Per Tom's suggestion I reached out to AINA and they were indeed helpful. Per their direction, I reduced my loads to the point that the primer piercing stopped. Unfortunately, I can only push a 139 Scenar at 2,670 fps. Anything faster and I start piercing primers - and I've tried three different lots of CCI primers which are considered the toughest. I'm told by AI that I might have carbon buildup so I cleaned my barrel thoroughly. I'm told by the AI distributor that I have copper buildup so I used Sweet's 7.62 until there was no more blue. I'm still piercing primers. I just got some Montana Extreme Copper Killer per the recommendation of the AI distributor and will give that a try. I'm about ready to buy a bore scope to see if there is indeed anything I am missing.
I love my AIAW and want it to work, but l have to make some tough decisions if I cannot get it to shoot a .260 at competitive velocities. By competitive, I'm talking a 139 Scenar at 2,800 fps from a 26" barrel with suppressor. I'm talking 42gr of H4350 - just above the 41.5gr starting load in the Hodgdon manual. I'm using Lapua .260 brass and CCI 200 or BR2 primers.
Since AI made the decision to offer a number of 6.5mm chamberings from the factory, I would expect them to come up with a plan to address the primer piercing issue. I would even be willing to pay for a factory bolt with a reduced firing pin aperture.
I have been told by one of the AI distributors that there is a gunsmith in the U.S. who will modify the bolt and I am awaiting contact information which I will share. I doubt I will go that course for obvious reasons but others might. Most likely I will sell my rifle and build up something on a Defiance action to shoot .260 if I can't get a resolution. If all I wanted to do was shoot .308 I would look no further than the AIAW - I honestly believe it's one of the finest rifles on the market. However, when you venture away from the .308 AI does not appear to be the best option unless you are content to shoot reduced loads.
With Shot Show coming up, I hope that AI will make an announcement along with their new products.
Edit: I just called up CCI and they told me that the cups on BR2 primers are thicker than the CCI200 primers. He said CCI200 use "standard cup" and BR2 uses "thick cup" like the magnum and military primers. He told me that the thickness difference is in the "10 thousands" range which he insists would make a noticeable difference. Many of you have seen the primer cup thickness chart circulating around the internet (
http://www.jamescalhoon.com/primers_and_pressure.php) and the CCI tech I spoke with said the measurements for CCI primers are incorrect. He was not at liberty to share the actual measurements, just that the chart was incorrect.
I am now going to revisit my 42gr load with BR2 primers to see if I have better luck. I have had cratering with BR2 primers in my .308 loads (43gr Varget with 175 SMK) but never a piercing. Please, please, please let this solve my problem.
Update: I tried BR2 primers with my 42gr load and I'm still getting primer piercing. This is very frustrating.
