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Buffers AR 9mm?


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Hello: Anyone using the KAK heavy 9mm buffer that uses 4 tungsten inserts? I am thinking of getting one and removing some of the tungsten weights and using steel and aluminum weights to get a lighter buffer that has reciprocating mass weights. The solid buffers give a sharper hit on the shoulder with more muzzle rise and fall. The RRA arms one I am using right now takes some of that out but it only has a little movement. I think a conventional type buffer should work better. Going to play with the JP silent buffer as well with different springs and weight setups also. Trying to find that magic setup has been fun. Using a timer and targets at different distances has helped quite a bit. If you have your magic setup for buffers and don't mind sharing it should help all of us here. Thanks, Eric

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Is there something the KAK with aluminum inserts would do that the Vltor A5 with appropriate steel/tungsten inserts wouldn't?

For me, going lighter is the magic setup. I like 18 oz total bolt/buffer weight best of what I have tried, but I suspect that is only because I haven't tried lighter yet.

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While still in the experimenting stages, I plan on replacing my current PSA 5.5 oz buffer with some springs and buffers from other guns in the safe.  Next time to the range I'll run a standard buffer and a H1 buffer with both the 9mm recoil spring and a .223 CS carbine spring.

The 3 oz standard buffer will get me to the 18 oz combined buffer + bolt weight.

If I decide to try lighter, I'll pick up a couple aluminum buffer weights from KAK.  They are only $1.00 each plus shipping.

 

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18 ounces total makes sense to me. My back of the napkin calculations are this- Stock 9mm carbines from Colt, CMMG, etc. set up for factory 9mm ammo are using a total bolt/buffer weight of roughly 21 ounces. Assuming that factory 9mm ammo is 150 power factor, and my reloads are 130 PF, then my ammo is 13.3% lighter. 21 ounces minus 13%  is a little over 18 ounces. My CMMG bolt weighs 15.8, so a 3 ounce buffer may be more appropriate than the 5.5 ounce that I've been using. Does this make sense?

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Hello: I have tried the 16-18oz setup and it feels a little harsh with lots of dot movement. The magic spot so far for me is right around the 19-22oz range. Another factor is the hammer spring weight. My CMC trigger feels different than my Jard trigger even with the same setup in the same rifle. I am going to test the spring weight of the triggers to see what the difference is. Maybe I am going at this too scientific but targets hits and the timer don't lie. I will look at the Vltor A5 buffer also. So many options, so little money. I appreciate all the info, keep it coming. Thanks, Eric

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I did some trials this morning, but didn't really weigh everything. Used a Spinta 9mm bolt. Tried a rifle buffer at 5.2 oz. if I remember correctly, rifle buffer with tungsten weights to get 7.9 oz., standard carbine buffer and spring, and a Spikes carbine buffer filled with tungsten powder, and a Wolff +15% spring.

I shot at a plate rack at 50 yards with a scope on 4x with the various combinations. Figuring at that distance watching the scope move should be a fair indicator. No comp installed on the rifle. In my main rifle I have a hydraulic buffer and JP .308 spring, which is as good as I've found so far. I was pretty happy with the rifle buffer and standard spring for a while. Out of everything, the Spikes tungsten powder filled buffer and Wolff +15% carbine spring is as close to the hydraulic set up as anything I tried. Rifle didn't really move much and follow up shots came easy. Worst combo for me was the standard carbine buffer and spring.

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7 hours ago, mscott said:

Out of everything, the Spikes tungsten powder filled buffer and Wolff +15% carbine spring is as close to the hydraulic set up as anything I tried. 

That's the Spkes ST-T2 (4 oz) tungsten heavy buffer, right?  Or is one of the other two offered?

Does the powdered tungsten make a difference compared to using weights?

Thanks.

Edited by Flatland Shooter
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I'll have to weigh it to be sure. I've had it for 3 or 4 years, so not sure at the moment. Plan to add some tungsten weights to a carbine buffer and try it, but haven't yet.

Just checked and it is 4.2 ounces

Edited by mscott
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I have an ATI rifle which I'm guessing has a bolt made by NFA since they make the lower, and I'm running the JPSCS2-9mm in it. It runs a lot smoother (and quieter) than the stock spring and buffer, but still had more red dot bounce than I wanted. After reading about preloading, I added $1.25 to the buffer tube which brought the JP buffer out to just behind the bolt catch. It seems to run a little softer now but I have no testing evidence upon which I can say that. I'm going to try using the shot timer app on my phone tomorrow and see if I can see spilt time differences.


Sent from my iPhone using Tapatalk

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Hello: Anyone change things up on there JP 9mm buffer setup? Looks like it comes with a 110% 308 spring since it is red/yellow. Anyone try the 223 springs on there buffer? Also thinking of lightening up the weights as well. It is 6.2717 ozs right now. I think I am going to like this system since I can tinker with spring rates and buffer weights. Thanks, Eric

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On January 1, 2017 at 6:55 PM, Flatland Shooter said:

That's the Spkes ST-T2 (4 oz) tungsten heavy buffer, right?  Or is one of the other two offered?

Does the powdered tungsten make a difference compared to using weights?

Thanks.

I'm currently running a Spikes T2 with a rifle spring in a Carbine buffer tune. With minor 147 ammo it shoots the smoothest of all the different combos I've been trying. I don't think the T2 even bottoms out in the carbine tube with a rifle spring.  Kind of a pain to get all of that spring in the tube though. 

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