Hi Everyone,

So I was considering building/assembling a mod 12 ar variant but then was thinking that I would much more enjoy such a setup in bullpup.

Anyway I have and AUG and a tavor and would love to setup one as a DMR. Kind of leaning towards the AUG because I think it would be easier to do and I like my TAV as a CQBR.

If I were to get a longer barrel for my AUG (20 in, maybe 24) would I see a notable increase in accuracy? Would I be comfortable with 400-600yd "target engagement"? I make this comparison because if my CMP build ar can do better with irons why bother?

Also what about getting the trigger to DMR quality?

Any input appreciated, thank you gents.

you'll see an increase in velocity but not accuracy.  the rumor going around for decades is that the 16" barrel is the most accurate (but not by a lot) due to barrel harmonics.  with good glass, either a 20" or 24" should do fine

Seen pics of IDF DMR Tavors.... They use 4 x ACOG's

I agree with the above in that a longer barrel does not translate to better accuracy.

Your are right of course.  The longer barrel won't necessarily have better barrel harmonics, and arguably slightly worse.  However, the longer barrel translates to a heavier rifle, with more weight out front.  Which tends to translate to a more stable platform for shooting - assuming you're not shooting from sandbags already.  Also, since DMR is generally intended for longer ranges, the longer barrel is pretty practical there too, since the extra velocity will help.  Not only on terminal ballistics, but also a greater margin of error on range estimations, since higher velocity means flatter trajectory.  

Going back to barrel harmonics.  This is all just conjecture, but AUG's have a gas design that's nothing like the AR's DI system.  It's super cool and super reliable - but it also involves gas jetting out the side of the rifle (which looks awesome in low light), moving a piston along side the rifle, and then that piston whacking the Hell out of another piston mounted along side the rifle.  These things can't be good for barrel harmonics.  Which is one reason I quickly abandoned the thought of getting a thinner AUG BBL for better weight, because I suspect accuracy will go to crap if you do.  All this happens at something like 12 inches down the barrel (or so).  So I can't help but wonder how much whip and vibration would be on a longer barrel, vs a shorter barrel with what is effectively a hammer strike 3 times real quick on the side of the BBL as the bullet is still moving.  So I guess that's why people say the longer barrel isn't quite as accurate.  That said, in all the accuracy groups I've seen posted (which isn't very many), I see no effective difference in the accuracy reported from 16" BBL as I do from 20" BBL.  All of which are equal or better than TAVOR groups, so most of this is academic.


Finally, on the trigger - that's the one weak point of the AUG.  The NeuTrigger is an excellent low-cost investment to greatly improve the trigger.  However, the sear travel distance is still quite long, and the spring weight still quite high.  With NeuTrigger this can be made into a good serviceable trigger well capable of hunting quality accuracy or better.  But it's complete shit compared to a good 2 stage NM AR trigger, and the only way it'll ever get there is with a completely replaced trigger group.  Which RATWOX is working on.  I don't think I'll upgrade beyond NeuTrigger, but it's good to know options are being worked on.  The TAVOR trigger is considerably worse, but with the (expensive) Geisle, you can get a pretty darned good trigger now - from what I hear.

Perhaps, and FYI:
http://www.ar15.com/forums/t_6_43/407907_AUG_trigger_weights__stock__Tamer__HTM___.html

Richard

Dave Fortier stated that harmonics wise...18 inch is about the perfect length.

In the AUG? Or was he talking about free-floated barrels?

The AUG barrel is mounted to the receiver in two places: at the barrel locking piece and at the gas block. The latter deadens barrel harmonics much the same way that full-length bedding does in a bolt rifle. Theoretically, that could explain why the 16-inch barrel has been noted by many as being more accurate than the longer barrels.