Any AR experts here? - JeepForum.com
 
LinkBack Thread Tools
post #1 of 5 Old 04-02-2018, 02:41 PM Thread Starter
jp360cj
Registered User
1977 CJ7 
 
Join Date: Oct 2007
Location: NC
Posts: 3,194
Any AR experts here?

I've been into shooting/hunting my whole life and have been wanting an AR for a good while now. I finally broke down and went with a 6.5 Grendel build (wanting something a little better for deer hunting than a .223). I like building stuff, so I assembled the rifle myself. Started with a stripped Anderson lower and added a rifle kit from 22mods4all.com. It included an Anderson lower parts kit, 20" Bear Creek Arsenal barrel (rifle length gas), BCG, A2 flash hider, 15" keymod handguard, gas block,etc. I added a 4-16x Primary Arms scope and 1 piece mount.

I realize this is a budget build, but it shoots horrible. ~5" group @ 100 yds (from a bench with bipod and rear bag) with Hornady Black 123gr ELD-M. Also, every ejected round is hitting the deflector and flatten the case mouth. My cousin and I both build one and they both shoot the same about the same and have the same ejection issue.

Will probably be a few days before I can get to it, but my first thought is pull the handguard and check the barrel nut, possibly try bedding it with lock tite (read mixed reviews, so I didn't do it the first time. I would also like to try different ammo, but it's tough to find right now.

I'm also curious about the ejection issue. From what I've read, I think the best solution will be an adjustable gas block. Any opinion/advice on this? Could it be affecting accuracy also?


77 CJ-7- AMC 360, Edelbrock cam, MC2100, Fenderwells, CJ T18/D20, Chevy D44/EB 9" rear, Trutrac f/r, 4.11, SOA, 1.25 lift shackles, 35x12.50 BFG KM2s, Shackle Reversal
jp360cj is offline  
Sponsored Links
Advertisement
 
post #2 of 5 Old 09-12-2018, 10:11 AM
dirtrail
Registered User
 
Join Date: Aug 2008
Location: Los Alamos
Posts: 18
Check to make sure everything TIGHT. No crazy gorilla tightness, but within reasonable torque specs. You might want to use some blue thread locker on the scope mount screws. Semiautos have a tendency sometimes to work screws loose quicker than bolt guns due to reciprocating mass.

Next I would shoot prone to get the most stability possible. I don't like shooting for precision from a bench unless the rifle is mounted in a fixed rest of some sort.

How's your trigger follow up? Position your trigger finger on that first joint and and steadily squeeze back straight and hold in position till the shot is done then release just enough to feel that reset. Don't slap or hammer the trigger.

You might try loading your bipod too while in the prone position. I've had mixed results with this with AR's though.

The flattened case mouth thing is normal. I doubt this is cause of your accuracy problems. Semiautos beat up cases. An adjustable gas block might help, but I doubt it'll eliminate it completely.

What trigger do you have? Stock AR triggers can be horrible to just ok. Though I think this isn't the cause of 5 inch groups it does help tremendously when trying to reduce that 1.5 inch group down to less than one inch. A Geiselle SSA-E or LaRue MBT is my go to or if more budget minded, a Rock River National Match.

I have a 6.5 grendel that I built also...18 inch Lilja barrel, Midwest industries free float hand guard, Aero precision mount, USO LR-17, Geiselle SSA-E, Magpul PRS stock. I get about .75-.625 groups with my own hand loads 123 AMAX or Nosler 123 OTMs. With Hornady 123 Amax or SST factory loads I get around 1 inch.

Hope this helps.

EDIT: I forgot to ask, Is your hand guard free floated? You actually might not want to load your bipod if it isn't.

Last edited by dirtrail; 09-12-2018 at 10:26 AM. Reason: add more to post
dirtrail is offline  
post #3 of 5 Old 09-12-2018, 06:31 PM
OldJackTheJeep
Registered User
2004 LJ Wrangler 
 
Join Date: Aug 2016
Location: Houston
Posts: 381
www,AR15.com

KE5PPH
OldJackTheJeep is offline  
 
post #4 of 5 Old 09-14-2018, 11:39 PM Thread Starter
jp360cj
Registered User
1977 CJ7 
 
Join Date: Oct 2007
Location: NC
Posts: 3,194
Quote:
Originally Posted by dirtrail View Post
What trigger do you have? Stock AR triggers can be horrible to just ok. Though I think this isn't the cause of 5 inch groups it does help tremendously when trying to reduce that 1.5 inch group down to less than one inch. A Geiselle SSA-E or LaRue MBT is my go to or if more budget minded, a Rock River National Match.

I have a 6.5 grendel that I built also...18 inch Lilja barrel, Midwest industries free float hand guard, Aero precision mount, USO LR-17, Geiselle SSA-E, Magpul PRS stock. I get about .75-.625 groups with my own hand loads 123 AMAX or Nosler 123 OTMs. With Hornady 123 Amax or SST factory loads I get around 1 inch.

Hope this helps.

EDIT: I forgot to ask, Is your hand guard free floated? You actually might not want to load your bipod if it isn't.

Thanks for the tips! The main problem actually ended up being the barrel. Contacted Bear Creek and they said to sent the barrel back, they'd check it out. Said it was defective and sent me a new one. They didn't elaborate on the defect and I didn't think to ask.

Last time out with the new barrel it was shooting ~1.5" @ 100yds. Not great, but not expecting perfect from a budget build. Handgaurd is free floated and it does shoot better if I load the bipod. And the trigger sucks. It's the standard trigger that came with the lower parts kit. I'm looking to replace it, but not very high on my list right now. And I still need to get some dies so I can load it. The factory Hornady Black 123ELDM and the 123 SSTs shoot the same so far.



Sent from my iPhone using Tapatalk

77 CJ-7- AMC 360, Edelbrock cam, MC2100, Fenderwells, CJ T18/D20, Chevy D44/EB 9" rear, Trutrac f/r, 4.11, SOA, 1.25 lift shackles, 35x12.50 BFG KM2s, Shackle Reversal
jp360cj is offline  
post #5 of 5 Old 09-17-2018, 02:10 PM
dirtrail
Registered User
 
Join Date: Aug 2008
Location: Los Alamos
Posts: 18
That's good to hear! Another inexpensive thing you could try is an Accuwedge. It helps get rid of excess slop between your upper and lower receiver, some guys even use a foam ear plug.
dirtrail is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome