Need help

[Belt Fed]

I have a friend who has a Diamondback 300 blk and has trouble with the same ammo I run through my Diamondbacks. I buy once loaded reloads from ventura tactical for plinking. I have run a crap load of this stuff through all four of mine without a hitch. He ordered some cause of my suggestion and his won't work with it. it's not blowing the BCG back far enough to strip another round out of the mag. his will run factory loads just fine.

His is a different model than mine, but I figured all of the inner parts are the same. He is using P mags. is his buffer and spring different from mine? I haven't seen his yet to compare. Would running a different buffer help his feeding? He has a 1000 rounds of this stuff, so buying a different spring and buffer would be feasible. His gun is also a new one.

[DNP]

Check the usuals. Gas tube location, buffer weights, get real crazy and check the size of the gas port. 

Work with any other ammo so far, or is this the first he’s run?

 

Edit- get more info. Tube depth, rifle specs, bought whole, changed anything?  Etc.  There’s probably a half dozen things it could be. Start with the easy ones. 

Edited May 28, 2019 by DNP

[Sisco]

When I got my Radical Arms 300 Blk. They recommended the frst 100 rounds be fresh factory ammo to break it in. I did that with a well lubed BCG and have been shooting personal and factory produced reloads since with out a problem, both regular and suppressed. Mine is a pistol gas system.

[Armed Eye Doc]

Did you try some of his ammo in your gun?  It could be a weaker batch of ammo.

Also, can he try a different lower on the 300BO upper?  Maybe one of your 300BO that you know works.

[Belt Fed]

I have not seen his gun yet, he just told me this yesterday. we are supposed to go shoot sometime soon and I will check all ya'll said. I will take a couple of mine and some of my ammo and will shoot some of his and let him shoot mine. swap lowers and see if things change. I'm sure the reloads are weaker than the factory loads. maybe his is weaker.

 

I just needed some ideas what to look for, I am no expert. I appreciate the replies.

[mrraley]

Make sure the gas port and the gas block are lining up correctly.

[Belt Fed]

1 hour ago, mrraley said:

Make sure the gas port and the gas block are lining up correctly.

Thanks, whats a good way to check that?

[mrraley]

First we need to look at if it is a pinned on sight/gas block or a clamp on sight/gas block.

If pinned, not much you can do except change it to a clamp on for better adjustability.

Clamp on will need to be checked for the simple one first.

• Is it level with the upper receiver?
• check for left and right shift.

if not...

• loosen the gas block, slide it forward, and  remove it, look for the carbon spot on the top of the barrel. (the carbon spot will give you an idea of how the gas block is sitting on top)
• measure the distance from the handguard cap or shoulder to the edge of the gas hole. (some gas blocks might have a shim if on a free float set up)
• remove the gas block and measure the distance from the edge of the gas block to the edge of the gas hole.

As long as the numbers are with in a few .001 (+/-) of each other there shouldn't be a problem there.

 

Notes:

1. use a good set of calipers you trust.  
2. for better readings on the holes. insert a drill bit that fits snugly in the hole to measure edge to edge.

 

Edited May 31, 2019 by mrraley

[Belt Fed]

Much thanks, I will check all that. Going to look at one of mine. his is probably the same. I think the only difference is stock forearm and grip. but I wouldn't swear to that.