaw of the aluminum cases. My light buffer didn’t keep the bolt closed long enough. I’m willing to bet your bolt, or your buffer (or both) aren’t heavy enough. A 5oz or heavier buffer is usually called for, but it’s possible to overdo. Some people go full stupid and buy 8+ ounce buffers before they even get the rest of the gun, then they wonder why they have problems ejecting light rounds. I would go with a 9mm-specific buffer (like KAK Industry’s 5.5 oz buffer) and see how it works with both aluminum and brass ammunition Now that the weather is getting less terribly hot, I plan to take both of my SBR lowers (standard AR and dedicated Glock) to the range with both my 16” and 10” uppers, and I’ll see if the heavier buffer I have helps with aluminum cases. |
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Posted: 9/29/2018 5:34:22 PM EDT
[#29]
Quote HistoryQuoted:
Does this buffer have anti-bounce sliding weights inside or is it a solid weight buffer? WOW!!! They must have been waiting for me to ask this, because they literally just replied. The 5+oz and their 8oz buffers are solid. If you want reciprocating weights, they recommend their "built it yourself" buffer kit. |
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Posted: 9/30/2018 10:20:06 AM EDT
[#30]
We are offering an 8oz buffer with reciprocating tungsten weights. They will go live at PA and Brownells in about 2 weeks.
FM did them for the .45 but found they really helped the 9mm too. It softened the recoil impulse and increased the dwell time on the trigger, allowing for better engagement on the dis-connector too. 8 oz buffer with reciprocating Tungsten weights... |
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Posted: 9/30/2018 2:24:30 PM EDT
[#31]
Quote HistoryQuoted:
We are offering an 8oz buffer with reciprocating tungsten weights. They will go live at PA and Brownells in about 2 weeks. FM did them for the .45 but found they really helped the 9mm too. It softened the recoil impulse and increased the dwell time on the trigger, allowing for better engagement on the dis-connector too. 8 oz buffer with reciprocating Tungsten weights... |
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Posted: 9/30/2018 4:48:47 PM EDT
[#32]
Quote HistoryQuoted:
The one thing I’ve heard negative about blowback buffers with reciprocating weights is that they “might” make bolt catch breakage worse and/or more common. Any experience to shed light on whether this is a real issue? BTW I have a QC10 Colt lower and the bolt catch is out of a RRA LPK. |
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Posted: 9/30/2018 10:29:45 PM EDT
[#33]
We saw the opposite, the bent sheetmetal stuff out there you should steer clear of. FM has sold thousands of our Billet Lowers and have had 0 issues with the LRBHO breaking. There are some rubber washers between the weights which help cushion the mass as it moves inside the buffer.
Have a look at what I mean, the weights are captured between the Bumper Buffer and weight, and there is a rubber washer between each Tungsten weight, like the H3 Buffers. section view of 8 ounce buffer |
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Posted: 9/30/2018 10:31:27 PM EDT
[#34]
Agreed on importance of a little longer buffer, it does help with reducing inertia before it hits Bolt Stop. Be carefull of buffers that are too long though, as they cause issues with dwell time for the trigger.
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Posted: 10/1/2018 6:15:53 AM EDT
[#35]
Quote HistoryQuoted:
NOW you tell me! ;). Thank you. Hopefully there is no damage to it. Other than the parts falling off, the receiver doesn't look damaged. Quote HistoryQuoted:
Quoted:
Aluminum case 9mm is generally NOT recommended in blowback guns like the AR9. Several manufacturers warn against it. |
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Posted: 10/6/2018 8:19:33 PM EDT
[#36]
Your problem is the aluminum cases. I also use the Taccom 3g buffer system.
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Posted: 10/21/2018 8:57:36 PM EDT
[#37]
Quote HistoryQuoted:
We are offering an 8oz buffer with reciprocating tungsten weights. They will go live at PA and Brownells in about 2 weeks. FM did them for the .45 but found they really helped the 9mm too. It softened the recoil impulse and increased the dwell time on the trigger, allowing for better engagement on the dis-connector too. 8 oz buffer with reciprocating Tungsten weights... |
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Posted: 10/21/2018 9:39:56 PM EDT
[#38]
Quote HistoryQuoted:
Did PA and Brownells ever get these listed? |
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Posted: 10/21/2018 9:56:50 PM EDT
[#39]
We shipped some to Brownells too, sometimes takes a while. They are a great add to a build as the reciprocating mass is awesome w 45, and will help w burst fire w triggers w short resets.
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Posted: 10/22/2018 8:13:16 AM EDT
[#40]
Quote HistoryQuoted:We shipped some to Brownells too, sometimes takes a while. They are a great add to a build as the reciprocating mass is awesome w 45, and will help w burst fire w triggers w short resets. Is this the one with the reciprocating tungsten weights? |
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Posted: 10/22/2018 10:19:18 AM EDT
[#41]
Yup the FM45-HB have the reciprocating tungsten weights.
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Posted: 10/26/2018 1:48:44 PM EDT
[#42]
Bear in mind... Aluminum cased ammo can have bullet setback easier due to the "slickness" of the cases.
Combine a "slick" Poly-Coated bullet and that makes it even more prone to have a bullet set-back. Now combine a "heavy mass" BCG jamming the bullet into the abrupt feed ramps / feed cone of a typical 9x19 Blowback.... All a recipe for bullet set-back. |
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Posted: 10/27/2018 11:30:36 AM EDT
[#43]
Agreed.
Think he was just asking about availability of our 8oz buffers. |
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Posted: 11/11/2018 11:20:13 AM EDT
[#44]
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Posted: 11/16/2018 8:54:49 PM EDT
[#45]
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Posted: 11/17/2018 11:03:48 AM EDT
[#46]
Quote HistoryQuoted:
The one thing I’ve heard negative about blowback buffers with reciprocating weights is that they “might” make bolt catch breakage worse and/or more common. Any experience to shed light on whether this is a real issue? The distance between the bolt face and bolt catch shouldn't be much more then 3/16" As an aside... my configurable "dead blow" ( moving weights ) 7.5oz buffer has caused no issue with the bolt catch.... even with a Tubbs .308 Flatwire in a carbine length tube ( with that 7.5oz buffer ) |
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Posted: 11/17/2018 11:07:11 AM EDT
[#47]
Quote HistoryQuoted:
Agreed on importance of a little longer buffer, it does help with reducing inertia before it hits Bolt Stop. Be carefull of buffers that are too long though, as they cause issues with dwell time for the trigger. In your experience, I am curious... how long is to long of a buffer ? And does a heavier recoil spring "help" or "hinder" trigger dwell time. Thank you ahead of time. |
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Posted: 11/18/2018 12:36:07 PM EDT
[#48]
Quote HistoryQuoted: @FM-Products In your experience, I am curious... how long is to long of a buffer ? And does a heavier recoil spring "help" or "hinder" trigger dwell time. Thank you ahead of time. Anything longer than 3.8" is problematic. A heavier spring actually helps with feeding as it aids in getting the round in the chamber. A buffer with reciprocating weights, will help keep the inertia of the bolt slamming into the barrel, from being transmitted to the dis-connector. If people experience burst fire, it can often be resolved by: 1) shimming the disconnector spring 2) a heavier disconnector spring 3) steering clear of a trigger with a very short reset, as the you need good disconnector engagement for reliable function. Having said that, we have seen a few instances where a customer was experiencing burst fire, and it was resolved by a heavy buffer with reciprocating weights. The reason we came up with one, was it allowed us to hit 8oz buffer weight by adding Tungsten, and keeping the OAL less than 3.8". What surprised us is it really seemed to soften the recoil impulse on a 9mm (as it was developed for our 45) Hope that helps... |
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Posted: 11/18/2018 4:31:54 PM EDT
[#49]
Quote HistoryQuoted:
This is a great question... Anything longer than 3.8" is problematic. A heavier spring actually helps with feeding as it aids in getting the round in the chamber. A buffer with reciprocating weights, will help keep the inertia of the bolt slamming into the barrel, from being transmitted to the dis-connector. If people experience burst fire, it can often be resolved by: 1) shimming the disconnector spring 2) a heavier disconnector spring 3) steering clear of a trigger with a very short reset, as the you need good disconnector engagement for reliable function. Having said that, we have seen a few instances where a customer was experiencing burst fire, and it was resolved by a heavy buffer with reciprocating weights. The reason we came up with one, was it allowed us to hit 8oz buffer weight by adding Tungsten, and keeping the OAL less than 3.8". What surprised us is it really seemed to soften the recoil impulse on a 9mm (as it was developed for our 45) Hope that helps... I'm having some issues with my new 9mm upper doubling when suppressed. Runs okay unsuppressed, but as soon as I put the can on it, I start getting doubles pretty regularly. Barrel: 4.5" Faxon Can: Trident 9 Bolt: Odin hybrid Lower: CMMG dedicated (Colt mags) FCG: stock DPMS (rounded hammer) Buffer spring: standard Buffer: custom solid steel, 7.4 oz I've tried two different loads - both subsonics. First, factory Winchester "Super Suppressed" 147gr, and then my own hotter 147gr loads (last time I chrono'ed them out of a pistol, they averaged 1047 fps). Now here's the thing: my buffer (which I turned myself) is ~3.95" OAL at the moment. I did try going with a regular 9mm buffer (the short ones that are ~5.3 oz or whatever), but the issue remained. But maybe the problem is that I need something heavier than that, but also not as long as my custom one. Sounds like maybe I should try turning it down a little more, and maybe beef up the disco spring for good measure. |
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Posted: 11/18/2018 10:26:01 PM EDT
[#50]
Quote HistoryQuoted: This is a great question... Anything longer than 3.8" is problematic. A heavier spring actually helps with feeding as it aids in getting the round in the chamber. A buffer with reciprocating weights, will help keep the inertia of the bolt slamming into the barrel, from being transmitted to the dis-connector. If people experience burst fire, it can often be resolved by: 1) shimming the disconnector spring 2) a heavier disconnector spring 3) steering clear of a trigger with a very short reset, as the you need good disconnector engagement for reliable function. Having said that, we have seen a few instances where a customer was experiencing burst fire, and it was resolved by a heavy buffer with reciprocating weights. The reason we came up with one, was it allowed us to hit 8oz buffer weight by adding Tungsten, and keeping the OAL less than 3.8". What surprised us is it really seemed to soften the recoil impulse on a 9mm (as it was developed for our 45) Hope that helps... |
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