StealthyBlagga

I'm in too, and can RO as well if it helps.

My experience is that the "factory configuration" rules are VERY loosely interpreted. If you have an AR15 that otherwise complies with the rules (number of optics, no bipod, 1"x3 comp) you should be fine.

Wow - I must run out and get one of them there Benellis... they ALWAYS work . The more I hear about these Italian POS's, the more comfortable I feel with my lowly 11-87 .

I don't think anyone is saying that the short gas systems never work. We are saying that they are more likely to have reliability and robustness problems than a middy or rifle length gas system. Like many here, over the years I have owned (and won local 3-gun matches) with short gas system rifles... a Dissipator and an M4gery. However, both guns showed more violent extraction and suffered from maddeningly intermittent ejection issues. The M4gery suffered port erosion so bad that I had to install an adjustable gas tube and crank it to the fully-closed position to minimize the excessive bolt speed. I will never use a short gas system on a 16" AR15 again. Remember, this poor guy knows nothing about ARs, and has the good fortune to be starting with a clean sheet of paper... lets not burden him with the distraction of a potentially unreliable rifle when he should be focussing on the fundamentals of practical shooting. Counsel for the midlength rests his case .

Sorry for the jargon. NFA means "National Firearms Act", and generally refers to gun required to be registered with the Federal Government; in this case, I am referring to Short Barrel Rifles (SBRs) or Machineguns (MGs). IMHO, the only reason to have a short/carbine gas system is because your barrel is below 16" and thus will not work with a midlength or rifle gas system. A "non-NFA AR15" is a rifle with a barrel at least 16" long (i.e. the kind of gun you can buy from any local gunshop just by completing a 4473 form). For the purposes of serious 3-gun competition, we always use non-NFA rifles, and so the short/carbine gas system should be avoided. Forget the M4 (even though it looks cool). Get a midlength instead... same functionality, but much more reliable, will last longer and shoots smoother. Any AR15, including the midlength, can be had with a flat top, flash hider, M4 stock etc. etc. Not quite. The gas bleeds from the barrel via a hole drilled in the barrel under the gas block (this hole is known as the "gas port"). This gas is fed back (via the gas tube) to the bolt carrier, pushing it back, unlocking the bolt and cycling the action. Gas is blown directly into the bolt carrier assembly and upper receiver - this method of operation is unique to the AR series of rifles, and is called "direct gas impingement". When you understand that a hole is drilled in the barrel, then you can see why it is not trivial to relocate the gas block. Instead, you need to choose your gas system (short/carbine, midlength or rifle) and then acquire the appropriate barrel already drilled with the gas port of the right size and location. Yes, you could MAYBE do this, depending on how the rifle was originally built, but why would you want to ? Just buy the exact configuration you want from the get go... no need to relocate or replace any parts.

Never never never get a non-NFA AR15 built with a carbine gas system. Too much gas results in excessive port erosion and over-violent cycling. If you must have a 16" barrel, the most reliable gas system will be a midlength (half way between carbine and rifle gas systems). If you are using optics, an off-the-shelf flattop midlength will work just fine. If you are using irons, you want to maximize your sight radius; get a midlength gas system, cut off the top of the FSB and install a second "dummy" gas block/front sight just behind the muzzle brake (if you like the Dissipator look, you can install a rifle length FF tue over the chopped gas block). If you go for something in the 17.5-18" range, either the midlength or rifle gas systems are workable options. Above 18", go for the rifle length gas system. Personally, I prefer a longer and heavier gun for IPSC/3-gun (I shoot a 20" HB in competition, but thats just me). If it helps, here are pics of my 16" midlength carbine and my 20" rifle: No. The Dissipator was originally a Bushmaster creation comprising a 16" barrel with a carbine length gas system with a rifle length sight radius. The gas block is hidden under the handguards. The Bushmaster Dissipator does indeed use the (undesirable) carbine gas system. Other manufacturers offer Dissipator copy-cats; some have carbine gas systems (too violent) ohters have rifle gas systems (too unreliable). Like I said - go with a middy.

I would imagine it depends on the ammo you are using... I would expect 55s to show more velocity loss than 75s, and Power Factor is obviously more dependent on velocity with the lighter bullets.

I'm in too - YESSSSS !

He said: I think the advice about using good ammo is right on. Hopefully the gun just needs to be broken in a bit. However, if it is not locking open every time with good ammo like American Eagle, then you still have an issue. Sometimes a leaky gas system can fix itself by depositing carbon and blocking the leak. Why not run 500 rounds of American Eagle through the thing and come back here if it is still not locking open on an empty mag reliably ?

Before you send this gun to a gunsmith, which will incur some expense and delay no matter who you use, I would suggest you attempt the repair yourself first. The AR15 is about the simplest rifle to work on for an amateur gunsmith. Parts are cheap, and most everything can be done with simple hand tools, a combination wrench and an action block (an investment you will use in the future - trust me). What you learn working on your own rifle will stand you in good stead for the rest of your shooting career. Sending the gun to a smith, while resolving the problem quickly, leaves you none the wiser. This is the "teach a man to fish" thing. Have you exhausted all the advice in the posts above ? If the carrier key is secure on the bolt carrier, confirm that it also slides reasonably snugly on the end of the gas tube (remove the bolt, then slide the BC into the upper and feel the fit). After that, the gas rings would be a leading contender and are cheap/easy to change out. Have you scrubbed away all the carbon crud in/on the bolt carrier assembly ? If everything else is tight, then I would suspect a partial misalignment between the gas port and the the front sight base. This is not so likely if it is a GI barrel, which FN would be, because the FSB is held in place with taper pins and the FSB gas port is bigger than the barrel gas port. I assume the FSB is not wobbly ? Gas port alignment could be a problem if the FN barrel were a QC reject (possible - FN supposedly do NOT sell M16 barrels to the civy market), or if someone has installed an aftermarket FSB/gas block that holds in place with set screws, and they did not align things properly. If you found the gas port to be misaligned, you could try realigning (with a set-screw FSB/gas block) or just replace the barrel with one from a trusted source. If you run out of ideas here, I'd encourage you to try the guys over at the Troubleshooting forum on AR15.com... they seldom lose a patient . Good luck !

I went with the JP/Lyman Globe front sight (w/ crosshair insert) and a DPMS A2 rear sight (which I modified by replacing the 3/6 elevation index with a 3/8 index). IMHO, its a great combination:

Patience is a virtue with the EZ Loader. I installed my own on my 11-87 back in the mid-90s, and it is still going strong. Apart from one broken roll pin a couple of years ago, it has worked 100%. If you are patient, then the instructions that came with the part are quite adequate. If you are impatient, then pay the $90. Here are the instructions:

I just installed a MagPul collapsing stock on my Tac Iron rifle so I can get a more consistent sight picture. I can conceive of situations when I might adjust the LOP during a stage (like when moving from standing to prone). Seems to me no different to adjusting my rear sight elevation drum during a stage for different ranges.

Jay Thanks for putting on a fun match. Please do it again next year, but be sure to order less wind next time . I agree that rifle-only and shotgun-only matches should be encouraged. The equipment burden is less, and the administrative issues around managing multiple weapons (safety, scoring) are eliminated. IMHO, the attraction of shooting all three guns in a match, and of weapon transitions, is often overstated. Russell ran an excellent rifle-only match in July, which hopefully will also become an anual event.

OK, I got my entry confirmation - thanks Jay. Any guidance on rules ? Will this be pretty much SMM3G rules as far as shotgun equipment goes ? The info I have so far just says there will be separate divisions for "Open", "Semi" and "Pump". Also, do you think there will be enough time for re-entry in a second division (for prizes or just for fun) ?

Third here !

What about local shooters ? I am fortunate in being able to afford travel to other matches, but many locals cannot... this is their one chance to shoot a match of this stature. It sucks to miss out on a match like this that is right in your back yard.

Looks like they have clarified to allow ONLY traditional 1911-pattern single-stack pistols in HM (no more STIs with half empty mags). Oh well, that decides it for me - Tac Iron again in 2007.

The Bushmaster Dissipator is a 16" barrel with a short (carbine length) gas system hidden under a full-length handguard. The front sight base is a sight only. I think they offer it with a heavy or light barrel profile, but both would suffer from harsh cycling and port erosion common with the carbine gas system. I would suggest you have a custom midlength dissipator upper made if you really have to have a dissy.

This is all about gas port size. I had a 21" deer barrel on my 11-87 for a while, but with the fixed size small gas ports (sized for slugs/buckshot presumably) it would only cycle reliably with hot loads. I simply changed the barrel - sold the slug barrel and installed a 26" vent-rib barrel with the gas compensation system that is standard on the 26" plus barrels. I then cut this barrel down to 21" and it runs great with everything I feed it. End of story. My most recent gas ring has probably had thousands of rounds over it... no sign of wear at all. If you have to keep changing yours, something else is wrong.

I guess what appeals most to me about my simple strong-hand technique is that I don't HAVE to practice constantly to be passably good. I can keep up with the rest of you even though I only shoot my shotgun about a dozen or so times/year .

Maybe I'll try this. Thanks.

I load my 1187 the old fashioned way... dismount, invert at belly-button level, cradle the shotgun with the weak hand right over the chamber (careful not to get burned) and stuff in the shells one at a time from the sidesaddle, forearm carrier or chest bandolier using my strong hand. Maybe not as fast as the more bizarre method, but it has a very low fumble-factor, particularly when moving. It also allows good peripheral vision, allows flexibility of movement, and is adaptable as you pull shells from different locations on the body. Works for me.

Has anyone posted any photos from the match on-line yet ?

This seems like sound advice - I am doing this already. As I don't bet my life on this gun (just my meager reputation) I guess this will be the path of least resistance.