has anyone here tried to do a gas op 9mm with a lightened carrier like the boomfab one advertised here ?

from what i have read it would appear the major hurdle is having enough pressure to cycle the action. could the pressure be made to work more efficiently by reducing the weight of the carrier so that what little gas there is does not have to work as hard in shorter barrels?

maybe a lighter spring would be in order as well?

thanks in advance for the input

Cycling the action isn't the problem......getting the action not to foul from little chunks of gilding metal blown off the projjectile into the bolt carrier do to the location of the gas port is the issue...I built one and had no issue getting it to cycle......but just didn't have time to develop it further. I know Ron Williams has had some success but (correct me if I'm wrong Ron) it is a reloaders gun......I ran abut 6 types of factory ammo and had issues with it all.

As stated above, its the factory ammo. Way to dirty. I did run some Win 147g personal defense without issue but the goal was to run bulk box.
yes my DI9mm is a reloaders dream. No recoil. It just sits in your hands. I dont use HOT loads. All factory pressure specs. I just use powders that burn 97-100% in given brl length.
If set up right there is no need for light buffers, springs or carriers. Here is stock setup with stock full auto carrier.DI9mm

that is exactly the type of set up im going after with the ddles (or clone now) lower. how short can you get the barrel running with factory ammo as im not set up to reload?

I have one of Ron's 9's but we left it at 16.X". I know Ron does have very short barrels running fine,
just not sure 3" or 4". My preference would be more in the 7-7 1/2" if going short. I really like the
Magtech ammo....

Good Luck,
Dave in Florida

I cant set my DI9mm up at any length with factory ammo.
i did video running my Di9mm running on the DDLES lower.Di9mm/ddles

i saw that do you have contact info or a website or something that you can pm me id like to run some ideas past you thanks

IM sent

Very nice. Does the DI 9mm for the DDLES/QC10 Glock receivers use a standard bolt carrier with just a 9mm bolt cut for the Glock magazine?

Std AR15/M16 carrier moded to take & feed  from the glock mag.

Ron, what is the minimum reliable barrel length that you would build a DI 9mm on for handloaders?

http://www.ar15.com/forums/t_3_15/658008_DI_9mm_carbine_with_lightweight_carrier_and_buffer_system.html

9"
With these new light weight carriers could go smaller.

I had seen your post here and wrote the other thread as a detailed guide and log of my experience. Though a bit long winded, the information you seek is in there but i'll recap the key points of the general issue and solution.

For starters, its important to know that the bolt/recoil assembly and gas/pressure system MUST be addressed as a symbiotic whole since the gas system drives teh recoil assembly and so the recoil assembly must be matched to the available gas supply lest you be under or over gassed and result in malfunctions, excess recoil or undue wear and tear. Simply put, you really cant go to a lightweight system unless you have the ability to fine tune the gas system through either an adjustable gas block or through load tuning.

Adjustable gas parts is an easier approach since its just a matter of a simple hardware swap and some wrench turning whereas load development takes quite a bit longer and locks you into that lightweight setup with no recourse to switch back to regular components if ever the need arises. Now if you wanted to just use the lightweight carrier, you probably could with simple changes to your load, but with all the other lightweight buffer components out there, you might as well take it to the max and lighten the entire system to reap maximum benefits.

The major hitch in these DI pistol uppers is in the proprietary gas systems. Many times the gas block is a non-standard item in a non-standard location that you just cannot replace with an aftermarket adjustable gas block. In some cases you can, but in others its a no go. For a DI 9mm, you're definitely locked into the proprietary gas block unless you have more advances fabrication capabilities so we must look to other options.

The new RCA Adjustable GAS KEY is perfect for this application since you can use it with any standard AR15 DI bolt carrier of which all these DI pistol uppers use so we're in luck. Combine that with the RCA lightweight buffer or any other and you instantly have the new found ability to adjust and compensate as needed with the simple turn of an allen wrench.

At long last, with an adjustable gas system available for this and any AR system where the gas block is non-negotiable (pinned/welded comp on a short barrel for instance), you can complete the puzzle with all the other lightweight goodies. Add a Taccom Delrin 2-piece carbine buffer, Wolff or TTI 10% reduced carbine spring, lightweight carrier from whomever you like and you have the lightest possible recoil assembly available on the market. I guarantee your carbine will never run as soft as this!

Any idea how SIG is handling this with the MPX?  Seems the same problem would apply to a piston - just fouling the piston instead of the carrier?  I've wanted a piston-driven 9mm carbine for ages - will probably end up with an MPX someday, but a standard AR setup would be infinitely preferable!

Richard

I also am interested to see how it pans out with the bulk box Win & fed. That stuff is real dirty.

Pure speculation, but a piston doesn't dump the fouling back into the action, so no worries about unburnt powder fouling yer bolt up.

Yeah, and I've seen some pretty fouled pistons which just keep running, maybe the higher pressure tends to flush the crap out?  Dunno....

Richard

@ronaldmwilliams or @Mad-Machinist, would either of you be interested in doing an experiment with a gas piston setup?  While I'm a huge fan of the Adams Arms-style piston setups, I was thinking that I have an Osprey OPS-416 carbine-length kit and an SLR Sentry-7 adjustable gas block kicking around somewhere that I'd earmarked for an oddball project which is still collecting dust.  Those two together would theoretically give an almost-infinitely adjustable gas piston setup (the OPS-416 taps off a standard gas block vs BEING a gas block like most other pistons) - so with a tweaked piston-compatible carrier I'd think it would make a pretty decent platform for a proof-of-concept.  My thought being that the adjustable block would serve instead of having to tweak the gas port size.

Am I missing something fundamental?  (Entirely possible!)  

If either of you is interested in giving the 9mm piston upper a try, please reply and/or IM me...

TIA!
Richard

PM me a phone number and I'll call you from the shop early in the week........I have a few ideas as well....