I have a legally registered M16 that I was building a 9mm Colt 635 type upper for. I have all the components except the 9mm bolt. It is using a Hahn 9mm Colt mag conversion unit with a 8 oz, 4” buffer and CAR flat spring buffer spring. I am looking at a Spikes bolt with a flat key, I believe it is a ST9BG01 model,ramped or a B King Firearms BKF bolt. It must be full auto rated/compatable. I am pretty sure the B King unit is good to go but not sure about the Spikes unit. Any advice is appreciated. Together, either unit with buffer is in the 22-24 oz sweet spot area.

New Frontier Armory 9mm bcg has the M16 cut outs on the bolt.

Works w/ Glock/Colt/MP5 mags.

Never had an issue with any of the ones I have for Colt mags and MP5 mags.

Just verify before you order any other 9mm bcg that it is cut for  the FA trigger group in your lower.




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Do you have a transferable RR M16 or is it a post sample?  I personally wouldn't run a straight blowback 9mm upper on a valuable transferable lower.
I also see you are in FL.  I try to go the Port Malabar SMG match which is the first Sunday of every month which has been going on since the 80's.   It is laid back and a lot of fun.  Back in the day we had a lot more full auto shooters and these days it is about 1/2 the shooters that show up to the match are running semi auto.  Everyone is welcome but always nice to have more full auto shooters.  
The stages are setup so full auto is encouraged.  When you engage strings of targets in bursts you get time deducted.
Here is a short clip of a couple of my setups on M16 lowers at last month's match:

this thread is in my interests as well. I'm just starting the journey into possibly doing a 9mm upper for my M16 (transferrable) just for fun shooting with my son.

Is there a lot of stress on the lowers with a blowback?

I run a hydraulic buffer right now on mine / 5.56 PWS upper.

Thanks

Yes, the only straight blowback upper I would run on a transferable M16 lower is 22LR.
Geissele and several other trigger manufacturers say shooting 9mm will void the warranty on their M16 and AR15 triggers.
Now I do run a Geissele SSF with my tuned 9mm M16 setups but I am not the type of guy to expect them to support me if it breaks either.

Back in the early 2000's I had a RR Colt SP1 and egged the hammer pins holes from shooting a Colt 9mm upper in SMG matches.

I don't know what else you have in your collection or what your background is but in a nutshell when it comes to full auto 9mm SMG's here is my take:
Open bolt - plenty of smooth running options
Closed bolt - MP5 is the king but it has a crappy trigger, ergonomics kind of suck, no LRBHO, difficult to work on, expensive and the cyclic rate is a tad too fast even after changing locking pieces so tuning is limited.
Straight blowback 9mm M16's are very bouncy in stock form and again can damage your lower.
The CMMG RDB came out in late 2017 and I've been messing with them since they hit the market.  
Out of the box maybe 60% the way there to an MP5 in regards to recoil impulse but not there yet.  Add the appropriate hydraulic buffer and flat spring and that will get you 90% there.  .40SW bolt in 9mm gets there but then you need a custom fixed ejector like I did and then the bolt will crack at around 25K rounds.

This is why I go through all the trouble I mention on my site here: https://c3junkie.com/?page_id=1733
I finally have what I've been after for like almost 20yrs.

The MEAN Arms Bearing Delay is soft shooting for sure but it uses a spring loaded ejector like the CMMG and it dies too.  I'm on my 3rd ejector spring with that system.  
So, IMHO, right now my hybrid Dissent is the best thing going for a full auto 9mm for the M16 today.

Thank you for education sir. I'll check out your link.

I've done just about 1 of every semiauto PCC on the market and none of them ever did it for me. They all missed the giggle switch. However, it seems that it isn't the best idea, for now, to use my transferrable for this. I'm ok with this as I'm stocked up pretty good in 5.56, but the allure was there to shoot up the mou tain of 9mm I have with my boy.

Again, thank you for all the info. I'll keep researching.

I made extra sets if you are serious reach out to me.  My hybrid CMMG Dissent I made has rivaled my FA MP5.

With all the advise; I think that I will forego the full auto and put the Colt 635 clone upper on my registered AR15 SBR with a Hahn conversion and just shoot semi automatic. I did reinforce the lower with SS trigger/hammer pins already. I do not want any damage to my M16.

Was this suppressed, or not?

Colt ended up making stainless hammer and trigger pins for the 635, because of broken hammer pins.

The stainless pins were tougher (as opposed to harder), and hoped to be less prone to breakage.

It's also why Colt 9mm bolts were "ramped,". by aftermarket customizers, to decrease the initial recoil impulse pressure on the hammer, which was the engineering employed to keep the bolt closed long enough. And then, those ramped bolts had tungsten inserts installed, to put more mass on the bolt.

IIRC, Colt incorporated the ramping and tungsten inserts into their later-production 9mms.

 Every blowback action has to recock the firing mechanism.  That's not engineering employed to keep the bolt closed long enough, that's done w/ the mass of the recoiling parts in a straight blowback.  Colt ramped their bolt b/c of the increased speed of the 9mm bolt vs the DI bolt carrier.

Not sure what you're arguing about.

It's obvious, comparing the mass of the AR-15 bcg to other blowback 9mm smg bolts, that there's not enough mass available to keep the bolt closed. The only other option is an increased recoil spring rate, which of course raises ROF and the potential for misfeeds.

Please explain why ramped bolts/tungsten inserts are now a thing? Those were introduced by the aftermarket.



Wonder why I bother posting anymore. Yeah, FFS, don't listen to someone who owned a NIB 635, along with a Sten, Swedish K, Sterling, S&W 76, UZI...

Did you own a Marlin Camp Carbine?  Doesn't suppress well.  That's an even lighter bolt.  Submachine gun bolts are heavier than needed to keep the rate of fire down.

Are you the guy that argues the AR-9 is a delayed blowback design b/c it cocks the hammer?

Yeah, honestly, at this point, I don't know what you're talking about.

We can agree that the 1" tube of the AR-9 makes supplying sufficient mass for a slow cyclic rate difficult compared to traditional open bolt guns, I think.

Yes, which is why the original Colt 9mm system used the mechanical (dis)advantage of the steep face of the bolt interior against the hammer to keep the bolt closed long enough.

This led to broken hammer pins, for which updated stainless pins was Colt's solution.

Aftermarket customers ramped the bolt to solve this, but then any possible additional mass was needed, so tungsten bolt inserts were used. The original Colt bolts had inserts made of steel.

It was later that Colt included these modifications into their own production.

Again, I don't understand your argument with me; this is all well-established historical facts.

Are you sure about Colt using tungsten bolt inserts?  Not trying to be a d!ck in any way, but if you have a book or website reference I'd love to see where this info comes from - seriously.  It is my understanding that Colt used the "fork type" bolt inserts that were steel and weighed  3-3.5oz., bringing their 12-12.5oz bolt up to 15.5oz. - 16oz.  I have a contact who made a tungsten "fork" type insert like the Colt insert from a scrap tungsten rod it weighed a full 7oz.

Example weights. Colt AFAIK, used something like the one on the left.  Most bolts today come with something like the one in the middle.

I pretty much agree.  It was my understanding that Colt developed their carbine length ~ 6 oz. hydraulic buffer for 9mm operational improvement and specifically ROF reduction.

MHO, YMMV, etc.

To be honest, I could be wrong about Colt doing that in more recent production, along with ramping the bolt. Pretty sure, I am correct about the historical issues Colt had with the 9mm.

I have a factory 635 upper from more recent production (2015?) in the safe. I will pull it out tomorrow and take a look.

I do know they've used a variety of buffers, including the hydraulic, the 2-piece with pinned floating head (C?), as well as the "A," "B," and "X."

Back then, I was running it both ways.  There also was a guy that used to run the matches with a fully transferable all factory Colt 9mm SMG which are pretty rare to see factory ones.   I remember that his lower had the pinned mag block looked well worn.  Engraved SMG NATO etc..  I'm not a Colt afficiando but assume it is a 635 which had the carry handle and I think 10.5 or so long barrel.
I was there when his gun went down due to the hammer pin breaking during a stage in a match.   Really nice guy but unfortunately he passed away.  His two sons used to shoot the matches but haven't seen either in a long time to ask them any details.  Not sure if any of them kept that particular gun.

I think you are probably referring to Ken Elmore of SAW. You can read about his career and time with Colt on his website here: https://www.specializedarmament.com/about-us-sar15.com
Back in the day just about all Colt 9mm bolts were not ramped.  Later Colt did ramp the bolts but never used Tungsten in the bolts.

Here is a link to an old web page on my site of my setup back in 2004: https://c3junkie.com/?page_id=752
Pictured below is my Colt 9mm bolt that SAW ramped before it was mainstream and added their Tungsten weight to it as well.


No matter what I did, I could never get the straight blowback 9mm Colt setup to run as smooth as an MP5.  I got 3rd place at the Knob Creek SMG match I think 2005 or so and back then I used that bolt but took the weight out, used a integrally suppressed ported LRM upper and an old Olympic Arms pneumatic buffer.  That was as smooth as I could get it as it brought the reciprocating mass down but that buffer ending up leaking and becoming useless after a short amount of use.

Fast forward to today if you want a full auto 9mm setup to use on a transferable M16 lower my preference would be:

1.  What I posted a Youtube link to above - my hybrid CMMG Dissent RDB (Radially Delayed Blowback) build which uses a fixed ejector in the upper detailed on my site here: https://c3junkie.com/?page_id=1733  .  As seen on my site, I had to do custom machine work to make this happen but I finally have a setup that is better than an MP5 for my needs, just as smooth, nicer cyclic rate which is very tune-able, LRBHO and ability to use various magazines and will also work with Colt, Glock (via mag block), Endomags (and upcoming Exomags), Sig and I guess even Beretta if you want to get a Stern block.  If you have a RDIAS or RLL you can also use MP5 mags with the appropriate upper / lower receiver and I've done the mods to make it work with Scorpion mags but still testing.  Obviously, if you have a RR/RLL getting a Glock lower is also an option.  I use a CMMG RDB small frame Glock lower for 9mm and .40SW full auto.

2.  You can get a CMMG 'Banshee' BCG/Barrel combo for under $400 but that is using the ejector in the bolt which is great for 5.56 or other gas operated calibers where the bolt is truly locked but with a delayed system, having the ejector spring inline with the recoil impulse I don't think lasts very long and dies around 1K rounds as I have documented here: https://c3junkie.com/?page_id=221

3.  The new MEAN Arms Bearing delay also works on a RR / RDIAS (RLL w/ typical carrier mods) but also uses the same ejector spring orientation like th Banshee and also dies quickly.  I am on my 3rd spring in less then 2000 rounds.  It is currently only available as a complete upper.  The MEAN also uses guide rods in the upper so you cannot use Colt mags with that system as they hit the rods that the carrier rides on.  I will say this system is very smooth and tune-able and possibly smoother than the MP5 but the ejector spring failures is a huge problem for me as well as the other additional proprietary wear parts mentioned in the manual.

4. The Angstadt MDP-9 is roller delayed and uses a spring loaded ejector that goes in/out of the path of the bolt like an MP5 but like the Dissent is bufferless and not full auto capable.  I had tested one of these but in the baseline testing before even trying to make it full auto, one of the rollers sheared apart and deformed the locking piece.  Everything in that upper is also proprietary.  I wouldn't even consider this an option but figured I would mention it as I did consider it but testing phase was a failure for me.