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 LAR Ops-4 ambi upper for my 7.62x39 AR build????
PD2BP253  [Member]
3/24/2011 3:47:25 AM
Hello everyone, this is my first post and I'm just going to jump right in there and start.

My current project is as follows:
YHM 7.62x39 16'upper from AR-15broker.com
MGI complete lower with interchangable magwells
C-Products magazines

These are so far the only items I have already purchased. Now for my questions.

Is the LAR Grizzly OPS-4 Ambidextrous upper rigid enough to handle the 7.62x39 cartridge, I keep reading about lack of rigidity.
Would the OPS-4 bolt carrier have to be modified to work with AK magazines?

Thanks in advance for any help, I look forward to anyones input
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Asmodeus  [Member]
3/24/2011 5:08:35 PM
Originally Posted By PD2BP253:
Is the LAR Grizzly OPS-4 Ambidextrous upper rigid enough to handle the 7.62x39 cartridge
Would the OPS-4 bolt carrier have to be modified to work with AK magazines?


I highly doubt the BCG will come clearenced for AK mags on that setup. As all their premade uppers are 5.56/.223 guns.
The upper will most likely need clearenced as well. As far as rigidity I haven't a clue.

Have you put any of that stuff together yet and installed an AK mag?

That's going to show you where your problems are going to be.


PD2BP253  [Member]
3/24/2011 6:07:13 PM
I haven't put anything together with an AK mag yet, I was told by the reps at MGI that I would have to have .030 machined off each side of the upper to allow for AK mag usage, I was also told by MGI that if I were to use the Ops-4 carrier, I would have to remove material for clearance issues as well.

All this would be an NON ISSUE if c-products would just send me my friggn' mags already!!! From the looks of it, C-products went out of business, because even their site is down now!
Asmodeus  [Member]
3/25/2011 5:41:37 PM
Originally Posted By PD2BP253:
I haven't put anything together with an AK mag yet, I was told by the reps at MGI that I would have to have .030 machined off each side of the upper to allow for AK mag usage, I was also told by MGI that if I were to use the Ops-4 carrier, I would have to remove material for clearance issues as well.

All this would be an NON ISSUE if c-products would just send me my friggn' mags already!!! From the looks of it, C-products went out of business, because even their site is down now!


You have an AK mag capable lower that doesn't require you to use CProducts magazines. You are golden. Everyone else is F'ed right now. Not you.
Get the machining done and POST PICS!

Bizarro  [Team Member]
4/20/2011 7:07:26 PM
How did the purchase of the upper from AR-15broker.com go. I am thinking of getting it in the 20" option.
PD2BP253  [Member]
4/21/2011 12:57:05 PM
Don't do it, I got the run around from AR15broker.com for a month and half, they guy stopped answering my calls, he was always like "It'll be shipped by Monday!" I heard that for like 3 weeks straight!!! I eventually cancelled my order and bought an upper from a member here, the guy was super cool and got me the upper in literally 1 day after he received payment.

I went out to test the rifle yesterday at the range, it had a couple of misfeeds with Wolf Ammo, but I think it needs to be polished and lubed up a lil bit, that was with the AK mags, performed MUCH better with the C-Products mags.

I must say, I put some 5.56 down range last night and it was no where nearly as fun as shooting the 7.62x39, I could feel the "thump" from the bigger round and it tore my paper targets up beautifully!
TrojanMan  [Team Member]
4/21/2011 4:30:31 PM
I just put an OPS-4 on my 6.5 Grendel build. It's an A+ fantastic product. It's probably twice the weight of a standard upper. They are BEEFY, to be sure.

But I wouldn't use it on a 7.62 build, especially one that requires additional fitting, and especially on something you already have an upper for.

Given that it's your first build, I'd think you would want to get it running first and then worry about cosmetic and comfort issues.

But that's just me.
PD2BP253  [Member]
4/21/2011 5:28:57 PM
Originally Posted By TrojanMan:
I just put an OPS-4 on my 6.5 Grendel build. It's an A+ fantastic product. It's probably twice the weight of a standard upper. They are BEEFY, to be sure.

But I wouldn't use it on a 7.62 build, especially one that requires additional fitting, and especially on something you already have an upper for.

Given that it's your first build, I'd think you would want to get it running first and then worry about cosmetic and comfort issues.

But that's just me.


I ended up with a Mega billet upper that is notched .030 for AK mags and an AR Performance matched barrel and bolt and a Young Mfg National Match Bolt Carrier Group w/Side Charger, so far I've had feeding issues, mainly while using AK magazines though, my C-Products seem to be working fine. It looks like the bolt isn't catching the cartridge to feed, I'll take a closer look when time permits.
Bizarro  [Team Member]
4/21/2011 7:33:13 PM
Thanks PD2BP253, I was afraid that was going to be the case. Guess Model1Sales is going get my money for a 7.62 upper unless there is a great price on the YHM piece somewhere else.
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