coryr

All good input. Think I'll just shoot this rifle the way it is and enjoy it. If a problem shows up in the future I'll revisit this. Thank you all.

Thanks for checking your guns and verifying I'm not imagining this problem. Contacted the barrel seller as you suggested, he measured the gas tube from the 16" barrel at 9.75", same as the gas tube from the 18" barrel. I don't know what the name of the shoulder on the barrel where it is turned down for the gas block is named, call it the "gas block shoulder". The dimension on the barrels that is different is the distance from the end of the barrel extension to the gas block shoulder. The dimensions around the barrel extension, the "ring" on the barrel that the receiver butts against and the barrel nut clamps on, the index pin, etc are the same on both barrels. The distance of the gas port hole ahead of the gas block shoulder match on both barrels. I know the barrel extension is actually a separate part from the barrel, assembled for us by the barrel manufacturer, the part that must be 1/4" longer on the 16" barrel is from the actual end of the barrel (which I can't get to to measure) to the gas block shoulder. Since the barrel seller said the gas tube would be the same length as the one that I have I did not order it. I went ahead and finished assembling the rifle. Fired just five test rounds through it and it cycled OK. I may order a rifle length gas tube and try to make a tube 10" long. I have a lathe. I would be really interested for someone who owns a 308 Oracle to check how far the gas tube extends into their receiver and to measure their barrel. By the way, the free floating hand guard no longer covers the barrel up to the gas block, it leaves 1/4" of the gas tube exposed. picture attached I already love the lighter barrel, like how the rifle balances, or I would consider going back to the bull barrel. I know I'll shoot this gun more with the 16" barrel. Thanks for all the great replies and help.

Contacted DPMS first and they asked if I was using the correct gas system, mid-length or carbine. Think that would be pretty obvious. The barrel index pin is fully seated, the feed ramps on the barrel extension and the feed ramp notches on the upper receiver are lined up perfect. Just contacted the guy who sold me the barrel and he says it was off a DPMS 308 Oracle. He still has the gas tube so I am going to try that. I hope it is longer than 9 3/4" when it gets here. Might try shooting the gun as it is, the only problem would be it might not cycle right?

Pictures - First picture is the two barrels, old 18" bull barrel on top, new 16" lighter barrel below. Yes, had to get a new gas block because the 16" barrel is lighter and smaller diameter. Second picture shows how far the gas tube extends into the upper with the 16" barrel installed. Not very far, doesn't look normal to me. I have not tried to shoot the rifle this way.

Hello, I'm new to this forum, hope this is posted in the right place. I've had an LR308B for a couple of years. Bought it new, had no problems, enjoy shooting it, but I'm pushing sixty and the weight is getting to me. I've taken off the bipod, put on a smaller scope. I've never been able to shoot the gun as accurately as the 18" bull barrel is capable of, so I bought another DPMS barrel, a lighter 16" barrel, to swap. I figured swapping one DPMS barrel with another there would be no problem. But the gas tube off the 18" bull barrel seems to be too short for the 16" barrel. The problem is not me trying to mix carbine and mid-length gas systems. The tube is just a small amount short, approx 1/4". The distance from the gas port to the rear of the barrel extension on the 18" barrel is about 8 1/8", on the 16" barrel it is about 8 3/8". The gas tube that I am trying to reuse is about 9 3/4". I've searched the web for dimensions on these parts but can't find any info. Has anyone seen this problem before, know what I've done wrong? Thanks

Hi, I've had an LR308B for a couple of years and enjoy shooting it. Decided to swap the barrel and ran into an issue so I joined this forum to get some help. Thanks