*UPDATE* Three Lowers turn into Three Rifles

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*UPDATE* at bottom of this first entry.

I bought the three LRB Arms lowers in the recent group buy with the intent to just hold on to them for awhile, building up over time. Then the elections were held in November...

Anyway - shortly thereafter I decided to go ahead and set up three AR's - one in a varmint configuration (in case I ever decide to go that route) and the others as range fun guns. I stayed with 5.56x45mm because ammo is (or was) plentiful, and relatively cheap. I also am set up to reload for that caliber.

Picked up a complete kit from M&A Parts for the varmint version, with a stainless 20' bull barrel and 2-stage Rock River trigger kit. I then added a Harris bipod and Redfield Revolution 3-9x50mm scope.



Came out pretty decent and really shoots nice. Love that RR trigger! And the Redfield scope is amazingly bright.

The lower of the first range gun was set up with a standard A2 stock and Bushmaster lower parts kit. I added a cheap Lo-Pro DPMS 16" Bull barrel, flat-top upper. This is the one with no dust cover, no brass deflector and no forward assist. For a fun gun, these parts don't really matter to me. I did want a fairly decent red dot optic, so I went with the Lucid HD7.







The second range gun had the same lower set-up, but I added a DPMS sportical flat-top upper. This had an A2 flash suppressor which I needed to switch out. Pullman Arms (Worcester) did a nice job removing the flash suppressor and installing a Carlson Mini Comp compensator (not a flash suppressor!). This was all topped off by an Aimpoint PRO red dot optic and YHM backup iron sights.







So here's a group shot of my three lowers that grew up to become rifles. Thank goodness for Black Friday discounts:



I think I need to take a break from all this new gun stuff now. I'm tired...

Of course, now I need more ammo.

UPDATE (12/18/12): I took both range guns out for a little spin and both shot very well using 55 gr Prvi Partizan. However, after a couple of mags, the trigger stopped working. On further investigation, I noticed the hammer pin had walked-out.

I began to research a solution - many pointing to the "non-walk-out devices" that could be installed for about $30:

https://www.midwayusa.com/product/857672?cm_vc=S014

But after reading several forum posts (AR15.com, etc), I discovered the real problem - the hammers in my Bushmaster Lower Parts Kits were missing the J-spring. That's the little piece of wire installed inside the hammer that holds onto the hammer pin slot when you push it through the hammer.

I called Bushmaster customer service, and they said they would "send me some J-springs." Oh great, I thought. Now I have to figure out how to install those.

However, today a little surprise came in the mail - two complete hammers, with J-springs! The hammers were actually from Remington, and looked almost exactly like the original hammers. I installed both new hammers, and the pins are now solidly in place.

Don't you love life's little surprises?


*
 
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Chris.Cal

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Nice write up, thanks for posting. As I'm planning a build in the near future, do you care to give approximate cost estimates for each set-up?
 
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Nice write up, thanks for posting. As I'm planning a build in the near future, do you care to give approximate cost estimates for each set-up?

No problem:

Varmint -
LRB Arms Group Buy Lower: $66
M&A Complete 20" stainless barrel Parts kit: $575
Rock River 2-stage (with lower parts kit): $80
Harris Bipod: $100
Redfield Revolution 3-9x50: $203 (after $30 rebate)
Total: $1024


Range Gun #1 -
LRB Arms Group Buy Lower: $66
DPMS A2 Complete Stock: $78
Bushmaster LPK: $50
DPMS Lo-Pro Flat-top complete upper w/16" bull barrel: $369
Lucid HD7: $198
Total: $761

Range Gun # 2 -
LRB Arms Group Buy Lower: $66
DPMS A2 Complete Stock: $78
Bushmaster LPK: $50
DPMS Sportical Flat-top complete upper w/16" barrel: $359
Carlson Mini Comp: $27
Pullman Arms Comp install: $70
Aimpoint Pro: $365
YHM BUIS - front and back: $134
Total: $1149

Obviously, the chosen optics make a big difference. I have a cheap Wal-Mart red dot that I could slap on the range guns and keep the total down to about $600. It still puts all the rounds in the 10-ring at 50 yards. Here's a target with the cheap red dot before I upgraded the optic:



Good Luck with your build!

*
 
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Twin brothers from another mother? with the exception of mine having the 24" fluted barrel, they are almost identical.
 

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But after reading several forum posts (AR15.com, etc), I discovered the real problem - the hammers in my Bushmaster Lower Parts Kits were missing the J-spring. That's the little piece of wire installed inside the hammer that holds onto the hammer pin slot when you push it through the hammer.

I called Bushmaster customer service, and they said they would "send me some J-springs." Oh great, I thought. Now I have to figure out how to install those.

Not sure what you mean by J spring. Are you talking about the hammer spring, trigger spring, or disconnector spring? More importantly, how did you assembly your lowers without one of those springs in place? Did you perform a function check prior to firing?

parts kit list with names of each spring here: http://www.ar15.com/forums/t_3_4/226782_Assemble_your_own_LOWER__UPPER__FREE_FLOAT__TRIGGER__GAS_BLOCK___Step_by_step_instructions_.html&page=1#i1847394

Where did you purchase the parts kits from?
 
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your j spring is inside your hammer .a bronze color wire. you can see it through the hole in the hammer,no spring and the hammer pin will walk out when you function check the trigger.

 
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your j spring is inside your hammer .a bronze color wire. you can see it through the hole in the hammer,no spring and the hammer pin will walk out when you function check the trigger.


That's exactly it. The parts kit was purchased from TargetSportsUSA - $49.95

I've heard of the j-spring missing from kits before, and most times a quick call to customer service takes care of it.

*
 
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How do you like the grip with the palm rest? Do you notice a difference in accuracy or control compared to a standard grip?

As far as accuracy goes, that grip has been on it since I built it, so I have no point of reference as far as this rifle goes. My other two ARs both have regular PGs, but they are both 16" carbines. So I can't really compare it to either of them either.
I will say that this one is the most accurate AR I own, but the jewel trigger and 24" bull barrel have a lot to do with that. It is adjustable, so it gives you the same, correct, repeatable grip every time. For a benchrest/varmint rifle I think it is a worthwhile addition.
 
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