Plethora of Problems

[Danimal]

Not Sure where this thread should go because there are so many things that I need to work out. But I will start here and see if I can figure out the best place to start in getting my upper to work at all.

My upper is a 16" Stainless Steel carbine length gas system BCM upper with standard milspec BCG and buffer setup.

So I finally got a little bit of range time and let me tell you that it was a nightmare. First I shot a box of 115gn factory Remington ammo. I had 2 fail to feed malfunctions where the empty was ejected but a second round was not chambered. It seemed to cycle fine, but I guess that it was short cycling. This made me think that it might be the gas port being misaligned or something along that line to cause the problem.

So then I went over to my reloads to see if I can get some ball park velocities that I want with the 208 grain A-max and then the 125 Nosler Ballistic tip. I am still trying to pick a powder so I am just looking to get a start charge range that is right below 1100 fps and I will fine tune it from there. So I was using 3 types of powders in .2 grain increments walking each up until I reached super sonic speeds. I never got the gun to cycle reliably and half the time had to use my forward assist to close put the bolt into battery. This is where I am getting concerned. I had one round fail to chamber and I could not drive it in with the forward assist. Fortunately I was able to eject the round using the charging handle. I took a look at it and the bullet appeared to have been driven in the case deeper and there were marks that appeared to be the lands of the rifling on one side of the projectile. I am not sure if it was just driven in at an angle, or if it was actually hitting the lands before the bullet was chambered completely.

After finding some ball park charges for the subsonics I switched over to what I hope will be my hunting round. I loaded up the mag with 10 rounds with sequentially heavier charge weights, and the first round fired. The second round that was partially chambered became so hopelessly stuck that I was forced to call it quits for the day. I had to soak it in WD-40 for an hour then drive it out from the muzzle end with an old cleaning rod because literally nothing else could get the round out. I tried using a wood block to drive the BCG down and out and it actually pulled the rim off of the case.

For further clarification I full length re-sized all of the cases and trimmed all of them to length prior to loading them. I checked all the dimensional specifications of the case that I ejected (the heavy case that would not chamber but I got out without damaging it was the one I checked) and they were all spot on with the SAMMI drawings. But it would not chamber even after I pulled the bullet. I grabbed some factory ammo and it too was so tight that it will not slide into the chamber without being pushed in. It was not too hard, but required me to actually push with a reasonable amount of force to get it in. This changed my whole perspective of the ejecting problem. Could it be that my chamber is too tight?

Any thoughts on where to go from here? I am going to bring it into a gun smith and have them check it out, but there is not one near by so I am going to have to wait to get down there when I have some time off of work.

[UtopiaTexas]

Could you post the web address on the BCM site that shows a BCM upper in 300 Blackout?

My experience with new uppers and new BCG's is that they can be very tight and until they are worn in a bit need to be kept very oiled so the parts don't bind. I sit in front of the tv and work new BCG's back and forth by hand really oiled if necessary until the bolt rotates and runs in and out the carrier smoothly. A tight BCG could cause poor cycling.

If the lands and grooves are are being imprinted on the ogive of the bullets it sounds like you have a headspace issue.

From all the re-loading discusions on this site and others there appears to be three powders that work well for the 300 Blackout depending on the weight of the bullets. What powders and at what grains with what weight bullets are you using?

[rjacobs]

I dont think I have seen a Bravo Company(BCM) 300blackout upper. Is this a custom build?

[SomeOtherGuy]

Who made the barrel? Who installed that barrel in your BCM upper?

The 115gr UMC supers have worked 100% of the time for me in two different uppers - a DSA SS, and a home-built with an AR-Stoner (Midway) barrel, with a couple different buffer weights on each. If it's not cycling the UMC, you most likely have a problem with the barrel or gas system. Although a brand new BCG that isn't wet enough can also slow things down a lot.

[Danimal]

Who made the barrel? Who installed that barrel in your BCM upper?

The 115gr UMC supers have worked 100% of the time for me in two different uppers - a DSA SS, and a home-built with an AR-Stoner (Midway) barrel, with a couple different buffer weights on each. If it's not cycling the UMC, you most likely have a problem with the barrel or gas system. Although a brand new BCG that isn't wet enough can also slow things down a lot.

This is a home build with a midway stoner barrel, not a complete BCM upper as my post would suggest. I run my BCG pretty wet, but it too was brand new. I think that the chamber is too tight so I am taking it to a place in Denver to get it spec checked and see if that is the problem before I chase too many other problems. I have heard that the gas ports on some carbine length barrels needed to be opened up a little. Did you have to do that with your build?

[Danimal]

If the lands and grooves are are being imprinted on the ogive of the bullets it sounds like you have a headspace issue.

From all the re-loading discusions on this site and others there appears to be three powders that work well for the 300 Blackout depending on the weight of the bullets. What powders and at what grains with what weight bullets are you using?

It might have a headspace issue but I do not have gauges or go-no go's for 300 BLK. I guess I will find that out when I bring it in.

As far as powder and loads go:
208 grain amax
AA No. 9, H110, A1680
CCI primers

125 grain Nosler ballistic tip
Same powder and primers. I did not have any indication of over pressure on any rounds that I fired. The 208 grain handloads were around 1050 fps and would not cycle the BCG.

[Dolphin_Shooter]

I've been using 200 grain seirra BTHPs I had problems using 12 grains of AA 2015 I bumped it up to 12.3 grains and it ran fine, crono'd at 1066 hope this helps
And Im using the same AR Stoner Barrel.