My First Little Monster

[aclark]

Well we are just about done! I am waiting on the barrel from the Lilja group buy and my build will be complete.

Specs
PSA Lower
PSA LPK w/o FCG
CMC 3.5# Trigger (flat)
CAA Tactical ARS Stock

Aero Precision Upper
PSA UPK (forward assist and dust cover)
LBC Bolt w/ AR Stoner NiB Carrier
Troy Alpha 15"

Topped off with a Nikon Prostaff 4-12x40 in an ADM or PEPR mount.
--This will be replaced with a Vortex 6.5-20x50 when funds allow

Just need to get the barrel (+comp and gas block) and scope mount, then I will be good to go.

[aclark]

Couple questions as well to finish it up.

For the gas block, a lot of people recommend the JP or the SLR. While both seem nice I'm leaning more towards the JP for the side adjustment. I liked the idea of the extended "knob" someone installed as well. Are there any less expensive blocks that hold up well? While I'm trying to use quality components, if I can slide a bit on the block I will, but if the quality is there at $100 but lacks at $50-75 I understand too. Oh yea .750 at the block.

As for the muzzle device. I would like a comp just to make spotting through the rifle, as well as follow up shots easier. I am getting 5/8x24" threads, but really don't have a clue. What about the DD Muzzle Climb Mitigator? (http://www.midwayusa.com/product/127601/...teel-matte) or the PWS Comp (http://primaryweapons.com/store/pc/viewP...roduct=127)

[LRRPF52]

I would steer you into a normal gas block without adjustments, as long as the gas port is right. We provided the correct gas port dimensions to Lilja, so you should be fine. There isn't a lot of recoil with the Grendel. If you need to regulate your operating system, I would start with the buffer first, then carrier, then recoil spring.

What barrel did you get?

[aclark]

I would steer you into a normal gas block without adjustments, as long as the gas port is right. We provided the correct gas port dimensions to Lilja, so you should be fine. There isn't a lot of recoil with the Grendel. If you need to regulate your operating system, I would start with the buffer first, then carrier, then recoil spring.

What barrel did you get?

Well you seem to be the resident expert so I will take your advice and try non adjustable. Would any low profile do the trick then?

I got the AR740.

[cory]

Personally I'm going with the SLR DA7 as I plan to run it suppressed eventually.

http://www.slrrifleworks.com/adjustable-gas-block

[LRRPF52]

As long as the gas block provides a good seal, is aligned properly, and has the tube hole and roll pin holes drilled correctly, it will be fine.

I've been using YHM lo-profile blocks for a while, but the VLTOR clamp-on is a higher end unit. You will be limited with internal clearance with the Troy Alpha, so low-profile set screw is usually the route people go with that handguard.

Your 15" handguard is going to cover the gas block.

[montana]

I have a Alexander Arms 18" barrel that came over gassed which was corrected with a Syrac Ordnance adjustable gas block. The SLR Rifle Works adjustable gas block works great and is even easier to adjust. I run different loads and it can be advantageous to be able to adjust your gas for different loads or if you run a suppressor. Both of these gas blocks fit under my 15" MI Gen 2 SS-series hand guards . You may not need an adjustable gas block but why limit yourself ?

[LRRPF52]

He ordered a 20" RLGS, which doesn't gas hard like an 18" MLGS. I doubt he will ever need an adjustable, even with the suppressor.

Montana. Did you say the SLR adjustable fits under the MI Gen 2 SS? There are very few gas blocks that will work under that handguard, which I learned the hard way.

The reason to avoid adjustables if not necessary is the torch-like environment that is being created in the gas port of the barrel by choking it above with the set screw, which focuses the gas in that point, leading to early erosion. This is where getting a port cut to the optimal dimensions comes into play for me.

I have also found that my adjustable gas block set screws have become welded in place with carbon and heat. I've tried thin penetrating oil, but no dice. Maybe I need to heat them up.

[aclark]

I'm thinking about just getting the Troy (should fit under a Troy rail).
http://www.midwayusa.com/product/275588/...teel-matte

Then I just need a gas tube and gas tube roll pin correct? Any brand to look at or stay away from?
http://www.midwayusa.com/product/395110/...roductDesc
http://www.midwayusa.com/product/384068/...roductDesc

[montana]

He ordered a 20" RLGS, which doesn't gas hard like an 18" MLGS. I doubt he will ever need an adjustable, even with the suppressor.

Montana. Did you say the SLR adjustable fits under the MI Gen 2 SS? There are very few gas blocks that will work under that handguard, which I learned the hard way.

The reason to avoid adjustables if not necessary is the torch-like environment that is being created in the gas port of the barrel by choking it above with the set screw, which focuses the gas in that point, leading to early erosion. This is where getting a port cut to the optimal dimensions comes into play for me.

I have also found that my adjustable gas block set screws have become welded in place with carbon and heat. I've tried thin penetrating oil, but no dice. Maybe I need to heat them up.

Yes, all of my SLR and Syrac gas blocks fit under my MI Gen 2 SS hand guards. The nice thing about an adjustable gas block is, if the gas port erodes you can still adjust it which is impossible with a standard gas block. I have not noticed any differences in barrel life with my adj gas blocks compared to the standard ones. The owner of SLR rifle works did say the adjustment screw can get carboned in if you don't move them every once in awhile. I have not had any problem with mine and I shoot a lot of rounds with my 5.56 rifles. I don't have the same high round count with my Grendels but they have been trouble free. If I have any stuck screws I heat the metal part up with a small torch,"butane for firearms" and put Kroil oil on it. The heat seems to speed up the Kroil oil penetration and has never failed me. I don't agree with your choke point theory because if you are using a load that worked with a standard gas port it would be the same. If a load is light and malfunctions all you are doing is opening the gas port to the optimum size. If the gas port is over sized like mine was the damage is already done but can be corrected with the adj gas block. My concern was with the spring in the adjustable gas blocks. Over heating any spring can not be good but I have been pleasantly surprised so far and have zero issues with them. Using the correct buffer is important but I like to be able to fine tune my loads with adj gas blocks.

[aclark]

Got it out for the first time yesterday. Only got to function test it at 50yds, but everything worked flawlessly. Five (5) rounds in one ragged hole and no malfunctions. Had just a thread protector on until my crush washer gets here for the comp, which is the last part, for now. I will start and updated thread with new pics and a 100yd range report/sight in ASAP.

[JASmith]

Which barrel did you ultimately use in your build?

[aclark]

The Lilja AR740, got it during the group buy.

[JASmith]

Thanks -- looking forward to seeing more results!

[Rugerfan.64]

That's what I'm talking about! 3 mos ago I didn't know what to think of all these fancy parts names that I've seen thrown around. Mostly those names = $$$,,,, I checked out your rifle and these are component parts I can identify with. I just learned a little something. I'm leaning towards a budget build and will slowly accumulate my parts, I have 2 years or so to build this thing good Lord willing. It will be for my youngest girl child. The only thing I refuse to compromise on is the barrel. I'm still studying on that. Very nice looking rifle sir.

[aclark]

Here's a quick phone snap shot for now. Pay no attention to the red nipple, that's Lilja's thread protector for shipping.


Currently its wearing a thread protector made by a local shooter, and it will have a Killer Innovations (http://www.shop.killer-innovations.com/3...tdtblk.htm) brake on it soon.


The AR Stoner BCG is going to be replaced with a PSA premium as of tomorrow. The scope mount ended up being a SWFA SSALT mount, same as the PEPR only $20 cheaper. The gas block is a Troy low profile.

Think that fills in most the info that was left out of the OP.

Oh yea, and its become apparent that I need a bigger charging handle. Probably end up with a BCM mod 3 (large).

[aclark]

Got a Killer Industries brake on it and got it back to the range on Sunday. Got it actually sighted in, and this is a sub MOA gun for sure, even in my hands, which are very inexperienced.


Image courtesy of Gunbunnies photographer Mark Smith
http://www.gunbunnies.com/

Some cell shots at the workbench.

[lamrith]

Awesome, mine looks allot like that but a different stock.
How do you like the Killer Innovations brake? Which one did you go with the 5/8-24 308 version?

[aclark]

Awesome, mine looks allot like that but a different stock.
How do you like the Killer Innovations brake? Which one did you go with the 5/8-24 308 version?

The brake is great. A buddy has a gill brake on his, which is VERY concussing to surrounding shooters, and still isn't as soft shooting as the KI brake. I went with the ".308 Tapered standard brake (black)" since I got the 5/8" threading for more brake options over the 9/16" AA threading. Below you can see the brake closer up. I had to grind the crush washer a tad to get it to index correctly at the correct torque, but it tapers pretty well back to the barrel

[lamrith]

Thanks for the extra info!! So the KI is gentle to fellow people at the range? That is a big concern as I shoot at a club and often have new and younger shooters in the range.

I have the 13" Troy alpha on my 18" barrel one.