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Posted: 1/13/2021 12:18:45 PM EST
I need help in defining the buffer to use on a 9mm set-up with a rifle length buffer and A2 stock.
Would you use the standard rifle buffer spring with rifle buffer or use a 9mm extended buffer (or standard 9mm buffer with spacer) - what weight would you use?
Thanks for your help.
Link Posted: 1/13/2021 12:37:56 PM EST
[Last Edit: 1/13/2021 12:42:23 PM EST by SecondAmend]
NVM
Link Posted: 1/13/2021 12:49:36 PM EST
I've been running a 16" AR9 with an A1 stock for about 4 1/2 years... first with a blow back bolt, and currently with a CMMG radial delayed bolt (not on a factory rifle)... original tests with weighted rifle length buffers

1/2" brass rod 6.2oz
5/8" brass rod 7.0oz
filled 7 1/2 lead shot   6.0oz
solid pour lead   9.0 oz

the least dot shake was with the 6.2 and an .079" factory rifle spring

later switched to an Enidine hydraulic from my 5.56 gun, rifle length with rifle spring

that is the set up I use with my CMMG rdb system, and a Miculek style 9mm comp, clocked pretty much to 3 o'clock
Link Posted: 1/13/2021 12:57:16 PM EST
[Last Edit: 1/13/2021 12:58:53 PM EST by WSAR15]
I am assembling a 9mm rifle from parts accumulated over the years based on Colt and Uzi mags.
I have a SS 16" barrel in a Colt 9mm upper receiver - this was built for me by Kurt Kustom years ago. Around the same time I had bought (and paid dearly) a used pre-ban Colt 9mm lower which originally had the pinned mag adaptor removed (small holes now). Regrettably the lower is pitted and I don't seem to find out how or where to have the holes filled and the lower refinished.
I have a Hahn 9mm mag block (bottom inserted - same era) and the 9mm bolt catch
I have a 9mm bolt which needs to be ramped - any ideas where I can have this done?
All my very best and thanks.
Link Posted: 1/13/2021 12:59:29 PM EST
[Last Edit: 1/13/2021 1:01:09 PM EST by WSAR15]
Originally Posted By SecondAmend:
NVM
View Quote


NVM?
What happened to your response which vanished? I responded to it above.
Link Posted: 1/13/2021 1:52:20 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By WSAR15:


NVM?
What happened to your response which vanished? I responded to it above.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By WSAR15:
Originally Posted By SecondAmend:
NVM


NVM?
What happened to your response which vanished? I responded to it above.

I had decided it was too wordy and needed to be edited, but had to do other things so I wiped it out.  Back now to say, when I had an M16 that had a rifle length buffer tube, I used the same standard rifle buffer and recoil spring for everything - 5.56/.223; 9mm; .45 ACP; and 7.62x39.  The 9mm barrel was 16" and not suppressed.  Used Uzi (i.e., non-LRBHO) mags.
Best of luck with whatever you pursue.
MHO, YMMV, etc. Be powerful; be well.
Link Posted: 1/13/2021 1:54:01 PM EST
ADCO can ramp the bolt.

Unsure if macon armory (mad machinist) offer this service.

Try using a rifle length buffer and standard spring 1st, and then modify things after you test fire it to ensure it functions.

Weights are available (search online) to increase the buffer weight if needed.



Link Posted: 1/13/2021 2:02:56 PM EST
[Last Edit: 1/13/2021 2:03:20 PM EST by WSAR15]
SecondAmend & IdahoPCCinc - Thanks
Link Posted: 1/13/2021 11:16:13 PM EST
My 9mm carbine came with the basic mil-style collapsing stock.  Which I hate.

When I put an A2 on it, to keep the same spring/buffer/bolt relationship I cut a plug of wood dowel the right length, put that in the receiver extension then a washer to give the spring a nice flat solid stable surface to rest on.  Well, truthfully I used a quarter.

You can buy commercial plugs  - Spikes has an expensive metal one, Armaspec has an inexpensive delrin one - or just use 7/8" dowel and measure appropriately.  It was just under 3 inches IIRC.

Link Posted: 1/13/2021 11:20:44 PM EST
The rifle buffer should run fine
Link Posted: 1/13/2021 11:37:52 PM EST
That's a lotta quarters.
Link Posted: 1/13/2021 11:38:49 PM EST
Link Posted: 1/14/2021 7:30:38 AM EST
Rifle buffers are supposed to weigh 5 ounces and contain 5 steel weighs. Most 9mm buffers are from 5 to 8 ounces. If desired, you can increase the rifle buffer weight by swapping the steel weights with tungsten weights.

I would also add quarters to the buffer tube as required to limit the bolt from traveling more than 1/4 inch past the bolt catch.



Link Posted: 1/14/2021 9:50:33 AM EST
Originally Posted By SecondAmend:

I had decided it was too wordy and needed to be edited, but had to do other things so I wiped it out.  Back now to say, when I had an M16 that had a rifle length buffer tube, I used the same standard rifle buffer and recoil spring for everything - 5.56/.223; 9mm; .45 ACP; and 7.62x39.  The 9mm barrel was 16" and not suppressed.  Used Uzi (i.e., non-LRBHO) mags.
Best of luck with whatever you pursue.
MHO, YMMV, etc. Be powerful; be well.
View Quote


Thanks, looks like I'll go the standard A2 rifle buffer set up at first.
I also bought a Foxtrot Mike 9mm kit (for 9mm Glock mags) form Brownells recently and it came with a 308 Carbine spring...
Have you had any experience or recommendation on also using stronger buffer springs such as Wolf?
Link Posted: 1/14/2021 11:42:00 AM EST
It'll help you break your LRBHO faster.
Link Posted: 1/14/2021 12:34:45 PM EST
You means the 308 Carbine Spring? Then why would they include it by default?
Link Posted: 1/14/2021 12:54:32 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By WSAR15:


Thanks, looks like I'll go the standard A2 rifle buffer set up at first.
I also bought a Foxtrot Mike 9mm kit (for 9mm Glock mags) form Brownells recently and it came with a 308 Carbine spring...
Have you had any experience or recommendation on also using stronger buffer springs such as Wolf?
View Quote


Like I told you above....

Start with a....Stock rifle buffer spring, Stock rifle buffer.

Fire the gun to verify function.
The point is....get the gun running reliably before you dick with it.

After that...you can experiment with weights, spring rates, adjust the bolt travel, etc.

Link Posted: 1/14/2021 5:09:33 PM EST
I used Spikes rifle to carbine spacer plus quarters to limit bolt travel.

Critical- Only use quarters from free States.

Link Posted: 1/14/2021 5:55:29 PM EST
Mad Machinist......AKA Rudy can ramp your bolt................
Link Posted: 1/14/2021 10:25:16 PM EST
[Last Edit: 1/14/2021 10:36:04 PM EST by CamW]
heavybuffers.com makes a spacer to use a carbine buffer and spring in a rifle tube.

https://heavybuffers.com/spacer.html
Link Posted: 1/15/2021 12:18:09 AM EST
As mentioned multiple times before, start out simple.

Standard rifle buffer, standard rifle spring, put a hundred rounds through it to make sure it works.

Then, add enough quarters to take up the bolt overtravel, I think I had $2.75 in mine, then I made a delrin spacer to equal that thickness to replace the quarters.

I built my rifle for competition in 2012, 16" YHM barrel, DDLES (pre QC-10) Colt mag lower and bolt, Pro-Mag poly mags, yes, Pro-Mag.  Got tired of dropping my $30 mags in the dirt, bought an $11 Pro-Mag, took it apart and deburred it until follower was completely free.  Worked flawlessly, bought a whole bunch more of them.  Had a GI trigger at first, put in a Rise Armament drop-in when they came out.

Probably 20K rounds, many wins, and the only issues I've had were operator induced.  You can over insert a Pro-Mag poly with bolt open, screws up your stage times.

I've seen lots of guys with lots of different combinations of buffers, springs, spacers, bolts, etc, have lots of problems, don't over complicate things.
Link Posted: 1/15/2021 10:25:25 AM EST
Then, add enough quarters to take up the bolt overtravel, I think I had $2.75 in mine, then I made a delrin spacer to equal that thickness to replace the quarters.
View Quote


A #4 rubber stopper will also work for this, and is available in nearly any hardware store.  Just trim to fit.
Link Posted: 1/15/2021 11:40:49 AM EST
Brownells also makes a delrin spacer for running a carbine buffer/spring in an A2 buffer.
That’s what I did when I switched my 16” 9mm carbine from an M4 stock to an A2 stock so I could keep using my 8oz dedicated length buffer.

If running the rifle buffer you can swap in tungsten weights or replace the hollow aluminum spacer with steel or tungsten weights for a heavier buffer.

If running a buffer with moving weights vs solid I’d check your spent brass for signs of bulging. If so, try some rubber spacers to eliminate movement, then add weight if that doesn’t fix it. I prefer a solid buffer, the heaviest I can reliably run with my preferred load.
Link Posted: 1/15/2021 11:47:14 PM EST
Sure are a lot of folks that want to over complicate this, and spend extra money. Use the rifle buffer and spring, it should work fine, you might need a spacer, though. I would try it first.
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