JonF

To clear up some confusion regarding blowback vs DI chamber and bolt differences, a pic is in order. The bolts and chambers are arranged differently since there are different needs for both. Since a blowback is just as its name implies, there is no need for a locking rotating bolt assembly that a standard gas operated ar15 uses. As such, the blowback bolt is a single piece carrier and breech face whereas the DI bolt is standard ar15 components. Similarly the blowback barrel has a different barrel extension that lacks the locking lugs and is mostly flat faced. Feed ramps are generally built into the mag block for conversions and lower receiver for dedicated receivers. You know what standard DI parts look like, but here is a blowback bolt vs di comparison.

Depends on whether you want a blowback .40 (brutal) or a soft shooting DI upper. Ron Williams can make you a .40 DI upper (or any caliber you want). Rudy @ Macon Armory can build a .40 blowback upper. You can get in touch with either of them through arfcom or thier web sites. But to answer some of your questions: The QC10 receiver is the nuts. You will HAVE to have the bolt ramp "thinned" by the gunsmith (or ADCO) to fit through the glock mag feed lips. If getting a DI setup, they will do that for you. Standard receiver extension and standard guts. But Action spring and buffer depends on the caliber and recoil system. Blowback will need a buffer heavier than shit to soak up the bolt inertia and you WILL feel all that mass banging back and forth. With my DI 9mm, i'm using a RCA lightweight bolt, wolff lightweight spring, taccom delrin buffer and an adjustable gas key turned down to limit gas and its softer than a mouse pissing on cotton. Use standard AR trigger (i like the Geissele 3G in mine, a very fast action trigger). If a DI setup, the bolt will come ramped as usual. If a blowback setup, make sure you get the bolt ramped by a gunsmith/ADCO. If not, you will break trigger pins. All the more reason to not get blowback. Upper receiver doesn't matter. I replaced the original standard RMW upper receiver with an ultralight 2A Armament Balios Lite. But i also thought about using a Spartan side charge for fun. With a DI upper, you use so many *standard* AR parts, you can use all the special goodies out there (except for gas block/tube, thats always the propriatary part). Blowback does not require any gas block or tube and there are "Dedicated blowback receivers" out there that dont have the gas tube hole drilled (not that its critical to have/not have it). You WILL need a dedicated blowback bolt which is the harder part. Any gunsmith can ream a barrel, but machining a bolt natively for the 40 cartridge head is the bigger hurdle. For DI, they can just ream out a 5.56 or 7.62. to accept the larger diameter. I use a NiB 5.45 bolt in my DI-9 and it works great. Muzzle brakes really dont exists for pistol carbines. They neither produce enough gas to run one, nor is there much demand for them to fuel production. You can NOT use piston system with pistol calibers. Although DI uppers are avaialble for 9mm, 40, 357sig, 45 and a slew of other variants, thier gas systems are no standard 5.56 carbine, mid or even pistol length systems. Some will be close, others not even remotely close. Without the standard lengths, you dont have enough room to run the piston between the block and the bolt.

I'm in. Can someone explain the sling usage in more detail and will it be mandatory? Ive never used one and am not set up for one at the moment.

I'm in.

Not sure who makes an out of the box lightweight upper, but its not hard to put together yourself. As i said in the other thread, a LW Anderson upper recvr, .625 profile 9mm barrel (Adco should be able to turn one if you send it to them) and a lightweight handguard will keep the overall upper weight under the 4lb mark as long as you dont slap a bunch of junk on the gun. My upper is a Balios Lite receiver, RMW Di9mm .625 barrel, RCA LTW bolt carrier with adjustable gas key and AP Custom CF handguard, the lower is the DDLES with a light MFT minimalist stock, TACCOM delrin buffer and the whole thing weighs 5.5 lbs with the red dot sight. Since the lower is non-negotiable, there's not much more you can do to shave weight other than doing some more exotic things like a carbon buffer tube, Fortis skeleton dot mount or start to hack and machine away at the factory bits.

That is very true. Balancing mass with recoil is important, but with the adjustable gas pressure, low mass recoil systems that we have out there, you can compensate and keep the overall recoil of the system balanced with its overall mass. Without that, these ultra lightweight builds would be much more uncomfortable to hairy to shoot. My ULW 5.56 rifle weighs under 5 lbs, but with the ultra lightweight recoil assembly and adjustable rifle length gas system, it recoils softer than a gun weighing much more than it. With that in mind, if you cannot balance your the recoil of the system to the mass of the gun, it may not be wise to go all out and build a 3-4lb rifle. In the case of a blowback 9mm carbine, it is going to slap even harder on the recoil and be prone to muzzle dip if your'e running a ultra heavy buffer system to soak up the blowback energy in a very light gun.

It's a novelty for most in the real world and one of the big negatives is fragility, but lighter weight has a large degree of usefulness in competitive action shooting. Plus its paving the way to some really cool developments.

Great match Vlad, I appreciate the time and effort it took to set this up vs a regular pistol match.

If you're going for a lightweight build, you;re going to have to put something custom together yourself. A few things i can recommend are these: The Anderson slick side lightweight stripped upper receivers are on sale at Aim Surplus and are cheap and very light. Get a 9mm blowback barrel and have a gunsmith turn it down to a .625 profile and it will be very light. Add a carbon fiber handguard or use the new MI keymod or BCM Keymod handguards (the current lightest aluminum) to wrap it up.

Definitely come out. you can even shoot your revolver with all the other bottom feeders and still be competitive, you know that! I have a spare AP customs 4x4 shell carrier that folks can share.

Try, you should check out Ron Williams DI 45 upper and the dedicated lower receiver he manufacturersmanufacturers of you weren't aware. Grease gun mags natively with no adapter and super soft DI upper system that runs on factory loads.

Yes you can. Earlier this year, the board made the decision that pistol carbines can be used in the pits and as a result, even the steel matches are now allowing them to be used in a separate division. I only mention that for legitimacy because the match directors would not generally allow you to shoot firearms that are prohibited by club rules.

I have been using this receiver for several years now for a 9mm steel match carbine and it runs like a champ. You'll love this one for sure.

This is where you dust off that old, neglected Beretta and go shoot for fun. Match doesn't count anyways

sweet, im in.

Another option to keep in mind is the glock lowers made formerly by DDLES, now made by QuarterCircle10 armory. QC10 bought the tooling from DDLES after they folded and have been making batches of them here and there. Several of us here have DDLES recievers and they are a work of art and function excellent. You can run them with a traditional blowback upper or a DI upper in 9 or 40. There is also a large frame glock mag version that takes the G21 mags for a 45acp carbine. They seem to be out of stock at the moment but should have some up again in the near future. You can buy these stripped like most receivers do you cna build them how you like without paying extra junky GI triggers or a pistol buffer from LoneWolf. One advantage of these other the LW is there is a last round hold open feature that works.

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So what was the verdict? Useful info or men arguing?

Starting a new assembly from scratch with these guys: 2A Balios Lite receiver set. Aiming for under 5lb before optics.

I can get that any day of the week but it costs a tad more than the $5/bottle RR charges at the brewery. How much would you be willing to spend for it?

No. Ideally, cases should land in the 3-4:00 area. sounds like your gun is a bit "overgassed". Your brass cased stuff is likely hotter than your steel case (russian steel case is traditionally weaker loads) and so the brass is chucked more forward. Only when you run the weaker steel case stuff is it ejected in the proper direction. So, in essence, it appears to actually be tuned to run good with the steel cased stuff which is a nice thing (many guns have trouble with teh weaker steel case stuff). What ammo do you mostly shoot? If its steel case, then you may want to leave it alone as its running perfect for that load. Is it a carbine length gas system by any chance? CArbine length gas systems run at a higher pressure than mid or rifle length so they tend to exhibit "overgassing" issues more thean "undergassing". The chart gives a rough idea of some potential issues and solutions.

i generally buy the Dirty Bird 8" 200 pack from midsouth. $47.50 http://www.midsouthshooterssupply.com/item/0001235871/Dirty_Bird_8%22_Round_Bulls_Eye_Splattering_Target_%28200_Pack%29 or sometimes Amazon has the same and if you have prime, shipping is free (though not through 3rd party resellers). http://www.amazon.com/Dirty-Round-Splattering-Targets-SHEET/dp/B00233U732/ref=sr_sp-atf_title_1_1?ie=UTF8&qid=1406646935&sr=8-1&keywords=dirty+bird+200

Then how can anyone even buy a window AC unit? Or an automobile with air conditioning? Don't they at least distinguish refrigerant sold for the purpose of filling vs sold precharged in an appliance for use for that appliance?

So how bad does that sucker shred your rifle bag?

i've had several buckmarks and have used them all fairly flawlessly in steel and other matches, but that's not to say i haven had any issues along the way. There are several potential things that can effect reliable extraction and ejection in a BM and i'll list them below in order of likelyhood/importance. If you are getting the types of 1. the extractor. these things are a tad on the small side and seem to be prone to both manufacturing defects and wear. I have personally worn out 2 extractors to where a performance degradation was noticible and a new extractor was the cure both times. When they are worn out, they no longer hold a spent shell tight to the bolt face and that is the source of the issue. The tip of the extractor hook rounds over and the flat face start to bevel and the shell can no longer be held securely while the spent shell is being fully extracted from the chamber. If the fit is "loose", then the shell may "shift" before it hits the ejector wire and cause the ejection pattern to be erratic. If you get ejection issues like a stovepipe where the shell pinched longways or sideways between the slide and breech or even the dreaded "Cross" jam where the spent shell is sitting sideways and stuck above the new shell trying to feed, you will want to start with the extractor. Additionally, i have also purchased brand new extractors that had manufacturing defects so that shows there is some tolerance and QC issues with that part which is a shame because the overall performance and reliability of the gun is so highly dependent on it. http://www.brownells.com/handgun-parts/extractor-parts/extractors/extractor-prod3987.aspx 2. magazines. Some folks claim that a magazine with a mag catch notch that is cut too low will cause the mag to ride high in the gun and interfere with smooth, obstruction free passage of spent shells from the chamber. On an extreme, the mag could be so high up in the chamber area that spent shells could bounce off the feel lips, and this could be exasperated even more so if the extractor is worn and letting shells slide down a bit. I did have 1 mag out of about 12 that had a notch a few thou lower than the rest. The height difference didn't seem to cause me any issues since it not only shot fine, but i also tested extraction manually with spent shells and it never physically interfered (but then i had a healthy extractor so shells were not wobbling around at all). Nonetheless, i filed the top of the notch a little higher since sitting lower in the gun increases the overall amount of leeway that spent brass has for combined clearance. 3. ejector wire. Some folks claim the ejector wire can get misaligned, and i suppose its true, but i havent personally experienced this issue since unless the wire is actually severely bent or malformed, a mis-alignment issue seems unlikely. Definitely check it though and make sure the wire protrudes out straight from the upper right corner of the notch in the slide (When looking straight at it).