01-26-2014, 09:37 PM
BjornF16 Wrote:My first AR build was a Grendel. I've built two Grendel AR15s and one Grendel bolt. I haven't had any issues. Both of the AR barrels are Satern (cut rifled, hand lapped).
As you have ascertained in reading the 34 pages of "hell", the issue is the Liberty barrel (AR Stoner and possibly Brownell's). It does look as if it is a matter of a "rough throat". It is interesting that Satern also produces the Liberty barrels...I look forward to Satern's assessment of their Liberty barrels that exhibit the issue.
There is no doubt the Grendel is not the typical chamber design...perhaps the compound throat lends itself to these issues if not lapped/polished.
I seriously doubt that the issue is with Hornady factory ammo. I don't believe the issue exists with any other barrel brand.
I am the original poster for this thread and after reading through hundreds of posts and having my experience with using Tubb's final finish throat and barrel polishing bullet kit; I am agreement with BjornF16 that the problem at least appears to be that the AR Stoner/Liberty barrels just have a rough throat that causes the bullets in some factory ammo to be tight when chambered. The results that I had where on my AR Stoner barrel, my after polish OAL measurement using a Hornady 123 gr A-Max bullet increased from my initial measurement of 2.246 inches to 2.300" tells me that the Tubbs barrel polishing kit took out some roughness in the throat. I have not had the time to check this new barrel for accuracy as I had to go back offshore to work on an oil rig in the Gulf but I am guessing that like all other barrels that I have used the Tubb's polishing system on I will be seeing around 0.5" MOA when I get back home to shoot for accuracy. I will also be using the Tubb's system to polish out a second AR Stoner Grendel barrel that I purchased at the same time and have changed my mind about sending it back now that I have a better understanding of throats and where the lands actually begin in the barrel. That second barrel has an OAL of 2.236" when measured using a Hornady 123 gr A-Max bullet. My concerns with these barrels have been relieved both due to my experience and those from dozens of other peoples posting about their experiences. I am only speaking for what I have done with one barrel and intend to do with the second barrel and am not making any hard recommendations for what anyone else should do with theirs.