And now... Something different

[HBi]

You are too nice! I did not want to be an inconvenience if you had already zero'd the scope... If you have not zero'd yet and were willing it would be great to know the weight of the rifle w/o optic, mount, or magazine, and with the XLR+KNS stock setup.

Really neat muzzle brake by the way... Is that make or buy?

And... really impressive work on the barrel/trunion/gas block. Very well done sir.

[BisonWorld]

no problem,

muzzle brake is made by PTG I believe, I'll get you the weights without the optic sometime this week.

[armoredman]

It was low 70s today...just sayin'...

[BisonWorld]

and I shot a bunch of clays,  haha, the 805 isn't my only project going on, just probably my most enjoyable one.  I'm going to try to make it out sometime over the long weekend.

[armoredman]

Outstanding, sir, outstanding.

[BisonWorld]

well things were pretty disappointing at the range, best 5 shot group was just a little under an inch at 100 yards, but everything else just got worse from there, some pretty significant diagonal stringing from high left to low right.  so back to the drawing board to find out what went wrong and fix from there.

[armoredman]

Darn.

[BisonWorld]

eh !@## happens, here is the best group of the day, right under an inch

and the worst, a little less than 3 inches 
i don't know why this picture only shows up upside down.

while this barrel was done on a cheap green mountain blank, I would expecta bit better than this, so I'll go and recheck everything (already eliminated the optic by trying a couple while I was out at the range.) shoot it with the muzzle brake off, borescope the barrel and make sure the crown wasn't damaged somehow, look at the throat to make sure it was cut square, etc.

it simply could be it doesn't like the factory hornady load or maybe just the bullet weight I'm shooting (though the diagonal stringing is a bit of a head scratcher).  on my precision .223 barrel it absolutely hates my 75 gr hpbt load that shoots well in just about every gas gun I've ever done, but loves 53 gr v-max bullets.  So I'll try some other bullets as well. 

one thing I did notice was some pretty significant denting of the brass on loading, so I'll look into getting that fixed at a minimum.

not giving up on it just yet 

[armoredman]

Both pictures show up here right side up. I'd be happy with 1-2 MOA with a military style semi auto rifle, but I'll bet you're gonna tinker this thing into being able to shoot National Match.

[RSR]

The stringing, is it happening in ascending/descending order? If so, might suggest barrel heating up...

If not, it might have to do w/ barrel oscillations which often seems to be in a figure 8 pattern, albeit not exactly repeated from shot to shot...  So furthest movement from center are fastest and nearest to center are slowest...  Part of tuning barrel and cartridge together.

BW -- are you using the standard gas block or is yours diy?  In 5.56 standard, the bren is advertised to have a "pencil" barrel.  When you up caliber and if keeping same barrel diameter, that would suggest increased flex...
However, you blank looks thicker, so this may not be the issue, but thought I'd throw this out there. 

Look forward to your continued updates on this build.

[BisonWorld]

barrel diameter is quite a bit thicker on mine as I open up the gas block.  shot placement begins high left and drifts to low right while firing. firing was done about one round every 3-5 seconds, with 3 5-shot groups shot before letting the barrel cool.  the barrel heating up is likely causing part of the issue as the largest group was also shot while the barrel was the hottest. there are a few things I'll be modifying

[armoredman]

Very interested in how this goes. 

[BisonWorld]

with the XLR stock without the optics and rings, the rifle weighs 9.4lbs. with the factory bren adjustable stock it is 8.6. probably a little less with the non-adjustable factory stock

[armoredman]

I doubt you're planning on humping this through the Outback, so weight probably isn't going to be a huge deal, but I do have to ask which stock you think you're going to "stick" with? Personally, I liked the factory folder I handled at SHOT 2015.

[HBi]

with the XLR stock without the optics and rings, the rifle weighs 9.4lbs. with the factory bren adjustable stock it is 8.6. probably a little less with the non-adjustable factory stock

Right on! Thank you sir!